\ ENVIRONMENTAL PROTECTION AGENCY
r OFFICE OF WATER PROGRAMS
PESTICIDE USASE AND ITS IMPACT ON THE AQUATIC ENVIRONMENT IN THE SOUTHEAST
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PESTICIDE STUDY SERIES - 8
PESTICIDE USAGE AND ITS IMPACT
ON THE AQUATIC ENVIRONMENT
IN THE SOUTHEAST
This study is the result of Contract No. 68-01-0118
awarded by the OWPO, as part of the Pesticides Study
(Section 5 (1) (2) P.L. 91-224) to Teledyne Brown
Engineering.
For Teledyne Brown Engineering:
Dr. Robert A. Baker, Director, Environmental Sci
The EPA Project Officer v/as:
Charles D. Reese, Agronomist
ences
ENVIRONMENTAL PROTECTION AGENCY
Office of Water Programs Operations
Water Quality and Non-Point Source Control Division
Non-Point Source Control Branch
September 1972
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The Pesticide Study Series *
1 A Catalog of Research in Aquatic Pest Control and
Pesticide Residues in Aquatic Environments
2 The Use of Pesticides in Suburban Homes and Gardens
and Their Impact on the Aquatic Environment
3 The Use of Pesticides for Rangeland Sagebrush Control
4 Development of a Case Study of the Total Effect of
Pesticides on the Environment, Non-Irrigated Croplands
of the Midwest
5 The Pollution Potential in Pesticide Manufacturing
6 The Effects of Agricultural Pesticides in the Aquatic
Environment, Irrigated Croplands, San Joaquin Valley
7 The Movement and Impact of Pesticides Used in Forest
Management on the Aquatic Environment in the Northeast
8 Pesticide Usage and Its Impact on the Aquatic Environment
in the Southeast
9 The Movement and Impact of Pesticides Used for Vector
Control on the Aquatic Environment in the Northeast
10 Patterns of Pesticide Use and Reduction in Use as
Related to Social and Economic Factors
11 Laws and Institutional Mechanisms Controlling the
Release of Pesticides Into the Environment
* The Pesticide Study Series has been prepared by the Office
of Water Programs Operations of the Environmental Protection
Agency. To date, eleven studies have been prepared.
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EPA Review Notice
This report has been reviewed by the Office of Water
Programs of the Environmental Protection Agency and
approved for publication. Approval does not signify
that the contents necessarily reflect the views and
policies of the Environmental Protection Agency, or
does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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ABSTRACT
PESTICIDE USAGE IN THE SOUTHEASTERN
UNITED STATES AND ITS EFFECT ON
THE AQUATIC ENVIRONMENT
The Southeast is a major agricultural region which accounts for
a significant portion of the total national production of diverse and impor-
tant crops. The pests which affect these crops are equally varied and
require multiple control methods. Pesticides are currently the most
important and extensively used controls. Unfortunately, they have not
always been wisely employed. This has led to deleterious effects, with
the aquatic environment often serving as the victim. Since undesirable
effects on lower forms of life may ultimately be carried over to man,
there has been an increasing awareness that judicious pesticide usage is
essential. Improved practices, though eagerly sought, are not always
readily evident because of gaps in knowledge.
A critical examination was made of pesticide usage and its effect
on the aquatic environment in the Southeast. This report summarizes
many aspects of existing technology, current regulatory statutes and
alternatives. Literature citations are supplemented by reports of
actual case studies. From these findings a number of conclusions are
drawn and recommendations formulated. Implementation of the recom-
mendations would have marked benefit beyond the Southeast.
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ACKNOWLEDGMENTS
This critical review was conducted by an interdisciplinary team.
Teledyne Brown Engineering (TBE) was the prime contractor.
Alabama A & M University (A&M) examined the agricultural aspects
under a subcontract.
Dr. Robert A. Baker served as project director. Other contributors
from TBE and their assignments were: route into water, Dr. M. D. Luh,
Robert Corbitt; impact and degradation, Dr. Donald Henley, Dr. Lee
Morin, Nancy Schoper, James Breece; and legislative, Dr. Richard
Shuford. S. K. Love provided liaison and report draft review.
Dr. Robert R. Bradford served as project coordinator for A & M.
Other contributors and their assignments were: inventory of uses,
Dr. Om Parkash Vadhwa; applications, Dr. Nirmal S. Dhillon; and,
alternatives, Dr. Govind C. Sharma and Dr. Baldev S. Mangat.
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TABLE OF CONTENTS
VOLUME ONE
I. INTRODUCTION
II. SUMMARY AND CONCLUSIONS
III. RECOMMENDATIONS
VOLUME TWO
IV. CRITICAL REVIEW
A. Pesticide Usage
1. Introduction
2. Major Crops and Soils of the Southeast
a. Crops
b. Soils
3. Historical Development of Pesticide Usage
4. Major Pests and Their Control
5. Regional and State Usage of Pesticides
a. Regional
v*(l) Combined States Information
(2) The Fire Ant Problem
b. Alabama
c. Florida
d. Tennessee
e. Kentucky
f. South Carolina
g. Georgia
h. Mississippi
6. Conclusions
7. Recommendations
8. References
B. Application Techniques and Types of Pesticide
1. Introduction
2. Pesticide Application Methods and Equipment
a. Sprays
b. Dusts
c. Granules
d. Foams
e. Soil Incorporation
3. Efficiency of Pesticide Application
a. Spraying and Dusting
b. Ultra Low Volume Spray
c. Droplet Size
d. Impingement and Uniformity in Coverage
e. Soil Incorporation
11
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4. Conclusions
5. Recommendations
6. References
C. Route of Pesticides into Aquatic Environment
1. Introduction
2. Properties of Pesticides
3. Sorption-Desorption Phenomena
4. Movement into Water
a. Direct Application
b. Overland Drainage
(1) Soil Erosion
(2) Irrigation
c. Atmospheric Processes
(1) Volatilization
(2) Dusting and Spraying
(3) Windblown Materials
d. Disposal Processes
5. Case Studies
a. Intentional
b. Accidental
6. Conclusions
7, Recommendations
8. References
D. Impact of Pesticide Pollution on the Aquatic Environment
1. Movement of Pesticides by Aquatic Organisms
a. Direct Uptake
(1) Plant
(2) Invertebrates
(3) Vertebrates
b. Indirect Uptake Through Food Chain
(1) Plant - Animal Chain
(2) Animal - Animal Chain
2. Impact of Pesticides on Aquatic Populations
a. Short-Term Effects
b. Long-Term Effects
(1) Population Changes
(2) Physiology and Reproduction
3. Synergestic Effects
a. Physical Synergisms
b. Biological Synergisms
4. Health Implications of Pesticide Contaminated Water
a. Contamination of Potable Water Supplies
b. Ingestion via Food.Products
5. Conclusions
6. Recommendations
iii
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7. References
E. Degradation of Pesticides in the Aquatic Environment
1. Introduction
2. Degradation Mechanisms, Rates and Products
a. Chlorinated Hydrocarbons
b. Organophosphates
c. Carbamates
d. Herbicidal Compounds
e. Inorganic Pesticides
3. Physical Influences on Degradation
a. Adsorption
(1) Chemical Reactions
(2) Biological Degradation
(3) Cycling (Physical)
b. Translocation
(1) Reservoir
(2) Estuaries
(3) Closed-Water Systems
4. Biological Degradation
a. Microbiological
b. Plants
c. Animals
5. Degradation Effects
a. Water Quality
b. Toxicity
6. Conclusions
7. Recommendations
8, References
F. Applicable Regulations and Laws Governing Pesticides Use
1. Introduction
2. Scope of Local Laws and Regulations
a. Registration
b. Application and Use Controls
c. Residue Detection
3. Effectiveness of Current Local Statutes
4. Assessment of Important Litigation
5. Conclusions
6. Recommendations
7. References
G. Alternatives to Pesticides in Southeastern United States
1. Introduction
2. Cultural Methods of Pest Control
a. Cultural Control of Southwestern Corn Borer
b. Cultural Control of Cotton Pests
(1) Insect Control
(2) Disease and Nematode Control
(3) Weed Control
IV
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3. Physical and Mechanical Methods of Pest Control
a. Inactivation of Plant Pathogenic Viruses by Vegetatively
Propogated Plant Materials
b. Disinfection of Plant Parasitic Nematodes by Heat
c. Use of Light Traps in Insect Control
4. Use of Resistant Varieties of Crop Plants
a. Wilt Resistance in Tobacco
b. Varietal Resistance to Cotton Pests
c. Control of Cyst-Nematode in Soybeans by Resistance
d. Breeding Vegetable and Fruit Crops for Resistance to
Diseases
e. Disease and Insect Resistance Research for Southern
Forest
f. Insect Resistance to Corn Earworm
g. Resistance to Potato Leaf Hopper
5. Biological Agents for Pest Control
a. Biological Control of Red Scale and Purple State in Florida
b. Biological Control of Cotton Bollworm and Tobacco Budworm
in Mississippi
c. Control of Pea Aphid by Aphidius Smithi in Kentucky
d. Introduced Wasps for the Control of Gypsy Moth in Alabama
e. Field Control of Nantu'cket Pine Tip Moth by the Nematode
DD-136 in South Carolina
f. Heliothis Control With Virus
g. Integration of the Heliothis Nuclear Polyhedrosis Virus into
a Biological Control Program on Control in Mississippi
h. Two-Spotted Spider Mite Control With Fungus in Alabama
i. Control of Aquatic Weeds by the Snail in Florida
j. Biological Control of Alligatorweed with Flea Beetle in
Southeastern States
k. Control of Pond Weeds by the Use of Herbivorous Fish
6, Sterility Approach to Insect Control
a. Eradication Program of the Screw Worm Fly in the South-
eastern States.
b. Eradication of the Cotton Bollworm from St. Croix, U.S.
Virgin Islands
c. Eradication of Cotton Boll Weevil in the Southeast
d. Control of House Flies With Chemosterilant Baits in Florida
e. Preliminary Work With Chemosterilants for Imp6rtant
Noctuids in Georgia.
7. Insect Attractant and Repellants
a. Use of Synthetic Attractants in Control arid Eradication
of Mediterranean Fruit Fly in Florida
b. Synthetic Pheromone of the Boll Weevil
c. Virgin Female Traps for Introduced Pine Sawfly
d. Sex Pheromones of the Southern Pine Beetle and Other
Bark Beetles.
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8. Insect Hormones
9. Integrated Control
a. Integrated Control of Cotton Boll Weevil in Southern States.
b. Integrated Control of Heliothis
c. Integrated Control System for Hornworms on Tobacco in
North Carolina
d. Integrated Control of Muscid Flies in Poultry Houses in
Kentucky
e. Integrated Biological and Chemical Control of Aquatic
Weeds in Florida.
10. Miscellaneous Methods
a. Seed Laws
b. Seed Certification
c. Disease Control Through Virus Free Stock
d. Quarantine and Regulatory Controls
e. Pest Surveillance
f. Genetic Manipulations
g. Development of Safer Pesticides
11. Conclusions
12. Recommendations
13. References
V. APPENDIX
vi
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PESTICIDE USAGE IN THE SOUTHEASTERN
UNITED STATES AND ITS EFFECT ON
THE AQUATIC ENVIRONMENT
Volume I
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PART I. INTRODUCTION
This critical review examines pesticide usage and its impact on
the aquatic environment in the Southeast: Alabama, Florida, Georgia,
Kentucky, Mississippi, North Carolina, South Carolina and Tennessee.
The study is one of a series authorized and required by Section 5 (1) (2)
of Public Law 91-224. The southeastern United States is one of the oldest
and major agricultural sections of the country. A variety of climatic
gradations from temperate to subtropical exist. Diverse soil types are
also characteristic of this region. These characteristics allow for pro-
duction of diverse crops. Of the total national production of tobacco,
citrus, peanuts, pecans, cotton and vegetables approximately 85%, 65%,
61%, 28%, and 12%, respectively, are produced in the Southeast. In
addition, peaches, corn and soybeans are important crops. These
crops serve as hosts and are infested by a variety of pests and conse-
quently require the use of multiple control methods for economic pro-
duction. Pesticides are currently the most important control method
and are used extensively. New hybrid varieties with high production
characteristics, monoculturing of crops and minimum tillage practices
have further increased the need for pesticides. ^ Eventually these pesti-
cides may enter the aquatic environment. It is to assess the resulting
effects,to indicate gaps in the existing knowledge, and to recommend
corrective measures that this study is dedicated.
Perhaps the most important factor determining the eventual entry
of pesticides into the aquatic environment is the application technique.
Efficient control depends upon the selection of the correct pesticide,
application at the proper time and the use of equipment that can most
efficiently place the toxicant in the micro environment of the pest. Of
o
the total pesticide applied, no more than 2% is effective. The remain-
der is indicative of the inefficiency of existing application techniques.
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Careful selection of existing application techniques would considerably
reduce the amount of toxicant required for effective pest control; with a
concommitant decrease in contamination of the ecosystem. Major bene-
fits would accrue from improved pesticide delivery systems.
An understanding of the movement of pesticides from application
to entry into the aquatic environment involves physical, chemical and
biological considerations of the pesticide, the application process, and
7-9
the air, soil and aquatic systems. Overland drainage, irrigation return
flows, atmospheric transport, intentional dumping and accidental spills
. . 7,10-13
are involved.
Once pesticides enter the aquatic environment they may exert
short-term or long-term detrimental effects. Biological organisms con-
14 15
centrate pesticides through direct and indirect mechanisms. ' The mecha-
nisms result in biomagnification with each successive step in the food
chain. Short-term effects or acute toxicities are reflected environmentally
as "kills". The toxic concentrations required to produce kills are, in
certain instances, considerably less than laboratory established
16
(median lethal concentration) values. Long-term effects include sub-
tle alterations in predator -prey relationships, decreased floral and faunal
fecundity and specific physiological alterations which reduce the ability of
17-19
organisms (target and non-target) to compete. Synergistic effects occur
in biological organisms when pesticides act in combination with other biolo-
gical, physical or chemical factors. ' Two or more contaminants or a
single contaminant together with a naturally occurring material may react
to give an effect far greater than the sum of their individual effects. This
is an especially important consideration in Southeastern waters. These
waters are rich in organic matter which tends to complex with normally
22
insoluble chemical substances such as certain pesticides. The com-
plexed material is readily distributed within the aquatic environment.
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This increases the opportunity for exposure to and concentration by aquatic
life forms. Eventually this constitutes a health hazard to man via contami-
nated water and food.
The degradation of certain pesticides may lead to even more toxic
25,26
reaction products. Others may either degrade to harmless products or
remain unaffected. The surface waters of the Southeast often contain chlo-
27
rinated hydrocarbons and other pesticides that are persistent and resist
biological or chemical degradation. Degradation of other pesticides is
affected by many factors. They may be in solution, associated with sus-
pended matter, or entrained in sediment. Each of these aquatic compart-
ments is characterized by a unique combination of biological and chemical
interrelationships which may modify the degradation process. Most avail-
able information on pesticide degradation mechanisms and rates has been
obtained, chiefly, through laboratory study. Extrapolation of such results
to field conditions is not valid because of the complicating effect of environ-
mental and other factors.
Public concern for the environment challenges the efficiency and
effectiveness of our form of legal and administrative framework. Among
the concerns is adequacy and effectiveness of existing state statutes regu-
lating the sale and use of pesticides. The provisions of the Federal
28
Insecticide, Fungicide and Rodenticide Act, (FIFRA) as amended and
29
the Miller Amendment to the Federal Food, Drug and Cosmetic Act,
as amended, provide the foundation for a comparative analysis of the pesti-
30 31
cide laws and regulations of the Southeastern states: Alabama, Florida,
oo "3*2 *3 >l ' OC *2^L
Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and
37
Tennessee. State laws regulating pesticides fall into three classifica-
tions. These are statutes:
• requiring economic poisons to be registered,
• governing pesticide application and use controls, and
• providing for th«* detection of pesticide residues on crops.
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Four factors serve as indicators of effectiveness. These are:
• adequacy of statutory authority to control areas of potential
abuse of public health and the environment,
• relative economic burden imposed on the private sector by
the statutes to achieve compliance,
• relative ease of public administration, and
• the ecological sensitivity of present statutes.
Many methods of pest control have been advanced as knowledge of
biology, ecology and agriculture increases. Within the last three decades,
overemphasis on the use of pesticides has caused unintentional side effects
and provided only a temporary solution to the pest control problem. In
many cases pest control, with minimum damage to the environment, can
be achieved by alternative procedures. These could utilize proper agri-
cultural management, physical, genetic, biological and nonhazardous
38
chemical methods. Eradication of the screwworm from the Southeast
by male sterilizatio'n techniques is an example of a successful alterna-
tive.
Parts II and III summarize the conclusions and specify recommen-
dations derived from the critical review, respectively. The detailed
findings, analyses and other supporting information are contained in
Part IV. This is divided into seven study areas:
• Pesticide Usage
• Application Techniques
• Route into Aquatic Environment
• Impact of Pesticides on the Aquatic Environment
• Degradation of Pesticides
• Regulations and Laws
• Alternatives
A comprehensive bibliography is appended to each of the study areas.
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References
1. Agricultural Statistics, United States Department of Agriculture,
U. S. Govt. Printing Office, Washington, D. C. , 1970.
2. Metcalf, R. L., Primer on Agricultural Pollution. A Publication of
Soil Conservation of America, 14-17, 1971.
3. Himel, C. M., The Optimum Size for Insecticide Spray Droplets,
J. Econ. Entomol., 62, 919-925, 1969.
4. Himel, C. M. , New Concept in Application Methodology, Southeast
Forest Insect Workshop, Charleston, South Carolina, 1-9, 1970.
5. Williamson, R. E. , Progress Report--Soil Incorporation of Pesticides,
South Carolina Agricultural Experiment Station, Clemson University,
Clemson, South Carolina, 1966.
6. Isler, D. A. , Methods for Evaluating Coverage and Drop Size in
Forest Spraying, Trans. American Society of Agricultural Engineers,
6, 231-233, 1963.
7. Bailey, G. W. , Entry of Biocides into Water Courses, Proceedings
of Symposium on Agricultural Waste Waters, Water Resources Center,
University of California, Davis, California, Report No. 10, 94-103,
1966.
8. Kunze, G. W. , Pesticides and Clay Minerals, Pesticides and Their
Effects on Soils and Water, Soil Science Society of America, Inc.,
Madison, Wisconsin, 49-71, 1966.
9. Bailey, G. W. and White, J. L., Review of Adsorption and Desorption
of Organic Pesticides by Soil Colloids, With Implications Concerning
Pesticide Bioactivity, J. Agr. Food Chem., 12, 324-332, 1964.
10. Hindin, E. , May, D. S. , and Duns tan, G. H. , Collection and Analysis
of Synthetic Organic Pesticides from Surface and Ground Water, Resi-
due Reviews, 7, 130-156, 1964.
11. Abbott, D. C., Harrison, R. B. , Tatton, J. O'G. , and Thomson,
J., Organochlorine Pesticides in the Atmosphere, Nature, 211, 259-
261, 1966.
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12. Barthel, W. F. , Hawthorne, J. C. , Ford, J. H. , Bolton, G. C. ,
McDowell, L. L., Grissinger, E. H. , and Parsons, D. A. , Pesticides
in Water, Pesticide Monitoring J. , .3^ 8-66, 1969.
13. Bugg, J. C., Jr., Higgins, J. E. , and Robertson, E. A., Jr.,
Chlorinated Pesticide Levels in the Eastern Oyster (Crassostrea,
Virginia) From Selected Areas of the South Atlantic and Gulf of
Mexico, Pesticides Monitoring J. ,.JL, 9-12, 1967.
14. Ferguson, D. E. and Goodyear, C. P. , The Pathway of Endrin Entry
in Black Bullhead, Ictalurus melas, Copeia, 1967, 467-468, 1967.
15. Chadwick, G. C. and Brocksen, R, W., Accumulation of Dieldrin,by
Fish and Selected Fish-Food Organisms, Journal of Wildlife Manage-
ment, 33, 693-700, 1969.
16. Report of Fish Kill Investigation in Lake Junaluska, Haywood County,
Dept. of Water and Air Resources, Water Quality Div. , North Carolina,
Nov. 1970- Mar. 1971.
17. Wurster, C. F. , DDT Reduces Photosynthesis by Marine Organisms,
Science, 159, 14,74-1475, 1968.
18. Goldberg, E. D., Butler, P. , Meier, P. , Menzel, D. , Risebrough,
R. W. , and Stickel, L. F. , Chlorinated Hydrocarbons in the Marine
Environment, National Academy of Sciences, Wash., D. C. , 1-21, >
1971.
19. Lane, C. E. and Livingston, R. J., Some A.cute and Chronic Effects
of Dieldrin on the Sailfin Molly, Poecilia latipinna, Trans. Am. Fish
Soc. , 99, 489-495, 1970.
20. Lincer, J. L. , Solon, ;J. M. , and Nair,J. H.:y DDT and Endrin Fish
Toxicity Under Static vs. Dynamic Bioassay Conditions, Trans. Am.
Fish. Soc. , 99_, 13-19, 1970.
21. Macek, K. J. , Hutchinson, C. and Cope, O. B., Effects of Tempera-
ture on the Susceptibility of Bluegills and Rainbow Trout to Selected
Pesticides, Bull. Environ. Contam. & Toxicol., 4, 174-183, 1969.
22. Bartha, R. , Fate of Herbicide-Derived Chloroanilines in Soil, J. Agr.
FoodChem., 19, 385-387, 1971.
23. Report of the Secretary's Commission pn Pesticides and Their Relation-
ship to Environmental Health, Parts I and II, U. S. Department of
Health, Education and Welfare, U. S. Government Printing Office,
Wash., D. C., 99-123, 1969.
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24. Schafer, M. L., Peeler, J. T. , Gardner, W. S. and Campbell, J. E.,
Pesticides in Drinking Water: Waters from the Mississippi and
Missouri Rivers, 3, 1261-1269, 1969.
25. Lamberton, J. G. and Claeys, -R. R. , Degradation of 1-Naphthol in
Sea Water, J. Agr. Food Chem., 18, 92-96, 1970.
26. Georgacakis, E. and Kahn, M. A. Q. , Toxicity of Photoisomers of
Cyclodiene, Insecticide of Freshwater Animals, Nature, 233, 120-121,
1971.
27. Cleaning Our Environment: The Chemical Basis for Action, A Report
by the Subcommittee on Environmental Improvement, Committee on
Chemistry and Public Affairs, American Chemical Society, Wash.,
D. C., 212-213, 1969.
28. Federal Insecticide, Fungicide, and Rodenticide Act, (61 Stat. 163;
7 U. S. C. 135-135K) June 25, 1947.
29. Federal Food, Drug and Cosmetic Act, Miller Amendment, (Sec. 404
(d) (2), 68 Stat. 512; 21 U. S. C. 346a (d) (2)), 1959.
30. Insecticides, Fungicides, and Other Economic Poisons, Article 20,
Title 2, Section 337, 1958, Recompiled Code of Alabama, 1951.
31. Florida Pesticide Law, Chapter 487, 1953 (Revised).
32. The Georgia Economic Poisons Act, Georgia Laws 1950, pg. 390 and
.Georgia Laws 1958, Pg, 389, 1949.
33. Kentucky Economic Poison Law, 1956.
34. Mississippi Economic Poisons Act, Chapter 509, Senate Bill No. 2145,
Laws of Mississippi 1971, 1950.
35. North Carolina Insecticide, Fungicide, and Rodenticide Act of 1947.
36. South Carolina Economic Poison Law, 1953.
37. Insecticide, Fungicide and Rodenticide Law (Pesticide Act) Tennessee
Code Annotated, Title 43, Chapter 7, Sections 43-701-703 as amended,
1951.
38. Knipling, E. F., Use of Organisms to Control Insect Pests, J.
Environ. Quality, 1, 34-40, 1972.
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PART II. SUMMARY AND CONCLUSIONS
Most pesticides used in the southeastern United States are directed
towards the following major pests:
• Insects: Cotton boll weevil, cotton bollworm, tobacco bud-
worm, tobacco hornworm, scale insects of citrus, cabbage
hopper, pink bollworm, codling moth and mealy bugs.
• Weeds: Broad leaf weeds, rag weed, Johnson grass, pigweed,
crab grass, barn-yard grass, green and yellow foxtail, water
hyacinth and goose weed.
• Disease: Citrus melanose, citrus and apple scab, leaf spot
disease of peanuts, wild fire of tobacco and cotton, anthracnose
of tobacco and cotton, root rots of corn, fire blight of apple,
downy mildew of beans, and leaf spot of apples, beans and
cotton.
An accurate inventory of pesticides usage is presently not obtain-
able because distributors, sellers or users of pesticides are not required
^*'
to report specific information to any responsible agency regarding pesti-
cides sold or applied. The most recent information available from U, S.
Department of Agriculture concerning quantities of pesticides used by
farmers on a regional level is five years old (1966). Certain information
is available for pesticide usage in a few states (e. g. Kentucky and
Tennessee) where special surveys were conducted. These surveys repre-
sent only a one year compilation. Recommended application rates for
the different pesticides are available for all states.
In the Southeastern states, the most widely used insecticides are
Toxaphene, Aldrin, Chlordane and DDT. Use of Parathion and Malathion
is increasing. The most commonly used are Treflan, Dalapon, 2, 4-D,
Atrazine. Sulfur compounds, copper sulfate, Thriam, Maneb, and Zineb
constitute the major fungicides used. Insecticide applications to cotton
exceed the combined total for all other major crops. A similar situation
exists for fungicides applied to citrus*.
8
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Practically all Southeastern soils used for agricultural purposes
are subject to moderate or severe runoff and erosion. Soils in most of
Florida are an exception because lack of adequate drainage is a .severe
problem.
Presently, 63 percent of all pesticides are applied by aircraft.
The remainder is applied with ground equipment. Most pesticides are
applied as sprays, either to the plant foliage or to the soil surface.
Some pesticides are incorporated in the soil. To minimize contamination
of the ecosystem by pesticides, improvement in spray application and
soil incorporation equipment is required.
Pesticide usage could be significantly reduced and still provide
an effective pest control program if the pesticides are uniformly distri-
buted and the major portion reached its intended target. The initial
problem is to atomize relatively non-volatile pesticide formulations into
uniformly sized droplets which are sufficiently numerous that the pest
cannot avoid contacting a lethal dose. The second problem involves
deposition of small particles or droplets on the target. One of the
methods that could improve deposition of pesticides is electrostatics.
The third problem involves incorporation or injection of some soil-
applied pesticides. These processes involve optimum depth considera-
tions. All of these problems merit intensive research and development.
The efficiency of a spray application is related to optimum drop-
let size, uniformity in spray coverage produced, and degree to which
drift and runoff is minimized. Ninety percent or more of spray droplets
produced by existing aerial and ground equipment are not of the optimum
size. This portion of the spray constitutes the major source of pestici-
dal pollution.
After two decades of intensive use, pesticides are found through-
out the world. They are present in the aquatic environment and in the
atmosphere, even in places far from any spraying sites. The persistent
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nature of certain pesticides permits them to be carried from the air and
soil into the aquatic environment. There they can move from one organism
to another via the food web or be cycled in the aquatic environment.
Physical and chemical properties of pesticides govern their move-
ment from one system to another. Sorption and desorption are the pro-
cesses which limit the rate of movement of pesticides from the soil into
the aquatic environment. Specific sorption and desorption mechanisms
for each pesticide under environmental conditions are not known. These
mechanisms are influenced by the clay and organic content, temperature,
degree of cation saturation within the soil, and by climatic conditions.
These factors also influence pesticide sorption-desorption at the benthic
level of the aquatic environment.
Pesticide movement into the soil environment is influenced by
sorption, thermal and biomass characteristics, and general chemical
composition. Knowledge of the chemical and physical nature of pesti-
cides, facilitates a prediction of their fate. Common fates in the soil
environment are sorption and desorption, photo-and oxidative decompo-
sition, hydrolytic and biochemical degradation, leaching, and phyto-
assimilation. Organic matter favors sorption of both non-ionic and ionic
pesticides. The soils of the Southeast are characterized by high clay
content and primarily sorb ionic pesticides. Many of the pesticides
applied to the soil are strongly sorbed and do not percolate through the
soil. Pesticides normally are confined to the top few inches of the soil.
Pesticides in the soil are generally in contact with water. The
quantity of water may significantly alter their reactions. For example,
phytoactivity is greatly enhanced in moist soil. Solubilities, partitioning
(soil, water, and air), and interaction of these properties alter the reac-
tions of individual pesticides.
The sorption process and its binding power must be examined re-
lative to leaching. Leaching of pesticides deserves greater attention
10
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because this is the process of most rapid movement from the soil into
the aquatic environment.
The direct movement of pesticides from the soil surface to a
waterway requires consideration of climatic conditions before, during,
and after application. Principal consideration should be given to volatili-
zation losses, movements into the soil, persistence at the site of appli-
cation, and movement of the remaining fraction to uncontaminated areas.
Pesticides move into the aquatic environment from the land even
though universally present in the air. Movement from land may take
several forms but overland drainage is the most significant. Good con-
servation practices reduce overland drainage. The occurrence of pesti-
cides in waterways is primarily attributed to their sorption by runoff
particles. Deposition and subsequent desorption of the sorbed particles
will provide a continuous source of pesticide to the aquatic environment.
Considerations should be given to rainfall as a climatic factor
influencing pesticide movement into water. Pesticides movement into
and over the soil is of a uniform nature during periods of low rainfall
intensity. This also occurs during overhead and flood irrigation practices.
High rainfall intensity and furrow irrigation, however, produce dispro-
portionate pesticide movements. This movement can result in waterway
contamination.
Pesticides enter the soil environment through mechanical in-
corporation or infiltration processes. Incorporation (or induced turn-
over) is favored since it reduces atmospheric and runoff contamination.
However, plant uptake and persistence of pesticides are increased.
Information on pesticide decontamination is needed. Sorption by
activated carbon is the only method presently available for removing
pesticides from water. However, suitable methods for disposal of the
sorbed materials has not been developed. Thermal, photochemical and
biological degradation are considered as possible decontamination methods
11
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in instances where concentrated pesticides occur. Photochemical, bio-
logical and sorption processes offer potential for removal of low-level
concentrations in waterways.
Current agricultural application practices result in contamination
of the aquatic environment through atmospheric processes. Those pro-
cesses which contribute to contamination include volatilized fallout and
washout, drift from dusting and spraying operations, and wind-blown,
pesticide-treated soils. Other aerial or atmospheric routes include
incineration of pesticide-contaminated materials and direct application
of pesticides into the aquatic environment.
Case studies have documented that runoff, accidental spills, and
' intentional pesticide dumping are prevalent means of entry into the aquatic
environment. Non-selective toxicity and subtle long-term effects can
create ecological imbalances. Therefore, there is an urgent need to use
^t •
existing and safer pesticide alternatives, to better educate pesticide
users regarding potential hazards, and to limit usage of persistent pesti-
cides.
Aquatic vegetation can sorb large quantities of pesticides. These
sorbed substances can be metabolically degraded or stored. The stored
compounds may either become part of a food web or be returned to the
sediment. Information is not available on sorption capacities and degra-
dation of pesticides by aquatic vegetation of the Southeast. Fish and
filter-feeding sedentary invertebrates sorb pesticides directly from the
water. Residue levels closely correlate with surface water concentra-
tions, which relate to seasonal agricultural practices and rainfall..
Pesticides such as DDT, Dieldrin, Endrin, Toxaphene, Mirex
and BHC are bioconcentrated. Food chain studies have been primarily
focused on DDT without regard for other stable chlorinated hydrocarbons.
Herbicides, in general, are less toxic to fauna than other pesticidal categories.
12
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This is attributed to the fact that these compounds degrade rapidly and
do not bioconcentrate. The effects of herbicides on nontarget aquatic
plant communities have not been specifically identified. However, it is
known that the reduction of consumer populations is accompanied by a
shift in plant species to hardier algae that are not consumed by grazers.
Considerable emphasis has been placed on testing fish for acute
toxicity. Acute toxicity levels have been established for several indivi-
dual species under laboratory conditions. These values serve only as
quantitative indices of toxicity under specific conditions and do not reflect
accurate responses under varying natural environmental conditions.
There is a need for toxicological information on Ipwer life forms obtained
under dynamic test conditions. In such studies, continuous flow of natu-
ral waters under environmental conditions at the .site, should be empha-
sized. Resulting information would be of greater value in assessing the
effect of contaminants such as pesticides than that obtained under static,
monospecific test conditions. More emphasis should be placed on the
chronic effects of pesticides. Toxicological information must be developed
for the lower and intermediate aquatic organisms as well as for fish. Popu-
lation changes in lower food chain organisms will ultimately be reflected
in the long-term stability of higher consumers, e. g. , fish.
Quantitative data .on residue transfers in fresh water and marine
food webs are not available., There is a lack ,of information on the com-
plex species interrelationships within the food web. Some forms establish
an intake, storage and elimination equilibrium.
The presence of PCB compounds in Southeastern water, its biota
and its sediment is widespread. These compounds,are stable, biocon-
centrate in tissues and interfere with calcium deposition in birds. This
effect has been demonstrated with DDT.
Pesticide synergisms with such factors as temperature, water
hardness, and stage of biological development have been established in
13
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species native to the Southeast. Synergisms, resulting from multiple
pesticide residues, have not been investigated although many pesticides
are applied in combination to ensure control of target species.
Chlorinated hydrocarbon residues at microgram per liter con-
centration are not completely removed by standard water treatment
practices. The adverse effects of long-term, low-level, pesticide
exposure in humans is not known. Monitored pesticide residues in fish,
shellfish, and ducks are not directly useful in assessing quantities of
pesticides reaching humans via these foods. Analyses are typically on
a whole-product basis and not the edible portions only.
The most frequently occurring pesticides in Southeastern waters
are chlorinated hydrocarbons whose persistence may be in the order of
years. In general, organophosphates, carbamates, and herbicidal com-
pounds disappear from the water within a matter of a few weeks or months.
Available data on degradation rates, mechanisms, and products are very
limited. Information is based on laboratory studies which cannot be
extrapolated to natural environmental conditions. For example, halo-
genated herbicides are readily degraded through photo-induced mecha-
nisms. How these mechanisms relate to degradation of herbicides in the
natural environment has not been established.
The sorption of pesticides by suspended material and substrates
in natural waters is an important factor in the degradation process. It
may facilitate chemical reactions and translocation of pesticides to the
estuary or to areas favorable for degradation.
Information on the occurrence and distribution of pesticides
reveals that, while no concentrations may be detected in the water, con-
centrations in the micrograms per kilogram range are found in the sedi-
ments of small ponds and estuaries. The transport of pesticides in the
aqueous medium, including that which is associated with particulate matter
and sediments, has not been defined. Pesticides concentrations which"'
14
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reach bottom sediments may be cycled into the overlying water. Cycling
can r.e$ult from fall and spring overturns following thermal de-stratifica-
tion or from the release or desorption of pesticides from the sediments.
The chemical degradation products of,certain chlorinated hydro-
carbons and carbamates are many time s more toxic than the parent
compounds. Such toxicities are vital considerations of impact on non-
target organisms.
The provisions of registration statutes of the Southeastern states
are quite similar to the statutory provisions of the original Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRAJ. All states have
not kept pace in modifying their, statutes to comply with changes in the
FIFRA in terms of coverage of categories of pesticides. The states
took an excessive amount of ;time tp enact comparable legislation to the
FIFRA to regulate intrastate commerce of pesticides. Amendments
have required several years before enactment.
There are significant differences in scope of coverage in some
state pesticide laws compared to the coverage of the amended FIFRA.
There are also considerable differences in the enforcement authorities
granted to the state administering agencies. The penalties enacted for
violations are weak and are not deterrents to violations. On the other
hand,,.the volume of litigation,does not indicate that a strong penalty
deterrent is required.
Two major loopholes exist in the present registration statutes.
First, the exemption of officials of state and federal agencies from
registering products used inrtheir official activities provides an oppor-
tunity for the aquatic environment to.be subject to. pesticide contamination.
This occurs without any possibility of assessing the type and volume of
chemipals entering the waters, ; Second, the registration statutes do
not prpvide coverage of an.jniportant consumer protection need. This
relates to the packaging aspect of pesticide containers to provide for
child safety,
15
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Some of the Southeastern states are ahead of the federal govern-
ment in the enactment of pesticide application and use controls. Until
recently these controls have been limited to regulation of aerial appli-
cators in only four of the eight states. There is no federal statute
governing aerial applicators despite the fact that the aircraft are re-
gulated by the Federal Aviation Administration.
Two information systems used, or which should be used, for
decisions affecting the federal pesticide program are either woefully
inadequate or warrant some improvement. Only a small number of the
incidences of pesticide poisonings which occur are being reported
(allegedly 10-15 percent) to the National Clearinghouse for Poison Con-
trol Centers. This level of reporting is inadequate to base federal or
state policy decisions. The South Carolina community pesticide surveys
for two separate years would indicate that the 10-15 percent figure for
the nation is a reliable estimate of the situation in the Southeastern
states.
One aspect of the National Transportation Safety Board's reporting
system on aerial application accidents needs improvement. This relates
to the toxicolbgical effects on pilots.
The Southeastern states registration statutes are slightly less
adequate than the FIFRA. There are some states with application and
use controls offering limited protection of the aquatic environment. The
pesticide laws and common law principles applicable to the use of pesti-
cides do a reasonably adequate job of protecting persons and property
from injury. There is a need for improvement in the administration of
present controls. Present state registration laws are inadequate with
respect to protection of the environment. On the whole, environmental
protection is just now being written into the statutory language of the :
Southeastern states in the form of application and use laws.
16
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Cultural methods of control (sanitation, tillage, dates of planting
etc.) along with the use of resistant crop varieties is the farmers first
line of defense against pests. These practices considerably reduce but
do not eliminate the need for other pest control.methods. For certain
pests, such as many plant viruses and nematodes, chemical treatment
is neither feasable nor economical. In such cases, physical, mechanical,
and regulatory (quarantine and certification) methods are utilized to re-
duce or prevent pest populations.
Many major economic pests in the United States have been intro-
duced from other countries without their natural parasites and predators.
In some cases importation and release of natural enemies have proven
to be effective in suppressing the pests. Broad-spectrum pesticide
applications have the adverse effect of destroying the natural enemies of
insects. This eliminates a natural check on pest populations in agricul-
tural ecosystems.
Efforts toward the development of biological control agents (virus,
bacteria, protozoa, fungi, nematode attacking insects) may result in
safer, and specific pest control practices, Similarly numerous insect hor-
mones (e. g. juvenile and ecdysone) have the potential of being utilized as
selective insecticides.
Many insect attractants have been characterized and developed to
lure insects into traps containing pesticides, pathogens and chemosteri-
lants. Chemical and electromagnetic radiation (light traps) attractants
also provide for early detection and location of insect infestation. This
is an important component in integrated and pest surveillance programs.
Eradication of selected insect species has been achieved by re-
leasing sterile males to compete with the fertile ones in the natural
environment. This method of pest eradication is successful only if the
natural insect population is low. In such cases, the sterile males "over-
whelm" the fertile males. Expanded use of this technique has been
17
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restricted by high cost and logistic factors. Sterilization of the natural
pest population by chemosterilants could reduce such time and cost
factors.
Integrated control is a pest population management system that
employs several suitable techniques to reduce pest populations and
maintain them at levels below those causing economic injury. Inte-
gration provides the best solution to a pest problem because all possible
controls are first evaluated. This approach requires ecological informa-
tion, pest threshold, and economic injury levels.
To date, public and private efforts in pest control have been
directed toward development of pesticides with little effort being directed
to alternatives. There is little inducement for industry to develop alter-
native methods until large-scale pilot studies have been proven success-
ful. Pesticides will continue to be used in the foreseeable future. Alter-
vi
native methods, if further developed and applied, can reduce excessive
dependence on broad-spectrum pesticides.
The aquatic environment in the Southeast is being subjected to
unnecessary pesticidal pollution. In many instances, there are deficiencies
in fundamental information which preclude creation of adequate preventive
and corrective measures. Programs and practices need to be implemented
which maximize the benefits of pesticide use while minimizing its impact
on the aquatic environment.
18
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PART III. RECOMMENDATIONS
The recommendations derived are the consequence of a critical
review of the information available on pesticide use and environmental
pollution in the Southeast. The scope of these recommendations fre-
quently transcends regional boundaries.
The national data collection systems supporting the federal pesti-
cide program should be improved. The federal government should en-
courage legislation at the state and federal levels to make mandatory
reporting by physicians of treatment of pesticide poisonings. The U. S.
Public Health Service should promote effective diagnosis and reporting
of pesticide poisonings among its physicians and physicians at large.
The National Transportation Safety Board should cause improved re-
porting of the toxicological effects on pilots by requiring investigation
and re-submission of future reports where this data category is impro-
perly completed. The Department of Commerce should expand its
annual reporting requirements. Information should be collected from
manufacturers and distributors on the quantity of pesticides shipped as
final sales to retailers or direct to consumers by county.
The Environmental Protection Agency should expand in-house and
supported monitoring activities to identify pesticides and their metabo-
lites in the aquatic environment (surface and ground fresh waters and
estuarine). This activity should be complemented by an expanded pro-
gram of development of improved pesticide concentration and analytical
procedures. The elimination of the masking effect of polychlorinated
biphenyls in analyses of pesticides is a specific analytical need. A
coordinated surveillance system must be established to provide in-depth
pesticide information on reservoirs, lakes, rivers, and estuaries. The
results must relate the movement of pesticides to hydrological conditions.
Quantification of the amounts and types of pesticides being transported
19
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to the estuaries relative to climatic and seasonal factors is needed.
Rates of interchange between biological organisms and sediment, must
be established.
The U. S. Department of Agriculture through its Extension
Service, should:
• encourage growers and custom operators to use the most
advanced pesticide application equipment under favorable
meteorological conditions;
• encourage growers to use cultural and management
practices which minimize sediment loss;
e expand its educational efforts on proper selection and
judicious use of pesticides;
• increase its crop and pest surveillance services;
• discourage use of pesticides where furrow irrigation
is practiced; and
• encourage incorporation of pesticides into the soil to
minimize the effects of overland drainage and atmospheric
contamination of the aquatic environment.
In a related activity, the Soil Conservation Service should expand its
soil erosion control program to emphasize retention of pesticide-treated
soils that now enter the aquatic systems. ..
Government and industry should engage in the development of
improved pesticide formulations and equipment capable of delivering the
minimum quantity of toxicant needed to control the pest. An integral
need is the design and manufacture of equipment capable of generating
droplets or particulates of narrow size range. Improved methods of
pesticide impingement using electrostatics and other techniques should be
evaluated.
The Environmental Protection Agency should:
• develop water quality standards for pesticides based upon
residue tolerances of sensitive and essential members of the
food web,
20
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• develop water quality standards which establish strict limits
on pesticide concentrations in effluents from point sources,
industrial and municipal outfalls. State water quality control
agencies should be responsible for enforcement of the stan-
dards, and
• promote development of standard methods and procedures for
use in decontamination of highly concentrated pesticide spillage.
Practical and efficient decontamination procedures for low
level pesticide concentrations, regardless of source, should
also be expanded.
The activities of the Working Group on Pesticides, an intergovern-
mental agency organization, should be continued. This liaison minimizes
the possibility of duplication of inhouse and sponsored studies. It pro-
vides a potentially valuable forum for input to development of improved
analytical techniques and water quality standards.
A set of national priorities must be established by the U. S.
Department of Agriculture for developing alternative methods of pest
control beginning with those situations which utilize the largest quantities
of broad spectrum, persistent pesticides. The Environmental Protection
Agency should reexamine the registration of pesticides which persist in
the environment more than one year, are very insoluble in water, and
are very soluble in animal fat. Focus of the examination should be with
the view of cancelling registration if safe, effective alternative methods
are available.
There are gaps in the knowledge of the effect of pesticides that
can only be filled after appropriate research. Long-term (chronic)
epidimeological information should be developed for the effect on life
forms ranging from microflora and microfauna to man. Programs of
the National Institutes of Health should be oriented to fill this need. The
Environmental Protection Agency should:
• increase inhouse and supported research to develop infor-
mation regarding specific pesticide degradation rates, mecha-
nisms, products and toxicities in fresh, brackish and salt
water; and
21
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• expand inhouse and supported toxicologic.al measurements of
the effect of pesticides on aquatic flora and fauna. Emphasis
must be given to dynamic rather than static test procedures.
Under these conditions the simultaneous effect of multiple
contaminants and environmental factors can be determined.
The Environmental Protection Agency and the U. S. Department of
Agriculture should jointly support programs to develop information
regarding the effect of pesticide sorption of particulate and organic
matter on the subsequent chemical and biological degradation mecha-
nism. Details are especially lacking on such processes involving soils
and aquatic bottom sediments of the Southeast.
Additional gaps in the knowledge of pesticides and their effects
will be filled only after field investigations produce relative, useful
information.
• Field testing to improve soil incorporation techniques for
pesticides and the injection equipment should be accelerated
by..government and industry.
• The Environmental Protection Agency Solid Waste Manage-
ment Office should develop safe disposal techniques for waste
pesticides, and pesticide containers, when landfill and re-
cycling methods are employed. These techniques should
provide for chemical and/or biological decontamination of
these wastes.
• The Environmental Protection Agency Air Pollution Control
Office should establish standards for incineration of pesti-
cides, and their containers, designed to limit atmospheric
contamination and the resultant damage to the aquatic envi-
ronment. This office should also determine the contribution
of pesticides to the aquatic and soil environment by atmos-
pheric fallout and washout.
• The Agricultural Research Service of U. S. Department of
Agriculture should receive greater support for large-scale
field testing to determine the effectiveness of promising
alternative methods of pest control. Successful programs
can then be adopted regionally to eradicate, reduce or main-
tain pest populations below economic injury thresholds. Pest
control at the farmer level should be reoriented to facilitate
management programs for the entire infestated region.
22
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• The Environmental Protection Agency and the U. S. Depart-
ment of Agriculture should jointly ascertain the long-range
effects of low-level concentrations of pesticides added to the
aquatic environment by irrigation practices.
Certain regulatory and legislative recommendations are derived
from the study.
• The Southeastern states must reduce the time required to
formulate pesticide legislation, enact legislation and imple-
ment pesticide programs as technical advances elucidate the
complex interaction between man and the other factors affecting
the environment.
• Annual registration of pesticide products as practiced by the
states should be adopted for federal registration.
• The registration procedures on pesticides should include an
assessment of packaging adequacy from the viewpoint of child
safety.
• An Executive Order should be issued by the President which
would cause all federal agencies introducing pesticide sub-
stances into public waters and onto public lands to file with
state water pollution agencies the chemicals used, the amount,
the time of use and the purpose.
• The federal government should encourage state water pollu-
tion control agencies to issue regulations requiring all state
government agencies using pesticides in state waters and on
public lands to file similar statements.
• The focus of the federal pesticide program should be shifted
to provide incentives for the states to enact and enforce a
high quality state pesticide program. Federal standards on
registration, inspection, and enforcement should be established.
States should be provided with federal grant assistance to oper-
ate and administer their pesticide programs which satisfy the
federal standards.
• The Federal Insecticide, Fungicide and Rodenticide Act should
be amended to provide for a joint, comprehensive, federal-state
pesticide program and to grant federal officials authority to
issue "stop-sale" and "stop-use" orders.
• The investigative function performed by the Accident Investi-
gation Section in the Pesticides Office of the Environmental
Protection Agency should be expanded.
23
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PESTICIDE USAGE IN THE SOUTHEASTERN
UNITED STATES AND ITS EFFECT ON
THE AQUATIC ENVIRONMENT
Volume II
24
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A. PESTICIDE USAGE
1. Introduction
The southeastern United States has traditionally grown crops,
such as cotton, tobacco, citrus, peaches and peanuts, which require
application of large quantities of pesticides for profitable production.
In the past, the Southeast has accounted for the largest share of organo-
chlorines used in the United States. Control of pests in cotton, alone
2
consumes 70% of the total DDT used nationally. The use of pesticides
is an almost inevitable consequence of the development of modern
intensive agriculture. High production characteristics of new hybrid
varieties, monoculturing of crops and minimum tillage practices have
increased the need for pesticides.
The national rate of increase in total pesticide usage has
averaged more than 7% a year. For herbicides the increase is sub-
stantially higher and their usage has more than doubled over a 4 year
period (1962-66). The sales of pesticides in the USA for the 8 year
period, 1962-1969, are shown in Table A-l.
3
Table A-l. Pesticide Usage in the U.S.A.
Year
1962
1963
1964
1965
1966
1967
1968
1969
Fungicides
97
93
95
106
118
120
124
127
Sales in millions
Herbicides
95
123
152
184
221
288
318
348
of pounds
Insecticides
442
435
445
473
502
489
498
502
Total
634
651
692
762
841
897
940
983
Source: Metcalf, R. L.
25
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Information on principal usage, types and volumes of pesticides
is important in this era of national concern for the environment. This
is particularly vital with respect to the persistent pesticides, to
determine the extent and trends of environmental pollution.
2. Major Crops and Soils of the Southeast
A variety of climatic gradations from temperate to subtropical
and diverse soil types makes the southeastern United States suitable
for profitable production of many crops.
a. Crops
The most commonly grown crops are tobacco, cotton, peanuts,
soybeans, corn, pecans, peaches, citrus fruit and vegetables. Of the
total national production of tobacco, citrus, peanuts, pecans, cotton
and vegetables in 1969 approximately 85%, 68%, 65%, 61%, 28% and 12%,
4
respectively, were produced in the Southeast. (Table A-2).
North Carolina and Kentucky lead in production of tobacco;
Florida in citrus production; Alabama and Georgia in production of
peanuts; and Georgia, Alabama and Mississippi in production of pecans.
For many years, the southeastern United States was the leading
producer of cotton, however, the region presently accounts for only 28%
of the total U.' S. production (Table A-2).
b. Soils
The soils of the southeastern United States are generally acid
jn reaction and low in organic matter, and fall either entirely or partially
5
into 13 physiographic regions. These are as follows:
26
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Table A-2: Production of Various Crops in the Southeastern States, 1969^
State
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Total for the
Southeast
0. S. Total
Z of U. S. Total
In the Southeast
Tobacco
1000 Ibs.
800
26,028
97,890
436,802
715,968
136,658
120,796
1,534,942
1,806,656
85
Cotton
1000 bales
461
9.4
282
5.8
1,328
100
205
422
2,813.2
10,015
28.1
Peanuts
1000 Ibs.
285,175
85,065
946,270
1,200
337,840
20,150
^1,675^700
2,523,399
66.4
Soybeans
1000 bu.
14,743
4,563
11,208
13,580
50,380
24,258
21,578
28,632
169,942
1,116,876
15.
Crops
Rice Corn
1000 cwt 1000 bu.
17,332
13,962
47,058
76,846
2,520 9,858
89,828
18,894
27,830
^520 301,608
91,303 4,577,864
1 2.7 6.6
Pecans
1000 Ibs.
36,000
4,600
83,000
14,000
3,000
3,500
144,100
235,600
61.2
Apples
mil. Ibs.
20.9
204.0
8.0
10.4
243.3
6,721.8
3.6
Peaches
mil. Ibs.
50.0
175.2
16.5
17.5
56.0
338.0
9.4
662.6
3,665.4
18.1
Citrus * Vegetables
1000 boxes tons
109,830
180,000 1,687,680
200.380
15,480
63,580
242,120
166,730
52,990
180,000 2,538,790
265,070 20,441,230
67.9 12.4
* Production of Crop for the growing season of 1968-69
Source: Agricultural Statistics - USDA (modified)
-------
The Coastal Plain soils - extend from South-Central Texas
to North Central North Carolina. Cotton production is
centered in this area and much of it is rolling or hilly.
Control of excessive soil loss by water erosion is a major
management problem.
The Southern Appalachia Plateau - comprises a series
of relatively flat-topped ridges in Northeastern Alabama
and Northwestern Georgia. The soils are developed from
sandstones and shales. Soils developed from shale tend
to be finer and shallower and present a problem of water
infiltration and erosion.
The Southern Piedmont - extends from North Carolina
..-••_ i -* i
Southwest through South Carolina and Georgia into Alabama.
Most of the Piedmont is hilly. Because of the steep slopes
and the erosive nature of the soils, erosion has been severe.
The surface soil has been removed in many places and
subsoils are now frequently farmed.
The Limestone Valleys - contain soils of limestone origin
and are mainly found in the Tennessee and Coos a River
Valleys in Alabama. Small areas are found in Northwestern
Georgia. The topography is level to undulating.
The Brown Loam Area - forms a belt east of the Mississippi
River flood plain which extends from Northwestern Tennessee
South across the Mississsippi to the lowlands of the Gulf
Coast. The topography ranges from level to hilly. Row
cropping has resulted in extensive erosion over the entire
area.
The Black Prairie Area or Black Belt - extends from the
eastern part of Alabama to the northeastern corner of
Mississippi. The land is gently rolling and the soils are
poorly drained.
The Piedmont Subregion - includes all of North Carolina
except the nothern one-third. The land is gently rolling and
rough. Soils erode easily and the fine-textured subsoil,
which is very difficult to cultivate, is exposed. Practices
such as contour farming and terracing should be extensively ,
used because of the relatively high eredibility of the many
sandy soils in this area.
28
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» The Blue Ridge Subregion - lies mostly in Western North
Carolina, but it also includes parts of, Tennessee, Georgia
and South Carolina. Sheet erosion is a severe problem.
• The Appalachian Valley Subregion - extends eastward across
Tennessee and several adjoining states. Surface erosion on
many slopes is severe.
• The Allegheny-Cumberland Highlands - include the Cumber-
land Plateau of Tennessee and the eastern mountainous region
of Kentucky. The soils are relatively shallow and moderate
erosion in cultivated fields is a serious problem.
• The Bluegrass Subregion - consists of two separate sections
one in Kentucky and the other in Tennessee. Soil erosion
is not a problem in this area.
• The Florida Peninsula adjacent Flatwoods - include parts
of South Carolina and Georgia and almost all of Florida^.
Runoff and erosion are of minor importance in this region.
Natural drainage of the soils varies from excessive to very
poor.
• The Mississippi Delta Region - is an alluvial plain of the
Mississippi Valley. At least 30 states have contributed,
through erosion, to the soils of this valley. Soil types
reflect the action of floodwater and soils vary from clay to
sand and have poor to excessive internal drainage. Most of
the land is gently rolling and erosion is a problem.
The soil types of the United States have also been classified
according to 7th Approximation which is a new system. Most of the
soils of the Southeastern States, except those in Florida and Kentucky,
belong to the order ultisols and suborder udults.
3. Historical Development of Pesticide Usage
Historical development of pesticide usage in southeastern United
States closely parallels the development for the entire country.
Plant protection by the use of chemical sprays or dusts or seed
treatment did not originate in the 20th century but has been practiced
on a small scale for a long time. However, large scale farming
practices of the twentieth century have hastened the evolution of
pesticides.
29
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The first insecticidal materials used for insect control included
the arsenicals, lime-sulphur, petroleum oils and nicotine. During the
intervals between World Wars I and II , flourine compounds, Pyrethrum,
Rotenone, synthetic organic materials, (e. g. dinitro compounds) and
thiocyanates came into use. Discovery of insecticidal activity of DDT
in 1942 led to concerted efforts by chemists and entomologists to find
other potentially effective insecticides. These efforts led to discovery
of such compounds as Benzene hexachloride, Toxaphene, Chlordane,
Aldrin, Dieldrin and several organic phosphates.
The history of weed control in crops began with the use of salt,
ashes, and smelter wastes. From 1887-1900, copper salt was used to
selectively kill broad leaf weeds in cereals. In the year 1900, calcium
eyanide was actded to the list of selective herbicides. Ferrous sulfate,
copper salt and sodium arsenate were used before World War II.
Auxin activity and selectivity of 2, 4-D were discovered in 1942 and
1944, followed by 2,4, 5-T in 1948 and phthalamic acid in 1952. Many
other herbicides belonging to the groups such as substituted ureas,
carbamates, triazines and substituted phenols have been developed and
8
are presently being used.
The history of fungicides use can be divided into three distinct
eras. These are the Sulfur Era (from ancient times to 1882) the Copper
Era (1882 to 1934) and the Organic Fungicide Era (began in 1934). Dur-
ing the 19th century, however, two classes of inorganic fungicides, first
sulfur, either alone or as lime sulfur, and then copper, principally a
mixture of copper sulfate and lime in water called Bordeaux .mixture,
were being applied to foliage to protect plants from disease fungi. These
developments continued and by the 1930's many of the important foliar
30
-------
diseases -were being controlled by spraying or dusting -with some form
of either copper or sulfur. In spite of the subsequent development of
organic fungicides, sulfur and copper fungicides are still being used.
9
However, the quantities of each being applied are decreasing.
Concurrently with the early development of foliage fungicides
development of chemicals for the control of seed-borne bunt or smut
fungi of cereals occurred. The use of copper sulfate soaks was for a
time popular, followed by the introduction of formaldehyde and copper
carbonate. In the early part of this century the development of organic
mercury compounds for seed treatment was initiated, the first being a
chlorophenol mercury. The nonmercury organic fungicides began in
1934 with the issuance of a patent covering a variety of derivatives of
dithiocarbamic acid. Development was slow but in the early 1940's
Thiram was introduced as a seed treatment. Thiram is also effective
on foliage but other dithiocarbamates such asFerbam, Ziram, Zineb,
and Maneb were more fully developed as foliage protectants. The
latter two compounds are in particular being widely used for control of
a great variety of foliar diseases. They are effective and safe at
economic rates of application and have contributed greatly to the
9
production of quality vegetables and other crops.
4. Major Pests and Their Control
There are several dozen destructive pests of crops in the south-
eastern United States that cause heavy losses virtually every year and
are responsible for the use of most of the pesticides. These major pests
and the pesticides recommended and widely used are presented in Tables
A-3, A-4, A-5. This information was compiled from the State Agri-
cultural Extension Service Bulletins.
31
-------
TABLE A-3 Economic Weeds of Major Southeastern Crops and Herbicides Recommended for Their Control.
CROPS WEEDS HERBICIDES RECOMMENDED
ro
Tobacco
Citrus
Peanuts
Cotton
Peaches
Vegetables
Soybeans
Corn
Apples
Annual grasses, broad
leaf weeds, white
clover
Broad leaf weeds and.'
grasses
Broad leaf weeds, grasses
Texas millet, nut grass
Annual grasses, broad
leaf weeds, crabgrass
green and yellow foxtails,
gooseweed
Annual grasses and broad
leaf weeds
Annual grasses, broad leaf
weeds, crab grass, Johnson
grass
Annual grasses, borad leaf
weeds, ragweed, Johnson grass,
barn yard grass
Annual grasses, ragweed, Johnson
grass, crab grass, velvet leaf
Annual grasses, broad leaf weeds
woody perennials, poison ivy
Pebulate, Benefin My lone,
Vampam, Tillam, Enide
Bromacil, Fenuron, methyl
bromide, 2-4-D, Dalapon
Vernolate, Benefin Naptalam,
DCP, Nitralin, Lasso, Dynanap,Balan
Trifluralin, EPTC, Nitralin,
DEPA, MSMA, CIPC, Planavin,
Cotoran, Diuron
Simazine, Dalapon, Dichlo-
benil
Vapam, Bromacil, Trifluralin, Linuron,
Benefin, Diphenamid, Randox, Vegedex
EPTC, DCPA
Amiben, Vernolate, Dalapon,
Lasso, Trifluralin, 2, 4-DB,
Tenoran, Dyanap
Atrazine. 2, 4-D, So.azome, Dalapon
Diuron, Paraquet, Linuron, Sutan, Lasso
Methyl bromide, Simazine, Dalapon
-------
Table A-4 Economic Insects of Major Southeastern Crops and Insecticides Recommended for Their Control
CROP
INSECTS
INSECTICIDES USED
Tobacco
Citrus
Peanuts
Cotton
Peaches'
Vegetables
Soybeans
Corn
Apples
budwonn, hornworm, cabbage
lopper, bollworm, aphids
Scale insects, mealy bugs,
White flies, aphids
Southern corn rootwonn,
corn earworm, southern
armyworm
Bollweevil, bollworm, pink
bollworm, tobacco budworm,
cabbage looper
Scales, oriental fruit, moth
Tomato and tobacco hornworm,
tomato fruitworm, cabbage looper,
aphids, imported cabbageworm,
root maggots
Corn earworm, bean leaf beetle,
stink bugs, green cloverwonn.
Armyworm, corn earworm, cutworm,
common stalk borer, corn leaf
aphid
Codling moth, leaf roller, cur-
culio, aphids
Carbaryl, Malathion,
Parathion
Azinphosmethyl, Parathion,
Systox
Diazinon, Malathion,
Carbaryl
Methyl parathion, DDT
Toxaphene
Azinphosmethyl, Parathion
Diazinon, Demeton, Phosdrin,
Carbaryl, Methoxychlor
Carbaryl, Methoxychlor
Malathion, Methoxychlor
Azinphosmethyl, Parathion
-------
Table A-5 Economic diseases of Major Southeastern Crops and Fungicides Recommended for Their Control
CROP
DISEASES
FUNGICIDES RECOMMENDED
<*»
Tobacco
Citrus
Peanuts
Cotton
Peaches
Vegetables
Soybeans
Corn
Apples
Wild fire, anthracnose
Blue Mold
Citrus canker, anthracnose,
melanose, scab, dieback
leafspot, seed rot, seedling
blight, pod rot
Dampling off, seed decay
angular leafspot, anthracnose,
wild fire
leaf curl, blossom flight, scab,
rhizopus rot
Downy mildew, anthracnose, scab,
leafspot, fusarium wilt, southern
blight
leaf spots, wild fire, downy mil-
dew, sclerotial blight, seed
decay
Seed decay, seedling blight, seed-
ling root rot
scab, rust, mildew, fire, blight,
leaf spot
Zineb, Ferbam, Maneb,
Meltiram, Streptomycin
Sulfate
Neutral Copper Compounds,
Metallic Copper, Zineb
Thiram, Captan, Terraclor,
Zineb, Methylisothiocyanate
Captan, Maneb, Terraclor,
Terrazole
Dichlone, Captan, Ferbam
Maneb, Zineb, Tri-basic
Copper, Terraclor
Thiram, Captan
Thiram, Captan, Maneb
Maneb, Zineb, Captan, Cyprex
-------
5. Regional and State Usage of Pesticide
realization of the potential acute danger to the public
posed by use of synthetic chemicals to control agricultural and other
pests led to the establishment of the Federal Insecticide, Fungicide,
and Rodenticide Act (FIFRA). This act provided for registration of
pesticidal chemicals shipped in interstate commerce as well as im-
ported pesticides.
Concern for the total quantities of pesticides applied for control
of agricultural pests, and the associated chronic health hazard to the
public and the environment, is of recent origin. Consequently, no laws
exist which require pesticide manufactuers, distributors, or users
(growers) to report actual quantities of pesticides sold or applied in
the different states to any state or Federal Agency. The absence of
such regulations prohibits an accurate inventory of pesticide usage
by states.
The Economic Research Service of the USDA published
information on pesticide usage by regions for two years. This
publication was terminated after 1966. The information published was
based on random sampling techniques and not on actual quantities of
pesticide applied by growers.
The existence and availability of inventory material and
information varies widely from state to state within Region IV. Several
states (e. g. Tennessee and Kentucky) have conducted special surveys to
obtain quantitative information on pesticide usage. Generally these
surveys provide information on pesticide usage for one year. Other
states such as, North Carolina, have very little or no information on
pesticide usage.
35
-------
A brief discussion of available inventory information for the
Southeastern states, other than North Carolina, follows.
a. Regional
Much of the information on pesticide usage compiled by the
Economic Research Service was published on a combined state basis.
In one case the information is combined for four states in Region IV
(Alabama, Georgia, South Carolina, Florida) and in another, for all
eight states. A discussion of this combined information is contained
in this section. Additionally, control of fire ants, which is a regional
problem, is also discussed.
(1) Combined States Information
In 1964 herbicide use was less than insecticides and fungicides.
Out of approximately 84 million pounds of herbicides used in the country,
the Southeast (Alabama, Georgia, South Carolina and Florida-four state
area) accounted for only 3.4 million pounds. Herbicides used in large
quantities were 2, 4-D, Dinitro, Atrazine, Trifluralin and Benefin. 10
Thirty-five million pounds of insecticides were used in the Southeast
in 1964. The Delta area (Mississippi, Louisiana and Arkansas) utilized
27 million pounds. The insecticides most frequently used were DDT,
Toxaphene, Carbaryl, and Methyl parathion. More acres were treated
with DDT in the Southeast than in any other region, 3. 5 million acres or
31 percent of the total of 48 states.
During the same year fungicides were applied in greater quantities
thin any other pesticidal group. This amounted to 73 million pounds or
44% of the total used nationally. Sulfur was the leading fungicidal
material applied (64. 5 million pounds).
36
-------
In 1966 insecticides applied to cotton exceeded the combined
11 12
>r all other major crops. ' A sirr
for fungicides applied to citrus (Table A-6).
11 12
total for all other major crops. ' A similar situation was observed
(2) The Fire Ant Problem
Some fifty years ago the imported fire ant Solenopsis saevissima
richteri Forel entered the United States from Latin America, probably
at the port of Mobile, Alabama. These ants construct large mounds,
have fiery stings and exhibit aggressive mobilization upon disturbance.
At least two species of native fire ants in the southeastern
United States so closely resemble the imported ant that it is difficult
13
and at times impossible for an expert to separate them in the field.
There have been three periods in the history of the ant's spread.
An initial period of a decade or two (1918-1932) when the ant became
established on about two or three hundred thousand acres within a
few miles of the Mobile Bay area; and natural spread peripherally
was less than one mile per year. A second period of perhaps two
decades (1932-1950) when the ant became established on about two to
three million acres within 50 miles of Mobile Bay area, and natural
spread was moving peripherally at a rate of one to three miles per year.
13 14
A third, seemingly explosive, period was during the last two decades. '
By 1957, these ants had spread over large land areas in Alabama,
Mississippi, Louisiana, and Florida, as well as small areas in
Texas and Georgia.
There is very little conclusive evidence that the ant actually
harms other insects, plants, or birds and wildlife. But it inhabits
open areas such as fields, where its large mounds inhibit use of farm
37
-------
Table A- 6 Pesticides Used on Major Crops of the Southeastern United States,
Federal Region IV, 1966 H. I2
Herbicides :
Pl t-T*11C3~__ — _•
Pn ^ f*r\n ______ •
Soybeans :
288
v**-
2,542
15
2,892
3,643
1,395
Pounds
: Insecticides :
2,355
32,786
3,330
5,529
428
2,712
active ingredients
Fungicides :
Ififin rtnunrlc
1,502
50
20
55
2
4
Other :
411
1,294
12,134
6,150
44
49
Total
pesticides
4,536
36,672
15,499
14,626
4,117
4,160
Source: Eichers, T. R. (modified)
38
-------
equipment. Its wasplike sting causes a great deal of pain and
inconvenience to livestock, farmers, laborers, picnickers, and
schoolchildren.
Results of research begun in 1949 on control of the insect in
Alabama indicated good control with 2 pounds of Heptachlor or Dieldrin
or 4 pounds of Chlordane per acre, when broadcast as granules, for a
period of 3 to 5 years. 1 ' 1? Aerial application of 5% or 10%
Heptachlor at a rate of 2 pounds of technical material per acre was
equally effective for control of this insect. Bait containing 0. 075,
0. 15, or 0.3% Mirex applied at rates of 3, 5 or 10 Ibs. per acre
18
respectively, all gave excellent control of ants in Mississippi.
Mirex was hailed on its introduction as "the perfect pesticide"
because it is quite precise in killing its target organism.
Mirex is a delayed-action bait. A first spraying is almost
entirely picked up by worker ants who take it back to their nests. There
it then kills the queens and ultimately destroys most of the colonies.
Two more sprayings aimed at killing off the remaining ants were
included in prior practice but this carries the risk that the bait, left
untouched by the now-sparse fire ant population, will be ingested by
other insects or birds or will flow into neighboring streams. 15
The use of Mirex has been critized because, in some field tests,
it has been toxic to shrimp, crabs, and other species of ants, such as
the carpenter ants. A final question arises because, like DDT and mer-
cury Mirex is highly persistent in the natural environment. It could
pass along the food chain to become concentrated in higher organisms.
Current methods of Mirex bait application attempt to limit these
hazards. Mirex is aerially sprayed at 1. 7 grams of Mirex chemical
39
-------
and 11/4 pounds of corncob grits and soybean oil per acre. This is
15
equivalent to about two thimblefuls of Mirex chemical per acre.
Despite the minute quantities applied, Mirex ranks as the
19
fourth most abundantly found pesticide in Southeastern water.
b. Alabama
Cotton, peanuts, soybeans, corn, pecans, peaches and vegetables
are the most important crops produced in Alabama.
The most commonly used herbicides, in the state in 1970, were
2, 4-D, Atrazine, Treflan, FLanavin, Cotoran, DSMA, MSMA, Dinitro,
20-24
Balan, and Lorox (Table A-7).
Gotten receives applications of both pre-and post-emergence
herbicides. The most commonly used herbicides are Treflan and
Planavin (preemergence) and DSMA and MSMA (postemergence).
Since much of the total cotton acreage receives application of both
pre-and post-emergence herbicides, the figures for acres of cotton
21
treated exceed the total acres planted. Approximately one-half of
the corn acreage receives applications of preemergence (Atrazine
22
and 2, 4-D) and post-emergence herbicides (2, 4-D).
The dollar value of insecticides used shows an increase from
1965 to 1969 but declines slightly in 1970 (Table A-8). Of all the crops,
cotton and peanuts were the major users of insecticides. Mirex has
o e _ Q A
been used extensively in attemps to control the fire ant.
Quantitative information on fungicide usage in the state is
presently not available.
40
-------
Table A-7: Herbicide Usage (acres treated with various herbicides)
for the Major Crops Grown in Alabama, 1970
20-24
Crop Acres Planted Acres Treated Preemergence
Herbicide
Cotton 550,000 846,068 Treflan alone
or
Planavln alone
Treflan and
Cotoran
Flanavln and
Cotoran
Cotoran alone
Others
Total Pre.-
. • emergence
Corn 694,000 306,923 Atrazlne
Lasso
Others
Total Pre-
emergence
Treatment
Acreage Treated
165,328
95,107
35,627
58,780
-
475.362
189,429
16,659
-
215,124
Postemergence Treatment
Herbicide
DSMA or
'MSMA
MSMA and
Cotoran
MSMA and
Karmex
MSMA and
Her ban
Others
Total Post-
emereence
2, 4-D
Atrazine
Others
Total Post-
emergence
Acreage Treated Remarks
118,530 Acres treated "over the
top" 58.679
50,260 layby - acres-89,089
treated with Karnex,
Cotoran, Lorox
20,050
17,415
-
222.938
46,837 Acres treated preplant with
butylate - 12,912
39,478
-
91,799
-------
Table A-7 (Continued)
Herbicide Usage (acres treated with various herbicides) for the Major Crops Grown in Alabama, 1970
-P.
ro
Soybeans 609,000 242,000
Sorghum 7,218 Propazine
24,200 - 9,680 Acres - 58,080 treated
preplant with some planavln,
some vernan
3,788 Atrazlne 4,300
2, 4-D 2,918
Sorghum 2,870
Sudan 2, 4-D
Coastal 8,546
Bermuda Slmazine
Peanuts 190,000 253,486
Cracking time
37,750 Dinitro alone 14,850 Acres treated preplant 78,370
with Balan, 29,800 with Balan-
Vernan, others -
Total 114,861
Dinitro and
Falone 18, 175
Dinitro and
Diphenamld 16,775
Total Cracking
Time 58,025
Source: Burns, E. (modified)
-------
Table A-8: Insecticide Usage on Crops, and Beef and Dairy Cattle in Alabama (1965-1970)
25-30
-
CO
A. Cot
1.
2.
3.
4.
5.
ton 1965
Total acres planted 816,604
Acres dusted
Acres sprayed
Non-treated acres
Systemic insecticides
treated as:
a. seed treatment
b. furrow treatment
B . Peanuts
1. Total acres planted 201,792
2. Acres treated with
sys temic insecticides
3. Estimated cost of control
programs $455,400
4. Estimated value $1,918,200
C. Soybeans
1. Total acres planted 280,987
2. No. of acres requiring
insect control
3. Estimated coat of control
program
4. Estimated value
1966
559,733
113,645
319,268
96,995
194,099
50,045
$352,074
$2,100,110
316,195
194,262
1967
89,209
273,884
10,430
91,950
47,176
59,975
$312,643.50
$1,510,804
177,815
1968
90,220
336,262
113,304
115,866
59,781
67,090
$281,941
$934,359
191,305
506,050
1969
79,951
354,802
139,827
742,752
77,865
$270,293
$1,013,509
273,370
$2,899,250
1970
47,075
310,953
206,797
170,125
121,336
84,690
$12 per acre
245,102
$1,462,160
-------
Table A-8 (Continued)
Insecticide Usage on Crops, and Beef and Dairy Cattle in Alabama (1965-1970)
D. Stored Grains
No. of bushels of all grain
In form storage funigated and/or
treated with a protect ant
E. Other crops (acres treated)
1. Commerlcal crops
2. Feacan trees
3. Peaches
4 . Apples
5 . Cloves
6. Alfalfa
7. Corn
8. Grain Sorghum
9 . Temporary grazing crops
F. Beef Cattle
1. Beef cattle treated
for all insects
2. Estimated value of control
program
G. Dairy Cattle
1. Dairy cattle, treated
for all insects
2. Estimated value of control
program
3. Dairy barns in which an
effective fly control program
was conducted
1965 1966
2,907,500 2,065,100
91,822
8,026
1,779
17,430
2,840
170
9,950
1,221,300 746,170
$3,098,850 $3,760,500
161,741 122,415
$1,499,185 $1,343,656
1,402 1,134
1967 1968
2,692,200 2,523,500
81,106 72,344
444
2,777
1,807
20,349 14,540
1,575 1,523
1,248 1,820
74,415 42,275
787,060 750,680
$4,032,500 $4,027,750
115,395 114,023
$1,339,295 $1,293,450
967 925
1969 1970
2,360,000 1,527,800
74,795
19,540
12,485 5,645
1,455 660
4,055 21,550
45,060 61,825
761,150 786,600
$4,411,500 $4,352,300
113,657 401,940
$2,233,400 $1,840,625
856 804
-------
Table A-8 (Continued)
Insecticide Usage on Crops, and Beef and Dairy Cattle in Alabama (1965-1970)
1965 1966 1167 1968 1969 1970~
Acres treated with mlrex
ftre ants control 226,397 578.711 585,716 278,681 180,205 273,890
Amount of Insecticides used
In all aspects of insect control
(dollar value) $12,854,500 $16,737,500 $17,717,500 $17,289,723 $21,473,500 $19,355,700
Source: Ledbetter, R. J. .(modified)
-------
c. Florida
A wide variety of field crops, fruits and vegetables are grown
in Florida. Control of pests in these crops requires extensive use of
pesticides.
Available information on herbicide usage indicates that Treflan,
Lasso, 2, 4-D, Hyvar X, Atrazine and Randox are the most commonly
31
used herbicides (Table A-9). Herbicides are also employed for aquatic
weed control (primarily water hyacinth) which is a serious problem in
Florida, It has been estimated that aquatic weed control measures are
needed on 2. 8 million acres of inland water. Presently only 10% of this
area is treated with herbicides.
Quantitative information on pesticide usage is lacking, particularly
with respect to insecticides and fungicides.
Projections on future use of pesticides in Florida indicate the
32
following:
• Herbicide usage will reach approximately 5. 5 million
pounds by 1975 and about 6 million pounds by 1980.
Increased acreage under treatment as well as use of
more than one chemical or application per crop will
be responsible for these increases.
• Fungicide usage will also increase considerably. Over
32 million pounds of fungicidal chemicals will be utilized
annually by 1975 and 40 million pounds by 1980. These
projections were based on chemicals which were available
in 1969. Should new fungicides with improved efficiency
become available the figures for projected usage will
probably be lower.
• Projected usage of insecticides and miticides, other than
oil and sulfur, will be approximately 17 million pounds
in 1975, and will reach approximately 19 million by 1980.
• The projected usage of fumigants and non-fumigant nematicides
for 1975 are about 6. 2 and 5.2 million pounds, respectively.
46
-------
TABLE A-9 Herbicides Usage on Various Crops in Florida, 1971
31
Crop
Corn
Soybeans
Peanuts
Tobacco
Cotton
Vegetables
Citrus
Woody
ornamentals
Acres Planted
357,000
204,000
53,000
11,000
12,000
800,000
10,000
% of acreage treated Herbicides used
in decreasing order
20 Atrazine, 2,4-D,
Sutan , Lasso
40 Treflan, Lasso, Dyanap
Tenoran
80 Balan, Lasso, Pr emerge,
Dyanap, Vernan
20 Tillam or Enide
90 Treflan, Organic Ar-
senicals (MSMA, DSMA) ,
Lorox
Randox, Vegedex, Diphe-
namid, Treflan, Eptam
70 Hyvar X, Casoron, Slnbar
Paraquat
Paraquat , Herbicide Oils
40 Simazine, Treflan
Source: Currey, W. L. (modified)
-------
d. Tennessee
Some of the most important crops grown in Tennessee are
cotton, tobacco, soybeans, corn, fruits, and vegetables.
The pesticide market in Tennessee is relatively large. A
survey conducted in 1965 by the Tennessee Agricultural Experiment
Station indicated that over 17. 3 million pounds of pesticide materials
valued at more than $16. 6 million, at the manufacturer's level, were
utilized. This represented 4. 6% of the total U.' S. sales for that year.
Of total pesticide sales, 56% were for insecticides, 28% for herbicides,
33
7% for fungicides, and 9% for rodenticides and other pesticides.
Another survey was conducted by the Tennessee State Department
of Agriculture in 1970. In this survey, acreage figures for various
crops were taken from the reports of the cooperative Federal-State
statistics on agriculture. Crops represented in the survey are, for
the most part, the major crops of the State's agriculture. Total
acreage of crops surveyed in the state represented more than 90% of the
cultivated acreage. Information obtained by the survey on acreage and
pesticide usage by crops were projected against the total acreage in. the
State to arrive at a prediction of total pesticide usage by crops. The
information indicated that herbicides were used more widely and in
greater amounts (67% of total) than all other pesticides combined.
34
Insecticides accounted for 30% of total usage and fungicides only 3%.
Use of preemergence herbicides for weed control in corn, cotton
and soybeans increased from 1966 to 1970. (Tables A-10, A-ll, A-12).
A similar situation existed for use of post-emergence herbicides on
cotton and soybeans. However, a slight decrease was observed for post-
35
emergence treatment in corn.
48
-------
Table A-10 Acreage of Corn Crop Treated with Various Herbicides,
in Tennessee, 1966-1970 35
vo
Total acres planted
Preemergence Herbicides
Alachlor (Lasso)
Atrazine (AAtrex)
Atrazine (AAtrex) 4-
butylate (Sutan)
Diuron (Karmex)
2, 4-D
Others (Paraquat, and
Simazine
Total acres treated with
preemergence herbicides
% of acreage treated
Postemergence Herbicides
Atrazine
Linuron
2, 4-D
Other (Evik)
Total acres treated with
postemergence herbicides
% of acreage treated
1966
1,018,000
234,278
11,930
40,382
9,002
295,592
29
12,691
6,305
8a,469
99,465
10
1968
783,000
294,350
6,130
31,841
26,749
359,070
53
20,790
4,905
53,811
79,506
12
1970
722,000
12,205
353,452
20,870
2,375
20,507
3,960
413,369
65
10,452
1,625
35,595
250
47,922
8
Source: Hadden, C. (modified)
-------
Table A-11 Acreage of Cotton Crop Treated with
various Herbicides, in Tennessee,
199-1970 35
Total acres planted
Preemergence Herbicides
Diuron (Karraax)
Fluoraeturon (Cotoran)
Nitralin (Planavin)
Prometryne (Caparol)
Trifluralin (Treflan)
Others (DCPA, and Norea)
Total acres treated with
preemergence herbicides
% acreage treated
4
Postemergence Herbicides
Herbicidal Oil
DSMA or MSMA + Surfactant
DSMA or MSMS + Karmex
DSMA or MSMA. + Caparol
DSMA or MSMA + Cotoran
DSMA or MSMA + Herban
Total acres treated with
postemergence herbicides
% of acreage treated
Lay-By Herbicides
Diuron (Karmex)
Fluometuron (Cotoran)
Linuron (Lorox)
Total acres treated
% of acreaee treated
1966
410,000
158,382
45,914
104,985
11,345
320,626
78
3,755
74,275
23,800
2,100
6,750
110,680
22
1968
392,462
70,440
115,815
34,710
92,262
19,840
333,067
94
6,600
93,640
28,300
3,000
17,515
6,750
155,805
44
15,500
6,275
5,050
26,825
8
1970
425,000
63,520
144,811
48,414
8,000
129,669
3,834
398,248
96
750
155,051
63,182
45,700
32,010
2,100
298,793
72
6,496
5,750
2,100
14,346
4
Source: Hadden, C. (modified)
50
-------
Table A-12 Acreage of Soybeans Treated with Various
Herbicides, in Tennessee
1966-197035
Total acres planted
Preemergence Herbicides
Alachlor (Lasso)
Amiben
DCPA (Dacthal)
DNBP (Dinitro)
DNBP + Napatalam (Dyanap)
Linuron (lorox)
Naptalan + Chlorpropham (Solo)
Nitralin (Planavin)
Trifluralin (Treflan)
Others (Paraquat, Naptalam
+ Chloropham (Alanap)
Total acres treated with
preemergence herbicides
% of acreage treated
Postentergence Herbicides
Chloroxuron (Tenoran)
Herbicidal Oil
DNBP (Dinitro)
Linuron (Lorox)
2, 4-DB
Other (2, 4-D)
Total acres treated with
postemergence herbicides
% of acreage treated
1966
933,000
33,275
14,345
24,470
85,850
223
158,163
17
6,740
9>484
95,858
112,082
12
1968
1,268,000
70,985
115,840
58,025
65,155
109,808
29,495
449,308
41
87,399
8,530
85,098
181,027
17
1970
1,293,000
27,395
67,870
1,007
12,585
72,893
161,756
11,700
94,681
186,777
.1,250
637,914
50
131,950
50
6,750
5,275
159,154
10,050
313,229
25
Source: Hadden, C. (modified)
51
-------
e. Kentucky
The major crops grown in Kentucky are corn, tobacco, soybeans,
hay and small grains. The overall agricultural gross product increased
36
approximately 350 million dollars during an eight year period (1960-1968).
Much of this increase is attributable to pesticide usage.
A survey of pesticide usage and sales was conducted in 1968 by the
36
Division of Environmental Services of the State Department of Health.
Information obtained by this survey indicated that a total of 2, 850, 734
pounds of pesticides were sold during that year. (Table A-13). Of the
total,herbicides accounted for 56. 1%,insecticides 31.4%, and fungicides
12%. The remainder (. 5%) was rodenticid.es.
Of the total sales of insecticides, chlorinated hydrocarbons
accounted for 69.4%, organophosphates 16.8%, carbamates 9.0%
and miscellaneous 4. 7%.
The use of DDT on tobacco in Kentucky has been banned as is
the case for other states. Additionally, the state has banned the use
of Aldrin-fertilizer mixture on tobacco.
f. South Carolina
The major crops grown in South Carolina are cotton, peaches,
peanuts, soybeans, corn and vegetables.
Estimates on herbicide usage on cotton, corn, soybeans, small
grains and pastures are given in Table A-14, This information is based
on herbicide usage surveys conducted in various counties and districts
37
in 1968 by the State Extension Service.
A majority of the cotton crop and approximately one-half of the
corn was treated with pre emergence herbicides. (Table A-14).
52
-------
Table A-13 Amounts of Various Pesticides
Sold in Kentucky in 196836
Pesticides _ Amount used in pounds
INSECTICIDES
CHLORINATED HYDROCARBONS
Product
DDT 151,015
Chlordane 127,778
Aldrin 101,079
Rothane (TDE) 94,449
Methoxychlor 46,967
Toxaphene 29,881
Dieldrin 26,979
Endosulfan (Thiodan) 21,393
Kelthane 8,898
Lindane 4.025
BHC 3,456
Heptachlor 2,347
Tedion 1.407
Endrin 500
Total 620,174
ORGANO-PHOSPHATE
Product
Malathion 51,467
Diazinon 20,728
Parathion 19,799
Di-syston 18,858
Dibrom (Naled) 14,800
Guthion 11,899
Systox (Demeton) 6,000
Ethion 1,975
Ciodrin 1,347
Korlan (Ronnel) 984
Cygon (Dimethoate) 871
Phosdrin 720
DDVP (Vapona) 536
Miscellaneous Organo-Phosphates (5)
Total 150,378
* Pesticides of less than 500 pounds are grouped under miscellaneous.
53
-------
Table A-13
(continued)
RODENTICIDES
Product
Warfarin
Arsenic Trioxide
Zinc Phosphide
Prolin
Miscellaneous Rodenticides (4)
Total
9,482
2,916
1,270
699
232
14,599
HERBICIDES
Product
Methyl Bromide
MH (Maleic Hydrazide)
Atrizine
2, 4-D Amine & 2, 4-D LV
Sodium Chlorate
Diphenamide, (Enide)
2, 4, 5-T
Dalapon
Trifluralin (Treflan)
Alanap (NPA)
Eptam
Amiben
Calcium Methanearsonate
Vernolate (Vernam)
Sodium Arsenite
Linuron (lorox)
DCPA (Dacthal)
CIPC
Simazine
Solan
DSMA
Paraquat
Sutan
Sodium Metaborate
Picloram (Tordon)
Dinitrocresol
Chloroxuron (Tenoran)
Planavin
Casoron
Vorlex
Hyvar (Isocil)
431,788
352,956
200,679
142,248
99,047
49,359
38,356
30,079
22,001
22,794
19,373
18,224
16,670
15,845
14,580
14,376
13,513
10,420
11,498
9,090
8,294
7,184
6,387
4,711
4,030
3,532
3,369
2,500
2,454
2,440
2,400
54
-------
Table A-13
(continued)
CARBAMATES
Product
Carbaryl (Sevin) 80,704
Total 80,704
MISCELLANEOUS
Lead Arsenate 31,467
Pyrethrims 3,076
Piperonyl Butoxide 3,025
Rotenone 2,254
Other Miscellaneous (9)
Total 41,774
FUNGICIDES
Product
Sulfur 126,180
Copper Sulphate 107,772
Captan 38,590
Zineb 20,620
Maneb 20,527
Ferbam 8,010
Lime Sulphur 6,062
Phaltan 5,905
Cyprex 3,210
Dithane (Nabam) 1,168
Polyram (Metiram) 1,168
Botran 1,200
Thiram 760
F.U£gjLci_des_(4) 1,523
Total 342,695
55
-------
Table A-13
(continued)
(Herbicides Continued)
Metham (Vapam)
Balan
Banvel-D
Dazomet (Mylone)
Silvex
Diuron (Karraex)
Monuron (Telvar)
Aminotriazole
CDAA (Randox)
Endothall
Miscellaneous Herbicides (21)
2,118
1,614
1,600
1,600
1,240
1,200
1,200
1,006
890
600
7,145
Total 1,600,410
Grand Total 2,850,734
Source: Moore, E. E. (modified)
56
-------
Table A-14
Herbicides Usage (acres treated) on
Important Crops in South Carolina
(1968)37
Crop & Treatment
Cotton
Preplant (incorporated)
Preplant (incorporated
plus premergence)
Treflan or; Planavin
Postemergence (early and
mid season)
Lay-by
Total Acres Treated
Corn
Preemergence-Atrazine
Postemergence
Total Acres Treated
Soybeans
Preplant (incorporated)
Treflan or Planavin
Preemergence
Pos temergence-Tenoran
2,4,D-B
Total Acreas Treated
Small Grains
Pos temergence
Permanent Pastures
Postemergence
Coastal Bermuda
Simazine
Total Acres Acres Treated
Planted
326,585
295,141
48,380
158,690
73,900
576,111
378,200
168,508
126,333
294,841
1,001,000
409,234
56,588
160,485
193,426
819,733
252,250
108,840
749,880
217,465
13,234
% Treated
90
15
47
23
45
33
41
6
16
19
43
29
5
Source: Nolan, C. N. (modified)
57
-------
Additionally, most of the soybeans and much of the acreage planted to
37
small grains also received application of herbicides.
The herbicides used in large quantities during 1968-70 were
38
Treflan, Atrazine, 2,4-D, DSMA, MSMA and Tenoran (Table A-15).
Quantitative information on pesticide usage, particularly with
respect to insecticides and fungicides, is lacking.
g. Georgia
The important crops of Georgia which are extensively treated
with herbicides are cotton, corn, peanuts, soybeans and pastures. The
most commonly used herbicides for weed control in these crops were
Treflan, Planavin, Cotoran, Karmex, CIPC, DSMA, MSMA, Lorox,
Caparol* Sutan, Atrazine, Lasso, 2,4-D, Banvel D, Vernam, Balan,
39 40
Sesone, DNBP, Amiben, 2,4-DB, Dyanap, Tenoran and 2, 4, 5-T.
Herbicide usage survey data indicated that the acreages of all
crops treated with herbicides increased considerably from 1965-1971.
(Table A-16). Prior to 1971, information on acreage of corn and soy-
beans which received herbicidal treatment but no tillage, was not
«. ^ 39»40
reported.
Presently, no information is available on the quantities of
insecticides and fungicides used in the state.
h. Mississippi
The most important crops grown in Mississippi are cotton,
soybeans and corn. Some of the commonly used herbicides for weed
control in cotton and soybeans were Treflan, Planavin, Cotoran, Karmex,
Telvar, Lorox, herbicidal oil, MSMA + Karmex, MSMA, Amiben, Dyanap,
58
-------
Table A-15 Amounts of Major Herbicides Used3g
in South Carolina During 1968-1970
Herbicide
Treflan
Planavin
Atrazine
Simazine
Karmex
Co tor an
Herb an
Tenoran
Lorox
2,4-D
2,4-DB
Banvel, 2,4,5-T etc.
Dyanap & Dinitro
MSMA & DSMA
Lasso & Amiben
and others
Source: Nolan, C, N.
1968
245,000
15,000
190,000
10,000
30,000
25,000
15,000
115,000
80,000
240,000
20,000
15,000
20,000
160,000
10,000
1.190.000
(modified)
Pounds of Active Ingredient
1969
265,000
35,000
195,000
15,000
30,000
35,000
25,000
135,000
85,000
250,000
30,000
15,000
45,000
175,000
10,000
1.345.000
1970
295,000
50,000
260,000
20,000
25,000
40,000
30,000
140,000
100,000
250,000
40,000
20,000
55,000
185,000
20,000
1,530,000
59
-------
Table A-16 Acreage of Various Crops Treated with Herbicides in Georgia (1965-1969)
39,40
Crop and Treatment
Cotton
Preplant and preemergence
Postemergence
Total
Corn
Preplant and preemergence
Postemergence
Total of preplant, preemergence &
Pos temergence
No Tillage (Atrazine + paraquat)
Peanuts
Preplant
Pre or post emergence
Total
Soybeans
Preplant and preemergence
Postemergence
Total
No Tillage (Paraquat)
Pastures
Postemergence
Fence rows or noncrop land
1965
403,117
403,117
164,332
2,389
166,721
66,797
229,575
296,372
17,832
17,832
Acres treated with herbicides
J.966 1967 1968 1969
347,625
62,883
410,508
162,831
199,754
362,585
151,514
259,862
411,376
95,395
11,495
106,890
252,216
292,875
67,402
360,277
272,482
347,971
620,453
273,652
180,369
454,021
191,020
45,467
236,487
311,324
356,247
180,829
537,076
309,847
380,489
690,336
387,039
107,007
494,046
190,065
42,696
232,761
342,515
372,460
168,732
541,192
412,309
373,655
785,964
430,503
173,667
604,170
236,858
49,583
286,441
350,816
1971
483,415
263,614
747,029
536,514
478,916
1,015,430
6,962
515,359
319,012
834,371
333,655
142,855
476,510
10,980
325,465
29,010
*1970 data not available
Source: Swann, C. W. (modified)
-------
41
Lasso, Solan, Dinitro, Tenoran, 2, 4-DB, and Wax bar.
Cotton and soybeans acreages treated with herbicides increased
each year from 1968-1970 (Table A-17). This trend in herbicide usage
is similar to that observed for most of the other Southeastern states.
Information on insecticide usage for 1970 indicated that
1, 371, 000 acres of cotton were treated for control of cotton bollworms
42
and boll weevil. The major types and quantities of insecticides applied
were as follows:
• Toxaphene -8.5 million pounds at an average rate of 2 Ibs.
per acre.
• Methyl parathion -5.5 million pounds at an average rate
of 0. 5 Ib. /acre
• DDT - 3 million pounds at the rate of 1 Ib. per acre.
Presently, no information on insecticides and fungicides is
available.
6. Conclusions
Most pesticides used in the Southeastern United State are
directed towards the following major pests:
• Insects: Cotton boll weevil, cotton bollworm, tobacco
budworm, tobacco hornworm, scale insects of citrus,
cabbage lopper, pink bollworm, codling moth and mealy
bugs.
• Weeds: Broad leaf weeds, rag weed, Johnson grass, pigweed,
crab grass, barn-yard grass, green and yellow foxtails,water
hyacinth and goose weed.
• Disease: Citrus melanose, citrus and apple scab, leaf spot
disease of peanuts, wild fire of tobacco and cotton, anthracnose
of tobacco and cotton, root rots of corn, fire blight of apple,
downy mildew of beans, leaf spot of apples, beans and cotton.
61
-------
Table A-17 Cotton and Soybeans Acreage Planted, and Treated with
Herbicides in Mississippi (1968-1970)41
Crop & Treatment 1968 1969 1970
Cotton
Total acres planted 1,120,079 1,151,552
Total acres treated
(preemergence) 1,232,036 1,548,084 1,335,432
Total acres treated
(postemergence) 1,359,215 1,857,323 2,127,899
Soybeans
Total acres planted 2,214,360 2,292,425
Total acres treated 964,050 1,866,550 1,637,795
(preemergence)
Total acres treated 683,625 1,374,135 1,539,288
(pos temergence)
Source: Anderson, K. L. (modified)
62
-------
An accurate inventory of pesticide usage is needed to determine
present trends and provide a basis for making future projections on
pesticide usage. Additionally, inventory information is required to
determine the extent and trends of environmental pollution by pesticide
usage. This is particularly important with respect to the usage of
persistent pesticides.
Information on pesticide usage (quantities used and acreage
treated) is presently not available mainly because distributors, sellers
and users of pesticides are not required to report specific information
regarding pesticides sold or applied, to any responsible agency.
The most recent information available from U. S. Department
of Agriculture concerning quantities of pesticides used by farmers on
a regional level is five years old (1966). Certain information is
availabe for pesticide usage in a few states (e. g. Kentucky and
Tennessee) where special surveys were conducted. These surveys
only represent a one year compilation. In most of the Southeastern
states herbicide usage surveys have been conducted more regularly
than for any other group of pesticides. Herbicide usage, on various
importnat crops of the Southeast, has increased considerably during
the past few years.
In the southeastern United States, the most widely used
herbicides are Treflan, Dalapon, 2, 4-D, Atrazine, Planavin, Cotoran,
DSMA, MSMA, EPTC, Dinitro, Balan, Lorax, Simazine, Methyl bromide
and Maleic hydrazide.
Most commonly recommended and used insecticides in the
Southeast are Toxaphene, BHC, Parathion, Malathion, Disyston,
Systox, Carbaryl, Methyl arathion, Diazinon, DDT and Chlordane.
DDT has been used extensively to control insects in cotton, tobacco and
other crops. However, its use is decreasing, while that of Toxaphene,
63
-------
Parathion, Malathion and Methyl parathion is increasing. Mirex has
been very extensively applied to control fire ants in the Southeast.
Insecticide applications to cotton in the Southeast exceed the
combined total for all other major crops. A similar situation exists
with fungicides applied to citrus.
The most commonly recommended fungicides in the Southeast
are Sulfur, copper sulfate, Captan, Zineb, Maneb, Cyprex, Dithane,
Botran, Thiram and Ziram.
Practically all Southeastern soils used for agricultural purposes
are subject to moderate or severe runoff and erosion. Soils in a large
portion of Florida are an exception because lack of adequate drainage
is a severe ^problem. Soil erosion and runoff problems could be
reduced by proper management practices.
7. Recommendations
1. A national and state reporting mechanism for documenting, as
accurately as possible, the total quantities of pesticides used should
be established. Initially, the reporting procedure should be established
at primary and secondary levels to provide a cross reference. Pesticide
manufacturers would represent the primary level while state or county
pesticide distributors could represent secondary level.
2. The Economic Research Service of the U. S. Department of Agriculture
should reestablish its program of compilation and publication of
information on use of pesticides. However, the information should be
published on a state as well as regional basis.
3. Growers should be encouraged to use less persistent pesticides as
they become available.
64
-------
4. The U S. Department of Agriculture through its Extension Service
should encourage growers to use cultural and management practices
which minimze loss of sediment. Special emphasis should be placed
on areas in which most pesticides are applied.
65
-------
8. References
1. Davis, V. W., Fox, A. S. , Jenkins, R. P. and Andrilenas, P. A.,
Economic Consequences of Restricting the use of Orgranochlorine
Insecticides on Cotton, Corn, Peanuts and Tobacco, USDA Publi-
cation Agricultural Economic Report No. 178, 52, 1970.
2. Campbell, J. P., Statement of Under Secretary of Agriculture
Before the House Committee on Agriculture, 1-12, 1971.
3. Metcalf, R. L., Pesticides, A Primer on Agricultural Pollution,
A Publication of Soil Conservation Society of America, 14-17, 1971.
4. Anonymous, Agricultural Statistics, U. S. Department of Agri-
culture, 627, 1970.
5. Anonymous, Soil, Yearbook of Agriculture U. S. Department of
Agriculture, 784, 1957.
6. Donahue, R. L., Shickluna, J. C. and Robertson, L. S. , Soils -
An Introduction to Soils and Plant Growth, Englewood Cliff, N. J.,
Prentice-Hall, Inc., 142-75, 1971.
7. Anonymous, Principles of Plant and Animal Pest Control,
Washington, D. C., National Academy of Sciences, 3_, 360-446,
1969.
8. Anonymous, Principles of Plant and Animal Pest Control,
Washington, D. C. , National Academy of Sciences, 2_, 160-193,
1968.
9. Torgeson, D. C., Fungicides and Nematicides: Their Role Now and
inFuture, J. Environ. Quality, 1_, 14-17, 1972.
10. Eichers, T., Andrilenas, P., Jenkins, R., and Fox, A., Quantities
of Pesticides used by Farmers in 1964, USDA Publication, Agri-
cultural Economic Report No. 131, 37, 1968.
11. Eichers, T. , Andrilenas, P., Blake, H., Jenkins, R,, and Fox,
A. , Quantities of Pesticides used by Farmers in 1966, USDA
Publication, Agricultural Economic Report No. 179, 61, 1970.
12. Eichers, T. R. , Estimates of Pesticides used on Selected Crops in
8 States in 1966, Personal Correspondence, 1971.
66
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References (continued)
13. George, J. L. , The Program to Eradicate "the Imported Fire Ant,
A Report to the Conservation Foundation and the New York Zoological
Society, 39, 1958.
14. Hays, K. B., Ecological Observations on the Imported Fire Ant,
Solenopsis saevissima richteri Forel in Alabama, J. Alabama
Acad. ofSci., 3iO (April), 1959.
15. Shapley, D., Mirex and the Fire Ant: Decline in Fortunes of Per-
fect Pesticides, Science, 172, 358-360, 1971.
16. Arant, F. S., Hays, K. L. and Speake, D, W., Facts about the
Imported Fire Ant, Highlights of Agricultural Research, Auburn
University, Auburn, Alabama, 5_ (4), 1958.
17. Blake, G. H., Eden, W. G. and Hays, K. L. Residual Effectiveness
of Chlorinated Hydrocarbons for Control of the Imported Fire Ant,
J. Econ. Entomol., 52, 1-3, 1959.
18. Lofgren, C. S., Bartlett, F. J., Stringer, C. E. and Banks, W. A.,
Imported Fire Ant Toxic Bait Studies: Further Tests with Granu-
lated Mirex-Soybeans Oil Bait, J. Econ. Entomol., 57, 695-698,
1964. ~~
19. Butler, P. A., Monitoring Pesticide Pollution, Bioscience, 19,
889-891, 1969.
20. Burns, E., Total Acreage of Peanuts'Treated with Herbicides,
Unpublished data (1970) from Weed Control Extension Specialist at
Auburn University, Auburn, Alabama, 1971.
21. Burns, E., Total Acreage of Cotton Treated with Herbicides,
Unpublished data (1970) from Weed Control Extension Specialist at
Auburn University, Auburn, Alabama, 1971.
22. Burns, E., Total Acreage of Corn Treated with Herbicides, Un-
published data (1970) from Weed Control Extension Specialist at
Auburn University, Auburn, Alabama, 1971.
23. Burns, E., Total Acreage of Sorghum and Sorghum Sudan and
Coastal Bermuda Grass Treated with Herbicides, Unpublished data
(1970) from Weed Control Extension Specialist at Auburn University,
Auburn, Alabama, 1971.
67
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References (continued)
24. Burns, E. , Total Acreage of Soybeans Treated with Herbicides,
Unpublished data (1970) from Weed Control Extension Specialist at
Auburn University, Auburn, Alabama, 1971.
25. Ledbetter, R. J. , Unpublished data for 1965., Compiled at the
Cooperative Extension Service, Agricultural Experiment Station,
Auburn, Alabama, 1971.
26. Ledbetter, R. J. , Unpublished data for 1966, Compiled at the
Cooperative Extension Service, Agricultural Experiment Station,
Auburn, Alabama, 1971.
27. Ledbetter, R. J., Unpublished data for 1967, Compiled at the
Cooperative Extension Service, Agricultural Experiment Station,
Auburn, Alabama, 1971.
28. Ledbetter, R. J. , Unpublished data for 1968, Compiled at the
Cooperative Extension Service, Agricultural Experiment Station,
Auburn, Alabama, 1971.
29. Ledbetter, R. J., Unpublished data for 1969, Compiled at the
Cooperative Extension Service, Agricultural Experiment Station,
Auburn, Alabama, 1971.
30. Ledbetter, R. J., Unpublished data 1970, Compiled at the
Cooperative Extension Service, Agricultural Experiment Station,
Auburn, Alabama, 1971.
31. Currey, W. L. , Unpublished data on Herbicide Usage in Florida,
University of Florida, Gainesville, Florida, Personal correspon-
dence, 1971.
32. Anonymous, Fertilizer, Lime, Soil Amendments, Pesticides and
Other Chemicals - Current Status, Trends and Projections; DARE
Report - Florida Agricultural Plans for the 1970's. University of
Florida, Publication No. 7, 163-72, 1969-
33. Badenhop, M. B. and Hunter, T. K. , Utilization of Pesticides by
Tennessee Vegetable Growers, Tennessee Agr. Exp. Sta. Bull 449,
34, 1968.
34. Thornton, G. F., A Summary of Pesticide Use and Pesticide Con-
tainer Disposition in Tennessee Agriculture, A Publication of
Tennessee State Department of Agriculture, 8, 1970.
68
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References (continued)
35. Hadden, G., Unpublished data (1970) on Herbicides Usage in Corn,
Cotton and Soybeans in Tennessee, University of Tennessee, Knoxville,
Tennessee, 1971.
36. Moore, E. E., Pesticides Sales and Usage in Kentucky in 1968,
A Publication of the State Department of Health, Frankfort, Kentucky,
16, 1968.
37. Nolan, C. N. , Herbicide Usage - South Carolina, Clems on University,
Clemson, S. C., Unpublished Information for 1968, 1971.
38. Nolan, C. N., Major Herbicides Used in South Carolina on Crops,
Pastures and Non-Crops (1968-1970). Unpublished data, Clemson
University, Clemson, S. C., 1971.
39. Swann, C. W. , Summary of Herbicide Usage in Georgia. University
of Georgia, Athens, Georgia, Unpublished data (1965-69), 1971.
40. Swann, C. W., Summary of Herbicide Usage in Georgia. University
of Georgia, Athens, Georgia, Unpublished data 1971.
41. Anderson, K. L., Herbicide Usage Survey in Mississippi, Mississippi
State University, State College, Mississippi, Unpublished data (1968-
1970), 1971.
42. Sartor, C. F. , Unpublished Information on Insecticide Usage on
Cotton in Mississippi (1970), Mississippi State University, State
College, Mississippi, 1971.
69
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B. APPLICATION TECHNIQUES
AND
TYPES OF PESTICIDE
1. Introduction
Economic control and safety have been twin objectives of pest
control for many years; however, both goals have been elusive. The
failure of the pest control profession to establish reasonable economic
thresholds and reticence of farmers to accept those available have led
to many problems associated with the use and misuse of insecticides.
The problems relative to resistance, disruption of natural control, and
pollution have proven much more difficult to evaluate. The price of
ignoring ecosystem contamination has been high. It appears clear
that steps must be taken to reduce the contamination by pesticides of .soil,
water, and air as well as on non-target organisms and man.
Efficient pest control using pesticides depends upon selection of
proper pesticides, application at the proper time and the use of equip-
ment that can efficiently place the toxicant in the microenvironment of
the pest. Of the total pesticides applied, no more than 2% is effective.
The remainder is indicative of the inefficiency of the existing application
techniques.
Careful selection of existing methods would considerably reduce
the amount of pesticide required for effective pest control; with a
concomitant decrease in contamination of the ecosystem. Major benefits
would accrue from improved pesticide delivery systems. The answer
to the past problem, therefore, does not lie in increasing still further
the use of pesticides. It lies in increasing the use of safe pesticides and
70
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in increasing the efficiency of application techniques.
2. Pesticide Application Methods and Equipment
Pesticide formulation is an important factor in selecting the most
appropriate method of application. Pesticide formulations can be grouped
on the basis of physical state as solid materials, liquids (common "spray"
materials) and gases. Dust, granules, baits and seed dressings are the
most common forms of solids. Sprays are formulated as solutions, wettable
powders and emulsions. Gases are generally used in confined spaces such
as greenhouses, seed storage areas, or for soil fumigation. A fumigation
effect is also created by foggers which produce effects similar to gaseous
forms of pesticides.
Pesticides may be applied as a broadcast, in narrow bands, individual
spot treatments, or directed to a particular part of the plant.
a. Sprays
A major portion of pesticides (herbicides, fungicides and insecticides)
are applied as sprays. In 1964, 46% of the farmers in the southeastern
U. S. owned power-driven sprayers compared to 23% who owned dusters.
Since then custom spraying, primarily by aircraft, has increased.
Sprayers are classified as high volume sprayers, low volume (LV)
sprayers and ultra low volume (ULV) sprayers. High volume sprayers
apply from 30 to 500 gallons of spray per acre; low volume sprayers from
one to 30 gallons per acre; and ULV concentrated formulations in amounts
4
less than two quarts per acre. Most spray equipment utilize pumps,
nozzles and booms to produce the different types of spray. Some examples
of ground-operated sprayers are the following:
71
-------
• Hydraulic sprayers in which the liquid mixture is
forced through a spraying system and released onto
the target area,
• Multipurpose sprayers which are designed to operate
over a range of pressures varying from very high to
very low and are primarily used for orchard spraying,
• Conventional low pressure, low volume sprayers
which are equipped with a boom and with nozzles that
are suitable for LV and ULV sprays,
• High pressure, high volume sprayers which are
employed for thorough coverage of plants having
dense foliage (e. g. bushes, vines, and truck crops), and
• Air blast sprayers which utilize a blast of air to propel
sprays in LV. Small droplets are created.
Improvements have been in ground equipment used to apply uLV
sprays. The major problem was the inability to adequately regulate the
flow rate of the pesticide. This problem was solved by using drilled
discs or small metering valves mounted in the insecticide lines.
Stainless steel or plastic tanks were used to hold the insecticide and,
in some models, filters were installed to help eliminate nozzle stoppage.
Aerial application of pesticides, either from fixed-winged planes
or helicopters, utilizes a modification of conventional low-volume, low-
pressure hydraulic spray, dust, or granular application techniques. The
most common dispersal apparatus used on aircraft is the pump, boom,
and nozzle spray system. Spray-deposit patterns are adjusted by shifting*
nozzle locations on the boom. Droplet size can be varied by changing the;
pump pressure, the orifice size in each nozzle, or the nozzle direction
in the slipstream of the aircraft. The application rate is changed by
5
increasing or decreasing nozzle size or number of nozzles in the boom.
Some types of aerial spraying equipment are:
o Fixed wing aircraft of single or multiengine types, equipped
with boom and nozzles used mostly to apply spray in LV or
ULV range, 5 and
72
-------
• Helicopters which utilize air blast of the rotors for
increased droplet impingement.
One of the more serious shortcomings of fixed-wing aircraft
as a pesticide applicator is that the underleaf coverage may be less than
with ground application or helicopter applications. Rotor downwashof the
helicopter ensures that there is a minimal drift of materials to adjoining
fields. Helicopters have the advantage over fixed-wing aircraft in
maneuverability and landing and consequently less time is lost in
ferrying. Theyare better suited in small fields. Helicopter operators
cannot increase their speed of application without sacrificing, uniformity
in coverage. The necessary low speed coupled with the low capacity is
a disadvantage from the cost standpoint where large areas are involved.
These advantages and disadvantages must be weighed in determining the
most effective, economical system.
Improvements in nozzles and booms are directed toward reducing
the volume of spray required for effective pest control. Recently developed
microfoil booms produce droplets of nearly uniform size and reduce drift.
Spinning-dis.c or screen-cage nozzles, such as the Mini-Spin and Micronair
89
nozzles, have a similar capability. ' Hydraulic nozzles with flat fan tips,
also produce droplets of acceptable sizes, and are relatively inexpensive;
However, problems :exist with the degradation of the diaphragms and
erosion of the tip orifices. Another type of nozzle, the hollow-cone, produces
droplets larger than those produced by nozzles 'previously discussed.
Air curtain, nozzles have been developed to be used in conjunction with the
techniques of electrostatic charging of the spray droplets.
b. Dusts
The development of dusting equipment is legs advanced than that of
spray equipment. Dusting appliances operate on the principle of emitting
73
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a blast of air in which the dust particles are airborne. Rotary-type
dusters, in which dust is fed onto fan blades, are used for ground
application. Aerial dusting, which was extensively employed for many
12
years in the Southeast, is decreasing. Aerial dusters are categorized
7
as follows:
• Standard dusters which consist of hopper, wind-driven
agitator, a feed control gate and a spreader suspended
bej.ow the fuselage,
• Breeches-type duster in which the lower part of the
hopper leads to the shutters and the dust is emitted into
emission tubes located on either side of the corner of
the fuselage, and
• Suspended tank-type dusters in which the dust is stirred
by a windmill type of agitator and emitted through gates
consisting of crosswise matching slots operated from the
cockpit.
Many problems inherent in the use of dusting as a method of
pesticide application restrict its use. Drift hazards, inefficient
deposition of active ingredient on the target, agglomeration and poor
settling are a few examples of the problems.
c. Granules
Granule applicators are designed to place in the target area pesti-
cides impregnated on a suitable carrier, such as corncob, clay minerals,
or walnut shells. Although variations in design occur, basic granular
applicators consist of a hopper for the pesticide, a mechanical-type
agitator at the base of the hopper, and a metering device, usually a slit-
type gate, to regulate the flow of the granules. Granules may be applied
as a broadcast or band treatment, before, or at a planting time, and worked
into the soil; as a postplant, side-dress application through drop tubes
74
-------
and fertilizer shoes; or from the air, to penetrate foliage. The last
procedure is used to apply Mirex
fire ant control in the Southeast.
procedure is used to apply Mirex, a slow-release pesticide used for
13
d. Foams
Foam delivery is one of the recent additions to pesticide application
14
methodology. The system which produces the foam varies with the
application. Land-based equipment generally consists of a water pump,
an air compressor, foam generator and regulation module. Various
chemicals are utilized to improve wettability and penetration of the spray.
Aerial foam application equipment has also been developed. This may be
mounted on fixed-wing aircraft or helicopters. Depending upon the need,
foams can be generated in a pattern varying from 1/16" droplet size to
continuous cover similar to that dispersed by an aerosol shaving cream
dispenser. Foam application is still in the experimental and trial stage
but the properties of the foam makes this, a desirable technique. Foams
have larger volume, higher viscosity, better structural strength (cohe-
siveness) and greater clinging ability against runoff than conventional sprays.
Additionally, foams have reduced evaporation characteristic and drift
hazard. Weeds, insect and disease control by foam application shows
considerable potential.
e. Soil Incorporation
Many preemergence herbicides, some insecticides, and fungicides,
are applied to the soil. For improved efficiency they may be incorporated
or injected into the soil. Conventional tillage equipment (discs, harrows,
rotary tillers, etc.) are used to incorporate surf ace-applied pesticides
to varying depths. Spray sweeps are used to pressure inject many
volatile herbicides, either in bands or in uniform swaths. Limited
developmental effort has been vested in improvement of soil incorporation
equipment.
75
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3. Efficiency of Pesticide Application
The ecological impact of widespread use and dissemination of
pesticides warrants renewed consideration of the efficiency of spray
application methods.
The efficiency of pesticide application equipment lies in its
ability to deliver a dose capable of killing or damaging the maximum
number of pests with the minimum amount of material. It is possible
to reduce pesticide usage significantly and still provide an effective
pest control program by generating critical droplet size and uniformly
distributing these so that the major portion of the pesticide reaches its
target.
An increase in the efficiency of application equipment with
commensurate reduction in the quantity of pesticide required would
reduce environmental contamination.
The following factors are considered in determining the efficiency
of pesticide application methods:
• Optimization of the pesticide droplet size for a target,
• Uniformity of coverage and impingement characteristics,
• Persistence of residue in the micr©environment of the pest, and
• Reduced drift, runoff and ecosystem contamination.
Methods of application, droplet sizes, and volumes of spray are
examined in an attempt to define these factors which might serve to
improve the efficiency of applied pesticides.
a. Spraying and Dusting
Highly toxic pesticides make effective pest control possible with
minute quantities of toxicants provided the application method delivers
a continuous film of minimum thickness. The manifestations of inefficiency
76
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in pesticide application are deposition of thick deposits, the existence of
gaps between zones of deposit, or in some cases, both. If the gaps are
of sufficient size, the pest will escape contact and/or ingestion will
not occur. For example, stomach insecticides intended to control white
pine weevil must be aimed to cover feeding areas which are only 0. 8 mm
in diameter.
Foliar applied dusts have the advantage that formulations emitted
from the machine do not evaporate. Water-based sprays evaporate
7
quickly before reaching the target and are inefficient jin dry, hot climates.
This shortcoming may be corrected by using oil as a carrier. In such
climates soil incorporated dust applications are better than wettable
17
powders. However, some disadvantages are also associated with
dust applications: 7' 18' 19
• Insecticidal dusts, when emitted from a blower, consist
of a mixture of discrete particles, with agglomerates,
which may consist of as many as 20 to 300 coalesced
particles. This factor of agglomeration leads to wide
variation of settling characteristics even in a dust
of uniform fineness of grind. °
• In addition to size, the shape and specific gravity of dusts
are important in deciding their settling characteristics.
Particles of high density such as barite or lead;arsenate
show good deposition on foliage, whereas Derris and
Pyrethrum dusts, whose particles are light and angular,
give poof deposits. Cryolite dusts deposit'poorly because
they show little agglomeration. The fractionation of
dusts during the settling process may also separate the
insecticide from its diluent. Dusts are deposited better
on foliage nearer the blower than at greater distances,
and more permanent deposits are produced with a strong
air blast.
• Comparatively dust formulations drift more than the sprays.
• The dust particles do not adhere to the plant as long as
spray deposits. The efficiency of pesticidal sprays is
superior to dusts.
77
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18
Improved efficiency of spraying over dusting is attributed to:
• Less drift and better deposition. Consequently a spray
achieves equal results with two-thirds as much pesticide
and a single spraying may produce the control equivalent
to as many as four dust applications.
• The capability of adjusting dosage rate, droplet size,
and formulation at any time which is not possible with
dusting.
Generally the efficiency of pesticidal spray exceeds that of
dusting. However, a potential still exists for major improvement in
spray methodology.
Spray conditions have been determined empirically because no
technically-based alternative has been available. In spite of years of
investigations, the physical factors critical in pesticide spray delivery
aie still largely undefined. Measurement has posed one problem. There
has been no way to monitor pesticide spray droplets delivered to the
target until the recent development of the fluoresent particle tracer
method. Results from the application of pesticide sprays were difficult
to correlate with the conditions existing at the time of application. Such
results are based mainly on the biological evaluation of pest levels over
intervals of days, weeks, or even months after the pesticide application.
Despite these problems, progress has been made in pesticide
application technology. This has involved primarily ULV application
techniques, optimum droplet size and improved impingement.
b. Ultra Low Volume Spray
The development of the ULV method ranks as one of the most
significant improvements in spray methodology. Application of an
undiluted pesticide in volumes of 1/2 gallon or less per acre is referred
78
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to as ULV. A pesticide is considered undiluted if nothing is added
4
after it leaves the manufacturer. Actually, ULV is a relative term
reflecting the progress primarily of aerial spraying since its initiation
during World "War II. At that time, the generally accepted application
rates varied from 30 to 40 gallons per acre. Eventually, as pesticide
formulations improved, the application rates -were reduced to as little
as one gallon per acre. Each incremental reduction in the total gallonage
was referred to as "low volume" spraying.
For many years, pest control officials contended that at least
one gallon of spray per acre was the absolute minimum that could be
applied by aircraft and still adequately cover the area regardless of
the vegetation involved. Thus, when the one gallon per acre barrier
was broken, it was logical to refer to this as ULV spraying.
Advantages of ULV application of pesticides over higher spray
volumes are that:
• It makes possible spray application with most droplets in
the 5-50 \L diameter range. These were once considered
to be beyond the range of commercial reality. 2» 4, 10,21
• To some extent, ULV spray reduces the amount of toxicant
applied, and the potential hazard to the total environ -
ment. 10, 16,22,23
• ULV-applied insecticides have more residual toxicity than
water-diluted sprays and are more resistant to washoff
by rainfall. 24» 25
e Savings result from the reduction or .elimination of
diluents. This is a major factor in reduced aerial
application costs. 10,23,26
• Relatively nonevaporative quality of the undiluted ULV
pesticides has permitted aircraft to fly higher, making
it possible to double and triple effective swath widths.^7*28
79
-------
Weather conditions are especially important in ULV applications
because the slightest wind carries minute amounts beyond the intended
10,29
area. A hazard exists to the applicator who is handling concentrated
pesticides under these conditions because of the increased degree of
exposure. Sufficient research has not been conducted to fully exploit
the ULV technique. Aircraft spray dispersal and pesticide formulations
must be improved. Hazards to nontarget organisms from pesticides
applied by ULV also need considerable delineation.
c. Droplet Size
The optimum size for pesticide spray droplets that must be
generated is one of the most elusive of all the factors which affect the
efficiency of insecticide sprays. The optimum size for pesticide
droplets is that which gives maximum control of the target pests with
2
minimum pesticide and minimum ecosystem contamination. It has
been hypothesized by one investigator that the ratio of recommended
dose to that needed for insect control would be the order of 1, 000:1
if droplets of the optimum size were used. Current practice requires
much lower ratios.
It is generally believed that spray droplets of 50 jo, diameter or
30
smaller are the most effective for the control of insects. Such small
droplets are subject to atmospheric transport and diffusion but they
effectively penetrate the microenvironment of the pest. Spray droplets
of 50-100 |JL have marginal efficiency. Droplets larger than 100 n
are the least effective in insect control programs because they do not
become airborne and are simply deposited on the ground or on
peripheral foliage. These are critical locations for potential entry
2
into the ecosystem and are of little use in pest control. Table B-l
80
-------
TABLE B-l Spray Droplet Size as a Factor in Eqosystem Contamination.
Range of droplet
aiam
Range of % by mass in an
avg Commercial spray
220-340
100-220
29
63
41-100
10-40
0.14
(usually less
than 1-5%)
Point of deposition
in ecosystem
Potential for Major
ecosystem .contamination
Ground, ground forage,
peripheral foliage,
target area crops
Ground, ground forage,
peripheral foliage,
drift to adjacent
areas, crops
Throughout most foli-
age, smaller size
range effective in
deep foliage penetra-
tion drift to adja-
cent areas
Maximum contact with
target insects dis-
tributed widely by
atmospheric trans-
port and diffusion
Extremely high by in-
gest ion and washing pro-
cesses into x^atershed
Extremely high by in-
gestion and washing pro-
cesss into watershed
Wide distribution of
minimum volume of de-
posit minimizes major
entry into arthropod
and vertebrate eco-
systems
Minor component of most
insecticide sprays. Re-
presents minimum amount
of insecticide
Source: Himel, C. M.
-------
00
ro
19
TABLE B-2 The Effect of Atomization on Coverage.
Droplet
Diameter,
&*
10
20
50
100
200
300
•500
Droplet
Volume,
( cu ^i)
525
4,200
65,520
525,000
4,200,000
14,175,000
Number of droplets
per sq in. a
1,148,100
143,190
9,224
1,164
142
43
9
Source: Brown, A. W. A.
a
Number of droplets per unit area for an application of 1 gal/acre.
-------
gives ecosystem contamination as a function of spray droplet size.
The number of spray droplets available from a given volume of
liquid spray is an inverse function of diameter cubed. A better
understanding of the discussion of small droplet compared to large
droplets can be obtained from Table B-2. The number of droplets
falling on a unit area decreases from about 10, 000 per square inch when
their diameter is 50 jo, to only 40 when their diameter is SOOfj. .
Proportionally, the volume of pesticide (Table B-2) carried in a droplet
increases considerably as the size of the droplet increases. This is
the major reason for the undesirability of large droplets.
The optimum droplet sizes for insecticides used to control
31
many major pests in the Southeast have not determined. Only a
few pests (house flies, mosquitoes, boll weevil, cotton bollworrn,
cabbage looper and spruce budworm, etc.} have been studied in this
regard. For house flies, it has been determined that the optimum
droplet diameter for maximum economy of the insecticide is 22 JA
32
Smaller droplet sizes are required for mosquitoes.
The droplet deposition on the cotton insects studied in Georgia
pro-vddes an interesting analysis (Table B-3). The maximum-sized
droplet of 4331 measured on 139 boll weevils was one of 63 jo.
diameter. These boll weevils were in a highly protected environ-
33
ment during spraying (9 a. m. Aug. 1, 1967 at Tifton, Ga.). A
free-flying insect like the boll weevil should have been subjected to a
significantly higher probability of contracting droplets of the larger
18
size ranges existing in the distribution.
Regardless of the initial droplet size distribution, an
examination of target species reveals that only a critical droplet
size range has been effective. This is exemplified by two case studies
from different parts of the country and on different target species,
83
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In a complex mountain -forest biophysical system relatively fewer spray
droplets were found on spruce budworms than on cotton insects
(Table B-3). The diameters of the maximum-size spray droplet in the
spray droplet spectrum, D of the spruce budworm and cotton insect
sprays were 350 |x and 950 JJL , respectively. In each of these foliage
systems, droplets greater than 120\± diameter were found on peripheral
and ground level foliage, or on artificial targets placed in open areas.
Large droplets did not reach the target insects. The question raised
is whether large droplets ( > 100|a. diameter) play any essential part in
the control of insects which live in a foliage environment? Yet these
larger droplets constitute 90-95% or more of many insecticide sprays.
The answer is the key to devising more efficient insecticide application
techniques, to reducing the amount of spray drift, and to reduce
contamination of the ecosystem. The data, summarized in Table B-3,
demonstrate that the limiting maximum diameter for efficient insecticide
spray droplets for diverse types of insects is less than 50 p, . There
is no evidence that 100 |jt droplets have any substantial effect because
the majority are unlikely to reach the target.
Droplets smaller than 100 JJL mass median diamter (MMD) of all
herbicidal formations tested were markedly more inhibitory to all weeds
34
than were droplets larger than 300 MMD. The greater effectivness
of small droplets may be ascribed to more efficient absorption and
translocation of herbicide. Large droplets of high concentration probably
become physiologically isolated. Their profound effects on the leaf cells
occur only at the point of direct contact. A larger number of contact
points are produced on the plants for the same application rate by the
more numerous smaller droplets. This means that more susceptible
tissue (e. g; the stem growing point) comes in contact with the herbicide
84
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TABLE B-3 Effect of Environment and Application Variables.
34
oo
en
Insect
Spruce budworm
Boll weevil
Bollworm
Cabbage looper
Nominal
gal/acre
1
1
1
1
Nominal
height of
applica-
tion (ft)
300-400
30
30
30
Max
diam
spray
00
350
950
950
950
Max size
droplets
on insects
00
100
63
114
114
Avg no.
droplets/
insect
3b
31
122
96
% of droplets of indicated diam 00
20-50a
98.0
99.8
99.8
99.4
50-100
2.0
0.2
.2
.6
100
0
0
0
0
a Under the conditions used, the (Fluorescent Particle) FP method does not identify droplets smaller than
the range of 20
-------
than in the case of the large droplets.
Components of a fungitoxic material must be closely spaced
over the leaf surface and deposited during weather periods suitable
for spore germination, if infection by causal fungus is to be prevented.
Continuity of the foliage deposition pattern and close spacing of the
particles of the fungicidal ingredients are considered essential to
good disease control. Toxicity to fungicide increases as particle size of
19
the active ingredient decreases. Exceptions to this general rule
have been reported. For example, droplets as large as 400 (a,
were claimed to produce essentially as good a disease and insect
control as did others of 100 to 150jj. MMD when applied to a number of
35
row crops.
d. Impingement and Uniformity of Coverage
The first problem in applying pesticide sprays is that of
distributing a small quantity of active material over a large target
area. The uniformity and extent of the distribution required depends
on the type of pest to be controlled and the mode of action of the
toxicant. A patchy distribution may be satisfactory for control of
mobile insects or to apply systemic pesticides to foliage. For static
pests and contact pesticides, a more uniform spray deposit is required.
The degree of distribution attained depends on:
• The effective area of the target surface,
• The shape of the target,
• The method of spray application,
• The volume of spray applied to the target surface,
• The droplet size distribution of the spray,
86
-------
• The extent to which the spray is capable of spreading
over the target surface, and
• The extent to which the deposit is subsequently
redistributed by rain or dew
The first two factors are invariable, while the next three can
be varied by the spray operator. The formulator can manipulate the
last three on this list. The size of the droplet can be controlled to
some extent by both the applicator and the formulator. In the latter
instance this is determined by modification of the physical properties
of the formulation. For improved distribution, understanding of
the effect of operating parameters on the droplet size is essential.
It is unlikely that such comprehension exists with most applicators.
Pesticide impingement and uniform coverage are closely
related to droplet size and to drift. Small droplets of lOOjo, diameter
or less tend to become airborne. They have a higher probability of
impinging on the target during low to mild conditions. For example,
with a droplet of 70 \i and a wind of three miles per hour, the
probablity is 10 times greater of its landing on a vertical surface
than on a horizontal surface. Since most crops grow vertically,
this drift phenomenon is utilized to achieve better impingement or
coverage. However, as wind velocity increases (approximately,
above 5 miles per hour) the probability of the droplet striking non-
target areas is increased. In addition, the very small droplets are
subject to undersirable upward movement via convective currents
(Table B-4). Under certain meteorological conditions, the ideal
droplet size for effective insect control may need to be adjusted if
the pesticide is to be delivered into the microenvironment of the pest.
There is another control on the application system. This is a lower
87
-------
TABLE B-4 Drift Pattern in Relation to Particle Size.
Drop
Diameter (u)
400
150
100
50
20
10
2
Particle Type
Coarse aircraft spray
Medium aircraft spray
Fine aircraft spray
Air carrier sprays
Fine sprays and dusts
Usual dusts and aerosols
Aerosols
Distance in ft. Particle
Would be Carried by a 3-
mph Wind While Falling 10ft,
8 1/2
22
48
178
1,109
4,436
110,880
Source: National Academy of Sciences.
as
-------
limit to the size of droplets for deposition on vegetation, weeds or
the food of the pests. If the droplets are too small they do not have
enough momentum to impinge upon the target surface.
For an aerosol to kill mosquitoes, in forested areas, the
droplets must be smaller than 30|JL in diameter; this prevents
18
excessive filtering by the foliage. For penetration through thick
jungle, it has been determined that the droplet size should be below
lOji . If, however, the aerosol is applied to forest from aircraft
with the aid of downdraft of the wing airfoil, it will penetrate and
impinge so long as the droplet diameters do not exceed 50 jo.
When emitted from generators on the ground, droplets of more than
40 jo. diameter do not remain airborne for a sufficient distance to be
useful. An increase in wind speed enables the larger droplets to
make better contact with the target. When penetration into coniferous
forest is required, the wind speed in the open should not be less than
19
five miles per hours.
It is apparent that the proportion of the spray occurring as
small droplets (50 |i or less) is of paramount importance in pest
control. Knowledge of the in-flight behaviour of small droplets and
of the mircrometerological factors affecting them would allow
delivery of small droplets to the target and reduce drift potential
from agricultural spray operations. The overall plant coverage and
deposition of small dust particles and spray droplets can be improved.
Two approaches have been advanced. Surf ace-active agents are
commonly used and the charging of aerosol particles has also been
considered for improvement in plant coverage. Adjuvants and surface
active agents added to pesticides improve their deposition, activity
and disperal. This is particularly useful for herbicide application.
89
-------
^ , 37,38
Examples are:
9 Wetting agents. These reduce interfacial tension and
bring the liquid into intimate contact with an object.
The addition of wetting agents to a pesticide, therefore,
increases its adherence to the pest.
• Emulsifiers. These tend to prevent tiny droplets from
coalescing.
• Penetrating agents. These may solublize the waxy
cuticle or membrane of the pest so that penetration
of pesticides is more readily achieved.
• Dispersing agents. These reduce cohesion between like
particles which aids in pesticide dispersal.
• Spreaders. These increase the spread of the droplets and
thus form a uniform coverage on the plant surface, and
4 Stickers. These prevent runoff of pesticides.
A number of studies concerning the efficiencies of the
charging and deposition process of the electrostatic pesticide application
11 39-42
method have been conducted over the past two decades. '
These field and laboratory studies reported indicate that the electrostatic
processes are effective. The equipment is reliable under all weather conditions
under which pesticide application might be considered, provided
properly designed equipment is used and satisfactory operational
procedures are followed. Dielectric nozzles were superior for inductive
39
spraying. Inductive spray charging significantly increased the spray
coverage of the bottom side of cotton leaves. An average increase of
3. 8 times the quantity of pesticide per unit area for the same
application rate was achieved over uncharged sprays. This difference
was measured on the leaf bottoms which is the critical area. The
bottom area hosts the majority of pests. In another test electrostatic
charging enhanced deposition 2. 7 times that of uncharged spray.
90
-------
Direct application of electrostatic charging to agricultural sprays using
high applied voltages similar to those for charging paint sprays has
not been tried. This is because safety, portability, and reasonable size
are difficult to achieve for equipment requiring high voltages, such as
50-100 KV, under field .conditions.
Electrostatic deposition of dust requires a different nozzle
than those previously described for spray applications. The nozzle
found most efficient for electrostatic dusting is of the air curtain type.
Air curtain nozzles give higher deposits per unit area of a more
uniform distribution than any of the commercial nozzles evaluated.
The average deposition efficiency of charged dust is more than double
that of the uncharged dust. However, this efficiency varies with the
properties of material and the operating conditions. The major variation
in performance of the electrostatic dusting equipment has been
attributed to variations in the electrical resistivities of the dust
41
formulation, and to the relative humidity at the time of dusting.
The efficiency of any pesticide spray and the degree of control
obtained is a function of the ultimate point of deposition of each of
the pesticide spray droplet produced. Although the initial justification
for electrostatic charging of pesticides was primarily a matter of
economics, the need to reduce environment pollution has become an
increasingly important additional consideration.
e. Soil Incorporation
Soil application of pesticide is, an essential agricultural
practice. It is required to control weeds prior to their emergence,
to reduce injury to crops from soil-borne diseases (root rot, seedling
diseases) and by insects active in the soil environment (corn borers,
cut worms.) Improvements in methods of application have been made
91
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to increase the effectiveness of soil-applied pesticides. Soil
incorporation is one of the most prominent of these methods. Injection
(subsurface spraying) is used to a lesser degree.
In a study conducted in Georgia, incorporation of pesticides into
the soil surface by rototilling caused a tenfold reduction of Lindane and
43
Dieldrin losses in run-off water. Greater loss occurred from soils
where the Aldrin was left on the soil surface following an emulsion
application. Increased persistence occurred after granules had been
44
incorporated into the upper 4 to 5 inches of soil layer. This
suggests .that where high levels of pesticides are present on a soil
surface, the possibility of harmful water pollution from the area could
be greatly minimized by incorporating the pesticides into the soil.
From the standpoint of agronomic practices and environmental
considerations, the following advantages can be obtained by soil
incorporation methods rather than surface applications of pesticides:
• Increased herbicidal effectiveness by dispersal in the root
and emerging shoot zone, increasing the possibility of
contact with weeds and other pests. 5-49 ;
• Reduced loss of herbicide through incorporation to appropriate
depths and maintainance of a lethal concentration in the sur-
face soil for increased residual action. Incorporation decreases
runoff and drift and increases residual action for prolonged
weed control. 7>50~52
• Decreased variability in the results from area to area and
from season to season have been clearly demonstrated.
Results with most surface applied chemicals are highly
dependent upon soil and climatic conditions. Several
investigators have shown that exposure to sunlight or
ultraviolet light plays a major role in decomposition of
herbicides on the soil surface, and the chemical volatility
and high temperature greatly affects the break down of
certain chemicals. Reduced variability in the performance
of a herbicide under varying soil and climatic conditions,^ .and
92
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51
• Decreased volatilization, runoff and drift.
The efficiency of weed control with soil-incroporated herbicides
is affected by many factors. These include soil conditions (moisture,
temperature, texture and structure), physiochemical properties of
herbicides and environmental conditions (sunlight, temperature and
rainfall). Depth of incorporation and the tools utilized have been shown
. rf . t, , , . ., . ...... 15,46,54-58
to affect the herbicidal efficiency.
The development of herbicides requiring soil incorporation
created the need for a device capable of uniform incorporation. However,
incorporation tools presently available do not provide the desired soil
placement. Development requires methods of evaluating these devices
with respect to uniform distribution of the chemical in the soil and
depth of mixing. Several investigations have used a traceable material
as a substitute for the herbicide. These included radioisotopes,
59
granules, magnetic particles and dyes. A fast and efficient method of
evaluating soil incorporators utilizes a fluorescent dye.
Because of the strong sorption of many pesticide residues to soil
particles, pollution by pesticide occurs through the transport of pest-
icides-laden soil particles to the aquatic environment. Erosion control
combined with soil incorporation provides a means of drastically
reducing surface runoff and volatilization losses.
4. Conclusions
Presently, 63 percent of all pesticides are applied by aircraft.
The remainder is applied with ground equipment. Most pesticides are
\
applied as sprays, either to the plant foliage or to the soil surface.
Some pesticides are incorporated in the soil. Consequently, any
research program designed to minimize contamination of the ecosystem
93
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by pesticides must include improvement in spray application and soil
incorporation equipment.
Pesticide usage could be significantly reduced and still provide
an effective pest control program if it is uniformly distributed and the
major portion reached its target. The initial problem is to atomize
relatively non-volatile pesticides formulations into uniform-size drop-
lets which are sufficiently numerous that the pest cannot avoid contacting
a lethal dose. The second problem involves deposition of small particles
or droplets on the target. One of the methods that could improve
deposition of pesticides is electrostatics. The third problem involves
incorporation and injection of soil-applied pesticides. These processes
involve optimum depth considerations. All of these problems merit
intensive research and development.
Spray efficiency is related to optimum droplet size, uniformity
in spray coverage produced, and degree to which drift and runoff is
minimized. Ninety percent or more of spray droplets produced by
existing aerial and ground equipment are not of the optimum size.
This portion of the spray constitutes the major source of pesticidal
pollution.
5. Recommendations
1. The program of the Agricultural Research Service of the U. S.
Department of Agriculture (USDA) to determine the optimum droplet
size range for major pests should be expanded. Research on improved
methods of pesticide impingement through the use of electrostatics and
other techniques should also be increased.
2. Government and industry should jointly engage in the development of
improved pesticide formulations and the design of equipment capable of
producing the desired droplet size.
94
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3. Government and industry should expand research to improve soil
incorporation and injection equipment.
4. The Environmental Protection Agency and USDA should jointly
sponsor studies on the comparative efficiency of methods of pesticide
application to minimize contamination of the environment.
5. The Department of Agriculture, through its Extension Service,
should encourage growers and custom operators to use the most
advanced pesticide application equipment under proper meterological
conditions.
95
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6. REFERENCES
•• 1. Rabb, R. L. and Guthrie, F. E. Introduction to the Conference,
Concepts Pest Management, Raleigh, North Carolina State
University Press, 1-3, 1970.
2. Himel, C. M. , The Optimum Size for Insecticide Spray Droplets,
J. Econ. Entomol. , 62, 919-25, 1969.
3. Jenkins, R. , Eichers, T. , Andrilenas, P. , and Fox, A. , Pesticide
Application Equipment Owned by Farmers, 48 States, Agr. Econ.
Report No. 161, US DA IRS, 1-15, 1969.
4. Koski, J. T. , ULV Brings New Benefits in Air War on Pest,
Washington, D. C.: USDA Year Book, 121-25, 1968.
5. Anonymous, Insecticide Application, Insect-Pest Management and
Control, Washington D. C.: Nat. Acad. Sci. , 394-424, 1969.
6. Smith, R. , Personal Communication, 1971.
7. Brown, A. W. A. , The Application of Insecticides from Aircraft,
Insect Control by Chemicals, New York: John Wiley and Sons, Inc. ,
414-66, 1951.
8. Kirch, J. H. , Waldrum, J. E. , and Bishop, P. W. , The Microfoil™,
An Aerial Device for Controlling Drift from Conventional Sprays,
Proc, 23rd Ann. Meetings, Southern Weed Conf. , 385-88, 1969.
9. Brazzel, J. R. and Watson, W. W. , Low Volume Spray Patterns
with Three Types of Aerial Application Equipment, Agr. Aviation,
18, 119-21, 1966.
10. Lofgren, C. B. , Ultra-Low Volume Applications of Concentrated
Insecticides in Medical and Veterinary Entomology, Ann Rev.
Entomol. ,15, 321-42, 1970.
11. Splinter, W. E. , Air-Curtain Nozzle Developed for Electrostatically
Charging Dusts, Transactions Am. Soc. Agr. Eng. , 11, 487-95, 1968.
12. Thornton, R. and Stamper, E. R. , Airplane Application of Herbicides
to Row Crops, Proc. 24th Ann Meeting, Southern Weed Conf, , 371-
75, 1970.
96
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13. Shapley, D. , Mirex and the Fire Ant, Decline in Fortunes of Perfect
Pesticides, Science,17_2_, 358-360, 1971.
14. Sachnik, N., The Use of Foamicide for the Application of Herbicides
by Aerial, Vehicle-Mounted Spray Booms, Blowers, and Handguns,
Proc. 22nd Ann. Meetings Southern-Weed Conf. , 392-96, 1969.
15. Williamson, R. E. , Progress Report, Soil Incorporation of Pesticides,
Clemson University, South Carolina, _1_, 28, 1966.
16. Bals, E. J. , Ultra Low Volume and Ultra Low Dosage Spraying,
Cotton Gr. Rev., 47, Z17-21, 1970.
17. Smith, H. R. , Dry Application DCPA and Other Herbicides, Proc.
23rd Annual Meetings Southern Weed Conf. , 379, 1970.
18. Brown, A. W. A. , Equipment Development for the Application of
Insecticides, Insect Control by Chemicals, New York: John Wiley
and Sons, Inc., 337-413, 1951.
19. Hough, W. S. and Mason, A. F. , Fungicides, Spraying, Dusting and
Fumigating of Plants, New York: The MacMillian Co. , 103-31, 1951.
20. Himel, C. M. and Moore, A. D. , Spruce Budworm Mortality as a
Function of Aerial Spray Droplet Size, Science, 156, 1250-51, 1967.
21. Hopkins, A. R, and Taft, H. M. , Deposits of Monocrotophos from.
from Low-Volume and Ultra-Low-Volume Sprays Applied Aerially or
from Ground Equipment, J. Econ. Entomol. , 64, 200-4, 1971.
22. Brazzel, J. R., Watson, W. W. , Hursh, J. S. and Adair, M. H. ,
The Relative Efficiency of Aerial Application of Ultra-Low-Volume
and Entiuls if iable Formulations of Insecticides, J. Econ. Entomol.,
61. 408-13, 1968.
23. Messenger, K. , Low Volume Aerial Spraying Will be Boon to
Applicators, Agr. Chemicals, 64-66, 1963.
24. Gilliland, F. R. , Dumas, W. T. , Arant, F. S. and Ivey, H. W. ,
Cotton Insect Control with ULV Applied Insecticides, Auburn University
Agr. Exp. Sta. Bull., 414, 1-23, 1971.
25. Awad, T. M. , Vinson, S. B. , and Brazzel, J. R., Effect of
Environmental and Biological Factors on Persistence of Malathion
Applied as Ultra-Low Volume or Emuls if iable Concentrates to
Cotton Plants, Agr. Food Chem. , 15, 1009-13, 1967.
97
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26. Skoog, F. E. , Cowan, F. T. , and Messenger, K. , Ultra Low
Volume Aerial Spraying of Dieldrin and Malathion for Rangeland
Grasshopper Control, J. Econ. Entomol. , 58, 559-65, 1965.
27. Adair, H. M. , Harris, F. /., Kennedy, M. V., Laster, M. L., and
Threadgill, E. D. , Drift of Methyl Parathion Aerially Applied Low
Volume and Ultra Low Volume, J. Econ. Entomol., 64, 718-21, 197l<
28. Knapp, F. W. , Swath Width Studies with Low-Volume Aerial Sprays,
Proc. North Central Branch - E. S. A., 21, 71-79, 1966.
29. Knapp, F. W. and Pass, B. S. , Low Volume Aerial Sprays for
Mosquito Control,. MOSQ. News, 26, 22-25, 1966.
30. Himel, C. M. , The Physics and Biology of the Control of Cotton
Insect Populations with Insecticide Sprays, J. Georgia Entomol.
Soc. , 4_, 33-40, 1969.
31. Himel, C. M. , New Concept in Application Methodology, S. E.
Forest Insect Workshop, Charleston, South Carolina, 1-9, 1970.
32. Wiedhass, D. E. , Bowman, M. C. , Mount, G. A., Lofgren, C. S.,
and Ford, H. R. , Relationship of Minimum Lethal Dose to the Opti-
mum Size of Droplets of Insecticides for Mosquito Control, MOSQ.
News, 3£, 195-200, 1970.
33. Himel, C. M. and Moore, A. D., Spray Droplet Size in the Control
of Spruce Budworm, Boll Weevil, Bollworm, and Cabbage Looper,
J. Econ. Entomol., 62, 916-18, 1969.
34. Ennis, W. B. and Williamson, R. E. , Influence of Droplet Size on
Effectiveness of Low-Volume Herbicidal Sprays, Weeds, 11, 67-72,
1963.
35. Wilson, J. D. , Hedden, O. K. , and Sleesman, J. P., Spray Droplets
Size as Related to Disease and Insect Control on Row Crops, Ohio
Agr. Exp. Sta. Res. Bull., 945, 1-50, 1963.
36. Ford, R. E. and Furmidge, C. G. L., The Formation of Spray Drops
from Viscous Fluids, Pesticidal Formulations Res. Am. Chem. Soc.,
86, 155-82, 1969.
37. Anonymous, Weed Control, Washington, D. C., Nat. Acad. Sci., 2,
233-256, 1968.
98
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38. Klingman, G. C. , Surface Active Agents: Weed Control as a Science,
New York: John Wiley & Sons, 81-91, 1961.
39. Law, S. E. and Bowen, H. D. , Charging Liquid Spray by Electro-
static Induction, Transactions Am. Soc, Agr. Eng. 9, 501-6, 1966.
40. Splinter, W. E. , Electrostatic Charging of Agricultural Sprays,
Transactions Am. Soc. Agr. Eng. , U, 491-95, 1968.
41. Bowen, H. D. and Webb, B. K. , Some Effects of Dust Resistivity on
the Electrostatic Pesticide Application Process, Transactions Am.
Soc. Agr. Eng., 11, 175-79, 1968.
42. Webb, B. K. and Bowen, H. D. , Electrostatic Field Breakdown
Phenomena in Applying Charged Particles, Transactions Amer.
Soc. Agr. Eng. , _13_, 455-461, 1968.
43. White, A. W. , Barnett, A. P., Dooley, A. E. , and Turnbull, J. W. ,
The Effects of Application Method and Time Interval Between Appli-
cation and Rainfall on Lindane and Dieldrin, Losses in Runoff from
Field Plots, Agron. Abst., Amer. Soc. Agron., 113, 1971.
44. Lichtenstein, E. P. , Myrdal, G. R. , and Schulz, K. R. , Effect of
Formulation and Mode of Application of Aldrin on the Loss of Aldrin
and Its Epoxide from Soils and Their Translocation into Carrots, J.
Econ. Entomol. , 57, 133-36, 1964.
45. Holstun, J. T. and Wooten, O. B. , A Promising New Concept:
Triband Application of Herbicides, Agr. Chemicals, 19, 24-25,
123-24, 1964. ~~
46. Ashton, F. M. and Dunster, K. , The Herbicidal Effect of EPTC,
CDEC, and CDAA on Echinochloa crusgalli with Various Depths of
of Soil Incorporation, Weeds, 9, 312-17, 1961.
47. Wiese, A. F. , Chenault, E. W., and Hudspetth, E. B., Incorporation
of Preplant Herbicides for Cotton, Weed Sci. , j/7, 481-83, 1969.
48. Linscott, D. L. and Hagin, R. D. , Precision Placement of Herbicides
for Weed Control in Seedling Alfalfa, Weed Sci,, 17, 46-47, 1969.
49. Garner, T. H. , Webb, B. K. , Gossett, B. J. , and Rieck, C. E.,
A Comprehensive Technique for Evaluating the Performance of
Soil-Incorporated Herbicides, Am. Soc. Agr. Eng. , Pullman, :
Washington, 1-23, 1971.
99
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50. Barnsley, G. E. and Rosher, P. H, , The Relationship between the
Herbicidal Effects of 2, 6 - Dichlorobenzonitrile and its Persistence
in the Soil, Weed Res., 1, 147-58, 1961.
51. Gray, R. A. , A Vapor Trapping Apparatus for Determining the .Loss
of EPTC and Other Herbicides from Soils, Weeds, 13, 138-41, 1965.
52. Fink, R. J. , Effects of Soil Incorporation Depths on the Trifluralin
Carryover Injury, Abst. , Amer. Soc. Agron, 32, 1971
53. Standifer, L. C. , and Thomas, C. H. , Response of Johnsongrass to
Soil-Incorporated Trifluralin, Weeds, 13_, 302-6, 1965.
54. Barrentine, W. L. , Wooten, O. B. , and Hols tun, Jr. J. T. , A
Progress Report on the Evaluation of Soil Incorporators - Dye
Techniques, Miss. Agr. Exp. Sta. Bull., 702, 1-6, 1965.
55. Hauser, E. W. , Preemergence Activity of Three Thiocarbamate
Herbicides in Relation to Depth of Placement in the Soil, Weeds,
13, 255-7, 1965.
56. Nishimoto, R. K. , Appleby, A. P., Furtick, W. R. , Plant Response
to Herbicide Placement in Soil, Weed Sci. , _17, 475-8, 1969.
57. Anderson, W. P., Richards, A. B. , and Whitworth, J. W.,
Trifluralin Effects on Cotton Seedling, Weeds, 13, 224-7, 1967.
58. Williamson, R. E. and Garner, T. H. , Development of Functional
Requirements for Soil Incorporation Equipment, Meeting Weed Sci.
Soc. Amer. , St. Louis, Missouri, 6, 1-7, 1966.
59. Williford, J. R. , Wooten, O. B. , and Barrentine, W. L. ,
Fluorometric Analysis for Evaluation of Soil Incorporation, Weed
Sci. , 16, 372-73, 1968.
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C. THE ROUTE OF PESTICIDES INTO AQUATIC ENVIRONMENT
1. Introduction
Pesticides may enter surface waters as a result of agricultural,
commercial, and domestic applications. They are used for diverse
purposes such as control of pests in agricultural products, stored food
and fabrics, structural material, parks, golf courses, home lawns and
gardens, etc. Other sources of pesticidal entry into the aquatic
environment are industrial waste discharges; pesticidal applications
directly onto water surfaces; drift from aerial applications; overland
drainage; intentional dumping; cleaning of contaminated materials and
equipment; incinerator and open burning gaseous and particulate
discharges; wind-blown, treated materials; and accidental spills.
Agriculture is the chief consumer of pesticides in the Southeast,
Their fate after application is complex. It may involve biological and
photo-degradation, chemical oxidation and hydrolysis, direct volatilization,
and migration into adjacent areas, translocation into plants, and sorption
onto airborne particulates and soil materials. It is difficult to accurately
determine the quantity of pesticides transported into the aquatic
environment from time and place of such applications, A more thorough
understanding of the physicochemical nature of the pesticide, as well
as the associated ecological system, will be necessary to comprehend
their roxite into the aquatic environment.
Soil is an important terrestrial sink for pesticides. It controls
\
the movement of the chemical through leaching and/or vaporization.
Transport into and within the water media is likely to involve parti-
culate matter and sediments via processes as yet not been well defined.
101
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Information is not available to describe the role of natural hydrologic
dynamics in controlling the movement of pesticides through the aquatic
environment. There is well-documented evidence that certain chlorinated
organic pesticides are rather widely distributed and persistent in the
environment and are accumulated in the aquatic food chain. Intensive
systemic research is required to provide a more complete understanding
of the interaction between pesticides and the water environment.
2. Properties of Pesticides
The nature of pesticides is one of the most important factors that
governs their movement into water courses. Like other 'chemicals, they
obey physical and chemical laws. By defining their behavior" and
properties, a better understanding of their effects in the environment
will be realized. The relevant physicochemical properties of pesticides
include the dissociation constant, molecular structure, size and
configuration of molecules, water solubility, and dipole moment. These
and other properties appear to influence the movement and retention of
pesticides in, through, and from soil surfaces . The dissociation constant
indicates the degree of acidity or basicity. This is an important factor
in the sorption and desO^ption of the pesticide in soils. The electronic
distribution within the molecule establishes its properties and will be
affected by the nature of aliphatic and aromatic substitutions onto the
parent molecule. In turn, these affect the ease of hydrogen bonding.
Van der Waals forces increase with increasing molecular size and
especially with increase of the number of double and triple bonds. The
nature of functional groups further influences inter-and intra-molecular hydrogen
bonding and affects the affinity of the molecule for the sorbing surfaces.
Sorption may be precluded through steric hindrance as a result of
molecular configuration. Water solubility will influence the partition
102
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of the pesticide among the liquid, solid, and vapor phases. This affects
transport of the compound from the area of initial application. The
degree of polarity of the pesticide affects its solubility in water and its
affinity for sorbing surfaces. Thus, the dipole moment may correlate
with the retention and movement of pesticides in soils and in aquatic
environment. Molecular chemical properties are closely related to the
functional groups and strucuture of the pesticide molecule. It is known that
the sulfur atom in the alkyl chain of an organic compound can be easily
oxidized in the atmosphere to sulfoxide or sulfone. Thimet and Temik,
organic phosphorus and organic carbamate pesticides, respectively, are
examples. They become more toxic when they are oxidized. Purely
chemical reactions taking place between pesticides and soils have been
2
reported . A detailed analysis of the chemical properties of pesticides
is beyond the scope of this report.
Organic phosphorus pesticides hydrolyze with comparative
rapidity. Although Parathion is long-lived (50 percent hydrolyzed in
water in 120 days), most of this class are hydrolyzed over intervals of
hours to a few days . An unusual case of persistence of Parathion has
4
been reported . About 0. 1 percent of the total Parathion applied to soil
remained 16 years after application. Parathion may have dissolved into
lipids of the soil organic matter and thus have been protected from
bacterial degradation and hydrolysis. Degradation of Parathion occurs
either via hydrolysis or by reduction to its amino form. The latter
alternative depends upon the population of soil microorganisms. In
soils of low moisture content and low microorganism activity, Parathion
5
persists over longer periods . Carbamate compounds are less persistent
and disappear in rivers within 8 weeks of application .
103
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Chlorinated hydrocarbon pesticides exhibit a very high photo -
and biological-resistance. Technical Aldrin, Chlordane, Endrin,
Heptachlor, Dilan, Isodrin, BHC, and Toxaphene remained in Congaree
' ' '
sandy loam soil up to 14 years and were measured at 40, 40, 41, 16,
23, 15, 10, and 45 percent of initial application, respectively/ Thirty-
nine percent of the DDT remained in three types of soil up to 17 years.
No measurable degradation nor chemical change was observed for BHC,
DDE, DDT, DDD, Dieldrin, Endrin, and Heptachlor epoxide after 8 weeks
in river water . The high stability and long persistence of certain
8 -12
organochlorine pesticides in soil have been reported . Persistence
of these compounds is influenced by soil type, moisture, 'temperature,
and mode of application. DDT, Aldrin, and Lindane persist longer in
muck soil than in Miami silt loam . The persistence of Aldrin is
affected by soil moisture. Water, apparently, causes a displacement of
the Aldrin from the soil particles and enhances evaporization of the
9
compound . Aldrin and Heptachlor persist longer in soils of low tempera-
ture than in soils of high temperature . Incorporation of Aldrin and
Heptachlor into the soil increased the persistence of these compounds by
a factor of ten .
Interaction between herbicides and soil microorganisms has
13 14
been studied ' . It was demonstrated that various phenoxyacetic
acid herbicides are more inhibitory to microorganisms under acid
conditions than under neutral or alkaline conditions and they disappear
more rapidly from soils under conditions favorable for microbial
14
development . Photo-and biological-stability are inherent properties
of individual pesticides and important in determining their persistence
in the environment. Organic herbicides in water may be completely
destroyed by exposure to intensive high energy radiation
104
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Picloram could not be detected in a solution which originally contained
an initial concentration of 1 milligram per liter (mg/1) after 30 minutes
or less exposure to high intensity ultraviolet irradiation. Enzymatic
conversion of chloromaleylacetic acid to succinic acid has also been
reported . In order to understand the route of pesticides and their by-
products into the aquatic system, these and other processes must be
considered. For example, photo-and biological-detoxification of
pesticides determine over what distance and time they effect the
aquatic environment. There is also an urgent need to develop effective
pesticidal decontamination methods suitable for use in various aquatic
environments. Activated carbon treatment of potable supplies is the
3
only established process . No comparable treatment of natural systems
exist.
3. Sorption-De sorption Phenomena
The principal source of water pollution by pesticides today is
runoff from the land. To ascertain directly the transport mechanism of
i
pesticides by overland flow, it is necessary to understand fully the
sorption and desorption of chemicals on soil and aquatic sediments.
Clay minerals are the major components of Southeastern soils and
complexation onto their surfaces is an important factor. Sorption
and desorption of organic pesticides by soils are closely related to
soil type and constituents, moisture, temperature, cation exchange
capacity and surface area, and the physiochemical properties of the
pesticide itself. Organic components of the soil appear to possess
the greatest sorption potential for cationic and molecular pesticides '
The clays, especially montmorillonite and vermiculite, play an
important role in sorption because of their high cation exchange capacity
and relatively large surface area. The oxide and hydroxide components
105
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of the soil may also contribute to the total sorption capacity through
high anion exchange capacity and large surface area.
The forces involved in sorption may be coulombic (chemical
sorption), Van der Waals (physical sorption), or hydrogen bonding.
Isotherms have been measured for a series of herbicides sorbed onto
17
clays and found to be highly dependent on pH and electrolyte concentration
The organic content is usually very low in many of the coarse-textured
soils of the Southern United States. In this situation the clay fraction
assumes a greater importance as sorption sites for pesticides.
Biodegradation markedly affects the stability of dilute organic
clay complexes in solution. If this is not recognized then misleading
19
information can result from sorption studies . Clay particulates are
usually negatively charged in aqueous solutions. Sorption is attributed
to the charge attractive forces between the negatively charged clay
surface and the positively charged organic ions . Unionized organic
molecules and organic anions are either not sorbed or are very weakly
sorbed because of competitive sorption of the more polar water molecule
20
and the repulsive force between the organic anions and clay surface
Sorption by organically treated clay indicates that the solubility of the
21
organic sorbate mainly governs the extent of sorption . This organo-
clay is often hydrophobic in nature.
Pyridine sorption onto kaolinite and montmorillonite is described
by the empirical Freundlich relationship (amount sorbed per unit weight
22
is an exponential function of the equilibrium concentration of the sorbate)
Significant sorption occurs in less than 17 minutes and is attributed to a
cationic exchange process. The amount sorbed depends on the aqueous
solution pH and temperature. Maximum sorption occurs at pH 4. 0 and
106
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5. 5 for sodium montmorillonite and sodium kaolinite, respectively. In
the case of desorption, pyridine desorption is directly related to the
number of stages and/or the volume of solution, with maximum
desorption occurring at pH 1 and 11. Desorption is much slower than
23
sorption at a comparable pH and clay to organic ratio . These
carefully-controlled studies must be repeated with many of the pesticides
if the processes affecting persistence are to be understood. Many of
the published results are suspect because adequate experimental
controls were not maintained.
Huang, et. al. reported that the sorption of DDT, Heptachlor,
andDieldrin by kaolinite, illite, and montmorillonite is very rapid
24 25
and exhibits Freundlich type isotherms ' . These investigators
concluded that the primary mechanism of the sorption of these pesticides
by clays is through the formation of hydrogen bonding and other strong
forces of interaction. Only Van der Waals forces contribute significantly
to the sorption of Dieldrin. These findings may be in error. Because
of the nonpolar nature of the chlorinated hydrocarbon, it is very
unlikely that they are retained by the pure clay particle via any of the
aforementioned sorption forces. In fact, these pesticides tend to
associate with or accumulate in the organic fraction of the crude clay.
The clays used in many studies are not properly characterized or
prepared to assure that they are not organo-clays at the outset. In
nature, they may be converted to organo-clays but the nature of these
converted materials is not known.
It has been reported that the sorption and desorption of Dieldrin
by montmorillonite sediment are not significantly affected by either
26
temperature (10 C to 30 C) or salt concentration (0. 03 to 3. 0 percent) .
The investigator also stated that soluble organic matter, such as glucose,
107
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alanine, and stearic acid, did not exert an effect on the rates and
equilibria of the sorption of Dieldrin, DDT, and Heptachlor by
montmorillonite and illite. These investigations are not scientifically
acceptable as reported. There is no specific description of the
physicochemical characterization of the clay or the experimental
27 28
techniques ' . The nature of saturating cation, source and purity
of the clay minerals employed, clay particle size and surface area,
and the pH of the aqueous system are important factors which will
affect the sorption properties of the clay. These must be reported if
the results are to be meaningful.
The sorption of dithio-carbamates (fungicides) by clays is
reported to be the result of coulombic forces because of the ionic
17
nature of the compound in solution . The ethylene dibromide ( a
fumigant) and organic phosphorus insecticides may be retained at the
clay surface through external hydrogen bonding. This is because of
the noncharge nature and unequal distribution of charge of the
respective molecules
The sorption of 2, 4-D by Bentone24(an organo-bentonite) is
rapid and considerable but sorption of the chemical by untreated
29
was below detectable limits . Greater sorption was found in more
concentrated sorbate solutions or under more acidic conditions. Sorption
is directly proportional to the organic fraction of the clay. Thus,
reports that clays sorb negatively charged molecules (such as 2, 4-D)
may be attributed to a mechanism not readily appreciated by those
making the studies. The clays complex organic molecules, such as
amines, cationic detergent, etc. , from aqueous solution and the
resulting organic clay surface then sorbs the 2, 4-D. The physical
and chemical nature of the organo-clay surface determines the extent
of subsequent sorption of other organics such as pesticides.
108
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It has been reported that clay minerals (illite, kaolinite, and
montmorillonite) sorb very little 2, 4-D or Isopropyl N- (-3 Chlorophenyl)
18 30
carbamate (CIPC) ' . Hamaker, et. al. found that organic matter
and hydrated metal oxides are principally responsible for the sorption
3
of 4-Amino-3, 5, 6-trichloropicolinic acid on soil . The poor sorption
of this compound's anionic species by clay minerals and the strong
sorption by hydrated metal oxides would appear to be consistent with
a process of replacing the hydroxyl ions from the metal oxide surface.
The greatest sorption of the acids, 2, 4-D, and 2, 4, 5-T was observed
onto soils containing a high percentage of organic matter and for red
and acidic soils .
Freundlich type isotherms were measured for sorption of a number
32
of herbicides onto montmorillonite . Regardless of the chemical
character of the sorbent, sorption occurs to the greatest extent on
highly acidic H-montmorillonite (a homoionic clay) as compared to the near
neutral Na-montmorillonite. The degree of sorption of organic compounds
with widely differing chemical characteristics is governed by the degree
of water solubility, the dissociation constant of the sorbate and the pH
of the clay system. The surface acidity affects the sorption of basic
organic compounds by the clay.
The organic content of the soil is the major factor influencing
retention of chlorinated hydrocarbon pesticides in soil. For example,
dieldrin retention is related to the organic content ot the soil and the
immobilized residues of herbicides-derived chloroanilines are chemically
34
bonded to humic substances of the soil . However, as stated earlier,
the organic content of many of the coarse textured soils in the Southern
United States is very low. In, these states, the clay fraction of the soil
is likely to be the principal factor involved in sorption of pesticide.
109
-------
Within the aquatic environment, it has been established that bot-
tom sediments exhibit higher pesticide concentrations than surface wa-
ter35' 36. For example, 0. 02 to 3. 58 parts per million (ppm) of DDT and
its metabolites and 0 to 2. 47 ppm of Toxaphene were found in the bottom
35
sediment of selected Delta Lakes in Mississippi . Lake waters are
generally low in pesticide residues. It has been found that the sorption
of both Endrin and Dieldrin by bottom sediment is time-dependent and
•2 /
pH sensitive . The sorption of Dieldrin occurs only at a low pH.
If the pH is adjusted above 7, Endrin will not remain associated with
the bottom sediments for an extended period of time. Similarly at pH
greater than 8, the sorption of Dieldrin is negligible. The sorption of
"Endrin is salinity-dependent, but not so, in the case of Dieldrin. BecauSfi
the pesticidal concentration is maintained by a dynamic equilibrium,
the desorptic of pesticides from bottom sediment may occur as a
function of changes in physical, chemical and biological stresses.
This provides a potentially continuous supply of these chemicals to
the aqueous solution. This tends to extend the potential contact time of
the pesticides to aquatic organisms and affects the aquatic food chain.
The aquatic organism can magnify many-fold the pesticide doses
originally introduced into the ecosystem. The dose is passed along and
concentrated in the aquatic food chain. Eventually it may reach man
or recycle in the aquatic environment. It has been determined that flora
and fauna contain DDT and its metabolites nearly 1, 000 times as great
37
as the concentration present in the water . Residues of DDT and its
metabolites, and Toxaphene in the flesh of fish from selected Mississippi
Delta Lakes have been found to be 0. 15 to 10. 60 ppm and 0 to 20 ppm,
35
respectively . The median concentrations of Endrin and Dieldrin in
oyster samples were determined to be less than 10 ppm in the lower
36 38
Mississippi River . It was found that DDT accumulated in lake trout
no
-------
39
and in marine phytoplankton . Toxaphene concentrates in aquatic
40
plants and fish . The biological magnification capability of aquatic
life significantly increases the hazardous and destructive potential of
pesticides originally present in the water. It also serves to localise these
materials and modify their transport within the aqueous system.
Pesticidal contamination is found on plants and agricultural
products grown on pesticide-treated soils. These pesticides are
apparently first sorbed by the root system and then translocated into
the plant. Aldrin andHeptachlor residues have been found in cucumbers
41
and alfalfa grown on pesticide-treated soils . Similarly, residues of
42 43 44
Endrin or DDT have been detected in turnips , soybeans- ' , and
44 45
peanuts and tobacco leaves ' grown in soil treated with these
pesticides. Cotton plant leaves accumulate different amounts of
Dimethoate under different light and humidity conditions. Both high
humidity and darkness greatly reduce Dimethoate accumulation in the
leaves . Five kinds of carrots were found contaminated with various
amounts of Aldrin or Heptachlor. This was a result of considerable
difference in rates of sorption^?, DDT, BHC, and Parathion are
translocated to root crops and cause decreased yields^S.
It can be concluded that sorption and desorption processes are
the major factors influencing pesticide movement into aquatic environ-
ment after application. Sorption is affected by soil type, clay and
organic content of the soil, soil temperature, physico-chemical nature
of the pesticide, the degree of the saturating cations on the colloid
exchange site, and pH of the ecosystem. Bottom sediments, aquatic
organisms and plants grown in pesticide-contaminated areas accu-
mulate large amounts of pesticides. Sorption capacity and desorp-
tion processes for various types of soil need investigation under varying
111
-------
field conditions, such as rainfall intensity, pH, temperature, etc. Less
persistent pesticides may be necessary at certain times. Appropriate
concentration and application techniques must be evolved.
4. Movement into Water
Water solubility, although important in the physical transport
of the pesticide from the area of application, is not considered to be
the major factor in leachability. A very water-soluble compound will
not leach if it is irreversibly sorbed and an insoluble compound will
49
leach readily if it is not sorbed . The moisture content of the soil
as well as the intensity and frequency of rainfall affect the overall
movement of pesticides in the soil. A low moisture content favors
retention of the pesticide in soil because it lowers total solubility and
enhances the competition of the pesticide for an adsorption site. Bailey
reported that a lower rainfall intensity resulted in greater removal
of a herbicide from the upper surface horizons than did less frequent
rainfall . Certain pesticides are leached in greater amounts and to
greater depths under lower rainfall intensities. Weather patterns may
be as important as total rainfall in determining the movement of herbicides
in soil17.
With readily available soil moisture, phytoactivity may be
enhanced. This action likely results from increased susceptibility
of a plant to the herbicide, increased transpiration, and/or increased
49
availability of the herbicide , Laboratory data showed that penetration
of Dieldrin into the soil is dependent on both soil type and moisture level
at the time of application. Thus, distribution in the soil may vary from
a thin layer of concentrated insecticide to a relatively thick layer of
less concentrated insecticide. Field penetration of Dieldrin was found
50
lowest in arid soils and highest in wet soils .
112
-------
The movement of water into the soil from the surface is known
as infiltration while the movement of water through the soil is known
as percolation. The infiltration of water into the soil depends on the
51
soil's initial moisture content . The forces of gravity, capillarity
and hydrodynamic factors cause the movement of water soluble pesticides
1 18
down through the soil. Soil texture will affect the movement of pesticides '
Pesticides leaching is greater in soils of light texture.
The three major means of pesticide transport within soil are:
• Diffusion in the voids of the soil
• Diffusion in the soil water
• Downward flowing water
The first and third are important in the movement of volatile and
nonvolatile pesticides, respectively. Pore size and pore size distribu-
tion affect the rate of water passing through the soil as well as the
extent of downward spreading motion of the pesticide.
If no appreciable attenuation occurred, a pesticide could pass
52
through the following parts of the environment in sequence
• Soil Surface
• Zone of aeration or the zone between the soil
surface and the water table
• Zone of saturation or the zone of groundwater
• Stream course
• The sea.
In some cases, pesticides extend through the zone of aeration
into the zone of saturation where they tend to spread laterally.
The depth of the zone ot aeration varies from near zero in
swampland to several hundred feet in arid regions. The zone of
113
-------
saturation may extend to a considerable depth, but as the depth increases^
the accompanying weight of the overlying soil arid material tends to close
pore spaces and, thus, relatively little potable water is found at depths
of more than 2, 000 feet. In the zone of aeration the moisture may be
present as gravity water in transit to large pore spaces, as capillary
water in small pores, as hydroscopic moisture adhering to a thin film
on the grains of soil, and as water vapor.
The movement of water vapor in the soil is related to tempera-
ture, i.e., vapor movement is from high to low temperatures. However,
for the most part temperature gradients are usually small and the quan-
tity of moisture moved is negligible.
Groundwater, in its natural state, is constantly moving and this
^
movement is controlled by established hydraulic principles. Darcy's
law is used to express the movement through aquifers, most of which
are natural porous media. The measure of the ease of flow through the
porous media is known as permeability.
Sorption and retention of cations on the surfaces of aquifers are
dependent upon the fine silt, clay, and organic fractions of the aquifer.
The principal cations involved are sodium, calcium, and magnesium.
The soluble products of soil weathering and erosion add salts to the
groundwater during its passage through soils. Irrigation water, perco-
lating to the water table, contributes large quantities of salt. This is
primarily the result of the drainage water salts being concentrated by
C4
the evapotranspiration process. -^
Generally, the chlorinated hydrocarbons, such as DDT, persist
in the soils and do not move in appreciable concentrations through the
soils and into the drainage effluent as groundwater. " Pesticide resi>-
dues do not penetrate deeply enough into the soil to obviate a biological
hazard. Downward movement is aided by cultivation. The preponderant
114
-------
of residue accumulations appears to be confined chiefly to the top one
foot of soil, and within this depth most residues'are found within the
cultivation layer (4 to 6 inches). In the fire ant control program, most
Heptachlor residues have been found within the top inch of soil. Humus
56
layers fall within the zone in which most residues occur.
The movement and distribution of DDT in a heavy clay soil has
been studied by several investigators. For example, Swoboda, et. al.
found that most of the DDT remained in the top 12 inches of soil but that
some DDT was found at the lower profiles probably as the result of
leaching.57 Breidenbach, et. al. reported that percolate water, inter-
cepted below the rooting depth at 2.44 meters (8 feet) contained no
Methoxychlor and only trace amounts of 2, 4, 5-T fourteen months after
application. The total amount of 2, 4, 5-T found in the percolate was so
small that it did not indicate significant contribution to groundwater con-
tamination. 5** A major portion of the applied pesticide was removed from
58
the soil by overland drainage.
The movement of micron-size particles through a sand bed has
been investigated using radiochemical tracers. ' The transport rate
of the finer particles was essentially the same as that of the cations in
solution,while the rate of the coarser particles appeared to be signifi-
cantly slower. Sodium humate, a common soil constituent, can solu-
bilize insoluble pesticides such as DDT in water,thereby,facilitating
the transport of the pesticide. Swoboda, et. al. suggest that the move-
ment of pesticides in soil in the Southern states is primarily caused by
leaching, movement with soil particles, and volatilization (because of
57
high soil temperatures).
A mathematical model has been developed to describe the move-
ment of DDT and its decomposition product, DDE, in an ecosystem.
Some predictions of the consequence of adding DDT to the environment
are possible and are based on its transport, accumulation, and concen-
tration, within ecosystems. vQ
115
-------
It can be concluded that a major portion of the applied pesticide
is removed from the soil by overland drainage.' Movement of pesticide
through the soil by infiltration and percolation is small and it contributes
in only a minor way to groundwater contamination.
a. Direct Application
Many organic pesticides are added directly to water to control
aquatic insects, trash fish, and aquatic plants. Examples include:
Dieldrin for control of sand fly larvae; Toxaphene and Rotenone for con-
trol of various species of fish; and phenoxy acetic and propionic acid for
aquatic plant control. In these cases, direct water contamination re-
sults .
It has been found that Fintsol can be used more effectively than
Rotenone under a wider variety of conditions for controlling sunfish in
catfish pounds. Aquatic weeds (Parrots Feather, Needlerush, Pitho-
phora sp. , Potamogeton sp. , and Microcystis sp. ) have been controlled
by the application of herbicides (2, 4-D, Aquion, Karmex, copper sul-
fate and Kuron) in conjunction with fish production. High rates of 2,
4-D application for water milfoil control in Tennessee Valley Authority
reserve
quality.
reservoirs have not produced adverse effects on aquatic fauna or water
64
In a sand fly eradication program, it was reported that during
1955, 2, 000 acres of salt marsh in St. Lucie County, Florida, were
3 65
treated with 1 Ib/acre of Dieldrin. ' Twenty to thirty tons of fish, an
estimated 1,117, 000, representing some 30 species, were killed and re-
production was not observed for four weeks. Crustaceans were virtually
eliminated; however, fiddler crabs survived in areas missed by the spray
treatment.
The presence of tree roots in sewer lines creates a major pro-
blem in urban areas. Control has been achieved by the flooding technique
for addition of herbicides such as Metham and Dichlobenil. °" However,
116
-------
this practice does not take into account that these herbicides will be intro-
duced into the sewage system and may then present a major contamination
problem.
To eliminate harmful side effects on non-target species,direct
application of pesticide to waters should be minimized and alternative
controls devised wherever possible.
b. Overland Drainage
Not all of the pesticides applied to land end up in a waterway,
but it is likely that almost all pesticides in streams result from storm
runoff or overland flow. ' The pesticides are initially sorbed
onto particulate matter and then transported as complexes to the water
course. Chlorinated hydrocarbon pesticides have been found in bottom
sediments in 126 locations of the Mississippi River. These deposits are
attributed to agricultural sources. °°» ™ Since chlorinated hydrocarbon
pesticides are only slightly soluble in water, they may be transported as
a film, emulsion, or in association with particulate matter. Chlorinated
hydrocarbons are found in surface waters of the Southeast. H* ?2 -phe
number of occurrences reached a peak in 1966. Their presence has de-
clined sharply since 1967. This trend is consistent with the decrease of
production and usage of chlorinated hydrocarbons and the increase in the
use of organophosphorus and carbamate compounds.
Instances of surface water contamination with chlorinated hydro-
7 3
carbon pesticides have occurred in certain areas of Georgia , in major
river basins of the United States, in the Mississippi River and Delta
7?7^7/r •»«•»
area ' ' , in sugar cane farming areas of Louisiana , and in farm
Ponds. '°» ' ' Surface runoff from fields was the main source of these
Pesticidal contaminations. For example, Toxaphene and BHC were de-
tected in all samples taken from a stream in northern Alabama from the
summer of 1959 through the winter of 1963. Analyses of treated and un-
treated drinking water showed that purification processes failed to com-
80
pletely remove these two compounds.
117
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{!). Soil Erosion
The transport of pesticides into the aquatic environment and
Rl
their persistence presents a complex problem. It has been established
that there is a relatively long persistence of certain chemicals which
have been in use since 1945. Eroded soils previously treated or incorpo-
rated with pesticides are major sources of surface water contamination.
It has been estimated that the gross sediment eroded each year in the
United States is around 4 billion tons. This loss occurs by the processes
DO
of sheet erosion, gullying, and a stream channel erosion. 0£< Entrain -
ment, transportation, and deposition of sediments depend on the proper-
ties of the sediment and the hydraulic characteristics of the waterway.
Q O
The seven principal sources of streamborne sediment are:OJ
• Sheet erosion, the removal of surface soils by
overland flow without the formation of channels
of sufficient depth to prevent cultivation or
crossing farm machinery;
• Gullying, or the cutting of channels in soil caused by
concentrated runoff;
• Erosion of stream banks and channels;
• Mass soil movements, such as landslides;
• Flood erosion; and
• Erosion associated with development, such as roadway
construction.
8Z
The modes of sediment transport may be classified as:
• Bed load, rolling or sliding of sediment along the
stream bed;
• Suspended load, suspension of sediment in the moving
water; and
• Wash load, fine particles carried into and through the
channel with no relation to the stream bed material.
An investigation of Atrazine associated with runoff and erosion
was made using simulated rainfall and surface applications to soil. It
118
-------
was found that greater losses resulted when the rain was applied imme-
diately after the herbicide application. The Atrazine content was highest
during the early stages of runoff as might be expected. Concentrations
in the soil fraction of the washoff (water-soil mixture) were higher then
in the water fraction. ®^ Simulated rainfall intensities and storm dura-
tion were used to investigate 2, 4-D contained in washoff from cultivated
Q C , .
fallow Cecil sandy loam soil. ° Concentrations of 2, 4-D in the washoff
were positively correlated with the application rate and were greatest
at the beginning of each storm. The iso-octyl and butyl ether ester for-
mulations of 2, 4-D were far more susceptible to removal in washoff
than the amine salt. ^ For Dieldr in-incorporated soils, losses were
appreciable when erosion occurred and reached 2. 2 percent of the amount
applied. 86
Effects of soil cultivation on the persistence and vertical distribu-
tion of pesticides were investigated over a ten-year period.11 After treat-
ment, DDT and Aldrin were rototilled into the soil. First one-half of
each plot was disked to a depth of approximately 5 inches for 5 consecu-
tive days each week for a 3-month period. The other half served as a
nondisked control. While only 26 percent of the applied DDT was lost in
a 4-month period from the nondisked portion, 44 percent was lost from
the disked portion. For Aldrin, 53 percent was lost in the nondisked and
70 percent in the disked plot. No difference in the distribution of the resi-
due in the soil layers was found between disked and nondisked soils.
Chlorinated hydrocarbon insecticides applied to the soil to con-
trol subterranean termites have moved through the soil very slightly
after 10 to 20 years of weathering in open fields in southern Mississippi.
There was only about 1 foot of vertical movement and only about 20 inches
of horizontal movement of DDT under the soil surface in 2 decades. 87
Aldrin and Heptachlor were applied either to the soil surface or
incorporated into the soil by rototilling to approximately 5 inches. ^
Recoveries of these pesticidal residues ranged from 2. 7 to 5. 3 percent
119
-------
of the applied dosages. Measurement was made 4 months after a soil-
surface application. However, incorporation of the pesticides into the
upper soil layers increased the persistence of the residues by a factor
of 10. One year after treatment of the upper soil layers, 90 percent of
the recovered residues were located within the upper 3 inches of the
soil. The highest concentration of the insecticides was found within the
second inch of the soil layer. A deeper penetration and a more equal
distribution of the residues was noticed 3 years after the soil treatment.
A field study examined losses of Dieldrin that had been disked
into a silt loam soil to a depth of 7. 5 centimeters. In general, the
amount lost in the runoff water was a very small fraction of the quantity
applied. At most, this amounted to 0. 07 percent of the original dosage
in the first season, with the largest losses occurring in the first 2 months
after application. Highest Dieldrin concentration in the water was 20
micrograms per liter (jag/l) soon after application. Concentration was
86
always less than 2 |xg/l in the second year.
Soil cultivation is one of many factors that affects the disappear-
ance of insecticides from soil. It must be cautioned that the disappear-
ance of the pesticides from soil does not mean its removal from the envi-
ronment. After the application of the pesticide to a soil, a partitioning
among soil, water, and air takes place. Distribution of the pesticide in
the environment is controlled by many variables including temperature,
soil properties, soil water content, and the nature of the pesticide. The
increased loss of pesticides from cultivated soils can be partially ex-
plained by the continued exposure of new surfaces. However, other fac-
tors such as soil moisture, organic content, and temperatures will affect
the loss rate.
The possibility of DDT accumulation in soils from spraying is
more likely in orchards and with crops where the green plants are turned
under and incorporated into the soil after each harvest. Pesticide move-
ment downward is aided by cultivation and rainfall and other natural
120
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In some newly developed irrigation fields it was found that after
irrigation began, use of organophosphates and carbamates increased
greatly. 94 The results indicate that irrigation water carries away some
of the applied pesticides which results in the need to increase pesticide
applications to compensate for the loss. Results also showed that there
was little vertical penetration of pesticides from surface applications
(penetration did not exceed 12 inches).
It is concluded that pesticides removed by irrigation runoff in
either the liquid form or settleable silt were only a small percentage of
the amount applied. Ground water contamination by,pesticides perco-
lating through the soil from irrigation can be considered very slight.
Irrigation practices do not constitute major problems for the aquatic
environment with respect to contamination by pesticides. However,
factual assessment of this situation will only be obtained after thorough
investigation. Information is needed regarding pesticidal residue distri-
bution, magnitude, and persistence in the ecosystem resulting from irri-
gation practices. Such information will permit long-range evaluation of
the effect of these chemicals and anticipate harmful environmental effects
before they occur. No such problem has been identified in the Southeast.
c. Atmospheric Processes
Pesticidal compounds may enter the atmosphere in several ways
and in various physical states and then be redeposited directly or indi-
rectly in the aquatic environment. Direct drift from spraying operations
contributes particulate or globular matter at concentrations which are
likely to vary inversely with the distrance from the site of application.
Such effects are usually local but the possibility exists for a more exten-
sive influence. Several organochlorine insecticides volatilize from
treated soils, thus adding a slow but long-term contribution to the atmos-
phere. 95 Effluents and vapors from industrial processes, such as pesti-
cide manufacturing or moth-proofing of garments, also contribute. Quan-
tities may accrue from the use of domestic aerosol insecticides and
121
-------
thermal vaporizers and the dust from treated soil, clothing, and carpets.
The concentration of these compounds in air is lower by a factor of 10
to 100 times that in rainwater. °5
Pesticides can be transported by wind and deposited in water far
from an area of application. Even a trace of precipitation may deposit
unusually large amounts of pesticides on sites far from the source of the
contamination if it falls through windblown dust clouds. Pesticides are
now considered to be universally present in the air. Their distribution
to sites remote from application areas depends on prevailing patterns of
wind circulation and deposition rates. The potential for atmospheric con-
tamination and subsequent transport during field application of pesticides
is high.
Since many variables are involved in aerial applications of pesti-
cides, no limited study will elucidate all factors or permit accurate pre-
diction of this mode of pesticide contamination. "" Atmospheric degra-
dation is enhanced by a highly dispersed particulate or droplet state.
Moisture, light and oxygen are factors in determining the rate of hydro-
lysis, photodegradation and oxidation, respectively. The danger of inha-
lation is greater with stable pesticides. To minimize atmospheric con-
tamination, the development of less persistent and less volatile pesticides
is needed. Pesticide application techniques must be improved to effect
maximum delivery efficiency of minimum quantities close to the target
under metereorologically suitable conditions.
(1) Volatilization
Pesticide residues may enter the atmosphere by codistillation
26 97 98 99
from water surfaces ' ' , by vaporization from plants and soils ,
and by aerial drift during application. The DDT residues in precipitation
in south Florida averaged 1, 000 parts per trillion at four sites between
June, 1968 and May, 1969. Based on precipitation content (80 parts
per trillion), some have estimated that one quarter of the total annual
122
-------
production of DDT could eventually be transported to the ocean. Volati-
lization can be a significant factor contributing-to the net loss of a pesti-
cide applied to a crop or to a soil surface. ' ' Field experiments
involving Endrin application to sugar cane showed that atmospheric con-
centration reached a maximum of 540 nanograms per cubic meter (ng/m3)
during the next three days. This concentration decreased rapidly to
30 ng/m3, 77 days later.
A water budget for Birmingham, Alabama indicates that during
the months of July, August, and September a deficit in soil moisture will
usually occur with the rates of actual evapotranspiration being very high. ^
Thus, the top soil layers will tend to be dry. It has been reported that the
rate of volatilization from a soil decreases with a reduction of moisture
content in the soil. As would be expected, the volatilization of pure pesti-
1 no
cides increases with temperature.1U£< One would expect to find a much
higher pesticide vapor pressure at the elevated ground temperatures found
in the Southeast. However, there is experimental evidence that increasing
the temperature results in a decrease in the relative vapor pressure. ^
This may be attributed to the formation of a stronger sorption force soil
for pesticides in dry and less competition from water molecules for the
sorption sites of the dry soil.
Experimental evidence,in conjunction with known meteorological
date for the Southeast,suggests that during those months when the tempera-
tures are high and soil moisture is depleted, 1?he amounts of pesticide
78
volatilisation is reduced.
The major source of DDT residues in soybean plants was found to
occur through vapor movement from contaminated soil surfaces. In contrast
the presence of Dieldrin, Endrin, and Heptachlor resulted primarily from
root uptake and translocation through stems to leaves and seeds. ^3 The
amount of DDT sorbed after vaporization from surf ace-treated soil was
found to be 6. 8 times greater than that obtained through root uptake. DDT
123
-------
losses were at the rate of about 2 pounds per acre per year in summer
and about 0. 3 pound per acre per year in winter. 1"4 The implication is that
about half the DDT applied to field crops may enter the atmosphere. The
soil moisture content and its influence on volatility was not considered in
the study.
A direct relationship between the initial DDT concentration (below
100 ug/1) and the DDT codistillation rate has been reported. 98 At the
highest concentration tested {1, 000 ug/1), the codistillation rate was as
much as six times greater than anticipated by theoretical dissemination
equations. This finding is in agreement with DDT's great affinity for the
air-water interfaces, which facilitates the high codistillation rate. How-
ever, the results of this study are subject to criticism since DDT solu-
bility is in the order of 1 (J.g/1. A non-homogeneous solution results when
27
greater pesticide concentrations are attempted at room temperature.
Experimental studies of the volatilization of soil-applied DDT and
DDD (incorporated into commerce silt loam) from flooded and nonflooded
plots showed that within the first two days, the atmospheric concentration
of DDT at 10 centimeters dropped from a maximum value of 1977 to 58ng/m3
above the flooded plot and from 2041 to 100 ng/m3 above the nonflooded plot.
Corresponding levels of DDD decreased from 405 to 30 ng/m3 and from
575 to 92 ng/m3, respectively. It is evident that the flooding treatment
effectively retarded the volatilization of both pesticides. Major changes
in the atmospheric concentrations of both pesticides above the nonflooded
plot^apparentl^are related to certain climatological factors. *^5
An investigation of the volatilization of Lindane and DDT from four
types of soils shows that neither pesticide was volatilized at 30° and 55° C
••when the soils contained less than a monolayer coverage of water. The
rate of pesticide loss was constant for each soil in the moisture range of
1/3 to 15 bars and the pesticides volatilized over a longer period of time
from the fine,r textured soil than from the coarser textured soils. For
124
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Lindane and DDT at 30° C, the rate of volatilization from soil was in
descending order: Valentine loamy sand, Hand loam, Raber silty clay
loam, Promise clay. It was assumed that an equilibrium existed
between the vapor phase and nonvapor phase of the pesticides. The
vapor density was independent of water content until the water content
in the soil approached a monolayer. Vapor density increased with
increases in pesticide concentration and increases in temperature, but
decreased with increases in surface area. In order to explain the dif-
ferent vapor densities between moist soils, one must consider factors
regulating the equilibrium between solid and solution phases as well as
diffusion in both the vapor and nonvapor phases. Neutral pesticides pro-
bably are held to the mineral fraction of the soil by weak physical forces.
One would expect more retention of the pesticide by the organic fraction
of the soil than the mineral surfaces. Both types of pesticide sorption
increase as surface area and organic matter content increases.
Aldrin and Dieldrin disappeared rather rapidly from agar in glass -
covered petri dishes. ' In most instances, this disappearance was con-
siderably retarded by inoculation with either fungi or bacteria. Thus,
volatile compounds which are low in water solubility may be lost to the
atmosphere under sterile conditions but this loss may be reduced by the
presence of microorganisms which consume, react, with or physically
cover the compounds.
Vapors are given off from Aldrin-, Heptachlorphorate-, Lindane-,
Heptachlor epoxide-, and Dieldrin-treated soils. An increase in the
rate of Aldrin volatilization from the soil resulted from increases in
insecticide concentration in the soil, soil moisture, relative humidity
of air passing over the soil, soil temperature, and the rate of air move-
ment over the surface of the soil. A decrease in the rate of Aldrin vola-
tilization was noted in dry soils containing increased amounts of clay
and organic matter and in wet soils containing increasing amounts of
organic matter. Vapor loss of Trifluralin from water was found to be
125
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proportional to concentration, with losses being greater during a 12-hour
period than during an 8-hour period. 109 Placement of the herbicide below
the soil surface (0. 5-inch) resulted in a very low vapor loss for both
moisture regimes,
(2) Dusting and Spraying
Fallout from aerial pesticide application is a principal source of
water contamination. &°»100» ^°» "•* High levels of the atmospheric contam-
nation by pesticides (DDT, Toxaphene, Parathion, and organophosphate)
have been measured in the agricultural areas of the Southeast including
Dothan, Alabama; Orlando, Florida; and Stoneville, Mississippi. Higher
pesticide levels were found when pesticide spraying was reported than
112
when no spraying was in progress.
Aerial pesticidal sprays usually reach the target in amounts equal
to or less than 50 percent of the quantity distributed. During practically
every spray operation, many nontarget organisms are killed. Many of
these may be predators of the organism that the spray attempts to control.
DDT residues may travel great distances once in the atmosphere, and
eventually enter the aquatic environment through precipitation or dry fall-
out processes. Pesticidal drift from Mississippi cotton field applications
has killed a large number of fish, snakes, frogs, turtles, and some egrets.
Aerial spraying of organophosphate pesticides on farm land has caused se-
ll "?
vere poisoning of a farm worker and the death of a 16 year old boy.
Spray drift from agricultural sprays is influenced by many factors
such as sprayer design, spray pressure, fluid properties, and meteoro-
logical conditions. Spray drift potential has been evaluated.
Spray techniques and droplet size are closely related to the over-
all control of pesticide residue passage to the waterways. An account
has been presented describing methods used, estimation of the spray cover-
age, and the size of spray particles. -^ Experimental results showed that
150 microns mass median diameter spray drops provided the most efficient
126
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swath pattern for forest spraying. 11& A review of findings between 1954 and
and 1961 showed that larger mass median diameter drops (500 micron)
required lower pressure, and usually lower dosages, than smaller drops
(100 micron mass median diameter) with essentially equivalent results. *'
It is necessary to further explore the significance of droplet size
on the effectiveness of pesticide spray applications. There is a need to
define the significance of droplet size on potential contamination of the
j
water resources. Spraying must be based on using the proper chemical
on a given crop in the right amount at the right time. Applications should
be terminated prior to harvest to prevent excessive residues on food and
fiber.
(3) Windblown Materials
Wind can sweep away surface soil to which pesticides are sorbed.
These particles can be deposited into the aquatic environment by rain or
by settling processes. ^5 High winds have created dust clouds from which
precipitation has deposited an unusually large amount of contaminated soil.
In this case, selected samples showed 1. 3 parts per million of total chlo-
rinated hydrocarbon. Pesticides detected were Chlordane, Heptachlor
epoxide, DDE, DDT, Ronnel, Dieldrin, and 2, 4, 5-T.118 Deposits of
Malathion and A zinphos methyl following aerial application were measured
at various wind speeds and flight altitudes. These pesticides were detected
as far as 800 meters (1/2 mile) downwind of application. Estimated re-
coveries from the adjacent areas, into which the spray drifted, ranged
from 18 to 96 percent of the amount applied. 9°
DDT residues have been found in the Antarctic. The analytical
results and the estimated snow volume (2, 4-3. 0 x 10^ cubic meters) were
used to project total DDT accumulation at 2.4 x 10^ grams. Concentra-
tions of chlorinated hydrocarbons in airborne dust, carried by the trade
winds from the Europe an -African land areas to Barbados, range from
127
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less than 1 to 164 part per billion. The lower limit of the average concen-
tration in 1 cubic meter of air is 7. 8 x 10 gram.
Analysis of rainwater and dust have revealed the presence of
chloroorganic substances in all samples examined. Proof that pesticides
can Be transported to earth by rainfall was obtained from a deposit of
dust on the Cincinnati, Ohio area on January 26, 1965. It is reasonably
certain that soil is constantly being picked up by winds, transported at
high altitudes over long distances, and deposited elsewhere either by
sedimentation or by rain. In order to minimize pesticidal losses from
the application area and possible inhalation hazard due to wind-blown
treated soil, less persistent pesticides are preferable and applications
should be avoided on windy days. Soil conservation practices are also
quite important.
d. Disposal Processes
The problem of the final disposition of pesticides falls into two
categories:
t> Disposal of pesticide residues and wastes and
o Disposal of pesticide containers.
Mississippi State University has conducted studies with an over-
all view of the pesticide disposal problem. ' The waste problem
is classfied into three general catagories:
e Disposal by land burial,
e> Disposal by chemical and thermal methods, and
o Recycling of waste and containers.
Mixtures or formulations were more biodegradable than single
pesticides, provided that at least one or two of the pesticides in a mix-
122
ture were relatively easy to biodegrade. However, biodegradation in
soil may result in the suppression of soil bacteria and favor growth of
Streptomycetes and fungi. If the bacterial population is suppressed for an
128
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extended period of time, important processes such as nitrification, nitro-
gen fixation, sulfur transformation, and others -are endangered. Thus,
the burial of pesticides presents problems beyond the contamination of
water.
Chemical and thermal disposal methods were compared and it was
123
shown that incineration was superior to chemical methods. Incineration
at 800 to 1, 200° C for five minutes is the most effective method for the
disposal of pesticide wastes. However, the process in itself is not entirely
satisfactory. Incineration without the entrapment of pesticides in the re-
sulting gases represents an environmental threat through air pollution.
Volatile pesticides and their degradation products could conceivably en-
danger the surrounding countryside. Another serious problem arises from
the residue that remains after incineration. The quantity of residues can
be considerable and the residues may retain other toxic elements, such
as arsenic. If pesticide residues are to be disposed by burning, it is pos-
sible that further chemical treatment will be needed.
Little is known about pesticides released from incineration
municipal and industrial wastes and treatment plant sludges. Because of
the large atmospheric releases could be sig-
nificant and widely dispersed.
Disposal of pesticide containers presents a particular problem.
These containers retain substantial residue. If the container, such as a
metal drum, is recycled, this problem is lessened. However, if these
containers should be disposed by dumping, the buildup of toxic material
could be significant and the material could subsequently be transported to
other areas by water movement.
The magnitude of the problem can be illustrated by an example.
The number of containers reportedly used in the state of Mississippi in
174.
1969 were: "
• 55-gallon drums - - 65,750
129
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• 30-gallon drums 16,000
o 5-gallon drums -*- -240,000
• 1-gallon cans - 401,000
• 0. 5-gallon (glasB^ metal, and plastic containers)-- 35,000
• 0. 25-gallon (glass, metal and plastic containers)-- 80,000
A 1970 survey of 75 counties in Tennessee indicated that 3, 33Z
124
empty pesticide containers were discarded as trash.
Much remains to be accomplished with respect to the safe dispo-
sition of used containers with pesticide residues although industry is de~
125
veloping guidelines. A nationwide disposal system should be initiated
as soon as possible. Open burning should be prohibited, even in rural
areas, because of air contamination. Research is needed specifically in
the following areas:
o Recycling techniques for pesticide containers,
o Chemical and biological decontamination methods, and
o Thermal degradation with special emphasis on
incineration research.
5. Case Studies
A number of documented cases reported in the Southeast
of either intentional or accidental nature have been reviewed.
a. Intentional
A Parathion and Methyl arathion manufacturing plant in Alabama
dumped its effluent into a creek when its treatment plant failed in. 1961. °^
Fish, turtles, and snakes died along 28 miles of the stream. Traces of
Parathion residues were recovered from the Coosa River into which the
creek entered. Lesser fish kills were reported 90 miles down the Coosa
River.
Five pesticide-formulating companies dumped waste materials into
city sewers; channels and sloughs near their plants; and onto city and
130
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private dumps where they could be washed away by rainfall. ™
Pesticides residues (Dieldrin, Aldrin, Endrin, Isodrin, Chlordane, Lin-
dance, and DDT analogs and metabolites) varied in concentration from less
than 0. 5 ppm in river bottom muds to thousands of ppm in the vicinity of
the industrial plants in the lower Mississippi River basin.
Dieldrin is used as a fungicide in an Augusta, Georgia, wool scouring
plant. This plant discharges the chemical into the Savannah River. A simi-
lar plant previously used and discharged Dieldrin into the Ogeechee River
1 -\r
near Statesboro, Georgia, but an alternative is now used.
Drums containing chemical wastes have been found in and along the
North Sea. The wastes were analyzed and found to contain lower chlorinated
aliphatic compounds, vinyl esters, chlorinated aromatic amines and nitro-
compounds, and the insecticide Endosulfan.127 This could occur in the
Southeast where pesticidal wastes and containers require disposition.
A fish kill took place in Indian Swamp, North Carolina, on or about
June 10, 1971. This occurred when a person deliberately discharged about
two gallons of Chlordane solution into the surface waters. On June 14 and
15, 1971, Indian Swamp waters exceeded from 2 to 10 times the recognized
•I o Q
toxic limits of Chlordane. Another fish kill occurred on July 6, 1971 in
Bear Swamp Creek at S. R. 1301 and was caused by spent pesticide jugs. ^°
The jugs, containing Endosulfan, were thrown onto the bank and allowed
Endosulfan to enter the creek.
Over-aged Parathion bags (15 percent dust) were dumped into the
Peace River near a bridge one mile upstream from the municipal water
67
intake of Arcadia, Alabama, a town of 6, 000 people. All but 8 to 12 bags
were eventually recovered. Subsequent analysis showed less than lug /I
concentrations in the local water distribution system.
Disposal of waste containers and discharge of pesticides into the
aquatic environment endangers the aquatic life and results in damage to
fishing operations. Measures must be taken to stop this practice. Proper
131
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methods for disposal of un-used pesticides, pesticide wastes, and pesti-
i?? i^n
cide containers have been described. ' Joint federal, state, local,
and industrial regulatory effort is requisite as it concerns safe disposal
of empty pesticide containers, vvastes, over-aged and unwanted pesticides.
b. Accidental
Accidents, caused by spills of pesticides in the Southeast, have
been reported. Studies of Parathion and Azinphosmethyl residues from
accidental and deliberate (research) spills showed that these compounds
81
do not break down as rapidly as expected. The soils studied were
silt loam with high organic content and pH of about 5. 0. The plots were
exposed to weathering and routine sprinkler irrigation. In the top one
inch of soil, Parathion and Azinphosmethyl concentrations were reduced
by 46 and 10 percent, respectively, over a two-year period.
A comprehensive examination has been performed on a shallow
farm1 well contaminated with persistent pesticides..131 The well was lo-
cated less than 25 feet from a site previously used for flushing an insecti-
cide sprayer. Pesticide levels in the swater have been monitored for more
than 4 years, during which time a gradual,decline in concentration has
occurred. Soil core samples indicate a relatively high surface contami-
nation but very little downward percolation. Sediment samples from the
bottom of the well exhibit the highest concentration of all samples.
Surveys of the chlorinated pesticide levels in South Atlantic and
Gulf of Mexico oysters, occasionally exhibit high concentrations of chlori-
132
nated pesticides. , This indicates a possible future problem i.e., contami-
nation of shellfish-growing waters. These waters should be kept under
surveillance.
The fire ant control areas of the Southeast, whether treated with
Heptachlor or Dieldrin, reported disastrous effects on aquatic life. In
Wilcox County, Alabama, most adult fish were killed within a few days
after treatment. Fish from ponds in a treated area of Florida were found
132
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to contain residues of Heptachlor and a derived chemical, Heptachlor
expoxide.
Mirex has been used extensively since 1962 in the Southeast to com-
bat the fire ant. The United States Department of Agriculture contemplated
a full eradication program. Mirex was to be applied aerially over 126 mil-
lion acres. The project was to require twelve years and cost an estimated
1 •>£
200 million dollars. Mirex is highly persistent in the natural environ-
ment and has been shown to be moderately carcinogenic in laboratory
mice. *3^'13^ In short-term field tests, Mirex has been shown to exhibit
a relatively low acute toxicity to marine crustaceans. However, subse-
quent long-term studies have demonstrated delayed toxic effects on crabs
and shrimp. Eighty percent mortality in shrimp and 60 percent mortality
in crabs occurred when they were exposed to only 0.1 mg/l'of mirex in
water for 15 days.1^0 Because it is very insoluble in water and very solu-
ble in animal fat, the chemical moves rapidly from water into aquatic
species and up the aquatic food chain. Current spraying techniques involve
Mirex impregnated corn cobs. This is a risky practice because the un-
touched bait may eventually be carried into waterways by runoff. Incorpo-
ration of the bait into the soil may solve this problem. A national survey
of 5, 000 oysters and other shellfish has demonstrated that Mirex is the
136
fourth most commonly found pesticide residue. It was also reported
that Mirex contaminates shellfish in estuarine drainage areas of the
Southern states.
During the summer of 1950, insect infestation was unusally great
in northern Alabama and some 80 to 95 percent of the cotton farmers began
heavy applications of Toxaphene. ' ' An acre of cotton was sprayed
with 63 pounds of Toxaphene. Frequent and heavy rains washed the pesti-
cide into nearby streams and caused extensive fish kills in 15 tributaries of
the Tennessee River. Two of these streams are municipal water supplies
but no harmful effects to humans were reported.
133
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Fish kills occurred in Choccolocco Creek and in the Coosa River
137
near Anniston, Alabama, during May, 1961. Parathion and /or related
organic phosphorus compounds were accidentally released by a local
chemical company. The pesticides entered Choccolocco Creek via the
Anniston city wastewater treatment plant.
In March, 1965, 2, 500 to 3, 000 pounds of 5 percent Chlordane
wettable powder were spilled from a truck passing through Orlando, Florida.
As much as possible was salvaged from the street. From 1, 300 to 1, 700
pounds were lost into the street's storm drainage system from which it
passed into a dry creek bed near one of the city's lakes. When the poten-
tial danger to the lake was realized, the concentrated water and soil were
67
disposed. The study did not cite the means of disposal.
On September 4, 1967, a truck lost a drum of Malathion in Cordele,
Georgia.1 The Malathion spilled in the street. The local fire department
was called to clean up the street as a traffic safety precaution. The Mala-
thion was washed into the storm sewer syttem which discharges into Gum
Creek, a tributary to the Flint River impoundment, known as Lake Blackshear.
A 0. 32 inch rainfall occurred that night. The next day a massive fish kill
was reported in Gum Creek. On November .2, 1969 another fish kill was
reported on Gum Creek. 138 By November 4, fish were dying over a three
mile reach of the stream below the Cordele wastewater treatment plant.
Approximately 1, 500 fish were killed. The fish kill was likely the result of
Malathion entering Gum Creek through the city wastewater treatment plant.
In August, 1971, a minor fish kill at a state fish hatchery near Cordele was
139
evidence of indiscriminate spraying by a local duster. 7 Two fungicides,
Benlate and Isobac 20, were being sprayed on an adjacent 90-acre peanut
field.
Three fish kills are reported for the state of North Carolina. The
first and third were caused by pesticides that washed into the stream by
heavy rainfall from cultivated fields. The first occurred in Symonds Creek
134
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beginning in May of 1970. The water was found to contain less than
0. 001 mg/1 of Preforam. Significant concentrations of insecticides such
as Toxaphene were measured in the bottom samples and in the flesh of the
fish samples. 14° The second occurred in Hyde County between August 27,
1970 and September 2, 1970, and was caused by aerial overflights of crop-
spraying aircraft applying DDT, DDD, DDE, Parathion, Thiodan, Toxaphene,
and Sevin to soybean fields in the area. These aircraft were observed to be
discharging pesticides into the surface waters. 4* The third occurred in
Lake Junaluska on November 21, 1970. It was caused by Endrin and the kill
continued until the latter part of March, 1971.142
On June 20, 1971, a fire of about ten hours duration occured at an
agricultural chemical warehouse in Farmville, North Carolina. The
warehouse contained a wide assortment of hazardous chemicals including
pesticides. Water was used to extinguish the fire. Dikes were constructed
to retain these waters until they could be pumped to polyethylene-lined pits.
This particular incident points out the need for a rapid response program for
unusually hazardous situations.
An aerial application of 30 pounds per acre of 10 percent Dieldrin
was made near Spring Creek, Hardeman County, Tennessee on March 24,
1961. Approximately 3, 400 acres were treated. Various species of ter-
restrial animals, fish, reptiles, and crustaceans were found dead as a re-
144
suit of this treatment. On February 2, 1962, 1, 500 acres in and near the
north end of Bradley County, Tennessee, were treated with 10 percent
Dieldrin at the rate of 30 pounds per acre by airplane dusting to combat an
infestation of white fringe beetle. Various kinds of fish and animals were
found dead as a result of this treatment. 145
On May 22, 1962, approximately 800 acres in the Crandull area of
Johnson County, Tennessee, were sprayed with 10 percent Dieldrin at 2
pounds per acre. Fish mortality began downstream from the treated area on
the first day after application and continued to be heavy for the next four
days. As a result of the nearly complete decimation of the resident fish
135
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population and the possible public health hazard, Beaver Dam Creek was
closed to public fishing for the remainder of the 1-962 season. 1^5
A heavy fish kill was reported on or about August 21, 1969 in the
lower 11. 4 miles of Beans Creek near Elora, Tennessee. The cause was
Endrin and Methyl parathion associated with runoff from cotton fields.
An estimated 73, 712 fish were killed.146
Although awareness of safety in handling pesticides is increasing,
the task gets more complex as new chemicals are developed. Educational
efforts must reach the entire population including scientists, regulatory
officials, educators, industralists, and the users of pesticides. The rea-
sons for accidents are preoccupation, clumsiness, forgetfulness, disre-
gard, inattention, unpreparedness, distraction, and in general, a common
denominator-lack of awareness. The goal must be complete protection
of the food supply from pesticide residues, protection of the aquatic envi-
ronment from pesticide contamination and total elimination of pesticide
accidents. Safe handling procedures in pesticidal application must be
followed by all users to prevent future accidental spills. 125,147, 151
6. Conclusions
After two decades of intensive use, pesticides are found through-
out the world. They are present in the aquatic environment and in the
atmosphere, even in places far from any spraying sites. The persistent
nature of certain pesticides permits them to be carried from the air and
soil into the aquatic environment. There they can move from one organism
to another via the food web or be cycled in the aquatic environment.
Physical and chemical properties of pesticides govern their move-
ment from one system to another. Sorption and desorption are the pro-
cesses which limit the rate of movement of pesticides from the soil into
the aquatic environment. Specific sorption and desorption mechanisms
for each pesticde under environmental conditions are not known. These
mechanisms are influenced by the clay and organic content, temperature
136
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degree of cation saturation within the soil, and by .climatic conditions.
These factors also influence pesticide sorption-^lesorption at the benthic
level of the aquatic environment.
Pesticide movement into the soil environment is influenced by
sorption, thermal and biomass characteristics, and general chemical
composition. Knowledge of the chemical and physical nature of pesti-
cides facilitates a prediction of their fate. Common fates in the soil
environment are sorption and desorption, photo- and oxidative decompo-
sition, hydrolytic and biochemical degradation, leaching, and phyto-
assimilation. Organic matter favors sorption of both non-ionic and ionic
pesticides. The soils of the Southeast have a high clay content and sorp-
tion of mostly ionic pesticides, is anticipated. Many of the pesticides
applied to the soil are strongly sorbed and do not percolate through the
soil. Pesticides normally are confined to the top few inches of the soil.
Pesticides in the soil are generally in contact with water. The
quantity of water may significantly alter their reactions. For example,
phytoactivity is greatly enhanced in moist soil. Solubilities; partitioning
(soil, water, and air); and interaction of these properties alter the reac-
tions of individual pesticides.
The sorption process and its binding power must be examined re-
lative to leaching. Leaching of pesticides deserves greater attention
because this is the process of most rapid movement from the soil into
the aquatic environment.
The direct movement of pesticides from the soil surface to a
waterway requires consideration of climatic conditions before, during
and after application. Principal consideration should be given to volatili-
zation losses, movements into the soil, persistence at the site of appli-
.cation, and movement of the remaining fraction to uncontaminated areas.
Pesticides move into the aquatic environment from the land even
though universally present in the air. Movement from land may take
137
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several forms but overland drainage is the most significant. Good con-
servation practices reduce overland drainage. The occurrence of
pesticides in waterways is primarily attributed to their sorption by run-
off particles. Deposition and subsequent desorption of the sorbed par-
ticles will provide a continuous source of pesticide to the aquatic en-
vironment.
Considerations should be given to rainfall as a climatic factor
influencing pesticide movement into water. Pesticides movement into
and over the soil is of a uniform nature during periods of low rainfall
intensity. This also occurs during overhead and flood irrigation practices.
High rainfall intensity and furrow irrigation, however, produce dispro-
portionate pesticide movements. This movement can result in waterway
contamination.
Pesticides enter the soil environment through mechanical in-
corporation or infiltration processes. Incorporation (or induced turn-
over) is favored since it reduces atmospheric and runoff contamination.
However, plant uptake and persistence of pesticides is increased.
Information on pesticide decontamination is needed. Sorption by
activated carbon is the only method presently available for removing
pesticides from water. However, suitable methods for disposal of the
sorbed materials has not been developed. Thermal, photochemical and
biological degradation are considered as possible decontamination methods
in instances where concentrated pesticides occur. Photochemical, bio-
logical and sorption processes offer potential for removal of low-level
concentrations in waterways.
Current agricultural application practices result in contamination
of the aquatic environment through atmospheric processes. Those pro-
cesses which contribute to contamination include volatilized fallout and
washout, drift from dusting and spraying operations, and wind-blown,
pesticide-treated soils. Other aerial or atmospheric routes include
138
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incineration of pesticide contaminated materials and direct application
of pesticides into the aquatic environment.
Case studies have documented that runoff, accidental spills, and
intentional pesticide dumping are prevalent means of entry into the aquatic
environment. Non-selective toxicity and subtle long-term effects can
create ecological imbalances. Therefore, there is an urgent need to
use existing and safer pesticide alternatives, to better educate pesti-
cide users regarding potential hazards, and to limit usage of persistent
pesticides.
7. Recommendations
1. Federal and state pesticide control programs should be expanded
to promote the development of more selective, less persistent,
less volatile pesticides, and more efficient application methods.
2. The Environmental Protection Agency should coordinate with
other governmental agencies, e.g. USDA, U. S. Army Corps
of Engineers, and state environmental agencies, to:
• Strengthen the present air, soil, and water monitoring
programs. Specifically, improvements in planning,
sampling, analytical testing and reporting are needed
and additional intergovernmented cooperation is required; and
• Upgrade the educational training programs for the general
public to increase the awareness of the hazards of pesti-
cides to the aquatic environment.
3. The Environmental Protection Agency Pesticides Office should
sponsor research to:
• Reexamine the registration of pesticides which persist
in the environment more than one year and those that
are soluble in animal fat. Registration should be can-
celled if safe, effective alternative methods are available;
• Define the details of persistent pesticide sorption and de-
sorption processes in relation to the specific soils and
aquatic bottom sediments of the Southeast. The competi-
tive relationship of water and pesticides for the sorptive
139
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sites on organic and inorganic substrates should be
determined. Other dynamic forces contributing to
physical movement of pesticides'should be elucidated
under natural environmental conditions;
• Ascertain the concentrations of pesticides added to
the aquatic environment through current irrigation
practices'; and
• Determine the contribution of pesticides to the
aquatic soil environment by atmospheric fallout and
washout.
4. The Environmental Protection Agency Water Quality Office
should:
• Promote development of standard methods and pro-
cedures for use in decontamination of highly concentrated
pesticide spillage. Practical and efficient ^decontamina-
tion procedures for low-level pesticide concentrations,
regardless of source, should also be expanded.
• Develop water quality standards which establish strict
limits on pesticide concentrations in effluents from
point sources, industrial and municipal outfalls. State
water quality control offices should be responsible for
enforcement of the standards.
• Undertake an educational and training program through
state agencies to train selected local government per-
sonnel in emergency procedures to protect the aquatic
environment from pesticide spills.
5. The Environmental Protection Agency Air Pollution Control
Office should:
• Establish standards for incineration of pesticides and
their containers.
• Promote investigations into thermal degradation of
pesticides.
6. The Environmental Protection Agency Solid Waste Management
Office should develop safe disposal techniques for waste pesti-
cides and pesticide containers when landfill and recycling
140
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methods are employed. These techniques should provide for
chemical and/or biological decontamination of the wastes.
7. The Department of Agriculture should:
• Encourage the incorporation of pesticides into the soil
to minimize the effects of overland drainage and atmos-
pheric contamination of the aquatic environment; and
• Examine the use of pesticides where furrow irrigation
is practiced.
8. The Soil Conservation Service should expand its soil erosion
program to emphasize soil retention on pesticide-treated
fields.
9. Federal and state governments, in collaboration with industry,
should expand their research programs to improve application
techniques. The studies should determine optimal droplet size
and area coverage relationships, while considering vaporization
and drift effects.
141
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8. References
1. Bailey, G. W. , Entry of Biocides into Water Courses, Proceedings
of Symposium on Agricultural Waste Waters, Water Resources Center,
University of California, Davis, California, Report No. 10, 94-103,
1966.
2. Kearney, P. C. and Helling, C. S. , Reactions of Pesticides in Soils,
Residue Reviews, 25, 25-44, 1969.
3. Nicholson, H. P. , Insecticide Pollution of Water Resources, Journal
American Water Works Association, .51, 981-986, 1959.
4. Stewart, D. K. R. , Chisholm, D. , and Ragab, M. T. H. , Long
Term Persistence of Parathion in Soil, Nature, 229, 47, 1971.
5. Lichtenstein, E. P. and Schulz, K. R. , Effects of Moisture and
Microorganisms on the Persistence and Metabolism of Some Organo-
phosphorus Insecticides in Soils, With Special Emphasis on Parathion,
Journal of Economic Entomology, 57, No. 5, 618-627, 1964.
6. Eichelberger, J. W. and Litchenberg, J. J., Persistence of Pesticides
in River Water, Environmental Science and Technology, 5_, 541-544,
1971.
7. Nash, R. G. and Woolson, E. A., Persistence of Chlorinated Hydro-
carbon Insecticides in Soils, Science, 157, 924-927, 1967.
8. Hermanson, H. P. , Gunther, F. A. , Anderson, L. D. and Garber,
M. J. , Installment Application Effects upon Insecticide Residue
Content of a California Soil, J. Agr. Food Chem. , 12, No. 4, 722-
726, 1971.
9. Lichtenstein, E. P. and Schulz, K. R. , Effect of Soil Cultivation,
Soil Surface and Water on the Persistence of Insecticidal Residues
in Soils, Journal of Economic Entomology, 54, No. 3, 517-522, 1961.
10. Lichtenstein, E. P. and Schulz, K. R. , Persistence of Some Chlori-
nated Hydrocarbon Insecticides as Influenced by Soil Type, Rate of
Application and Temperature, Journal of Economic Entomology, 52,
No. 1, 124-131, 1959.
11. Lichtenstein, E. P., Fuhremann, T. W. , and Schulz, K. R. , Persis-
tence and Vertical Distribution of DDT, Lindane and Aldrin Residues, ,
10 and 15 Years After a Single Soil Application, J. Agr. Food Chem. ,
, 718-721, 1971.
142
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106. Guenzi, W. D. , and Beard, W. E. , Volatilization of Lindane and DDT
from Soils, Soil Science Society of America Proceedings, 34, No. 3,
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107. Lichtenstein, E. P., Anderson, J. P., Fuhremann, T. W. and
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109. Bradsley, C. E. , Savage, K. E. and Walker, J. C. , Trifluralin
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in Poisoning of Some Farmlands, The Wall Street Journal, July 16,
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in Chemistry Series No. 86, ACS, Washington, D. C. , 135-154, 1969.
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154
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D. THE IMPACT OF PESTICIDES ON THE AQUATIC ENVIRONMENT
1. Introduction
The use of pesticides affects a great variety and number of
organisms. Benefits derived from pesticides are measured by their
effectiveness in reducing populations of pest species. Conversely,
detriment is equated to adverse effects on nontarget species. Because
pesticides are rarely applied in such a manner that only the target
species are exposed, nontarget species mortality will continue to be
expected. Long-and short-term effects on nontarget organisms,
occurring through specific pesticidal usage in the Southeastern region,
are discussed. The movement of pesticide residues through the aquatic
food chain is considered. Physical, chemical and biological synergisms
associated with pesticides in the natural environment are examined.
Finally, the occurrence of low-level concentrations of pesticides in
drinking water is evaluated relative to human health.
2. Movement of Pesticides by Aquatic Organisms
An aquatic organism may be exposed to pesticides through several
mechanisms: direct entry of pesticides into the habitat, movement of
an organism into areas previously contaminated by and retainingpesticides, trans•
portation of pesticides from contaminated habitats via suspended material
or other organism "carriers", or a combination of these. Uptake of
pesticides by aquatic organisms may be direct or indirect. Direct uptake
refers to ingestion or absorption either from direct contact with the
pesticide or from various abiotic, pesticide-contaminated attributes of
the aquatic environment. Indirect or secondary exposure results from
-------
oral ingestion of organisms previously contaminated by pesticides.
For example, such exposure occurs as pesticides and their metabolites
are passed from organism to organism in a food web. The pesticides
1 2
involved in this process are relatively stable.
a. Direct Uptake
The distribution of pesticides in water influences the pathway of
biological uptake. Algae, higher plants, and invertebrate and vertebrate
animals sorb large amounts of pesticides from the water and the sediment.
The quantity accumulated by each biological entity is dependent upon the
physiology and behavior of the organism, the chemical characteristics
of the pesticide, and the seasonal periodicity in the quantities of pesticide
available within a given aquatic habitat.
(1) Plant
Algae are the primary producers in the aquatic environment.
Grazers and higher consumer organisms depend upon algae as a food
source, either directly or indirectly. Therefore, any accumulation of
3
a toxicant by algae constitutes a potential hazard to consumer organisms.
Axenic algal uptake of DDT has been shown to be related to specific
4
partitioning coefficients between a species of organism and seawater.
The need to view accumulation of pesticides in biological material as
5
a partitioning mechanism has been emphasized. This implies that an equi-
librium is established between ambient and internal concentration of pesticides.
Experimental measurement of the pesticide-absorbing ability of diatoms
6
has been performed. In doing so, unnaturally high concentrations of
4
pesticides were employed. Erroneous estimates of uptake may be
obtained since it has been shown that high concentrations may affect the
156
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partitioning coefficient of an organism for DDT residues in water.
Axenic cultures of three species of phytoplankton, Syracosphaera
carterae (a coccolithophorid), Amphidinum carteri (a dinoflagellate),
and Thalassiosira fluviatilus (a centric diatom) were used to determine
4
DDT uptake. Sixteen to 54 percent of the pesticide was removed
the media by the algal cells. An expected value of 30 ppm (parts per
million) DDT residue was obtained. This was based on an estimate of
5
1. 9 x 10 for a relative partitioning coefficient estimate of DDT con-
centration in whole seawater at 15 ppt (parts per trillion). This predicted
value was found to be within the 95 percent confidence interval of
analytical values obtained by electron capture detection, gas-liquid
chromatography of the phytoplankton samples. This report, however,
is open to criticism since it does not present the times required for
each algal species to attain equilibrium uptake.
Filamentous algae are capable of accumulating very large amounts
8
of chlorinated hydrocarbons. The accumulations of Dieldrin by communities
of benthic algae dominated by Stigeoclonium subsecundumin early stages
and later by Synedra ulna, Epithemia sorex, Cocconeis placentula
euglypta and Nitzschia sp., have been studied in laboratory streams.
The influence, of current velocity, light intensity and difference in algae
3
community structure was considered. Dieldrin concentrations ranging
from 0. 05 to 7. 0 ppb (parts per billion) were maintained in the laboratory
streams of natural water for periods of 2 to 4 months. Algal samples
vvere found to contain Dieldrin concentrations ranging from 0, 1 to 100
milligram per kilogram (mg/kg). Algal concentrations of Dieldrin were
as much as 30, 000 times those occurring,in the water. The physical
factors studied had little effect on Dieldrin accumulation but did, however,
exert a strong influence on the species composition of the algal communities.
157
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This indirect influence can affect accumulation. Communities
dominated by filamentous algae accumulated greater amounts of
Dieldrin that did those in which unicellular diatoms were dominant.
Extensive pesticide sorption by select algal communities constitutes
contaminated food source for animals which feed on these forms.
(2) Invertebrates
Daphnia magnais a planktonic organism and is considered to
be among the first animal links in the aquatic food chain. . D aphnia
concentrated DDT by a factor of 16, 000 to 23, 000-fold during exposure
9
to 8 ppb for 24 hours. Uptake was principally through the carapace
and was initially rapid. The DDT level in the living D aphnia reached
75% of its final value within one hour.
The direct uptake of pesticides from the sediment by shrimp
and crabs is associated with feeding habitats. Oysters continously
pump water through their valves during respiration. Simultaneously
extraction of food occurs. The organisms can in this fashion accumulate
pesticide-contaminated particles. These are important food chain
intermediates and commercial food products.
Organic particulate matter, occurring in estuaries, is an
important food source for benthic organisms. In areas where the bulk
of the primary production occurs through the slow bacterial-decomposition
of plant materials such as marsh grasses, rushes and mangroves, there
may be a release of pesticide residues to the substrate. As this decaying
plant detritus is utilized by other microorganisms it becomes an
enriched food source. DDT and its metabolities in the Carmans River
158
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marsh of New York were found to be most abundantly associated with
particles of 250 to 1000 micron diameters. Detritus particles of this
size are ingested by consumer organisms and, in this way, enter
diverse food webs. The mud-dwelling fiddler crab, Uca pugnax, was
shown to concentrate DDT residues in its muscle tissues after consumption
10
of detrital food material from sediment. Similarly, poly chlorinated
biphenyls, PCB, are biologically mobilised. Aroclor 1254-contaminated
sediments from Escambia Bay, Florida, were placed in separate aquaria
containing local, uncontaminated populations of the adult pink shrimp, Penaeus
duorarum, and shore burrowing fiddler crabs, Uca pugilator. Both species
accumulated Aroclor 1254 in their tissues by ingesting contaminated-
sediment particles or by absorbing the leached chemical through the gills.
The amount of Aroclor 1254 in individual crabs in sandy silt sediments
12
averaged 80. 0± 25. 0 mg/kg (wet wt. ) while the hepatopancreag of the
shrimp averaged 60. 0 mg/kg (wet wt.). These tissue concentrations were
found to be directly related to the amount of Aroclor 1254 contained within
the sediment (61. 0 ppm, dry wt.). Greater concentrations of Aroclor 1254
residues were accumulated by shrimp exposed to sandy silt sediments than
from contaminated silt sediments. This was attributed to the chemical
leaching from the sediments, followed by direct absorption through the
gills from the aqueous phase.
Oysters efficiently store trace amounts of pesticides. A
study of uptake rates and retention by 4 different mollusc, showed that
the Eastern Oyster, Crassostrea virginica contained 26 mg/kg; the
hooked mussel, Brachidontes recurvus, contained 24 mg/kg; the European
oyster, Ostrea edulis contained 15 mg/kg and the Crested Oyster, O.
eguestris, contained 23 mg/kg after exposure for 7 days to 1. 0 mg/1
(micrograms per liter) DDT inflowing water. The European Oyster is
extremely sensitive to changes in trace-level concentrations of chlorinated
hydrocarbons. For several years it has been used as an estuarine
159
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monitor organism by the Bureau of Commercial Fisheries at Gulf
14
Breeze, Florida. High-river stages and seasons of maximum pesticide
14
usage in drainage basins correlate with peak residue levels in oysters.
Oysters provide a sensitive indes of the initiation, duration and extent
of chlorinated hydrocarbon pollution in an estuary. The ability of oysters
to concentrate or eliminate residues is dependent upon the level of
pollution, the water temperature and the position relative to the water
flow. DDT residues of 150 mg/kg may require 3 months or longer to
be eliminated while residues of less than 0.1 mg/kg may disappear in
about two weeks. Fresh water mussels and crayfish are filter- and
substrate-feeders, respectively, and are capable of concentrating high
15
levels of pesticides.
It can be concluded that:
o Daphnia, an important fish-food organism, concentrates
DDT rapidly upon exposure to low concentrations in solution.
« DDT and its metabolites are associated with organic
detritus especially in particle sizes ranging from 250 to
1000 microns.
« Detritus feeders concentrate DDT and PCB's from the
sediment. PCB's biologically accumulate in concentrations
approximately equal to sediment concentrations.
e Shrimp are capable of accumulating greater PCB
concentrations from sandy silt sediments than sand
sediments because of leaching of the compound from
the sediments.
e Pesticide monitoring of certain sedentary, filter-fee ding
organisms is useful in assessing the degree of chlorinated
hydrocarbon pollution in a given habitat.
160
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(3) Vertebrates
Tests have been conducted on several freshwater fish native to
the Southeast to determine the pathway of Endrin entry into fish. The
mosquitofish, Gambusia affinis and the black bullhead, Ictalurus melas
_ _^17
demonstrated the ability of accumulate Endrin directly from solution.
.G. af finis assimilated 10. 48 mg/kg during 40 minutes of exposure in a
solution containing 250 fig /I Endrin. The principal mode of entry into.
I. melas was found to be via the gill surfaces.
The ability to accumulate and eliminate pesticide residues has
been demonstrated to occur in certain freshwater and estuarine fish.
Small bluegills, Lepomis macrochirus, and goldfish, Carassius auratus,
14
were exposed to 0.03 mg/1 concentrations of C -tagged DDT, Dieldrin
and Lindane for 5 to 19 hours. The fish were rinsed with uncontaminated
water following exposure and placed in pesticide-free aquaria. Lindane
was eliminated from both species of fish within two days. More than 90
percent of the Dieldrin was eliminated in the first two weeks. Less
than 50 percent of the DDT was eliminated after 32 days. The DDT and
Dieldrin were shown to be readily transferred from .contaminated,to
18
Uncontaminated fish in the recovery aquaria. Similar experiments were
performed using pinfish, Lagodon rhomboides, and croakers, Micropogon
19
undulatus, collected from an estuary near Pensacola, Florida. Each
species was exposed to p, p1 -DDT at 1. 0 mg/1 for two weeks or 0. 1 mg/1
for five weeks under dynamic test conditions. In the latter case, the fish
Were placed in pesticide-free water for eight additional weeks after
exposure to establish elimination rates. Pinfish and croakers exposed to
0. 1 ug/1 DDT accumulated a maximum DDT concentration of 10, 000 to
38, 000 times the aqueous concentration in two weeks. This concentration
161
-------
remained constant thereafter. After eight weeks in pesticide free water,
pinfish lost 87 percent and the Atlantic croakers 78 percent of DDT.
There was no increase or decrease in body concentrations of the
metabolites DDD or DDE. However, fish from the estuary usually
contained as much DDD and DDE as DDT. This indicates that fish
from the estuary obtained the pesticide after it had been metabolized
and passed through the food chain or that DDT was rapidly metabolized
within the fish.
The uptake, retention and release of organophosphates and
herbicides by fish has also been studied. Malathion can be directly
20
absorbed by carp, Cyprinus carpio. Uptake from exposure to 5 mg/1
of Malathion was time dependent for a period up to four days. Subsequently,
equilibrium conditions were established. The equilibrium concentration
was 28 mg/1. The greatest Malath'ion concentrations were found in the
liver. The compound degraded within a week following exposure. Uptake
took place primarily through the gills.
The uptake and release of the herbicide, Simazine, by green sunfish
(Lepomis cyanellus) were measured after exposure to contaminated
21
water and food. Fish absorbed Simazine in amounts directly proportional
to the concentration in the water, i. e., 0. 95 and 2. 29 mg/kg total
residue were measured after three weeks exposure to 1. 0 and 3. 0 mg/1,
respectively. Simazine residues were eliminated from fish after seven
days in freshwater. Little or no Simazine was found in the tissues of
fish 72 hours after feeding. The residue which was detected, occurred
in the viscera.
It can be concluded that fish can readily take up pesticides via
the gills. An equilibrium is established between the body and water
concentrations. Simazine can be accumulated in higher concentrations
through direct absorption than through contaminated food pathways.
162
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Chlorinated hydrocarbons and organophosphates can be absorbed and
concentrated to levels much greater than that of the aqueous phase.
DDT metabolites, measured in fish taken from estuaries, are at much greater
concentrations than those in fish exposed to DDT within the laboratory.
This indicates that substantial quantities are acquired from food chain
organisms. Chlorinated hydrocarbon residues are stored, whereas,
organophosphates are metabolized within a few weeks to a month.
Species differences reflect varying storage ability. For example,
pinfish stored 2.4 times as much DDT as croakers when both were
exposed to 0. 1 /ig/1 DDT. The elimination of stored pesticides from
previously contaminated fish moving into uncontaminated waters,
renders these residues available for uptake by uncontaminated fish.
b. Indirect, Uptake Through Food Chain
Organisms may obtain pesticides directly from the environment
or indirectly through the foods they consume. Lower members of a
food chain may accumulate these compounds and, subsequently, pass
them on to consumers.
(1) Plant-Animal Chain
The primary producers in aquatic food chains are bacteria,
phytoplankton, periphyton and aquatic macrophytes. They can accumulate
pesticide residues. They provide food for herbivorous animals. Thus,
the pesticide residues become biologically transferred and are magnified
as they are passed from plant to animal.
163
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Bacteria are nutrient regenerators which serve as food for
filter-feeding aquatic organisms. A common shallow-water marine
bacterium, Pseudomonas piscicida, was subjected to various levels of
'." - - 2
DDT and Malathion. The bacterium exhibited no alterations in growth
rate or morphology when exposed to 10 mg/1 labelled DDT or 100 png/1
of Malathion. DDT uptake was rapid in a medium containing 1. 0 ug/1
(90 percent uptake in 24 hours). The DDT was found localized in the
cell wall, whereas, the metabolites DDD and DDE occurred in greater
concentration inside the cell. An artificial foo'd chain has been
established using this bacterium as the primary link. In addition,
filter-fee ding oysters and pipefish represented higher consumers. - DDT
was converted to its metabolites, DDD and DDE, during progression
through this chain of organisms. The parent compound is less stable
than the degradation forms. Conversion of the parent compound to its
metabolites is significant since may explain the high levels of DDE
occurring in terminal food chain members (birds and mammals) of
natural ecosystems. A similar conversion with metabolite storage
could occur with other chlorinated hydrocarbons. However, such
metabolites have not been identified, "in situ".
Malathion has a half-life of 55 days in water at pH 6 and four
....,• 2 ; •
to five days at a pH of 8. P. piscicida maintains a high pH (9. 5) in its
surrounding microenvironment. It was proposed that Malathion was
rapidly hydrblyzed in this fashion. Rapid degradation was checked
by allowing the bacterium to hydrolyze Malathion in phosphate-free water
for 48 hours. After that period, the bacteria were removed and algal
cells (Chlorella sp. )were introduced. An untreated Malathion solution
served as a control. Twenty-five percent more algal cells were noted
in the bacterially-degraded solution than in the solution containing
Malathion alone. The increased algal growth was considered to have
164
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resulted from phosphate fertilization provided by the hydrolysis of Malathion.
Other phytoplankton organisms have shown varying responses to
22
chlorinated hydrocarbons. Four species, Dunaliella tertiolecta,
j^occolithus huxleyi, Skeletonema costatum and Cyclotella nana, were
14
subjected to short-term exposures (24 hours) of C -labelled DDT,
Dieldrin, and Endrin in concentrations varying from 0. 01 to 1, 000
ug/1, Seven-day exposures to DDT and Endrin were performed to
determine the effects on cell division. Dunaliella was not affected by
any of the three insecticides in concentrations up to 1, 000 jig/1.
14
The rate of C (photosynthetic carbon) uptake by Skeletonema and
Coccolithus was reduced by each insecticide in concentrations abo've
10 ^ig/1. DDT added daily at 100 jig/1 stopped cell division in
Skeletonema but had no effect on Coccolithus. Endrin had little effect
on cell numbers of Skeletonema, although the rate of growth was
slower. Cyclotella was inhibited by all three insecticides in
concentrations above 1 jig./l. These pesticides could affect natural
populations of food chain organisms through inhibition of cell division,
photosynthesis and growth. Concomitantly, this reduced food source
would be reflected in reduced consumer populations.
The gonads of the marine phytophagus fish, Mugil cephalus, or
mullet, sampled in Florida, have been found to contain concentrations of
DDT ranging from 3 to 10 mg/kg. The bottlenose dolphin, Tursiops
truncatus, feeds extensively on mullet and might be expected to further
concentrate the pesticide. Blubber samples of beached, dead dolphins
were found to contain up to 800 mg/kg DD'T confirming accumulation.
23
Whether DDT was the cause of death was not determinable.
165
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The transfer of persistent pesticides from plants to animals is
of importance in an ecosystem. There may be direct toxicity to the
primary producers or indirect toxicity to consumers. The latter occurs
as a result of feeding on producer organisms within which pesticides
have accumulated. Either form of toxicity will reduce consumer
populations. Eventually decomposers convert the biological material
of higher trophic levels into inorganic products. These products then
become available for production of organisms. Persistent pesticides
could be recycled in this fashion for many years.
(2) Animal ~ Animal Chain
Certain aquatic organisms assimilate pesticides directly from
and establish an equilibrium concentration with the environment. Oysters
establish equilibrium with the water concentration and eliminate body
23
concentrations of DDT when placed in waters free of DDT. Similar
24
observations have been recorded with freshwater fish.
The body concentration does not decline in organisms continuously
exposed to chlorinated hydrocarbons once equilibrium has been established.
The organisms pass the stored pesticides on to their consumer. The
actual quantity accumulated varies with the pesticide. Daphnia containing
24
DDT or Methoxychlor were fed to guppies to complete a food chain.
DDT was rapidly concentrated in the fish to about 8 mg/kg in 20 days while
Methoxychlor never rose above 0. 17 mg/kg. Similar results were
reported as a result of feeding midge larvae and tubificid worms, containing
25
accumulated Dieldrin, to the reticulate sculphin. Methoxychlor appears
readily degradable in certain fish. Snails metabolize neither DDT nor
24
Methoxychlor but accumulate both to high levels.
The food chain pathways and biodegradation of persistent pesticides
166
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(DDT, DDE, DDD, and Methoxychlor) have been studied in a model
ecosystem. Terrestial and aquatic components were involved.
Sorghum was the terrestial factor to which DDT was applied . Food
chain pathways for the labelled pesticide in the system were:
Sorghum—»• Estigmene larva (salt marsh catepillar)
Estigmene (excreta)—»-Oedogonium (alga)
Oedogonium-^-Physa (snail)
Estigmene (excreta)—»• diatoms (4 species)
diatom.s-*-plankton (9 species)
plankton-«-Culex (mosquito larva)
Culex—*-Gambusia (fish)
The fate and conversion of DDT to stable and persistent DDE
14
has been assessed. The application rate of C -labelled DDT
corresponded to 1 pound per acre (1 Ib/acre). One month after
application to Sorghum, 52 percent of the radioactivity in the snail,
58 percent of the radioactivity in the mosquito larvae, and 54 percent
of the radioactivity in the fish was DDE. This indicated that DDT had
been metabolized to DDE. In the fish, DDE was present at a concent-
ration of 110, 000 times and DDT at 84, 000 times the water concentration,
respectively. These accumulations by the fish occurred in three days.
Methoxychlor was rapidly degraded with very little reaching the fish.
However, the snail Physa, stored large amounts indicating that it was
Unable to metabolize Methoxychlor. Biornagnification of DDT and its
residues, DDE and DDD, have been substantiated in natural ecosystems,
27,28,29
food chains and food webs.
The occurrence of persistent pesticides in estuaries has been
reported. During the period 1964 to 1966, a total of 133 samples of
coastal oysters from South Carolina, Georgia, Florida, Mississippi,
167
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Louisana and Texas were analyzed for pesticide residues. Ninety-
four percent of the oysters contained one or more pesticides; 89. 5 per-
cent contained two or more; 81. 2 percent contained three or more; 63. 9
percent contained four or more; and 31. 9 percent contained five or more.
The most frequently observed pesticides were DDE (123 of 131 samples),
DDT (117 of 131 samples), DDD (81 of 81 samples), BHC-lindane (55 of
133 samples) and Dieldrin (54 of 115 samples). The concentration of
the individual pesticides was low. The median values ranged from
0. 01 mg/kg for Aldrin, Chlordane, Endrin, Heptachlor, Heptachlor
epoxide and Methoxychlor to 0. 08 mg/kg for Toxaphene, when present.
BHC-lindane had a median value of 0. 01 mg/kg. The median values for
DDD, DDE and DDT were 0. 02 mg/kg. Although not stated, the total
concentration of the combined pesticides could have been important.
The presence of pesticides in the oysters correlated with spraying
operations in areas adjacent to the estuaries.
31
The fate of pesticides in the estuary has been assessed.
Estuaries are the primary breeding ground and nursery areas of many
oceanic species. Any pesticide accumulated by these species during
their inshore activities will subsequently be carried to the ocean. Fish,
e.g., menhaden and sardines, feed in the estuary, and then move offshore
where they become subject to predation by pelagic fish and birds. In
this way coastal dwellers can pass substantial concentrations of pesticides
to higher trophic forms of the open ocean.
The movement and magnification of persistent pesticides (DDT,
DDE, and DDD) in the food chain have been documented. These
studies have involved species associated with estuarine,environments.
Studies involving inland water species have been limited and mainly
confined to the laboratory. Quantitative information is needed on rate
of transfer and accumulation of other pesticides within food chains and
food webs in each aquatic environment, i. e. , lakes, ponds, rivers,
32
estuaries, and oceans.
168
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3. Impact of Pesticides on Aquatic Populations
Populations of aquatic organisms exhibit both short-and long-
term effects upon exposure to pesticides. Short-term effects include:
immediate kills, reduced activity, loss of equilibrium, and paralysis.
Long-term effects include: population resistance, elimination of prey
or predator organisms competitive ability and alteration of breeding
patterns.
onort-ierm tllects
Organomercurial fungicides in concentrations'as low as 0. l'ug/1
have been shown to reduce photosynthesis in lake phytoplankton isolates
from Florida. Merismopedia sp. , Navicula sp. , .Crucigenia sp. .
Staurastrum sp. and Ankistrodesmus sp. were exposed to four different
commonly used organomercurial fungicides in concentration varying
from 0 to 50 jig/1. Diphenylmercury was least toxic. One jug/1 of
Phenylmercurie acetate; Methyl mercury dicyahdiamide; arid N-
Methylmercuric-l.Z.S^-tetrahydro-S, 6-methano-3, 4, 5, 6, 7, 7-
hexachloropthalimide (MEMMI); caused a significant reduction in
photosynthesis and growth of each culture. At 50 jag/1, uptake of
inorganic carbon ceased. The tentative proposed drinking water quality
standard for mercury is 5. 0 ;ig/i. This is considerably higher than
•5 o
the 0.1 ^ig/1 effective level for phytoplankton.
The green alga, Scenedesmus quadricaudata, has been treated
with Diuron; Carbaryl; 2, 4-D; DDT; Dieldrih; T'oxaphene; and Diazinon.
Diuron and Carbaryl induced the most pronounced effects. Dramatic
reduction in cell numbers and biomass occurred at concentration of 0. 1 mg
Cell density was reduced in four days after treatment with 0. 1 mg/1 of 2,
4-D. DDT, Dieldrin and Toxaphene reduced cell numbers at all treatment
169
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levels {0, 1-1.0 mg/1) within two days of application. Diazinon was the
only compound tested which had no effect on cell numbers, biomass or
35
carbon uptake.
Four species of coastal oceanic phytoplankton, representing
four major classes of algae, were subjected to doses of DDT ranging
from 1 to 500 jug/1. Photo synthetic activity of diatoms was measured
by carbon uptake. All species exhibited reduced carbon uptake with
exposure to less than 10 ;ug /I of DDT. Complete uptake inhibition
occurred at approximately 100 iig/1.
In South Carolina, the marine diatom, CyjLindrptheca olosterium,
has been exposed to the polychlorinated biphenyl, Aroclor 124Z. The
diatom absorbed and concentrated the chemical to levels 900 to 1, 000
times that of the water. This PCB inhibited growth at 0. 1 mg/1.
Decreased levels of RNA and chlorophyll synthesis were observed.
The herbicide, 2, 4-D, reduced the cell density of the green
35
freshwater alga, Scenedesmus. The Gulf Breeze Laboratory in
Florida measured no alteration of photosynthesis in 7 of 9 species of
unicellular, marine algae when exposed to concentrations of 0.1 to
37
10 mg/1 of purified 2, 4-D. In 2 of the 9, photosynthetic enhancement
was observed. Therefore, different algal species respond differently
to specific pesticides. Information is needed to determine whether this
is a result of different environmental conditions or is a basic genetic
difference. Even in very small doses, the quality and the quantity of
the basic food chain populations, (the phytoplankton) were adversely
affected by pesticides.
Tetrahymena pyrifprmis cultures have been exposed to DDT
3 8
from 0.1 to 10 mg/1. Growth decreased with increasing concentrations
of DDT. Populations were reduced by 13. 8 percent at 0.1 mg/1, 20. 2
percent at 1. 0 mg/1, and 25. 7 percent at 10 mg/1. T. pyriformis is more
sensitive to DDT than Paramecium multimicronucleatum and P. bursaria.
170
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The latter cilitates have been reported insensitive to 1 mg/1 DDT over
a period of seven days. During this exposure, P^ multimic ronucleatum
accumulated DDT 264 times greater than the medium concentration and
38
.P. burs aria accumulated it 964 times the medium concentration. This
also demonstrates a wide range of DDT tolerance in ciliates.
Information has been compiled regarding specific pesticides and
their respective lethal concentrations to marine invertebrates (crab,
shrimp and oyster). The chlorinated hydrocarbons are toxic to
fish and mollusc at concentrations as low as 0. 001 mg/1. Organophos-
7
phates have a pronounced effect on crustaceans at equally low levels.
Insecticides, as a group, are more toxic in low concentrations than
are other pe strides, with two exceptions. The fungicide, Delan and
an experimental antifouling arsenical, ET-546, are extremely toxic
to oysters at 2.1/ig/l.
Mirex has a delayed effect on crabs and shrimp. Juvenile blue
crabs and pink shrimp exhibited no adverse symptoms during a 96-hour
41
exposure to 0. 1 mg/1 technical Mirex. These crustaceans, however,
became paralyzed and died within 18 days. Similar paralytic effects
42
Have been demonstrated in freshwater crayfish. Juvenile
.Procambarus blandingi and P. hayi, of Louisiana and Mississippi were
'exposed to 1 to 5 jug/1 Mirex for periods varying from 6 to 144 hours.
After exposure the organisms were transferred to clean water and observed.
Mortality reach 100 percent within 5 days for P. blandingi following a
144 hr. exposure to 1 Jig/I of Mirex. Exposure of P. blandingi to 5 ;ug/l
for 6, 24, and 58 hours, yielded 26, 50, and 98 percent mortality,
respectively, 10 days after initial exposure. A greater sensitivity of
Mirex was observed in P. hayi than P. blandingi. Delayed mortality
"Was apparent in all tests.
171
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The poly chlorinated biphenyl, Aroclor 1254, is an industrially
valuable chemical which eventually becomes a pollutant. It merits
attention because it is similar to chlorinated hydrocarbons in its
persistence and lethality to certain aquatic organisms once it enters
waterways. Laboratory studies in Florida have demonstrated that
42
juvenile shrimp are killed upon exposure to 5. 0 ug/1 of this PCB.
Adult shrimp taken from an estuary were found to contain a maximum
of 2. 5 mg/kg of the PCB. Gammarus oceahicus, exposed to 0. 001 and
0. 01 mg/1 of the PCB for 150 hours died and were found to have severely
44
necrosed branchiae.
Acute toxicity of herbicides to aquatic Crustacea is an important
consideration since they are used in direct applications to control
aquatic weeds and algae in lakes, ponds and waterways. Assessment
of the impact of herbicidal treatment on the microfauna of natural systems
has been neglected. Microcrustacea are significant in the diet of young
and adult fish in the temperate regions. Daphnia magna was exposed to
45
16 aquatic heribicides to determine toxic levels. Dichlone, Molinate
and Propanil were extremely toxic to Daphnia,over the concentrations range
of 0. 014-4* 8 ,mg/1. Thirty -one: herbicides, have been bioassayed to
determine toxicity levels in microcrustacea. Test animals included
the scud, Gammarus. fas,ciatus; glass shrimp, Palaemonetes kadiakensis;
sowbug, Asellus breyicaudus; crayfish, Qrconectes nais; daphnia, Daphnia,
magna; and the seed shrimp, Cypridopsis vidua. Dichlone was most toxic
to these six species. The 48 hour TL (the concentration in water which
... •. " 01) ; , . . .
causes 50% of the test population to exhibit a specific response at a given
time) ranged from 0. 025 nig/I for D. magna to 3.2 mg/1 for crayfish.
The least toxic herbicide to D. magna was 2, 4-D. No adverse effects
were noted at a concentration exceeding 100 mg/1. The first sign of
toxicity was observed as irritability or excitability. This was followed
by loss of equilibrium and coordination, immobilization, and death.
Toxicity patterns (immobilization and equilibruim loss) in natural
172
-------
environments would make affected species more susceptible to prey-
predator pressures. The amphipod, Hyalella, was found to be highly
sensitive to Diquat. The 96 -hour mean TLm value was 4. 8 ug/1.
Immature stages of aquatic insects; dragonflies damselflies, tendipedids,
mayflies, and caddisflies had variable 96 -hour mean TLm values. They
were respectively, > 100, > 100, >100, 33.0, and 16. 4 mg/1.
The DDT susceptibility of Daphnia magna and the seed shrimp,
is vidua, have been measured in terms of TL_ ... Dt magna
.50 - v .....
and the seed shrimp were completely immobilized within 48 hours by
4 and 54 ;ig/l of DDT, respectively. The TL Q Values for the damselfy
(Ischnura verticalis) and the scud (G. fasciatus) were 22, 5 and 3. 6 mg/1,
respectively, in 48 hours. The TL for the fathead minnow, Pimephales
jyomelas, was 24. 6 mg/1 in 24 hours and that of the channel catfish,
jctalurus punctatus, was 25. 8 mg/1 in 24 hours.
It can be concluded that certain members of the arthropods
(crustacea and immature aquatic insects) are acutely susceptible to
chlorinated hydrobarbons and herbicides. These organisms serve as
food organisms for other invertebrates and vertebrates (amphibians
and fish). Any alteration or depletion of their populations:could seriously
affect the entire aquatic food chain.
The most obvious short-term effect of pesticide pollution in the
natural habitat is a fish kill, The Southeast Water Laboratory has
49
documented agriculture runoff of pesticides as a pollutional source.
Several instances of spills associated with pesticide manufacture have
resulted in fish kills. In May 1961, a plant in Alabama manufacturing
Parathion and Methyl parathion accidentally diverted untreated waste
into a small stream.4** Fish, turtleSj and snakes, died along a 28 mile
reach of that stream with lesser kills occurring 90 miles downstream
173
-------
in the Coosa River. A second kill occurred in the same creek in March
1966. This was traced to the same source. Periodic fish kills since
1961 in the Ashley River in South Carolina have been traced to a plant
manufacturing organophosphate pesticides.
Investigations of fish kills in Alabama are made by the Water
Improvements Commission and State Department of Conservation. 50
In 1967, 21 fish kills were reported in the state, 4 of these were attributed
to agricultural insecticides. All occurred in the Tennessee River basin.
in 1968, 48 fish kills were reported. Three were caused by agricultural
insecticides; one in the Lower Tombigbee River and two in the Tennessee
River. The specific insecticides and their sources were not reported.
Information on short-term, high-concentration exposures of
freshwater and marine forms under dynamic test conditions is needed.
Acute toxicity testing of fish under static conditions has been performed;
however, the impact on microflora and microfauna have not been considered
in detail. Large populations of these organisms form intermediate steps
in the food chain. Higher aquatic forms, e. g. , fish, can avoid large
concentrations of pesticides but the sedentary or slower forms cannot.
The latter are also more sensitive than fish to low-level pesticide
concentrations. Therefore, short-term exposure may reduce or
eliminate the food source of fish. If so, fish population reduction or
elimination would follow.
b. Long-Term Effects
Chronic toxicological effects are elicited in an organism as a
consequence of continuous or repeated exposure to low-level concentrations
of pesticides. The time span involved may range from weeks to years.
Chronic effects are dictated by the degree of exposure and by the fate, of
pesticide residues within the animal. If the degree of exposure is greater
than the capacity of the animal to detoxify and eliminate the residues, a
toxicity hazard exists. This is particularly important when pesticide
174
-------
effects are additive or when residues are temporarily stored in tissues.
If the interval between exposures are insufficient to allow for complete
purging, then toxic effects become additive. If uptake rates exceed
those of degradation and elimination, then excess fat-soluble residues
may accumulate to high levels. Such accumulations may cause toxic
effects when fatty tissues are mobilized. Stored residues of a given
concentration may not produce demonstratable toxic effects in the
directly exposed animal but rnay induce toxic effects after being passed
and magnified at higher trophic levels.
(1) Population Changes
Long-term population and ecological changes are subtle and less
obvious than acute effects. Causal factors may be just as subtle and
difficult to identify and assess. Animal populations can be indirectly
affected by pesticides through reduction in food supply. The productivity
of phytoplankton (basic food organisms) can be reduced by exposure to
very small amounts of pesticides. Species of estuarine phytoplankton,
isolated in the Southeast, were exposed to chlorinated hydrocarbons in
4-hour controlled tests. Aldrin, Chlordane, DDT, Dieldrin,
Heptachlor, Methoxychlor,and Toxaphene ,each at a concentration of
1. 0 mg/1, reduced productivity by 70 to 94%. Endrin, Lindane and Mir ex
reduced productivity by 28 to 64%. Exposure of plankton to herbicides
has reduced productivity to a highly variable extent according to
published reports. Certain DDT toxicity tests of marine plankton, 21» °
32
3-re ecologically questionable. The concentrations necessary to induce
significant inhibition far exceeded expected concentrations in the open
32
ocean and exceeded by ten times the solubility of DDT (ng/1) in water.
175
-------
Effects of long-term, low-level concentrations of pesticides on
plant populations are not known. Aquatic plants function ecologically by
producing food and oxygen and by serving as spawning areas and substrates
52
for other organisms. Increased herbicide usage poses a threat to the
stability of estuarine ecosystems which support shrimp, fish and shell-
52
fish. Tests have been performed in Florida, to determine an aquatic
ecosystem response when rooted plants were eliminated. Two natural
coastal ponds were used. One was treated with Dichlobenil and
the other served as an untreated cpntrol. The ponds were without
tidal effects. Physical factors such as sunlight, air temperature,
wind speed and organism behavior were measured. Dissolved oxygen,
pH, nitrates, dissolved carbohydrate, salinity and chlorophyll A were
monitored. Gross algal primary production was determined by light -
and dark-bottle techniques. Both pond basins were approximately 1
meter in depth. Bottom substrata were composed of sand and fine
organic matter. Chemical and physical parameters of the two ponds
were similar prior to treatment. Chara vulgaris^ and Potamogeton
pectinatus were the dominant hydrophytes. Dichlobenil was injected
beneath the water surface to achieve a concentration of 1. 0 mg/1. One
month after treatment, Potamogeton and 80% of the Chara were elimi-
I
nated. An intense bloom, dominated by blue green algae, developed.
This was attributed to the release of nutrients from decomposing vascular
hydrophytes. Four genera of filamentous algae predominated during the
bloom: j)edogonium, Lyngbya, Oscillatoria and Spirogyra. Three species
of zooplankton; Diaptomus dorsalis (copepod), Keratella cochlearis (rotifer)
and Gonyaulax sp. (dinoflagellate) also increased, Homeostatic chemical
conditions were established by the algae during the period of maximal
herbicide effect on vascular plants. Concentrations of phytoplankton
chlorophyll rose to 29. 3 mg/1 after herbicide application, but fell
176
-------
sharply during the period of hydrophyte recovery. Phytoplankton
produced over 90% of the dissolved oxygen during the period of rooted
plant absence but resumed a secondary role after vascular plant
recovery. The herbicide had disappeared from the water and hydros oil
64 days after application. Residues did not persist in the organisms
53
nor -was the degradation product, 2, 6-Dichlorobenzoic acid, detected.
This study has shown that subtle ecological changes can occur when
pesticides are introduced into the aquatic environment. Factors
operating over the long-term could result in trophic population
alterations. For example, a population change from carnivorous to
phytophagus fish species as terminal members could result from a
shift in the populations of lower food organisms. Such a change would
be reflected in increased numbers of plankton-feeding mullet, in an
estuarine environment.
Crustacea are vital food chain organisms. Estuarine shrimp,
fish and shellfish are commercially valuable species. However,
pesticides and other synthetic organic contaminants, transported to
•• * ' 7 ' ••••••.
estuarine basins, stress these populations. Continuous exposure of
white shrimp, Penaeus setiferus, and pink shrimp, P. duorarum, to
low-level concentrations of DDT (0.2 >ig/l) caused a 100 percent
-12 ' ••''. '.:•••:> ' - '
mortality in 18 days. Shrimp exposed to 0. 12 jig/1 died within 28 days.
The largest concentrations were found in the hepatopancreas. Residues
found in natural populations of shrimp from Texas, Florida and South
Carolina contained 0. 01 mg/1 of DDT and its metabolities. These field
residue levels differ from those of laboratory exposed samples by a
factor of 10 or 20 to 1. For example, shrimp exposed to t). 14 >ig/l
of DDT accumulated 0. 21 mg/kg total body residue after 13 days and
0. 15 mg/kg after 19 days. Shrimp that died during exposure had
accumulated a minimum of 0. 13 mg/kg. Concentrations of 0. 03 jig/1 of
DDT would seriously threaten the survival of penaeid shrimp populations
12
in estuaries. Concentrations of this magnitude have been detected
54
in certain areas of the Gulf coast.
177
-------
Small blue crabs, Callinectes sapidus, live in shallow estuarine
waters. In these areas, they may be exposed to chronic sublethal con-
centrations of pesticides. Test crabs fed, molted and grew for 9 months
in seawater containing 0.25 /ig/1 DDT. They survived only a few days at
55
concentrations in excess of 0.5 jug/1. This suggests that the thres-
hold of toxicity is very critical. Populations that can exist in estuarine
waters containing low levels of DDT may be seriously affected by a sudden,
moderate increase, as might occur from runoff.
In two separate chronic exposure tests, immature oysters
(Crassostrea virginica) were first exposed to 1. 0 ug /I concentration of
DDT, Toxaphene and Parathion for 48 weeks. In the second test, the oysters
were exposed for 36 weeks to a mixture of all three of the pesticides at
56
a total concentration of 3. 0 mg/1. Relatively high levels of DDT and
Toxaphene were accumulated but only small amounts of Parathion. The
immature oysters grew to sexual maturity in flowing seawater in both
of the tests. The weights of oysters grown in the pesticide mixture were
5% lower than control oysters. There was no statistical difference in
the weights of oysters grown in solutions of the individual pesticides
and the controls. There were histopathological damages in the kidney,
visceral ganglion, gills, digestive tubules and tissue beneath the gut in
the oysters exposed to the mixture of pesticides. A mycelial fungus was
also present, indicating a breakdown in the oyster's natural defense
against this parasite. These changes were not observed in the oysters
exposed to the individual pesticides. It can be concluded that although
oysters can survive and grow in a low concentration mixture of pesticides,
subtle pathological changes can be induced. Such changes reduce the
ability of the organism to survive under competitive pressures. It was
not established in this study whether these changes were due to a
synergistic effect of all three pesticides in combination or an additive
effect.
178
-------
Chronic exposure to sublethal concentrations of pesticides has
been shown to elicit three observably different population responses in
fish: an adverse effect on population size and number, no demonstratable
57-67
effect or an acquired resistance. Adverse effects on populations
have been observed as changes in mortality or growth rates. Mortality
rates among populations of fish subjected to sublethal doses of chlorinated
hydrocarbons have been found to be proportional to the magnitude of
dose. Dichlobenil elicited numerous concentration-related responses
57
in the bluegill, Lepomis macrochirus. Dose-dependent mortality
has also been observed in the freshwater sailfin molly (Poecilia
latipinna) exposed to Dieldrin. More than half the experimental fish
survived 1. 5 and 0. 75^ig/l Dieldrin but showed a 10% decrease in
growth after 34 weeks. However, 0. 012 mg/1 Dieldrin killed all exposed
58
fish within the first week. Similar dose-dependent mortality and
growth responses have been observed in goldfish and bluegills upon
exposure to Mirex, ' and in spot fish upon exposure to Endrin. "" Off-
spring of a population of sheepshead minnow, Cyprinodon variegatus,
which survived chronic sublethal concentrations of DDT, were found to
be more sensitive to DDT and Endrin than were offspring of unexposed,
control fish. No observable pathological changes were reported for
the continuous exposure of the spot, Leiostomus xanthurus, to sublethal
Endrin concentrations (0. 05 ^ig/1) for 8 months. However, these
same fish were further tested to determine whether sublethal exposure
to Endrin had affected their resistance to acute toxic concentrations
(0. 75 and 0. 56 ug/1) of Endrin. They were less tolerant than controls
during the first 24 hours of exposure. A similar increased sensitivity
of response was observed with the same fish during chronic exposure to
62
Toxaphene. No effects on growth or mortality of the spot fish were
observed when they were subjected to 10 jig/1 concentrations of
63
Malathion for 26 weeks. This may be attributed to the rapid detoxifi-
cation of the organophosphate in seawater. One week after the
termination of the chronic exposure test, the same fish were subjected
179
-------
to lethal concentration of Malathion. However, differences in mortality
rates between control and test fish were not significant. Fish that
survived chronic toxicity testing were further stressed by placing them
under reduced salinity conditions (from 26 percent salinity to 2. 8 and
1. 5 percent). No effects were observed between test and control fish.
Development of resistance to chlorinated hydrocarbons, following
64
long-term exposure, has been demonstrated by freshwater fish. Once
resistance is acquired by fish, the level remains unchanged for several
64
generations if they are reared in insecticide-free environments.
Resistance to high pesticide concentrations were first noted in mosquito-
fish, G. affinis, localized in heavy cotton producing areas of the
Mississippi Delta. Two thousand-fold levels of resistance have been
65
acquired by fish in this area. Resistant populations of G. af finis,
Notemigonus cyrsoleucas, L. cyanellus, L. macrochirus have been
64,66-68
obtained from pond and ditch areas in the Mississippi Delta. These
areas bordered large cotton plantations and are subject to contamination
/ *j £.A_
by run-off, spray drift, and possibly, direct application. ' Resistance
was demonstrated when the fish were exposed to the 36-hour TLm con-
centration of DDT, Toxaphene, Aldrin, Dieldrin and Endrin, The fish
from the Twin Bayou area of the Delta, as compared to control populations
taken from non-agricultural areas, were resistant to all test insecticides
64
except DDT. These fish exhibited resistance to Endrin, considered to
be the most toxic insecticide to freshwater fish, at levels approximately
50-fold greater than those which would affect controls. The fish com-
munities from which these populations have been taken are represented
65
by large numbers of a few species. Top-level carnivores, such as large
mouth bass or crappie were absent. Blood analysis of resistant and non-
resistant strains of N. cyrsoleucas, revealed a 64-fold greater concen-
67
tration of Endrin in the former than in the latter.
180
-------
Population resistance is not limited to fish. ' Freshwater
shrimp, P. kadiakensis, from 3 areas of the Mississippi Delta were up
to 25 times more resistant to 7 chlorinated hydrocarbons, 3 organo-
70
phosphates and 1 carbamate than were non-resistant control shrimp.
Pesticide resistance and accumulation by non-target organisms
in the aquatic environment has caused community structure imbalance.
Top-level carnivores, such as the largemouth bass, egrets, and gar,
are absent in waters supporting pesticide-resistant populations. Resistant
strains of the mosquitofish, G. affinis, can tolerate a body burden of
214. 28 mg/kg after two weeks exposure to 500 ug/1 Endrin. These fish
released Endrin in sufficient concentration when placed in fresh tap
water to kill green sunfish in 15. 5 hr. Adaptive physiological mecha-
nisms that produce resistance in fish and shrimp have not been identified.
Resistance in a species may occur via alteration of membrane permeability,
increased fat content, or altered metabolic pathways.
(2) Physiology and Reproduction
72 73
Organophosphate pesticides inhibit the enzyme, cholinesterase. '
This enzyme is functional in nerve-impulse transmission and ion transport
processes. Tests have been performed on the sheepshead minnow which
relate acute toxicity of Diazinon, Guthion, Parathion and Phorate to in vivo
inhibition of brain cholinesterase. '^ Adult minnows were exposed to acute
doses which killed 40 to 70 percent of the fish in 24 and 48 hours, respec-
tively. The enzymatic activity of exposed 'fish was compared to that of
control fish. The number of fish killed by each organophosphate was pro-
portional to cholinesterase inhibition. The average level of cholinesterase
inhibition in the brain of fish does not always correlate with the percentage
72 74
of fish killed by a particular pesticide. ' Differences within and among
181
-------
populations of fish indicate that cholinesterase activity of a species
74
fluctuates with time. Some organophosphates increase in toxicity with
time. For example, Parathion can be converted in the liver of certain
75
fish to the more toxic Paraoxon, thereby increasing toxicity.
Specific physiological modes of action by chlorinated hydrocarbons
76
are not known. It has been shown that DDT impairs osmoregulation
and active membrane transport. These mechanisms require cholinesterse
32
(ATPase) enzymes. Chlorinated hydrocarbons, including DDE and
78
PCB, induce mixed-function oxidase enzymes. These enzymes are
functional in metabolizing steroid hormones, such as estrogen and
testosterone. Numerous general observations on the impairment of
motor and sensory systems by sublethal concentrations of chlorinated
(\f\ f\*7 V Q
hydrocarbons have been reported. ' ' Symptoms indicate central
nervous system disorders including convulsions, loss of equilibrium,
increased ventilation rate, hyperactivity and hypersensitivity to stimuli.
Although exact mechanisms of pesticide toxicity are unknown,
certain structural abnormalities in tissues and organs are associated
80
with pesticide presence. Nimmo and Blackman, of the Gulf Breeze
Laboratory, have shown that exposure of pink shrimp to a sublethal
concentration of DDT (0. 1 |ig/l) produces blood protein effects. Prelimi-
nary studies demonstrated a decrease in serum protein levels of up to 41%
after 45 days of exposure. Follow-up experiments are being conducted
to determine if a "threshold" concentration is reached prior to this
observable gross effect. Blood changes have been reported for marine
81
puffer fish, following chronic pesticide exposures. Endrin caused an
increase in serum sodium, potassium, calcium and cholesterol,
Chronic exposure to chlorinated hydrocarbons induces systemic
lesions and other structural disorders. Gill changes in goldfish, characteriaed
182
-------
by swollen filaments, appeared 112 days after an initial concentration of
59
1. 0 mg/1 Mirex was applied to a pond. Chronic exposure of spot fish
to 0. 075 p,g/l Endrin for three weeks produced systemic lesions throughout
the brain, spinal cord, liver, kidneys and stomach. Lesions of the
central nervous system, kidneys and stomach were attributed to primary
effects of Endrin. It was probable that necrotic liver lesions were also
attributable to Endrin. Loss of hepatic fat and glycogen was considered
secondary to systemic toxicity. The appearance of lesions offers an
C £ op
opportunity for bacterial and fungal infections. ' Exposure of pinfish
and spot fish to sublethal (5 ug/1) concentrations of the PCB, Aroclor 1254,
82
over a maximum of 45 days produced fungus-like lesions on the body.
These were pronounced and hemorrhagic around the mouth. The affected
spot fish usually ceased feeding, became emaciated, and developed frayed
fins and lesions on the body. These exposure -associated changes could
significantly reduce long-term viability of a species.
Dichlobenil caused karyolysis of hepatocytes and an increase in
83
connective tissue stroma in the liver of bluegills. Chronic exposure
of bluegills to 2. 4-D caused rapid shrinkage and loss of vacuolation in
57
parenchymal cells and a depletion of stored glycogen in the liver. These
fish also exhibited a reduced circulation and simultaneous depletion of
liver glycogen. Blood stasis resulted from congestion of larger blood
vessels in the central nervous system, gills, liver and kidneys. Conges-
tion was caused by amorphous, eosinophilic deposits of serum protein pre-
cipitates. Histopathological damage, induced by chronic pesticide expo-
sure, may or may not be related to function of a particular tissue. There
is inadequate knowledge in tissue -effect mechanisms of pesticide toxicity.
Until these mechanisms are resolved, the effects of pesticide -induced
histopathologies on survival of species in the natural environment cannot
be understood.
183
-------
Survival of a species depends on its ability to reproduce efficiently
and maintain population size. Pesticides are known to interfere with
this process. ' ' However, specific factors contributing to repro-
ductive failure and the frequency and extent of their occurrence are not
57
known. These factors can create subtle changes in population behavior.
Exposure to 5 and 10 mg/1 of 2, 4-D for 5 months caused L. macrochirus
to spawn two weeks later than individuals in pesticide-free water.
Exposure to 1000 |ig/l solutions of Dursban for a period of time sufficient
to kill 50 percent of the test population, caused female mosquito fish,
66
G. affinis, to prematurely terminate gestation. Mosquito fish abortion
has been induced by several chlorinated hydrocarbon insecticides.
Exposure to Dieldrin in concentration of 0. 075 and 1. 5 ug/1 for 34 weeks,
eg
caused the sailfin molly, P. latipinna, to produce fewer numbers of young.
Populations of guppy, Poecilia reticulata, showed a change in size-class
distribution after 7 months exposure to 0. 0018, 0. 0056, and 0. 01 mg/1 of
Dieldrin. The greatest increase was in the number of young. This was
84
attributed to decrease in cannibalism of the young by the parent fish.
The presence of pesticide in an estuary could adversely affect
o c
the breeding behavior of resident Crustacea and fish populations. In
addition, breeding and migratory behavior of fish which spend only a
portion of their life cycle in these fertile nursery grounds could be affected.
For example, fish may avoid pesticide contaminated water and, thereby,
be unable to reach proper spawning grounds. Some fish in Tennessee Valley
Authority lakes moved out of the area when 2, 4-D was applied for the
86
control of Eurasian water milfoil. Avoidance behavior was demonstrated
87
by the estuarine sheepshead minnow (Cyprinodon variegatus). These
were subjected to water containing DDT, Endrin, Dursban, 2, 4-D,
Malathlon and Sevin. Concentrations ranged from 0. 0001 to 0. 1 mg/1 for
DDT, 0. 00001 to 0. 01 mg/1 for Endrin, 0. 01 to 10 mg/1 for Dursban, 0. 01
to 1. 0 mg/1 for Malathion, 0.1 to 10. 0 mg/1 for Seven, and 0. 01 to 10. 0 mg/1
for 2, 4-D. The fish avoided four (DDT, Endrin, Dursban and 2, 4-D)
of the pesticides at the concentrations tested. They avoided neither
Malathion nor Sevin. The fish did not appear to differentiate between
184
-------
differences in lower concentration of the same pesticide but did display
the ability to seek water free of pesticides. Therefore, a prerequisite for
avoidance in nature would be a reasonably distinct boundary between clean
and pesticide-contaminated water and free access for migration. Estuaries
are often characterized by conditions that create such boundaries or inter-
87
faces. There is evidence to suggest that DDT in estuaries may affect
the migratory mechanism of certain fish. The greater the DDT concentra-
88
tion, the greater the preference for high salinity. This could interfere
with spawning behavior since it suggests a tendency of fish exposed to pes-
ticide pollution to return seaward.
The reproductive organs of aquatic organisms are major storage
7 31 89
sites for chlorinated hydrocarbons. ' ' The gonads of the oyster,
Crassostrea virginica, stored approximately twice as much DDT as the
89
digestive tract and other organs. The residues accumulated in such
organs could directly affect gamete maturation and viability, cell cleavage,
89
and vitality of the developing larvae. Fish store chlorinated hydrocarbons
23
in the gonads and in the egg yolk. Pinfish and Atlantic croaker populations
of Pensacola Bay lose an estimated aggregate of 1/2 Ib. of DDT and meta-
31
bolities during egg deposition. The DDT concentration of speckled sea-
23
trout in some areas of the Gulf average about 8 mg/kg. The specific
mechanisms of pesticide influence on egg development and viability of
young of aquatic Southeastern species have not been defined.
Chlorinated hydrocarbon residues have seriously affected repro-
duction of adult water fowl. Eggshell thinning and consequent population
90 91
decline have been attributed to chlorinated hydrocarbon residues. ' DDE
concentrations as high as 2, 500 mg/1 have been found in the yoke portion
90
of eggs with the thinnest shells. Dieldrin, PCB's and Endrin were also
found in lesser amounts. DDT and DDE have been included in the diets of
mallard ducks in controlled experiments. Thin eggshells and reduced
hatching success were abserved. A nationwide survey was conducted
to determine the chlorinated hydrocarbon residue levels in the mallard
185
-------
92
and the black duck. Alabama recorded the highest average level of
DDE in the survey (2. 17 mg/kg in wing samples). Dieldrin, Lindane,
and Endrin were also found in varying amounts. Raptorial birds, such
as the herring gull, Larus argentatus, the bald eagle, Haliaeetus
leucocephalus, and the peregrine falcon, Falco peregrinus, feed on birds,
rodents, mammals and fish. Their populations are suffering a decline
93
in correlation with observed eggshell thinning. In 1967, herring gull
93
eggs were collected from five states including Florida. The shell
thickness had decreased from 1947 to 1952 values while chlorinated hydro-
carbon residues had increased. Brown pelican eggshells from Florida
94
and South Carolina have shown significant thinning (16-17% decrease) as
compared to pre-1947 indices and a related decline in local populations.
Transport of ionic calcium across membrances of the shell gland
90
in birds is an energy-requiring process dependent upon ATPase. Inhi-
bition by DDE could account for certain concentration-effect correlations
(DDE concentration vs. shell thickness) obtained for eggs of the brown
90
pelican and herring gull, DDE, and PCB's have been found to inhibit
90
carbonic anhydrase. The enzyme is functional in deposition of calcium
carbonate in the eggshell and for maintenance of pH gradients across
membranes such as those of the shell gland. Associated with eggshell
thinning is the problem of increased egg eating by parents, decreased
95
clutch size and increased embryonic mortality. Unknown is the impor-
tance of PCB's to observed reproductive failures in species of birds
known to accumulate high concentrations of these substances.
In summary, low level pesticide contamination of water systems
produces subtle and complex changes of aquatic life as a result of chronic
exposure. Physiological changes of individuals are reflected as long-term
changes in biotic community structure. In nature, such changes usually
go unnoticed until climatic damage occurs. For example, elimination
of species considered desirable by man. Waters of the Southeast are
186
-------
contaminated with pesticides and the extent depends on seasonal fluctuations.
Concentrations are often greatest in estuaries during the spawning season
of certain Crustacea and fish. The level and persistence of DDT in Gulf
estuarine fauna suggests that commercial species of shrimp may be endan-
gered in certain sections. Information is needed regarding ecological
alterations induced by chronic stress from pesticides in fresh and estua-
rine waters.
4. Synergestic Effects
Synergism occurs when the simultaneous action of separate factors,
operating together, produce effects greater than the sum of the effects of
the separate factors. Through synergism, a pesticide may act with other
pesticides or with other physical, chemical or biological factors to cause
an adverse effect at concentrations far less than the toxic level of that
substance acting alone. Anomalous laboratory results and field observa-
tions suggest that many interrelationships and mechanisms of synergism
, . .56, 96
remain unexplained.
a. Physical Synergisms
Temperature and pesticides may combine in a synergistic manner
to adversely affect aquatic organisms. For each 10° C increase in tempera-
ture, the metabolic rate of an organism can be expected to double. As
temperature rises, dissolved oxygen concentration of the water decreases.
Temperature effects may combine with pesticide action to increase toxicity.
In Florida it has been demonstrated that oysters are more sensitive to
DDT and Endrin at the same concentration during the summer than during
89
89
the winter. The reverse is true of organophosphate compounds which
can be explained by the reduction in the rate of hydrolysis in colder water.
Trout and bluegill have been exposed to the presence of pesticides
97
and varying temperature. Increased susceptibility was noted with most
compounds as temperature increased. Exceptions were noted for bluegill
susceptibility to Lindane and Azinophosmethyl. They were unaffected by
187
-------
b. Biological Synergisms
Mirex has been found to affect juvenile and adult crayfish
42
differently. Mortality from treatment with 1 to 5 [ig/1 of Mirex for
6 to 144 hours increased with time and was inversly related to animal
size. Juvenile crayfish exhibited higher mortality rates than did adult
crayfish. Juveniles at a length of 1. 5 cm. showed a 55 percent mortality
3 weeks after consuming one granule of Mirex bait while adults of a
3. 0 cm length showed no mortality. Increased toxicity to juvenile
forms over a period of time was attributed to delayed toxic effects of
Mirex. Juvenile forms of other crustacean species frequently display
greater mortality factors than do adult forms. This has been, and will
7
continue to be, increasingly significant in the nursery areas of estuaries.
More information is needed regarding toxicity levels of specific pesti-
cides to immature stages in the life cycle of aquatic organisms.
Amitrole, Dalapon, Endothall, Fenuron, Dichlobenil, Dimethylamine
salt of 2, 4-D, isooctyl ester of 2, 4-DP, and the potassium salt of
Silvex at various concentrations over varying lengths of time had no
appreciable effects on hatching of fish eggs (bluegill, green sunfish,
102
smallmouth bass, lake chub-sucker and stone-roller). However,
the fry were found to be more susceptible to the toxic action of some
herbicides than were fertilized eggs. Concentrations greater than 5 mg/1
of Silvex and 10 mg/1 of Fenuron reduced the number of fry produced
from fertilized eggs. Different formulations of some herbicides showed
different toxicities. Endothall did not affect the fry at concentrations
of 10 and 25 mg/1. Carp eggs have been exposed to DDT, Ghlordane,
Dieldrin, Endrin, Diazinon and Guthion at a concentration of 1. 0 mg/1.
Embryo development was stimulated and the incubation'time was reduced
by one -third.
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temperature increases to 23. 8° C from 12. 7*C in the presence of Methoxychlor.
Susceptibility decreased as the temperature increased. This anomaly could
be the result of decomposition of the pesticide at higher temperatures.
Similar experiments have been performed in Mississippi with mosquito
fish, golden shiner, bluegill and green sunfish. They were exposed to
DDE, Endrin, Aldrin, Dieldrin and Toxaphene at different seasons of the
64
year. Higher tolerance levels were measured during March and April
than during June and July. For example, green sunfish tolerance to Endrin
over 36 hours declined from 575 to 160 |xg/l. Seasonal sensitivity to lethal
concentrations of DDT and Endrin has been noted in sheepshead minnows of
Florida. Sensitivity to 15 mg/1 of DDT decreased during colder months,
March to June, and increased during warmer months, August to September.
98
Salinity has been tested as a synergist. Salinity-tolerant mos-
quito fish, Gambusia affinis were acclimated at 0.15, 10 and 15 parts per
thousand (ppt) salinity. DDT, DDD or DDE were introduced. A salinity
of 15 ppt reduced the amount of DDT, DDE and DDD accumulated. DDT
uptake was less than either DDE or DDD. DDT has been shown to impair
the osmoregulatory system of the marine eel, Anguilla rostrata. This
effect may explain reduced DDT uptake with increased salinity.
The fathead minnow, Pimephales promelas, was exposed to Endrin
99
or DDT under static and dynamic conditions. Comparative 48- and
96 -hour Endrin exposure indicated a slightly higher LCgQ value during
static as compared with dynamic tests. The higher toxicity of Endrin
under static conditions was not explained. However, the sharp increase
in toxicity of DDT in static conditions as opposed to dynamic was attributed
to decreasing oxygen concentrations and/or synergism with fish-produced
metabolites (e.g., ammonia or CO). Assessing toxicity of pesticides,
99
under static test conditions, can result in significant error. The
189
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pesticides could interact synergistically with numerous and varying
physical and chemical factors of the aquatic environment. A greater
emphasis must be placed on dynamic bioassay testing under natural
conditions.
Certain chemical compounds have been shown to increase the
toxicity of specific pesticides. Copper sulfate pentahydrate (CSP) has
been applied in conjunction with Diquat to control hydrilla, egeria
and Southern naiad. This combined treatment yields better control
than does individual application. Submerged plants absorbed more
copper from pools containing both substances than from pools containing
only CSP.
Pesticides can synergize with pH. This could be a result of pH
induction of hydrolysis products that are more toxic than the parent
compound. The fathead minnow has been exposed to Malathion under
varying pH conditions. When Malathion was introduced under high
pH conditions, the metabolic product, Diethyl fumarate was formed. The
metabolite was found to be more toxic in the presence of the parent
compound than either substance acting alone. More information is
needed on synergisms between parent compound and degradation products.
Oysters exposed to a mixture of 1. 0 |xg/l each of DDT, Toxaphene and
Parathion showed less growth and developed tissue pathology. Changes
were not evident in organisms reared in 1.0 |ig/l of either DDT, Toxaphene
or Parathion. The results suggest that the effects may have been caused
by a synergism among the three toxicants.
In summary, the abiotic environment can alter the effect of a
pesticide by either increasing or decreasing biological uptake and
activity. Physical and chemical factors of the environment must be
considered in conjunction with pesticide usage.
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The egg stage of an animal can be relatively resistant to pesticides.
The yolk material nourishes the developing embryo. Oxygen and water
are obtained from the external environment. The offspring may not be
exposed to pesticides until the yolk material has been depleted and/or
hatching occurs.
Fingerling mosquito fish have been grouped into size-class and
104
exposed to 41 ppt concentrations of DDT. The smaller fish were
more efficient in DDT uptake than were older fish within a 48-hour period.
This was attributed to increased surface area to volume ratios in the
smaller fish relative to those of larger fish. This relationship may
be another factor that acts synergis tic ally to alter toxicological effects.
Pesticide synergisms with such factors as temperature, pH,
other pesticides, and stage of biological development have been estab-
lished to species native to the Southeast. Synergisms, resulting from
multiple-pesticide usage, have not been investigated thoroughly. Static
Moassays are likely to result in limited toxicity information that do
not recognize synergestic effects. The results would be of little use
in predicting the effect in natural systems. Dynamic, carefully-de signed
tests are needed.
5. Health Implication of Pesticide Contaminated Water
The routes of pesticides from the contaminated-water environment
directly to man are limited. Potable water is the most obvious route.
Less obvious is the route through consumption of pesticide-contaminated
food such as crabs, shrimp, fish and waterfowl.
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a. Contamination of Potable Water Supplies
DDT residues were found in the Tennessee and Chattachoochee
Rivers, while Dieldrin was reported in the Savannah River during
105
1962. A 1964 survey of 56 U. S. rivers revealed that 44 were con-
taminated with chlorinated hydrocarbons in concentrations ranging
from 0. 002 to more than 0. 118^ig/l. Dieldrin occurred in 39 rivers,
DDT or DDE in 25 rivers, and Endrin in 22 rivers. Between 1964
and 1967 water samples were obtained from 10 selected municipal
107
water supplies and analyzed for chlorinated hydrocarbons. Raw water
sources for these systems were either the Missouri or Missippi Rivers.
The only sampling site located in the Southeast was at Vicksburg, Mississippi.
Of the 41 samples obtained at this site in 1964, four were positive for
Aldrin, 29 for DDE, 28 for DDT, 23 for Dieldrin and 34 for Endrin. The
survey was expanded to monitor 5 additional pesticides in 1965.
Lindane was present in 4 of 6 samples, BHC in 5 of 6, Aldrin in 3 of 45,
Heptachlor in 1 of 24, HCE in 6 of 37. Chlordane was not detected in 6
samples. Ingestion of at least 9 known pesticides was involved in con-
sumption of this water.
The Flint Creek basin of Alabama was monitored for pesticides
108
between 1959 and 1962. The entire 400 square mile basin is located
in a predominately cotton producing area. Flint Creek and the West
Fork of Flint Creek are the principal streams of the basin. A water
treatment plant is located downstream from the junction of the forks and
serves Hartselle and Flint, Alabama. Pesticide analyses of treated and
raw water samples at the treatment plant revealed chronic contamination
by Toxaphene and BHC. Treated water contained pesticide concentrations
comparable to the raw water. DDT was not found although it was used
extensively within the basin. BHC contamination was attributed to crop
dusting in the basin. The concentration of pesticide reaching the public
via drinking water was less than ljng/1. Such levels go unnoticed by the
consumer.
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Five municipal wells in Florida were found to be contaminated
100
With 1 >ig/l of Parathion. Canal water in the area contained Parathion
as a result of extensive agricultural use. It was postulated that the
109
wells were contaminated by percolation of ground water.
Chemical and biological evidence indicates that surface waters
of the United States are contaminated with chlorinated hydrocarbon
insecticides. In localized areas, surface waters are polluted with
herbicides. Organic pesticides can contribute tastes and odors to
potable water. Several organic triphosphates and 2, 4-D produre
tastes and odors far below toxic levels. Establishing standards for
selected pesticides in drinking water based on taste and odor levels
could offer a margin of safety to consumers in those specific cases.
Once pesticides reach water treatement plants, removal through
conventional coagulation and sand filtration becomes selective. This
is attributable to variations in solubility and adsorption. In one case,
DDT at a concentration of 10 jig/1 was effectively removed while Lindane
and Parathion were not. The latter was presumably a result of greater
water solubility. Chlorine treatment did oxidize Parathion to its toxic
derivative, Paraoxon. Potassium permanganate at 1 to 5 mg/1 and
ozone at dosages up to 38 mg/1 were ineffective. Powdered activated
charcoal was of limited effectiveness. Lindane reduction from 10 to
1 }ig/l, required 29 mg/1 carbon. Percolation through a bed of granular
carbon was the most effective means of treatment. More than 99 percent
of the applied DDT, Lindane, Parathion, Dieldrin, 2, 4-D, 2, 4, 5-T ester,
and Endrin concentrations were removed. Recent information indicates
that occasional high pesticide concentrations may be reduced to acceptable
112
levels by standard water treatment practices. However, chronic, low-
level concentrations are difficult to remove by current practices. At^
present, removal of pesticides from large bodies of water is economically
unfeasible. Therefore, long periods will be required for renovation
by natural processes. As persistent pesticides are replaced by more
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readily-degradable compounds will be facilitated.
Increasing population growth and industrialization of the Southeast
has resulted in more intensive use of available surface waters. Major
supplies in this area are contaminated with persistent pesticides.
Removal of low-level concentrations is not accomplished by conventional
treatment practice. Hence, pesticides become available to humans in
their drinking water. These low-level concentrations, if accumulated,
may constitute health hazards.
b. Ingestion via Food Products
The main source of general population exposure to DDT and Dieldrin
114
occurs via ingestion of residues in food. Residues of DDT and its
metabolites have been reported in processed fisheries products (fishmeal,
115
oyster, and shrimp). These residues ranged from 0. 02 to 0.063 mg/1.
Nine of fifty river monitoring stations in the United States are located in
the Southeast. Game fish from these stations have been shown to
contain chlorinated hydrocarbons. Channel catfish of the St. Lucie
canal in Florida and largemouth bass from the Tombigbee River in
Alabama contained 58 mg/1 and 10 mg/1 of DDT and its metabolites,
respectively. These levels were greater than those generally reported
for other species of fish in other locations. Thes4 results were
obtained from whole body samples and not exclusively from edible
portions. Chlorinated hydrocarbons accumulate in the fatty tissues of
fish. Once fish are processed for consumption, the pesticides generally
remain with discarded visceral portions. Shrimp primarily accumulate
pesticides in the non-consumed hepatopancreas. Oysters concentrated
pesticides in their tissues to levels thousands of times greater than the
water concentration. These tissues normally rid themselves of pesticides
within a short period if placed in uncontaminated water. Where oyster-
harvests are contaminated by pesticides, they can be decontaminated prior
to marketing by placement in clean water.
194
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Six of seven pesticide residue levels in domestically-processed
117
seafood for the years 1964 to 1969 exceeded those of imported products.
BHC was the exception. Domestic fish products contained 74. 4 percent
of chlorinated hydrocarbon residues compared to 56. 1 percent for
imported varieties. DDE was present in 66. 3 percent of the domestic
varieties at an average of 0. 49 rng/1. It was present in 49. 1 percent
of the imported varieties at an average of 0. 06 mg/1. Heptachlor,
Heptachlor epoxide, Aldin and Chlordane were not found in imported
shellfish products. DDE ranked highest in terms of incidence and
averaged 0. 005 mg/1. Forty-eight percent of the domestic shellfish
products contained chlorinated hydrocarbon residues compared to 16. 8
percent for imported products. More agricultural pesticides are used
in the United States than in any other country. Runoff amounts are
deposited in streams and rivers. These are eventually deposited, in
part, into estuaries and become available to estuarine organisms.
The effect of human ingestion of DDT over a two-year period
118
has been determined. Ninety men were divided into three groups:
one group received no DDT, another received 3. 5 mg/man/day, and the
last received 35 mg/man/day over the two years. The dosages were
established at 20 and 200 times the normal dietary intake leve] for DDT.
The highest dosage was chosen to represent one-fifth of the smallest
amount known to cause mild, transient sickness in man. Careful
physical examination and laboratory testing failed to establish clinical
evidence of adverse effects. DDT was confined to the body fat and was
proportional to dosage. About one year was required to establish constant
tissue storage levels of 234 to 340 mg/kg. Tissue biopsy examination
revealed no further increase in storage level once equilibrium was
attained. DDT release from body fat was found to be a much slower
process than its deposition. The storage form was DDE.
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Prolonged occupational exposure of an individual to DDT has
been reported. A storage level of 64. 8 mg/kg of DDT and its metabolites
118
was established. The individual exhibited no adverse effects.
Autopsies were conducted of 146 persons accidentally or violently
killed in Dade Cotuity, Florida. These examinations included measurement
of Dieldrin storage in the adipose tissue. A range of 0. 19 to 0.24 mg/kg
119
was obtained when samples were grouped according to age, race and sex.
This level was not statistically different from results obtained in other
parts of the world. Worldwide distribution fell into a range of 0. 15 to
0.29 mg/kg. However, a value of 0. 03 mg/kg was reported in India.
It was concluded that Dieldrin storage does not vary significantly
according to age, race, and sex. This contrasts with the significant
differences calculated for concentrations of DDT and DDE associated with
these demographic variables in the same fat samples.
Individuals ingesting persistent pesticides establish storage con-
centration relative to the amount ingested, i. e. , storage is proportional
to dosage. Information regarding the time required to establish equilibrium
storage of DDE is not available. Pesticide concentrations in excess
of storage levels are excreted in the urine. Amounts in fresh-water fish
and marine shellfish are below storage levels. Continued monitoring is
essential to maintaining low-level concentrations in the aquatic environment
and resources derived therefrom. Low-level exposure of healthy adults
118
to certain pesticides over periods of two-years , did not show obvious
hazard. Such studies must be extended to provide a sound epedemiological
basis for defining safe chronic exposure limits.
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6. Conclusions
Aquatic vegetation can sorb large quantities of pesticides. These
sorbed substances can be metabolic ally degraded or stored. The stored
compounds may either become part of a food web or be returned to the
sediment. Information is not available on sorption capacities and degra-
dation of pesticides by aquatic vegetation of the Southeast.
Fish and filter-feeding sedentary invertebrates sorb pesticides
directly from the water. Residue levels closely correlate with surface
water concentrations, which relate to seasonal agricultural practices
and rainfall.
Pesticides such as DDT, Dieldrin, Endrin, Toxaphene, Mirex and
BHC are bioconcentrated. Food chain studies have been primarily focused
on DDT without regard for other stable chlorinated hydrocarbons.
Herbicides, in general, are less toxic to fauna than other pesti-
cides. This is attributed to the fact that these compounds degrade rapidly
and do not bioconcentrate. The affects of herbicides on nontarget aquatic
plant communities have not been specifically identified. For example,
the reduction of consumer populations is accompanied by a shift in plant
species to hardier algae that are not consumed by grazers.
Considerable emphasis has been placed on testing fish for acute
toxicity. Acute toxicity levels have been established for several individual
species under laboratory conditions. These values serve only as quantitative
indices of toxicity under specific conditions and do not reflect accurate
responses under varying natural environmental conditions.
There is a need for toxicological information on lower life forms
obtained under dynamic test conditions. In such studies, continuous
flow of natural waters under environmental conditions at the site, should
be emphasized. Resulting information would be of greater value in
assessing the effect of contaminants such as pesticides than that obtained
under static monospecific test conditions..
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More emphasis should be placed on the long-term (chronic) effects
of pesticides. Toxicological information must be developed for the
lower and intermediate aquatic organisms as well as for fish. Population
changes in lower food chain organisms will ultimately be reflected in
the long-term stability of higher consumers.
Quantitative data on residue transfers in fresh water and marine
food webs are not available. There is a lack of information on the com-
plex species interrelationships of food webs. Some forms establish an
intake, storage and elimination equilibrium.
The presence of PCB compounds in Southeastern water, its biota
and its sediments is widespread. These compounds are stable,biocon-
centrate in tissues and interfere with calcium deposition in birds. This
effect has been demonstrated with DDT.
Pesticide synergisms with such factors as temperature, water
hardness, and stage of biological development have been established in
species native to the Southeast. Synergisms, resulting from multiple
pesticide residues, have not been investigated although many pesticides
are applied in combination to ensure control of target species.
Chlorinated hydrocarbon residues at microgram per liter con-
centration are not completely removed by standard water treatment
practices. The adverse effects of long-term, low-level, pesticide
exposure in humans is not known.
Monitored pesticide residues in fish, shellfish and ducks are not
directly useful in assessing quantities of pesticides reaching humans via
these foods. Analyses are typically made on a whole-produce basis and
not the edible portions only.
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7. R e c omm end ation s
1. The Environmental Protection Agency should expand in-house and
supported monitoring activities to identify pesticides and their metabolites
in the aquatic environment (surface and ground fresh waters and estuarine).
This activity should be complemented by an expanded program of develop-
ment of improved pesticide concentration and analytical procedures.
The elimination of the masking effect of polychlorinated biphenyls (PCB)
in analyses of pesticides is a specific analytical need.
2. The Environmental Protection Agency should expand in-house and
supported toxicological measurements of the effect of pesticides on
aquatic flora and fauna.. Emphasis must be given to dynamic rather
than static test procedures. Under these conditions the simultaneous
effect of multiple contaminants and environmental factors can be deter-
mined.
3. Long-term (chronic) epidimeological information should be developed
for the effect on life forms ranging from microflora and microfauna to
man. Programs of the National Institutes of Health should be oriented
to fill this need.
4. The Environmental Protection Agency should sponsor the development
of water quality standards for pesticides based upon residue tolerances
of sensitive and essential members of the food web.
5. The activities of the Working Group of Pesticides, an intergovern-
mental agency organization, should be continued and expanded if necessary.
This liaison minimizes the possibility of duplication of in-house and
sponsored studies. It provides a potentially valuable forum for input
to development of improved analytical techniques and water quality
standards.
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life, Anal. Meth. for Pest. , Plant Growth Reg. and Food Add. , 5,
147-189, 1967.
2. Johnson, R.F., Food Chain Studies, Bureau of Commercial
Fisheries, Report, Gulf Breeze, Florida, Circ. # 260, 9-11, 1966.
3. Rose, F. L. and Mclntire, C. D. , Accumulation of Dieldrin by
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4. Cox, J. JL., Low Ambient Level Uptake of 14C-DDT by Three Species
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Biphenyl (Arochlor 1242): Effects of Uptake on Growth, Nucleic Acids,
and Chlorophyll of a Marine Diatom, Bull. Environ. Contam. &
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55. Lowe, J. I. , Chronic Exposure of Blue Crabs, Callinectes sapidus,
to Sublethal Concentrations of DDT, Ecology, 46_, 899-900, 1965.
56. Lowe, J. I. , Wilson, P. D. , Rick, J. , and Wilson, Jr. , J. ,
Chronic Exposure of Oysters to DDT, Toxaphene and Parathion,
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-------
59. Van Valin, C. C. , Andrews, A. K. , and Eller, L. L. , Some
Effects of Mir ex on Two Warm-Water Fishes, Trans. Am.
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60. Lowe, J. I. , Some Effects of Endrin on Estuarine Fishes, Presented
at the 19th Annual Conference of Southeast Association of Game &
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61. Holland, H. T. , and Coppage, D. L. , Sensitivity to Pesticides in
Three Generations of Sheepshead Minnows, Bull. Environ. &
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62. Lowe, J. I. , Chronic Exposure of Spot, Leiostomus xanthurus, to
Sublethal Concentrations of Toxaphene in Seawater, Trans. Am.
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63. Holland, H. T., and Lowe, J. I., Malathion: Chronic Effects on
Estuarine Fish, Mosquito News, _26(3), 383-385, 1966.
64. Ferguson, D. E. , Culley, D. D. , Cotton, W. D. , and Dodds, R. P. ,
Resistance to Chldrinated Hydrocarbon Insecticides in Three Species
of Fresh Water Fish, BioSc'ience J.4(1I), 43-44, 1964.
65. Ferguson, D. E. , The Effects of Pesticides on Fish: Changing
Patterns of Speciation and Distribution, In: Gillett, (Ed. ) J. W. ,
The Biological Impact of Pesticides in the Environment, Proceedings
of a Symposium, Environmental Health Sciences Series No. 1,
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66. Ferguson, D. E. , Gardner, D. T. and Lindley, A. L. , Toxicity
of Dursban to Three Species of Fish, Mosquito News, 26(1),
80-82, 1966.
67. Ludke, L. J. , Ferguson, D. E. and Burke, W. D. , Some Endrin
Relationships in Resistent and Susceptible Population of Golden
Shinners, Notemigonus crysoleucas , Trans. Am. Fish. Soc. ,
97, 260-263, 1968.
68. Ferguson, D. E. and Bingham, C. R. , Endrin Resistance in the
Yellow Bullhead, Ictalurus natalis, Trans. Am. Fish. Soc. ,
325-326, 1966.
69. Ferguson, D. E. and Gilbert, C. C. , Tolerances of Threfe Species
of Annuran Amphibians to Five Chlorinated Hydrocarbon Insectic ides,
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205
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70. Naqui, Syed M. and Ferguson, Denzel E. , Levels of Insecticide
Resistance in Fresh Water Shrimp, Palaemonetes kadiakensis,
Trans. Am. Fish. Soc. , 99, 696-699, 1970.
71. Ferguson, D. E. , Ludke, L. J. , Finley, M. T. and Murphy, G. G. ,
Insecticide - Resistant Fishes: A Potential Hazard to Consumers,
J. Miss. Acad. Sci., 13, 138-140, 1967.
72. Coppage, David L. , Enzyme Systems of Estuarine Organisms,
Bureau of Commercial Fisheries, Report, Gulf Breeze, Florida,
Circ. #325, 31-32, 1969.
73. Weiss, C. M, , Physiological Effect or Organic Phosphorus In-
secticides on Several Species of Fish, Trans. Am. Fish. Soc. ,
2P_, 143-152, 1961.
74. Gibson, J. R. , Ludke, J. L. , and Ferguson, D. E. , Sources of
Error in the Use of Fish Brain Acetylchlorinesterase Activity as
a Monitor for Pollution, Bull. Environ. Contam. and Toxicol. ,
4(1), 17-23, 1969.
75. Gibson, J. R. and Ludke, J. L. , Effect of Sesamex and Brain
Acetylchbrinesterase Inhibition by Parathion in Fishes, Bull.
Environ. Contam. fc Toxicol.
76. Janicki, R. H. and Kinter, W. B. , DDT: Disrupted Osmoregulatory
Events in the Intestine of the Eel, Anguilla rostrata, Adapted to
Seawater, Science, 173, 1146-1147, 1971.
77. Yarbrough, J. D. and Wells, M. R. , Vertebrate Insecticide
Resistance: The in Vitro Endrin Effect on Succinic Dehydrogenase
Activity on Endrin-Resistant and Susceptible Mosquitofish, Bull.
Environ. Contam. k Toxicol, 6/2), 171-176, 1971.
78. Yap, H. H. , Desaiah, D. , and Cutkomp, L. K., Sensitivity of
Fish ATPases to Polychlorinated Biphenyls, Nature, 233, 61-62,
1971.
79. Warner, R. E. , Peterson, K. K. and Borgman, L. , Behavioral
Pathology in Fish: A Quantitative Study of Sublethal Pesticide
Toxication, J. Appl. Ecol. , 3_(suppl), 223-248, 1966.
80. Nimmo, D. R. and Blackman, R. R. , Shrimp Physiology, Bureau
of Commercial Fisheries, Report, Gulf Breeze, Florida, Circ. #335,
29-31, 1969.
206
-------
81. Eisler, R. and Edmunds, P. H. , Effects of Endrin on Blood and
Tissue Chemistry of a Marine Fish, Trans. Am. Fish. Soc. ,
£5, 153-159, 1966.
82. Hansen, D. J. , Parrish, P. R. , Lowe, J. I., Wilson, Jr., A. J. ,
and Wilson, P. D. , Chronic Toxicity, Uptake, and Retention of
Aroclor 1254 in Two Estuarine Fishes, Bull. Environ. Contam.
& Toxicol, 6(2), 113-119, 1971.
83. Cope, O. B. , McCraren, J. P. and Eller, L. L. , Effects of
Dichlobenil in 'Two Fishpond Environments, Weed Sci. , 17(2),
158-165, 1969.
84. Cairns, J. J. and Loss, J. J. , Changes in Guppy Populations
Resulting from Exposure to Dieldrin, Progr. Fish Cult., 28(4),
220-226, 1966.
85. Hansen, D. J., Behavior of Estuarine Organisms, Bureau of
Commercial Fisheries, Report, Gulf Breeze, Florida, Giro. #335,
23-26, 1969.
86. Smith, G. E. and Isom, B. G. , Investigation of Effects of Large-Scale
Applications of 2,4-D on Aquatic Fauna and Water Quality, Pesticides
Monitoring J. ,_1_(3), 16-21, 1967.
87. Hansen, D. J. , Avoidance of Pesticides by Untrained Sheepshead
Minnows, Trans. Am. Fish. Soc., 9£(3_K 426-429, 1969.
88. Hansen, D. J., Effect of Pesticides on the Salinity Preference of
Fish. , Bureau of Commercial Fisheries, Report, Gulf Breeze,
Florida, Circ. #335, 26-28, 1969.
89. Butler, P. A., The Problem of Pesticides in Estuaries, Am. Fish.
Soc., Spec. Publ. #3, 110-115, 1966.
90. Risebrough, R. W. , Davis, J. and Anderson, D. W., Effects of
Various Chlorinated Hydrocarbons, In: Gillett, (Ed.), J. W. , The
Biological Impact of Pesticides in the Environment, Environmental
Health Sciences Series, No. 1, Oregon State University Press,
40-52, 1970.
207
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91. Stickel, L. F. , Organochlorine Pesticides in the Environment,
Bur. of Sport Fish, and Wildl. , Fish, and Wildl. Serv. , Kept.
#119, 17-22, 1968.
92. Heath, R. G. , Nationwide Residues of Organochlorine Pesticides
in Wings of Mallards and Black Ducks, Pesticide Monitoring J. ,
115-123, 1969.
93. Hickey, J. J. and Anderson, D. W. , Chlorinated Hydrocarbons
and Eggshell Changes in Rapotrial and Fish-Eating Birds,
Science, 162, 272-273, 1968.
94. Blus, L/. J. , Measurements of Brown Pelican Eggshells from
Florida and South Carolina, Bioscience, 20, 867-869, 1970.
95. Ratcliffe, D. A. , Decrease in Eggshell Weight in Certain Birds
of Prey, Nature, 215, 208-210, 1967.
96. Report of Fish Kill Investigation in Lake Junaluska, Haywood County,
Dept. of Water and Air Resources, Water Quality Div. , North
Carolina, Nov. 1970-March 197 1.
97. Macek, K. J. , Hutchinson, C. and Cope, O. B, Effects of Temperature
on the Susceptibility of Bluegills and Rainbow Trout to Selected
Pesticides, Bull. Environ. Contam. & Toxicol. , _4J3), 174-183,
1969.
98. Murphy, P. G. , Effects of Salinity on Uptake of DDT, DDE and ODD
by Fish, Bull. Environ. Contam. fcToxicol., 5_(5), 404-407, 1970.
99. Lincer, J. L. , Solon, J. M. , and Nair, J. H. , DDT and Endrin
Fish Toxicity Under Static Versus Dynamic Bioassay Conditions,
Trans. Am. Fish. Soc. , 99(1), 13-19, 1970.
100. Sutton, D. L. , Weldon, L. W. and Blackburn, R. D. , Effect of
Diquat on Uptake of Copper in Aquatic Plants, Weed Sci. , _18_( 1),
703-707, 1970.
101. Bender, M. E. , The Toxicity of the Hydrolysis and Breakdown
Products of Malathion to the Fathead Minnow (Pimephales promelas,
Rafinesque), Water Res. , Pergamon Press, _3, 571-582, 1969.
102. Hiltibran, R. C. , Effects of Some Herbicides on Fertilized Fish
Eggs and Fry, Trans. Am. Fish Soc., 96(4), 414-416, 1967.
208
-------
103. Malone, C. R. and Blaylock, B. G. , Toxic ity of Insecticide
Formulations to Carp Embryos Reared in Vitro, J. Wildl. Manag. ,
34(2), 460-463, 1970.
104. Murphy, P. G. , The Effect of Size on the Uptake of DDT from
Water by Fish, Bull. Environ. Contam. & Toxicol., jb[l), 20-23, 1971.
105. Breidenback, A. W. and JLichtenberg, J. J. , DDT and Dieldrin
in Rivers: A Report of the National Water Quality Network Science,
141, 899-901, 1963.
106. Weaver, L. , Gunnerson, C. G. , Breidenback, A. W. and
Lichtenberg, J. J. , Public Health Rep. , U. S. , JJO, 481, 1965.
107. Schafer, M. L. , Peeler, J. T. , Gardner, W. S. , and Campbell, J. E. ,
Pesticides in Drinking Water: Waters from the Mississippi and
Missouri Rivers,. Environ. Sci. & Technol. , 3_(12), 1261-1269,
1969.
108. Nicholson, H. P. , Grzenda, A. R. , Lauer, G. J. , Cox, W. S. ,
Teasley, J. I. , Water Pollution by Insecticides in an Agricultural
River and Treated Municipal Water, Limmol. & Oceanog. , _9_,
310-317, 1964.
109. Nicholson, H. P., Pesticides: A Current Water Quality Problem,
Trans. Kan. Acad. of Sci. , (Suppl. ), 70J3), 39-44, 1968.
110. Faust, S. D. , Pollution of the Water Environment by Organic
Pesticides, Clin. Pharmacol. Therap. ,_5_, 677-686, 1964.
111. Robeck, G. G. Dostal, K. A., Cohen, J. M. and Kreisse, J. S. ,
Effectiveness of Water Treatment Processes in Pesticide
Removal, J. A. W.. W. A. , 57, 181-199, 1965.
112. Report of the Secretary's Commission on Pesticides and Their
Relationship to Environmental Health, Parts I and II, U. S. Dept.
of Health, Education, and Welfare,- 99-123, 1969.
113. Chesters, G. , Konrad, J. G. , Effects of Pesticide Usage on
Water Quality, BioScience, 21(12), 565-569, 1971.
209
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114. Durham, W. F. , Benefits of Pesticides in Public Health Programs,
In: Proceedings of the Symposium on the Biological Impact of
Pesticides in the Environment, J. W. Gillett (Ed.) FDA,
Chamblee, Georgia, No. 409, 153-155, 1969.
115. Butler, P. A., Commercial Fishery Investigations, In: The
Effects of Pesticides on Fish and Wildlife, Fish and Wildlife
Service, U. S. Dept. of Inter. , Circ. #226, 65-77, 1965.
116. Henderson, Croswell, Inglis, Anthony and Johnson, Wendell, L.
Residues in Fish, Wildlife, and Estuaries, Pesticide Monitoring
J. , _5(1), 1-11, 1971.
117. Duggan, R. E. , Lipscomb, C. Q. , Cox, E. L. Heatrwale, R. E.
and Kling, R. C. , Residues in Food and Feed, Pesticide
Monitoring, J. , 5_(2), 73-212, 1971.
118. Hayes, Jr., W. J. , Durham, W. F. and Cue to, Jr., C. , The
Effect of Known Repeated Oral Doses of Chlorophenothane (DDT)
in Man, J. A. M. A., 162, 890-897, 1956.
119. Edmundson, W. F. , Davies, J. E. and Hull, W. , Dieldrin
Storage Levels in Necropsy Adipose Tissue from a South Florida
Population, Pesticide Monitoring J. , _2(2), 86-89, 1968.
120. Dale, W, E. , Copeland, M. F. and Hayes, Jr. , W. J. , Chlorinated
Insecticides in the Body Fat of People in India, Bull. Wld. Hlth.
Org. , 33, 471-477, 1965.
210
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E. THE DEGRADATION OF PESTICIDES
IN THE AQUATIC ENVIRONMENT
1. Introduction
Surveys show that most of the surface waters of the U. S.
contain chlorinated hydrocarbon insecticides and certain herbicides.
These pesticide residues and their degradation products are of
particular concern because of their potential toxicity to many aquatic
organisms. Subsequently, they could exhibit adverse effects on man
through his drinking water and food. Before it is possible to
adequately protect the aquatic system it will be necessary to assess
the effect of current pesticide practices and to adjust efforts accordingly.
There are gaps in the knowledge. A large number of variables are
associated with the fate of pesticide residues. Many are only poorly
defined and others must be identified and evaluated.
The term "degradation" is used in a broad sense and will
refer to any measurable chemical change in a pesticide under natural
environmental conditions. Degradation may be "complete degradation"
to inorganic end-products or "partial degradation" to intermediate
2
organic products.
2. Degradation Mechanisms, Rates and Products
The rates at which pesticides and their by-products degrade
Under natural conditions are the first consideration in examining the
effect on the aquatic environment. A compilation of 58 potentially
Waterborne pesticide compounds for which degradation rates and
product information are available is presented in Table E-l. The
great majority of these results were obtained under laboratory
conditions. A wide variety of procedures and test conditions were
211
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PAGE NOT
AVAILABLE
DIGITALLY
-------
employed in these studies. The results, though valuable, are not
readily interpretable on a common basis. Only a limited number of
field studies have been reported for the Southeastern region.
Extrapolation of the laboratory results to field conditions is not valid.
For example, discrete differences in time of persistence may occur
for a single compound because it may be degraded via several physical,
biological, chemical or a combination of these ways. The pathway
depends on such environmental parameters as temperature, oxygen
concentration and the presence of other reactive substances. To
facilitate evaluation of existing knowledge the pesticides will be
considered as chemically-related groups.
a. Chlorinated Hydrocarbons
The chlorinated hydrocarbons include DDT. This was one of
the first and most extensively used of this group. It has been of great
benefit but belatedly, concern has been expressed regarding its effect
on life systems. Certain generalized statements can be made about
chlorinated hydrocarbons subsequent to inspection of the laboratory
and field studies presented in Table E-l. The chlorinated hydrocarbons
are synthetic organic compounds of which a number are known for their
"persistence" or longevity (periods longer than one year) of residues.
Chlorinated hydrocarbon compounds which have received considerable
public attention are Endrin, Dieldrin, Toxaphene and Mirex. In fact,
these compounds are the ones most commonly found in Southeastern
3
"waters. Persistent residues of these compounds have a low water
solubility and have strong tendencies to sorb onto soil-and sediment
1 4
particles within natural waters. ' The biological persistence of DDT
is attributable to the high lipophilic character of the molecule. This
characteristic enables it to be stored and concentrated in the fat
deposits of aquatic organisms and higher life forms. The residues
223
-------
5
become magnified with each successive step in the food chain.
Degradation of chlorinated hydrocarbons has been shown to occur
faster under anaerobic conditions than under aerobic conditions,
wherein high bacterial numbers and high temperature regimes were
2
utilized. This is an important consideration. The waters of the
southeastern United States are classified as warm since the annual
average is 65" F. This condition would appear to favor accelerated
degradation in this region as compared to colder regions of the United
States. However, quantitative documentation for such a deduction is
not available.
Understanding of the degradation of chlorinated hydrocarbon pesti-
cides in the Southeastern region is deficient. Especially important is the
need to intensify long-term degradation field studies under natural conditions,
b. Organophosphates
In recent years, there has been a gradual increase in the use
of more readily degradable organophosphates in place of chlorinated
hydrocarbons. These compounds are classified as non-persistent
because their residues last for only a few months, under normal
4
application rates. This group includes Malathion, Methyl parathion
Parathion, and Diazinon. These compounds undergo hydrolysis in the
aquatic environment where microbial activity and pH greatly influence
this rate. The hydrolysis rate in distilled water increases with
decreasing sulfur content of the phosphate ester. At pH greater than
8
7. 0, the duration or half-life is decreased.
Southeastern field work has included limited identification and
measurement of persistence in sediment residues. These studies have
not been designed to define degradation rates "in situ"
224
-------
c. Carbamates
Another class of non-persistent pesticides are the carbamates.
The compounds have agricultural applications and are a comparatively
new class of chemicals. These compounds contain neither chlorine nor
phosphorus but their cholinesterase-inhibitory action is similar to that of
organophosphates. Carbamates are generally referred to as non-
persistent pesticides. Carbaryl has been shown to degrade in sea
9
water to form unidentified toxic products.
d. Herbicidal Compounds
Herbicides are included in a variety of chemical classes
(see Table E-l) including a few chlorinated hydrocarbons, organo-
phosphates and carbamates. These compounds have a range of
persistence from several weeks to months and exhibit varying degrees
of water solubility. Photo-induced transformations of halogenated
herbicides have been widely demonstrated under laboratory conditions*0.
Water yields hydroxylated and reduced products. Degradation mech-
anisms for other types of herbicides involve oxidation or hydrolysis
to nonphytotoxic products.
e. Inorganic Pesticides
The inorganic pesticides often yield residues that are virtually
non-degradable. The cation remaining is often potentially toxic and is
represented by such metals as mercury, arsenic, copper, and lead.
Copper sulfate has been widely used to control the growth of some
submerged vascular plants. Mercury compounds, on the other hand,
12
have found' great usage as fungicidal agents. These fungicides may
be transported to water systems. However, once applied, the elemental
forms remain in soils unless removed through leaching. ^
225
-------
Laboratory studies -which have been performed are not readily
applicable to field conditions for the Southeast. Therefore, any
correlation which exists between these respective degradation rates and
pathways remain undefined.
3. Physical Influences on Degradation
The degradation of pesticides in the aqueous environment is
influenced by physical factors unique to each individual system. The
physical factors may be sorption onto organic or inorganic particulate
surfaces, transport between the aqueous and benthic phases along a
waterway, or volatilization into the atmosphere. The result is con-
comitant adjustment in the concentration of residue at the original site.
Quantitative information on these processes has been obtained only very
recently and is still meager. The interrelationship of the physical
processes and degradation mechanisms and their rates is still largely
undefined.
a. Adsorption
Many pesticides are almost insoluble in water but can be found
in significant quantities in the aqueous and sediment phases of water
bodies. Often, they are present because they have been sorbed by
13
various solids that act as condensation nuclei. Therefore, it is
important to understand the phenomena of sorption prior to evaluation
of degradation and transport processes. Sorption is not a degradation
mechanism "per se" but it alters the availability of the pesticide for
subsequent chemical or biological degradation.
The extent of pesticide sorption is related to the solubility of
the compound, the nature of the material on which it is sorbed and
226
-------
other properties of the aqueous system. Strong sorption bonds to clay
minerals are characteristic of some pesticides, such as DDT.
(1) Chemical Reactions
Hydrolytic mechanisms are accelerated by sediment sorption.
The rate of reaction is time and pH dependent, i. e. , if the pH is held
constant, the rate of degradation is related to time by first-order
kinetics. Atrazine hydrolyzes to the non-toxic compound, Hydroxyatrazine.
The reaction has been shown to be catalyzed by sorption onto colloidal
surfaces. 15,16 -phe catalysis is apparently associated with sorption at
-COOH groups of the sediment. The literature is generally deficient in
similar sediment-catalyzed degradation for other chlorinated hydro-
carbons. The relationship of the sorption process to chemical degra-
dation mechanisms of pesticides has not been specifically established.
(2) Biological Degradation
Sorption onto sediment influences degradation by enabling pesticide
compounds to settle to the bottom of water systems where they become
13 17
subject to microbial activity. ' Bacteria have been found to sorb
pesticides during flocculation and settling processes. Gram-positive
bacteria isolated from Lake Erie have demonstrated the capacity to
sorb 1 part per million (ppm) of Aldrin from water in 20 minutes.
Chlorinated hydrocarbon degradation, subsequent to settling of the
pesticide particle complex to microbially active sediments, has been
demonstrated.17'1*?
Organophosphate degradation in sediments is also catalyzed by the
presence of microbiological organisms. °» 20» 21
227
-------
Parathion is considered the most resistent of the organophosphates.
However, this compound has been shown to be readily subject to
biodegradation in microbially active lake sediments. It has been
concluded that without microbial activity, Parathion would remain
in the natural environment for months, while in microbially active
environments, is degraded in a matter of weeks. °
(3) Cycling (Physical)
Sorption of pesticides followed by settling does not assure
that the resulting material remains in the bottom sediments of aquatic
systems. Eventually the pesticide may be cycled into overlying
waters. This could result from spring ;and fall overturns in lake and
reservoirs, and from an increase in the scouring velocity of flowing
streams. * * Changes in pesticide concentrations can also occur as a
result of release or desorption of the pesticide from the particle through
stresses on dynamic equilibrium processes. Heptachlor, Dieldrin and
DDT sorb very quickly onto clay materials. ^ After sorption, desorption
may occur although the rate of desorption is usually lower than for
22
sorption. Sorption-desorption rates in aqueous systems are partic-
ularly influenced by salinity, pH and organic materials. A study con-
23
ducted with Endrin and Dieldrin demonstrated this effect. An analysis
of the estuarine sediment showed 14 to 18% organic content, 31% sand,
25% silt, 16% clay, and the balance other organic material and compounds.
Table E-2 relates the effects of added organic material, pH and salinity
to sorption of Endrin and Dieldrin.
228
-------
Table E~2
Factors Influencing Sorption of Endrin and Dieldrin
23
Pesticide
Presence of
organic materials
Salinity
)ndrin
Heldrin
High initial sorption
however, after 7 days
of contact, insignifi-
cant amount of Endrin
associated with
sediment
Insignificant in-
fluence during 7
day period.
38-43% uptake within
one day in pH range 3
to 10. 5 after 7 days at
pH 7. 0 most of initially
sorbed Endrin released
from sediments
Initial uptake at pH
3. 8 was Z6%; At pH
8. 0, initial uptake
was 0%, after approx-
imately 70 hrs. of
contact, maximum
sorbed quantities
ranged from 58-64%.
At pH 8. 0 complete
desorption after approx.
170 hrs. of contact.
Sorption maximum
in range 13 to 17%
after 1 hour. Complete
desorption after 7
days. Salinity above
17% and pH 7 to 8-no-
sorption occurred.
Sorption independ-
ent of salinity
Source: Rowe, et. al.
It can be concluded that sorption of both Endrin and Dieldrin is the
time-dependent and pH sensitive. Endrin sorption is salinity dependent
but Dieldrin sorption is not. These processes of sorption, sedimentation
and subsequent return to solution suggests a mechanism by which aquatic
organisms can be exposed to pesticide effects long after the initial release.
Very little has been documented regarding the relationship between
sorption-desorption and degradation mechanisms.
b. Traiislocation
(1) Reservoirs
Natural hydrological dynamics involve consideration of factors
such as current, turbidity and temperature. These control the
229
-------
transport of pesticides in the aqueous media. The distribution of
pesticides in the water influences the rate and mechanisms of chemical
degradation and the availability of these substances for biological
uptake. These factors can be observed in the case of direct application
of a pesticide to a reservoirs' surface. Widescale applications of the
herbicide 2, 4-DLchloro-phenoxyacetic acid (2, 4-D) have been made to
reservoirs of southern Tennessee, northern Alabama and northern
Georgia. The Tennessee Valley Authority (TVA) made these in 1967
24 25
and 1971 to control the aquatic plant, Eurasin Water Milfoil. '
The area of application was extensive. Pesticide was monitored in
flowing and static zones.
In the first study, 888 tons of the 20% butoxy ethanol ester form
of 2, 4-D were applied in granular form to 8, 000 surface acres of seven
reservoirs in eastern Tennessee and northern Alabama. These resevoirs
are spread over a main-channel distance of 352 river miles. Application
varied from 60 to 100 Ibs. of 2, 4-D, acid equivalent, per acre. Seven
monitoring stations were located on the Guntersville Reservoir in
Alabama. Five stations were located on Watts Bar Reservoir in
Tennessee. Twenty-four hours after application, water milfoil samples
contained concentrations up to 8. 26 milligram per kilogram (mg/kg)
indicating active uptake of the herbicide. Sediment samples, taken
from static water areas (embayments), contained higher and more
persistent residue concentrations than did areas of rapid current. In
Watts Bar Reservoir, significant concentrations of 2, 4-D were found
in mud samples as high as 58. 8 mg/kg after 10 months . At eight
of nine water treatment plants located along the Tennessee River
concentrations of 2, 4-D were less than 1 micrograms per liter
(Ag/1) 2 to 3 weeks after application. At the ninth plant 2, 4-D was
applied directly above the water supply intake. Concentrations
230
-------
were 2 /6fg/l three days after application and 1 JU g/1 nine days after
application. Municipally-treated water samples contained less than 1
JL( g/1 of the herbicide.
In the 1971 study, over 18,000 surface areas in the Nickajack
and Guntersville reservoirs in Tennessee and Alabama.respectively,
were treated with approximately 170, 000 gallons of the Dimethylamine
salt (DMA) of 2, 4-D in April. Postreatment monitoring continued for
four months. Application amounts were 20-40 Ib./acre. The liquid
form proved to be more suitable than the granular form because of its
direct toxic action to the root crowns of the water milfoil and dispersal
to marginal areas of the beds. One monitoring station was located such
that it was restricted to static water. At this site, vertical stratifi-
cation of 2, 4-D occurred between the time of application and the eight-
hour sampling period in Guntersville Reservoir. A concentration of
5 mg/1 was present at the surface while only 1.5 mg/1 occurred at the
level of milfoil root crowns following a 40 Ib. /acre application. Within
two weeks, the 2, 4-D content in this embayed area was uniform at 0. 65
mg/1. One month later it was 1.0 //g/1. This treatment level
prevented regrowth for approximately 12 months. A pH decrease
of 2. 1 units, from 8. 5 to 6. 4, occurred between first and the fourteenth
day after treatment. The pH returned to the pretreatment value a
month later. Another monitoring station was established in an area
adjacent to the main channel of the Tennessee River where conditions
were favorable for rapid dilution of the herbicide. Less than 0. 87
mg/1 was present in the water within 24 hours after treatment with
40 Ib. /acre. Less than 5.0^g/l was measured 14 days later. Lower
applications rates of DMA 2, 4-D, as opposed to the 'granular form, led
to variable residence times in the water. Concentration level and
residence time were closely related to water flow rates and effectiveness
of plant control. Liquid DMA 2, 4-D was readily sorbed by planktonic
231
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organisms. The plankton removed 24% of the herbicide within 1 hour
after application and a proportional amount during the next 7 hours.
A trend of progressive downstream dilution of waterborne 2, 4-D was
observed over 214 miles. This was indicated by the concentrations of
2, 4-D that accumulated in mussels located on the bank edges of tributaries and
channel slopes. One anomalous pretreatment sample of mussels below
Guntersville dam contained the highest 2, 4-D concentration found at
any time during the monitoring. The source of 2, 4-D was unknown.
Water from the treated areas continued to be used for domestic purposes
during this period without user complaints. Finished drinking water
contained 1 to 2 ppb concentrations of 2, 4-D after standard treatment
practices.
Hydrological influences on the distribution of other chlorinated
hydrocarbons and organophosphates under natural flowing and static fresh
water systems have not been reported for the Southeastern region.
A number of conclusions can be formulated regarding the
transport and distribution of pesticides in reservoirs:
• Pesticides are more persistent in static water areas
(both aqueous and sedimental levels considered) than
in those subjected to dynamic current action.
• Pesticide concentrations in the aqueous-phase are further
influenced by: (a) presence of thermal stratification and
(b,) the amount of plankton present.
• The physical form in which the pesticide is applied
(aqueous vs. granular) influences the degree of desired
effectiveness upon application to water.
• Pesticides such as 2, 4-D are not completely removed from
raw water during conventional treatment practices.
232
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(2) Estuaries
Pesticides can reach estuarine basins from direct application
to its waters and from discharges of municipal and industrial wastes.
But the largest contribution of pesticides to the estuary occurs through
26
run-off from orchards and farmlands. Clay, silt and detritus sorb
insoluble, persistent pesticides and, depending on the degree of ero-
sion, transport them to estuarine basins. It has been estimated that
11 tons of soil per acre may be washed away in a year where farming
practices are poor. However, under optimum practices, there is no
26
erosional loss. The exact quantities of pesticides which reach the
estuary by this process are not known. There is a seasonal fluctuation
in the concentrations detected in the water and in the sediments. Since
most pesticides are introduced into hydrological systems between early
spring and late summer, the highest levels in the sediments are expected
several months later. A majority of streams are at low flow during
October and November; hence, most of the erosion product transported
during and immediately following the pesticide application season are
deposited in the streams beds by this time. Relatively little amounts
would have an opportunity to pass from subbasins to costal waters.
During the spring rains of April and May, however, the streams are at
high flow, transporting a near maximum suspended sediment load to
the estuary just prior to pesticide application season. Thus, the detected
residues in the estuaries may be indicative of the residual effect of
the previous year's (or years') applications of pesticides. 27
Published results of pesticide distribution in an estuarine
environment are limited to a single study on the movement of DDT in
28
a tidal marsh ditch. DDT distribution after direct application of
0. 2 Ib. /acre was immediately influenced by the wind and by the ocean-
directed flow of the water. The amount of vegetation and fauna influenced
233
-------
the amount of DDT which moved out of the marsh outlet through
biological uptake and sorption of the pesticide. The amount of DDT
detected in the sediment and vegetation and the times of survey are
given in Table E-3.
Table E-3
DDT Uptake by Selected Southeastern
Estuarine Substrates
26
Substrate
vegetation
(sedges and
grasses)
sediment
Max. Concentration (mg/kg)
75-3 to 5 wks. post treatment
3.35 - 6 wks. post treatment
Average Concentration
(mg/kg) 7 wks. postreatmenf
9. 1
0.76
Source: Croker and Wilson
It was demonstrated that fish and vegetation accumulated 1500 times the
maximum concentration of DDT detected in the water. Snails, crabs
and sediments accumulated 144, 99, and 66 times as much, respectively.
The persistence of residues in the water, sediments and biota beyond
4 months was not measured. The amount of DDT which moved out of
the tidal marsh was detected in the sediment at the marsh outlet 11 weeks
after treatment.
It has been assumed that a major portion of the pesticides which
enter estuaries are dissipated through the processes of dilution, chemical
decay, flocculation and precipitation to bottom sediments, and biological
. , 26, 29
uptake.
Preliminary results of studies on the stability of pesticides in
seawater were reported by the Bureau of Commerical Fisheries in Gulf
Breeze, Florida. The degradation rates of 4 pesticides in seawater
maintained under laboratory conditions, are shown in Table E-4. 30
Degradation under natural conditions has not been reported for other
chlorinated hydrocarbons and organophosphate compounds.
234
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Table E-4
Stability of Pesticides in Natural Seawater 30
(salinity 29. 8 ppt; pH 8. 1) Concentrations in |jig/l 30
Pesticide
p, p'-DDT
p, p' -DDE*
p, p'-DDD*
Aid r in**
Dieldrin*
Malathion
Parathion
Dav After Start of Experiment
0
2.9
2.6
3.0
2.9
6
.75
.096
.58
.74
0.2
1.9
17
1.0
.95
.081
.096
1.0
0.2
1.25
24
.27
.065
.041
0.01
1.0
1.0
31
. 18
. 034
.038
0.01
.75
.71
38
. 16
.037
.037
0. 01
.56
.37
Source: Wilson, et. al.
* Metabolites of parent compound.
** From the seventeenth day onward, 2 unidentified peaks appeared on
the chromatographic charts after Aidrin had eluted.
Pelagic animals may consume pesticide-laden detritus or food
organisms and transport the pesticide to other parts of the environment.
Oysters can concentrate up to 70, 000 times the test water concentra-
tion of DDT. Pinfish and Atlantic Croker populations in Pensacola Bay
move offshore to spawn. During the Spawning process they deposit
1/2 Ib. of DDT, previously accumulated in the estuary. 26
It may be concluded that:
• The physical factors influencing pesticide translocation in
estuaries are, in the main, undefined. The physical
stability of pesticides under laboratory conditions bears
little relationship to natural systems.
• Biological organisms influence translocation through uptake.
Sessile macrophytes inhibit translocation, whereas, motile
forms (fish) enhance translocation.
(3) Closed-Water Systems
The majority of degradation studies have been performed under
laboratory and closed-water field conditions. Closed water or standing
235
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•water systems (lotic) are those confined within a basin (lakes, ponds,
swamps, etc. ) and possessing limited horizontal movement.
15 31 32
During sediment-water simulations and field monitoring, ' '
pesticide concentrations have been shown to decrease in the aqueous
phase while increasing in the sediment. The rate of removal from the
aqu.eous phase depends on the chemical characteristics and concentration
of the pesticide, the chemical and physical aspects of the water, the
sediment characteristics, and the ratio of pesticide compound to
l f\ "^ 1
sediment. ' Results of a laboratory study show that the ratio of
Lindane to sediment,controls sorption. ^0 The lower the ratio, the
greater the extent of sorption. Influencing the process are the concen-
tration of organics in the sediment, the concentration of suspended
matter, the initial Lindane concentration,and the quantity of clay. These
variables were ranked in order of importance. They were sediment
concentration, Lindane concentration, clay content and Lindane to
sediment ratio. In another study, approximately 57% of X-BHC
added to a simulated lake impoundment system, was sorbed within 24
hrs. 32 "With Parathion, approximately 60% of the applied concentration was
6
associated with lake sediments after a 24 hour period. Thermal
stratification effects on the settling characteristics of sorbed particles
are not available.
The presence of biota strongly affects the distribution of
pesticides in lotic systems. Sorption by algae was reported to be
several orders of magnitude greater than it is by clay, which in turn is
2
greciter than it is by sand. A natural pond in Florida was treated with
Dichloroben.il to yield a final concentration of 1. 0 mg/1 and compared with a
similar pond which was untreated. Thermal stratification did not
occur in either pond. Seven days after treatment, the hydrosoil zone
contained greater quantities of Dichlorobenil than did the aqueous phase.
Within 4 months, the concentration within the aqueous phase had returned
236
-------
to pretreatment levels. Biological organisms concentrated significant
quantities of the pesticide. One day after treatment, Gam bus ia
affinis ( a minnow fish) contained approximately 11 mg/kg; Poecilia
latipinna (sailfin mollie) approximately 5. 0 mg/kg; plankton 7. 2 mg/kg;
and Chara 1.16 mg/kg. By the second day, plankton contained 2. 9 mg/kg;
G. affinis, 6. 62 mg/kg; P. Latipinna, 4. 2 mg/kg; and Chara, 0. 77 mg/kg.
In summary, sorption of pesticides by particulate matter (biological and
inorganic) is an important mechanism in the translocation of pesticides
between the aqueous-phase and the sediment of the system. The rates of
translocation have been determined to be pesticide concentration depen-
dent.
The results published for these rate studies must be considered
as applicable only to those particular systems. Extrapolation to other
systems is not valid because of limitations of the experimental design
and inadequate assessment of all of the important environmental para-
meters. Only approximations of the effect of pesticidal translocation
on degradation rates and mechanisms in closed-systems can be presently
made.
Determination of the physical behavior of a specific pesticide, under
conditions simulating those of the natural system to which the compound
is to be introduced, must be established prior to "in situ" application.
Without appropriately designed experimental efforts, using dynamic
systems, there is little likelihood that substantial progress will be made
in identification and evaluation of physical degradation mechanisms.
4. Biological Degradation
Flora and fauna are important factors in the translocation and
degradation of many pesticides. Residues of certain chlorinated
237
-------
hydrocarbons persist in biological material for extended periods and
5
are magnified through the food chain. Research has been mainly
focused on DDT.
a. Microbiological
Microbial degradation plays a major role in the degradation of
pesticides. Even the persistent chlorinated hydrocarbons show some
degree of microbial degradation. Environmental factors, such as,
oxygen concentration and the amount of light exert significant
2 34 35
influence on the rate of microbial degradation. ' '
Partial dechlorination of DDT leads to ODD. In invertebrates
(fish) the process requires molecular oxygen, but in microorganisms,
the presence of oxygen has been reported to inhibit the reaction.
Dechlorination in microbial systems is believed to involve the cytochrome
oxidase iron-carbonyl complex. ^4, 37 The absence of oxygen enables the
cytochrome-Fe to remain in an activity-dependent reduced state.
Facultative anaerobes, such as, Escherichia coli, Aerobacter aerogenes
and Klebsiella pneumoniae have demonstrated the ability to convert 80%
34
of DDT to DDD within 12 hours. The cytochrome oxidase iron-carbonyl
complex has also been shown to dissociate under the influence of light.
These two factors may partially explain the persistence of DDT residues
in aerobic sediments.
In comparative sediment studies, anaerobically-catalyzed microbial
degradation of chlorinated hydrocarbons occurred faster than aerobically-
2 6 32
catalyzed microbial degradation. ' ' The by-products produced
under each condition were different. Heptachlor epoxide and Dieldrin
have demonstrated the strongest resistance to either anaerobic or
aerobic degradation. Chlorinated hydrocarbons have been ranked in order
of increasing persistence as follows: Lindane, Heptachlor, Endrin, DDT,
2
DDD, Aldrin, Heptachlor epoxide, Dieldrin.
238
-------
Degradation of DDT occurs in the presence of oxygen and
a common shallow-water bacterium native to Florida, P s eud o m on a s
piscicida. The cultured bacterium was able to degrade 90% of an
applied 1 ppb DDT in 24 hours. Direct removal (presumably sorption)
of DDT from solution was also demonstrated. The metabolized end-
products were DDD and DDE. The latter is considered less toxic than
DDT. Because of the liposoluble character of DDT and the large
lipoprotein surface area of the bacterial cell, it was postulated that
uptake was enhanced.
Organophosphates break down at a pH greater than 7. 0 and since
bacteria create a microenvironment of high pH (9. 5) immediately
adjacent to the cell, it has been proposed that P. piscicidas readily
8
metabolizes Malathion in this fashion.
b. Plants
Plants rapidly sorb and accumulate large quantities of
herbicides. Other pesticides may be accumulated with little or no
38
degradation occurring. Marsh grasses and sedges accumulate
large quantities of DDT (1500 times the maximum water concentration of
DDT). Subsequently plant death leads to deposition of the previously
stored DDT in the sediment. The extent of degradation by plants varies
with the type of plant and pesticide. Field studies of aquatic plant
residues in the Southeast have been cursory. There is a need for
information regarding these degradation pathways.
c. Animals
Some invertebrates and vertebrates can remove pesticide
39 40 41
compounds directly from the water. ' ' There is considerable
variation with species in the amount of pesticides accumulated and the
extent of degradation. ' ' ' Most degradation studies have been
239
-------
focused on DDT. Fish and oysters are capable of eliminating
41, 45
accumulated concentrations when placed in pesticide-free water.
It was demonstrated in a laboratory investigation that Tilapia and
sunfish,exposed for 31 days to DDT and Methoxychlor,concentrated
these substances 10, 600-fold and 200-fold,respectively. Tilapia
were able to metabolize DDT to a greater extent than sunfish. DDD
was the major metabolic product. Tilapia were able to metabolize
Methoxychlor faster than sunfish. Tilapia contained higher amounts
of the bis-phenols, produced by o-demethylation of the parent compound.
5. Degradation-Effects
When agricultural chemicals are introduced into the aquatic
system, two effects may occur as a result of degradation processes:
alteration of the water quality and formation of compounds more toxic
than the parent compound. These secondary effects may stress
nontarget organisms.
a. Water Quality-
Water quality may be altered as a result of the degradation of
a pesticide or its target species, producing a temporary toxic effect
to non-target species. Such alterations may be, for example, a sharp
decrease in pH due to acidic degradation by-products,or a depletion of
the oxygen due to decaying organisms. ' Silvex application to a
backwater of the Santee River in South Carolina was made to control
47
alligator weed. The herbicide killed the weed which then settled
to the bottom and began decomposing. After several weeks, there was
no dissolved oxygen in the bottom two feet of water. This contrasted
with oxygen concentration of 6-8 mg/1 in adjacent untreated areas.
240
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b. Toxic ity
Laboratory studies have shown that photoisomers of Aldrin,
Dieldrin, and Heptachlor are more toxic than the parent compounds to
such freshwater organisms as fish, amphibia, flatworms and Crustacea.
48, 49
Sunlight catalyzes the production of such photoisomers.
Photoaldrin is 11 times more toxic to mosquito larvae than Aldrin.
Photoisodin, however, was shown to be less toxic than either
Isodrin or Endrin.
The seawater hydrolysis product, l-Napthol,of Carbaryl
(Sevin) has been shown to be twice as toxic to fish as the parent
compound when both were tested at 1. 3 mg/1. It is also more toxic
9
to young clams at a concentration of 6. 4 mg/1 than Carbaryl.
A reddish precipitate results from the instability of 1-Napthol under
alkaline conditions. This precipitate was found to be two-thirds as
9
toxic as 1-Napthol to bay mussels.
It was demonstrated with the fathead minnow, Pimephales
Jgromelas that the basic hydrolysis product, Diethyl fumarate, was
51
more toxic than Malathion. A pronounced synergistic effect
between Malathion and its basic hydrolysis products was shown.
Diethyl fumarate could be produced in an amount sufficient to
produce a TLm (median tolerance limit) concentration. This would
occur when 64% of the TL. m concentration of Malathion had hydrolyzed
to form Diethyl fumarate. Therefore, the difference of a day or two
in the application time of Malathion on two adjacent areas could result
in a condition in which a considerable quantity of the breakdown product,
along with a substantial quantity of the parent compound, could be washed
into a common water source.
241
-------
Two areas of degradation research which are in need of greater
support are: (1) determination of the toxicities of degradation compounds
to nontarget species and (2) determination of the synergisms between
mixtures of the parent and degradation compounds.
6. Conclusions
The most frequently occurring pesticides in Southeastern waters
are chlorinated hydrocarbons whose persistence may be in the order of
years. In general, organophosphates, carbamates, and herbicidal com-
pounds disappear from the water within a matter of a few weeks or
months.
Available data on degradation rates, mechanisms, and products
is very limited. Information is based on laboratory studies which can-
not be extrapolated to natural environmental conditions. For example,
halogenated herbicides are readily degraded through photo-induced
mechanisms. How these mechanisms relate to degradation of herbicides
in the natural environment has not been established.
The sorption of pesticides by suspended material and substrates
in natural waters is an important factor in the degradation process. It
may facilitate chemical reactions and translocation of pesticides to the
estuary or to areas favorable for degradation.
Information on the occurrence and distribution of pesticides
reveal that, while no concentrations may be detected in the water,
concentrations in the^g/kg. range are found in the sediments of small
ponds and estuaries. The transport of pesticides in the aqueous medium
including that which is associated with particulate matter and sediments,
has not been defined.
242
-------
Pesticides concentrations which reach bottom sediments may be
recycled into the overlying water. Recycling can result from fall and
spring overturns following thermal de-stratification or from the release
or desorption of pesticides from the sediments.
The chemical degradation products of certain chlorinated hydro-
carbons and carbamates are many times more toxic than the parent
compounds. Such toxicities are vital considerations of impact on non-
target organisms.
7. Recommendations
1. The Environmental Protection Agency and U. S. Department of
-Agriculture should jointly support programs to develop information
regarding the effect of pesticide sorption by particulate and organic
matter on the subsequent chemical and biological degradation
mechanism.
2. The Environmental Protection Agency should increase inhouse and
supported research to develop information regarding specific pesticide
degradation rates, mechanisms, products and toxicities in fresh,
brackish and salt water.
3. A coordinated surveillance system must be established to provide
in-depth information on reservoirs, lakes, rivers, and estuaries. The
results must relate the movement of pesticides to hydrological conditions,
Quantification of the amounts and types of pesticides being transported
to the estuaries relative to climatic and seasonal factors is needed.
Rates of interchange between biological organisms and sediment, must
be established.
4. Federal and State requirements must be established to insure that
extended' field analyses are performed in conjunction with pesticide -
related fish kills and go beyond the minimum establishment of a cause.
These analyses should include those factors enumerated in the afore-
mentioned recommendations as much as the individual case permits.
243
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8. References
1. .Cleaning Our Environment: The Chemical Basis for Action, A
Report by the Subcommittee on Environmental Improvement, Com-
mittee on Chemistry and Public Affairs, American Chemical
Society, Washington, D. C., 212-213, 1969.
2. Hill, D.W. and McCarty, P. L. ., Anaerobic Degradation of
Selected Chlorinated Hydrocarbon Pesticides, J. Wat. Poll.
Contr. Fed., .39(8), 1259-1277, 1967.
f
3. Butler, P. A. , Monitoring Pesticide Pollution, BioScience, 19(10),
889-891, 1969.
4. Report of the Secretary's Commission on Pesticides and Their
Relationship to Environmental Health, U.S. Dept. of Health,
Education, and Welfare, 99-123, Dec. 1969.
5. Goldberg, E. D., Butler, P., Meier, P., Menzel, D. , Risebrough,
R. W. and Stickel, L. F. , Chlorinated Hydrocarbons in the Marine
Environment, National Academy of Sciences, Washington, D.C.,
1-21, 1971.
6. Graetz, D. A. , Chesters, G. , Daniel, T.C., Newland, L. W.,
and Lee, G. B., Parathion Degradation in Lake Sediments, J.
Wat. Poll. Contr. Fed. 42_(2), R76-R94, 1970.
7. Cowart, R. P. , Bonner, F. L. , and Epps, E. A. , Jr., Rate of
Hydrolysis of Seven Organophosphate Pesticides, Bull of
Environ., Contam. kToxicol., 6_ (3), 231-234, 1971.
8. Johnson, R. F. , Food Chain Studies, Bureau of Commercial
Fisheries, Report, Gulf Breeze, Florida, Circ. #260, 9-11, 1966.
9. Lamberton, J, G. and Claeys, R. R. , Degradation of 1-Naphthol in
Sea Water, J. Agr. Food Chem. , J_8_(l), 92-96, 1970.
10. Plimmer, J. R, The Photochemistry of Halogenated Herbicides,
Residue Reviews, 33, 47-74, 1971,
11. Sutton, D. L. , Durham, D. A. , Bingham, S.W. and Foy, C. L. ,
Influence of Simazine on Apparent Photosynthesis of Aquatic
Plants and Herbicide Residue Removal From Water, Weed Sci.
17, 56-59, 1969.
244
-------
(References - Continued)
12. Menzel, D.W., Anderson, J. ,. and Randtke, A., Marine
Phytoplankton Vary in Their Response to Chlorinated Hydrocarbons,
Science, 167, 1724-1726, 1970.
13. Pfister, Robert M. , Dugan, P. R. and Frea, James I., Micro-
particulates: Isolation From Water and Identification of Associated
Chlorinated Pesticides, Science, 166, 878-879, 1969.
14. Huang, J. and Liao, C. , Adsorption of Pesticides by Clay Minerals,
Journal of the Sanitary Engineering Division, AS,CE, %. (SA5),
1057-1078, 1970.
15. Chesters, G. and Konrad, J. G. , Effects of Pesticide Usage on
Water Quality, BioScience, 21(12), 565-569, 1971.
16. Hance, R. J. and Chesters, G. , The Fate of Hydroxyatrazine in a
Soil and a Lake Sediment, Soil Biol. BioChem. , j_, 309-315, 1969.
17. Veith, G.D. and Lee, G. F., Water Chemistry of Toxaphene - Role
of Lake Sediments, Environ. Sci. & Tech., 5J3), 230-234,
1971.
18. Leshniowsky, W. O. , Dugan, P. R. , Pfister, R. M. , Frea, J.I.
and Randies, C. I. , Aldrin: Removal from Lake Water by
Flocculent Bacteria, Science, J.6_9, 993-995, 1970.
19. Lichtenstein, E. P. , Schuliz, K. R. , Skrentny, R. F. and Tsukano,
Y. , Toxicity and Fate of Insecticide Residues in Water, Archivi
Environ. Health, J_2, 199-213, 1966.
20. Eichelberger, J. W. and Lichtenberg, J. J. , Persistence of
Pesticides in River Water, Environ. Sci. & Tech., J5_(6), 541-
544, 1971. ~
21. Randall, C. W. and Lauderdale, R. A. , Biodegradation of Malathion,
Journal of the Sanitary Engineering Division, ASCE. 93(SA6),
145-156, 1967.
22. Huang, J. C. , Effect of Selected Factors on Pesticide Sorption and
Desorption in the Aquatic System, J. Wat. Poll. Cpntr. Fed.,
43 (8), 1739-1748, 1971.
245
-------
(References - Continued)
23. Rowe, D. R. , Canter, L. W. and Manson, J.W., Contamination of
Oysters by Pesticides, Journal of the Sanitary Engineering Division,
ASCE, 96_(SA5), 1221-1234, 1970.
24. Smith, G. E. , and Isom, B.C., Investigation of Effects of Large-
Scale Applications of 2,4-D on Aquatic Fauna and Water Quality,
Pesticides Monitoring Jour., _1(3), 16-21, 1967.
25. Wojtalik, T.A. , Hall, T. F. and Hill, L. O. , Monitoring Ecological
Conditions Associated with Wide-Scale Applications of DMA 2, 4-D
to Aquatic Environments, Pesticide Monitoring J, , 4^4), 184-190,
1971.
26. Butler, Philip A., Pesticides in the Estuary, Symposium at
Louisana State U. , J. D. Newsom, Ed., July 19-20, 1967.
27. Feltz, H. R. , Sayers, W. T. and Nicholson, H. P., National
Monitoring Program for the Assessment of Pesticide Residues
in Water, Pesticide Monitoring J., j>(l), 54-62, 1971.
28. Croker, R. A. and Wilson, A. J. , Kinetics and Effects of DDT in
a Tidal Marsh Ditch, Trans. Am. Fish. Soc., 94, 152-159, 1965.
29. Duke, Thomas W. , Estuarine Pesticide Research-Bureau of
Commercial Fisheries, Gulf and Caribbean Fish. Inst., 146-153,
22nd Annual Session, Nov., 1969.
30. Wilson, Alfred J. , Stability of Pesticides Sea Water, Bureau of
Commercial Fisheries, Gulf Breeze, Florida, Circ. #335, 19-20,
1969.
31. Walsh, G. E. , Miller, C. W. and Heitmuller, P. T., Uptake and
Effects of Dichlobenil in a Small Pond, Bull. Environ. Contam.
& Toxicol. , ji(3), 279-288, 1971.
32. Newland, C. W. , Chesters, G. and Lee, G. B. , Degradation of
y-BHC in Simulated Lake Impoundments as Affected by Aeration,
J. Wat. Poll. Contr. Fed.. 41_{5), R174-R188, 1969.
33. Lotse, E. G., Graetz, D. A., Chesters, G. , Lee, G. B. and
Newland, L. W., Lindane Adsorption by Lake Sediments, Pesticide
Monitor. J. , 2(5), 353-357, 1968.
34. Wedemeyer, Gary, Dechlorination of DDT by Aerobacter aerogeneSj
Science, 152(3722), 647, 1966.
246
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(References - Continued)
35. Schwartz, Henry G. , Jr. , Microbial Degradation of Pesticides in
Aqueous Solutions, J. of Wat. Poll. Contr. Fed., JJ9J10), 1701-
1714, 1967.
36. Focht, D. D. and Alexander, M. , DDT Metabolities and Analogs:
Ring Fission by Hydrogenomonas, Science, j/70, 91-92, 1970.
37. Miskus, R. P. , Blair, D. P. , and Casida, I.E., Conversion to
DDT and DDD by Bovine Rumen Fluid, Lake Water, and Reduced
Porphyrins, J. Agr. Food Chem. , J_3, 481-438, 1965.
38. Rose, F. L. and Mclntire, C. D. , Accumulation of Dieldrin by
Benthic Algae in Laboratory Streams, Hydro. Biol., 35(3/4),
481-493, 1970.
39. Butler, Philip A. , Bureau of Commercial Fisheries Pesticide
Monitoring Program, Proceedings, Gulf and South Atlantic States
Shellfish Sanitation Research Conference, 1969.
40. Ferguson, D. E. , Ludke, J. L. and Murphy, G.C., Dynamics of
Endrin Uptake and Release by Ressistant and Susceptible Strains
of Mosquitofish, Trans. Am. Fish. Soc. , 95J4), 335-344, 1966.
41. Bender, Michael E. , Uptake and Retention of Malathion by th°
Carp, Progr. Fish Cult. , 3J_(3), 155-159, 1969.
42. Reinbold, K. A. , Kapoor, I. P. , Childers, W. F. , Bruce, W. N.
and Metcalf, R. L. , Comparative Uptake and Biodegradability of
DDT and Methoxychlor by Aquatic Organisms, 111. Natural History
Survey Bull., 3£(6), 405-417, 1971.
43. Gutenmann, W. H. and Lisk, D.J., Conversion of 4-(2, 4-DB)
Herbicide to 2, 4-D by Bluegills, New York Fish and Game J. ,
12(1). 108-111, 1965.
44. Wedemeyer, Gary, Role of Intestinal Microflora in the Degradation
of DDT by Rainbow Trout, Life Sciences, _?• 219-223, 1968.
14
45. Gakstatter, J. H. and Weiss, C.M., The Elimination of DDT-C ,
14 14
Dieldrin-C and Lindane-C from Fish Following a Single
Sublethal Exposure in Aquaria, Trans. Am. Fish. Soc., 93(3),
301-306, 1967.
247
-------
(References - Continued)
46. Faust, S. D. , Pollution of the Water Environment by Organic
Pesticides, Clin. Pharmacol. The rap., ji, 677, 1964.
47. Cope, O. B., Agricultural Chemicals in Fresh-Water Ecological
Systems, In Research in Pesticides, Chichister, C. O. , Editor,
Academic Press, 115-127, 1965.
48. Georgacakis, E. and Khan, M. A. Q. , Toxicity of Photoisomers of
Cyclodiene Insecticide of Freshwater Animals, Nature, 233, 120-
121, 1971.
49. Henderson, G.L. and Crosby, D. G. , The Photodecomposition of
Dieldrin Residues in Water, Bull, of Environ. Contam. & Toxicol.
_3_, 131-134, 1968.
50. Khan, M. A. Q., Rosen, J. D. , and Sutherland, D.J., Insect
Metabolism of Photoaldrin and Photodieldrin, Science, 164, 318-
319, 1969.
51. Bender, Michael E. , The Toxicity of the Hydrolysis and Breakdown
Products of Malathion to the Fathead Minnow (Pimephales promelas,
Raf.), Water Res. , Pergamon Press, 3, 571-582, 1969.
52. Matsumura, F. , Patil, K. C. , and Bousch, G. M. , DDT Metabolized
by Microorganisms from Lake Michigan, Nature, 230, 325-326,
1971.
53. Hartung, Rolf and Klingler, Gwendolyn W. , Concentration of DDT
by Sedimented Polluting Oils, Environ. Sci. & Tech. , 4J5), 407-
410, 1970.
54. Wedemeyer, Gary, Biodegradation of Dichlorodiphenyltrichloroethane:
Intermediates in Dichlorodiphenylacetic Acid Metabolism of
Aerobacter aerogenes, Appl. Microbiol. , 15(6), 1494-1495, 1967.
55. Bloom, S. G. and Menzel, D. B. , Decay Time of DDT, Science,
173, 213, 1971.
248
-------
(References - Continued)
56. Chau, A. S. , Rosen, J.D. and Cochrane, W. P., Synthesis of
of Known and Suspected Environmental Products of Heptachlor and
Chlordene, Bull, of Environ. Conlam. & Toxicol. , 6(3), 225-
230, 1971. ~
57. Leigh, Gerald M. , Degradation of Selected Chlorinated Hydrocarbon
Insecticides, J. Wat. Poll. Contr. Fed., 41_(11), R450-R460,
1969.
58. Terriere, L.C., Kiigemagi, U. , Gerlach, A. R. , Borovicka, R. L. ,
The Persistence of Toxaphene in Lake Water and Its Uptake by
Aquatic Plants and Animals, J. Agr. Food Chem. , 14, 66-69, 1966.
59. Werner, A. E. and Waldichuk, M. W. , Decay of Hexachlorocyclo-
hexane in Sea Water, J. Fish. Res. Board of Canada, JJU2), 287-
289, 1961.
60. Van Valin, C.C. , Andrews, A. K. , and Eller, L. L. , Some Effects
of Mirex on Two Warm-Water Fishes, Trans. Am. Fish. Soc. ,
r?, 185-196, 1968.
6l. Nicholson, H. Page, Webb, Hubert!., Lauer, Gerald J. , O'Brien,
Robert E. , Grzenda, Alfred R. , and Shanklin, Donald W. ,
Insecticide Contamination in a Farm Pond, Part I-Origin and
Duration, Limnol. and Oceanog, , £, 213-127, 1964.
62. Windeguth, D. L. , von and Patterson, R. S. , The Effects of Two
Organic Phosphate Insecticides on Segments of the Aquatic Biota,
Mosquito News, .26(3), 377-380, 1966.
63. Aly, O. M. and Faust, S. D. , Studies on the Fate of 2,4-D and Ester
Derivatives in Natural Surface Waters, J. Agr. Food Chem. , 12(6),
541-546, 1964.
64. Johnson, J. E., The Public Health Implications of Widespread Use
of the Phenoxy Herbicides and Pichloram, BioScience, 21(17),
899-905, 1971.
65. Bailey, G.W., Thurston, Jr., A. D. , Pope, Jr., J.D. and Cochrane,
D. R. , The Degradation Kinetics of an Ester of Silvex and the
Persistence of Silvex in Water Sediment, Weed Sci. , JJ5(3), 413-
419, 1970.
249
-------
(References - Continued)
66. Walker, Charles R. , Endothal Derivatives as Aquatic Herbicides
in Fishery Habitats, Weeds, 11, 226-231, 1963.
67. Plimmer, J. R. and Hummer, B. E. , Photolysis of Amiben, (3-
Amino-2, 5-Dichlorobenzoic Acid) and Its Methyl Ester, J. Agr.
Food Chem. , _Tm), 83-85, 1969.
68. Plimmer, J. R. , Weed Killers, In Encyclopedia of Chemical
Technology, £2, 174-220, 1970.
69. Cope, O. B. , McCraren, J. P. , and Eller, L. L. , Effects of
Dichlorbenil in Two Fishpond Environments, Weed Sci.
17(2), 158-165, 1969.
70. Rodgers, Charles A. , Uptake and Elimination of Simazine by
Green Sunfish (Lepomis cyanellus.Raf. ), Weed Sci. , L8_ (1),
134-136, 1970.
71. Stadnyk, L. , Campbell. R. S. and Johnson, B. T. , Pesticide
Effect on Growth and C Assimilation in a Freshwater Alga,
Bull, of Environ. Comtam. & Toxicol., 6J1), 1-8, 1971.
72. Chin, Wei-Tsung, Stone, G.M. and Smith, A. E. , Degradation of
Carboxin (Vitavax) in Water and Soil, J. Agr. Food Chem. , 18(4)»
731-732, 1970.
73. Loeb, H. A. and Engstrom-Heg. R. , Time Dependent Changes in
Toxicity of Rotenone Dispersions to Trout, Toxicol. & Appl.
Pharm. , J_7, 605-614, 1970.
74. Finucane, J. H. , Antimycin As a Toxicant in a Marine Habitat,
Trans. Am. Fish. Soc., 98_(2), 288-292, 1969.
75. Wedemeyer, Gary, Dechlorination of 1, 1, 1 -Trichloro-2, 2-bis
(p-chlorophenyl) ethane by Aerobacter aerogenes, Appl. Micro-
biol. , 15(3), 569-574, 1967.
250
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F. APPLICABLE REGULATIONS AND LAWS
GOVERNING PESTICIDES USE
1. Introduction
Public concern for the environment has created another area to
challenge the efficiency and effectiveness of our form of legal and administrative
framework. Among the concerns is adequacy and effectiveness of existing
state statutes regulating the sale and use of pesticides. This section
analyzes the applicable laws and regulations of the eight states in the
southeastern case study area. The provisions of the Federal Insecticide.
Fungicide and Rodenticide Act, (FIFRA) as amended and the Miller
2
Amendment to the Federal Food, Drug and Cosmetic Act, as amended ,
provide the foundation for a comparative approach. Additional laws
extending beyond the scope of federal statutes have been deemed necessary
in many of the southeastern states. These are examined and generate
recommendations for amending the federal pesticides program.
Pesticides have been regulated by both federal and state govern-
ments for many years. When the FIFRA was first enacted in 1947, there
were relatively few pesticides used on the agricultural croplands. The
initial objective was threefold: (1) to protect the farmer by insuring
that the pesticides marketed would be effective, (2) to assure sufficient
food and fiber supply by controlling pests, and (3) to protect the public
health. These original purposes remain viable.
New factors have been introduced which provide an additional
legislative intent. Many new agricultural chemicals have been formulated
marketed and are in use. Knowledge has been expanded regarding the
effects of pesticides on beneficial and harmful insects. There is also
an increased awareness within the scientific community regarding the
relationships of man to the ecological system. These developments
add a regulatory requirement or purpose --"to protect the environment"--
under the concept that each generation is the trustee of the environment
251
-------
for succeeding generations. Throughout this section analyses and
assessments are predicated upon these four objectives which also served
as criteria for testing the adequacy of current statutes and regulatory
controls.
2. Scope of Local Laws and Regulations
State laws regulating pesticides fall into three classifications.
These are statutes:
e Requiring economic poisons to be registered
• Governing pesticide application and use controls
o Providing for the detection of pesticide residues on crops.
a. Registration
Each of the eight states in the southeastern case study area has
enacted laws to regulate the intrastate commerce of economic poisons.
These laws require the manufacturer, dealer or any person to register
the pesticide with the state department of agriculture or another designated
administrative agency, such as South Carolina's Crop Pest Commission
4
and Kentucky's Agricultural Experiment Station .
There was a considerable lag in the time between the passage
in 1947 of the FIFRA regulating interstate commerce of economic poisons
and the date the last southeastern state had comparable laws. Table 1
indicates the date registration laws for economic poisons were passed in
each southeastern state.
252
-------
TABLE Fl
State
Alabama
Initial Pesticide Law - Southeastern States
Year
Enacted
Registration Laws
1951 Insecticide, Fungicide, and Rodenticide Act
Florida
Georgia
Kentucky
Mississippi
North Carolina
1953 Pesticide Law
7
1949 Economic Poisons Act
1956 Economic Poisons Law"*
1950 Economic Poisons Act ®
c
1947 Insecticide, Fungicide, and Rodenticide Act
South Carolina 1953 Economic Poisons Law
Tenness
ee
1951 Insecticide, Fungicide and Rodenticide Act
10
Four years was the median time required for these states,to
enact legislation after the federal statute was passed. Amendments to
the federal statute since 1947 have generally required a period of several
years before there were counterpart state laws.
Most state laws adopted the basic definitions used in the original
FIFRA, substituting only the names of governmental offices. Where there
are differences in language the intent in the FIFRA is preserved although
the actual language may be dissimilar. In 1959, the FIFRA was amended
to expand coverage of the act to include the agricultural chemicals known
as nematocides, defoliants, desiccants and plant growth regulators.
5 4
Until 1971, the Alabama statute and currently the Kentucky statute
have not been amended to add the expanded coverage of the 1959 amendeme
to the FIFRA. The pre-1971 Alabama law and the current Mississippi
statute do not cover, by definition, the term "device". Mississippi's
statute as amended does include other coverage by adding in their
253
-------
definitions the terms "disinfectant", "bactericide", and "adjuvant",
These three terms are not found in the registration statutes of the
other southeastern states nor in the FIFRA.
The lack of uniformity in the state laws does not significantly
influence whether or not each and every economic poison is registered.
Instead, where there is a difference between state and federal coverage
(regardless of which is stronger) a loophole exists which allows a reduced
level of regulatory protection. For example, the FIFRA controls the
registration of devices intended for sale and distribution in interstate
commerce but devices manufactured in Kentucky solely for intrastate
sale and distribution are technically unregulated.
There is a high degree of uniformity in the acts prohibited
by the state registration statutes. Basic prohibitions are keyed to the
commercial and selected consumer protection functions. Other typical
prohibitions relate to enforcement and the unauthorized disclosure of
formula information by officials. Table F2 lists the prohibited functions
or acts and illustrates the uniformity among the southeastern states.
Only two states include provisions prohibiting persons from
giving a false guaranty in product registration. Other states limit
restrictive language on falseness to the relationship between the contents
in the original container and the label of the original container under the
term, "misbranded". There are two regulatory concepts involved. One
pertains to all matter, material and documentation submitted in support
of registering the product and the other to the generally implied
warranty of all manufacturers that the product is as stated on its label.
254
-------
TABLE F2 BASIC PROHIBITED ACTS — PESTICIDE REGISTRATION STATUTES
SOUTHEASTERN STATES
ACTS PROHIBITED
Distribute an unregis-
tered, adulterated, or
misbranded product
Sell an unregistered,
adulterated, or mis-
branded product
Offer for sale an un-
registered, adulterated
or misbranded product
Deliver for transport
an unregistered,
adulterated, or mis-
branded product
Transport in intra-
state commerce an
unregistered, adul-
terated, or mis-
branded product
Detach a label or an
original container
Alter the label of an
original container
Add substance to an
original container
Take substance from
an original container
Any official to
reveal formula infor-
mation to unauthor-
ized persons
Any person to deny
officials access
to records
Any person to give
a false, guarantee
Any person to inter-
fere with the Com-
jnissioner or his
designee
ALA.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
FLA.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
GA.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
KY.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
MISS.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
N.C.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
S.C.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
TENN.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
255
-------
This discussion of guaranties is not significant in terms of
the litigation produced nor administrative activity created. Rather,
it discloses two aspects of regulatory control which have not been uni-
formily adopted by the southeastern states. It also considers the
sensitivity of the statutory language to the various controlling concepts.
There are many situations in which registration of pesticides
are exempted and penalties for violation of the state statutes are not
applicable. The provisions are reasonably uniform among the south-
eastern states. These exemptions are:
• Any carrier while lawfully engaged in transporting economic
poisons within the state provided that he will permit the
administrative agency to copy all records showing the trans-
actions in and movement of articles.
• Public officials of the state and of the federal government
engaged in the performance of their official duties.
• The manufacturer or shipper of an economic poison for
experimental use only.
• By other parties if the economic poison is not sold, and if
the container is plainly marked "for experimental use orily--
not to be sold", etc.
• Shipments of economic poisons between plants within the
state.
These exemptions appear reasonable when examined under the
doctrine of laissez-faire. On the other hand, when viewed under the
concept of environmental protection they provide a loophole by not requiring
registration of products used by state and federal public officials in the
performance of their official duties. This loophole allows agencies such
as fish and game commissions, forest service, park service, and the
U. S. Army Corps of Engineers to introduce into the environment pesticides
formulated by their personnel for which:
256
-------
Composition and quantity are known only to that agencyj
• Effectiveness in pest control is not subjected to the same
criteria as commercial items, and
o Toxicological implications are not readily determinable.
There are significant dissimilarities in the authorities granted
to state administrative agencies for the enforcement of their respective
pesticide registration statutes. Table F3 presents an analysis of the
enforcement authorities granted.
TABLE F3
Enforcement Authorities Granted by Current
Pesticide Registration Statutes
_ State
Alabama (pre-1971)
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Enforcement Authorities Granted
Emercency
Suspension of
Registration
NES
NES
NES
NES
Yes
Yes
NES
NES
Registration
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Stop Sale
Stop Use
Removal
NES
Yes
Yes
Yes
NES
Yes
Yes
Yes
Seizure
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Injunction
NES
Yes
Yes
NES
NES
Yes
NES
Yes
NES - Not expressly stated
Most of the administering agencies in the southeastern states
do not have authority to invoke the emergency suspension of registration.
Without such authority the agency may not have the legal power to act
Promptly to protect the public against hazards disclosed by new scientific
information. The 1971 Alabama Law did not grant emergency suspension
authority to the Commissioner of Agriculture.
257
-------
Mississippi's agencies have no authority to stop sale of
products found in violation nor do these agencies have authority to
obtain injunctions. Prior to the 1971 act Alabama's Commissioner of
Agriculture could not issue a "stop sale order" nor obtain an injunction.
Such authorities are important. Their absence has been the reason
why state and federal enforcement officials have not always been
able to cooperate fully. The FIFRA gives the Agricultural Research
Service (now Environmental Protection Agency's Pesticide Office) no
authority to issue stop sale orders. Federal enforcement officials have
frequently requested state officials to use their stop sale authority to
assist in a federal enforcement action. Cooperation has been good but
on some occasions cooperation could not be obtained because the action
sought by the federal enforcement officials was not in violation of the
state statutes. Detailed records on the cooperative effort are not
available, but the magnitude of federal enforcement activities in the
southeastern states is shown in Table F4. ^
There has been a significant increase in federal enforcement
activities since 1969. A 250 percent increase occurred in seizure
actions from 1969 to 1970. Likewise a 285 percent increase in recalls
occurred over the same period. For 1971 actions are at an even
higher rate. This surge in federal enforcement activities coincides with
the timing of Congressional hearings concerning deficiencies in the
administration of FIFRA.
13
The North Carolina Pesticide Report for 1970 contains
selected enforcement statistics. The following enforcement data are
shown:
Total number of inspections made 1743
Total number of "Stop Sale Orders" issued 315
Total number of "Stop Sale Orders" resulting
from failure to register 230
258
-------
TABLE F-4
FEDERAL ENFORCEMENT ACTIONS
SOUTHEASTERN STATES12
Year
and
Month
1969
January
February
March
April
May
June
July
August
September
October
November
December
Citations
Shipper
Located in
•Region IV
3
1
7
20
18
10
23
9
39
14
11
14
Consignee
Located in
Region IV
8
1
5
f5
20
.B
23
14
28
14
17
19
Seizures
0
0
0
0
0
1
0
0
0
1
0
0
Recalls
1
0
0
1
4
0
0
2
3
0
2
0
Total
169
17Z = 341
13
1970
January
February
March
April
May
June
July
August
September
October
November
December
31
15
28
8
20
13
13
10
1
11
9
28
21
17
23
11
15
12
11
11
4
11
10
18
0
0
0
1
0
0
0
4
1
1
0
0
2
0
0
17
3
1
0
0
2
8
5
12
Total
187
164 = 351
50
1971
January
February
March
April
May
June
July
16
22
20
11
24
18
26
Total (7 mos) 137
13
25
21
8
30
21
26
144 = 281
1
0
1
2
2
0
1
9
5
9
7
4
2
38
Source: Environmental Protection Agency
259
-------
It is significant that among the 1970 pesticide enforcement
activities in North Carolina, 18 percent of the inspections made resulted
in the use of "stop sale orders". This is an enforcement authority which
Federal officials do not possess. Of the "stop sale orders" issued, 73
percent were for failure to register. This high incidence of failure to
register and the substantial percent of inspections requiring the issuance
of "stop sale orders" indicates that North Carolina relies heavily on this
provision of its law.
The penalty provisions for violation of the registration statutes
of the southeastern states are lenient. Table F5 summarizes the
statutory provisions on penalties.
State
Alabama
Florida
Georgia
Kentucky
Mississippi
TABLE F5
Penalties for Violating Provisions of
Economic Poisons Law
Type Offense
Misdemeanor
Misdemeanor
Misdemeanor
Misdemeanor
Misdemeanor
North Carolina Misdemeanor
South Carolina Misdemeanor
Tennessee
Misdemeanor
260
Penalty (First Offense)
Punished as prescribed by law
Fine of $100 or $500 or imprison-
ment from 10 to 30 days based on
provision violated
Fine not less than $100 and not more
than $1000, or six months imprison-
ment, or both
Fine not less than $25 nor more than
$500
Fine not more than $500, or im-
prisonment for not more than one ye.ar,
or both based on the provision violated
Fine not less than $100, nor more than
$1000, or imprisonment for not more
than 60 days or both
Fine of not more than $100, or im-
prisonment for not more than 30 days,
or both
Punished at the discretion of the
court
-------
There is a high degree of uniformity between the provisions
in the registration statutes of the southeastern states and the provisions;
included in FIFRA. Penalty provisions of the FIFRA--misdemeanor
with first offense conviction subject to fine or not more than $500,
or imprisonment for not more than one year, or both fine and imprison-
ment--are somewhat stronger than the penalties shown in Table F5.
14,15,16
Many of the regulations issued for the administration
of FIFRA are similar in scope of coverage to the type regulations
17 18 19
issued by Florida , Tennessee and Georgia . The Mississippi
regulations are not as complete as FIFRA regulations. The regulations
21 22 23
in Alabama , North Carolina and in South Carolina are limited to
one printed page. Kentucky has no regulations and considers their statute
24
sufficiently clear so as not to require regulations . None of the south-
eastern states has found it necessary to issue interpretations of its
25-44
regulations similar to the interpretations issued by the Agricultural
Research Service on the FIFRA regulations.
The primary reason for the large number of interpretations at
the federal level is the volume of registrations handled. In processing
a large volume the incidence rate of registration cases requiring
clarification on a particular point is likely to be higher than when the
volume is small. Administratively these clarifications are handled at
the federal level by promulgating interpretations for general distribution.
At the state level the volume of registrations is substantially less and
clarifications are handled administratively on a case-by-case basis.
261
-------
b. Application and Use Controls
The laws used to regulate the application and use of pesticides
45
generally fall into three classes • These are laws:
o Requiring the examination and licensing of persons engaged
in the business of applying pesticides (custom applicators).
° Regulating persons in professions concerned with the use or
application of pesticides; e.g. entomologists, horticulturists,
plant pathologists, tree surgeons, etc.
o Prohibiting the use of certain pesticides, or requiring the
purchaser to obtain a permit before purchasing or using
highly toxic pesticides, or requiring dealers in restricted
use pesticides to be licensed, or any combination of these
provisions.
In keeping with the scope of this study, a fourth class of application
and use laws known as structural pest control laws has been intentionally
omitted. These regulate entomological or pest control or eradication
work in household structures, commercial buildings, or other structures
where pesticides are employed.
The oldest major area of application and use control in the case
study area is the regulation of custom or aerial application of pesticides.
Such regulatory control is used by only four of the southeastern states.
North Carolina's law and regulations came into being in 1953.
48 49 50
Tennessee's law is dated 1965. Mississippi's two laws with
51 52
accompanying regulations w'ere enacted and published in 1966.
Kentucky does not have a separate statute but exercises control by
regulation of aerial applicators through the Kentucky Department of
53
Aeronautics . This regulation was promulgated in 1954.
262
-------
An analysis of the National Transportation Safety Board's aerial
54-58
application accident records for the period 1964-68 disclosed
that generally there were fewer accidents in those four southeastern
states controlling custom application than in the four states without
this class of law. Table F6 shows the southeastern trend in aerial
application accidents. The findings in 1968 by Reich and Berner
59
reflects a similar trend for the southeastern states . The use pattern
for aerial applications versus vehicular or manual application by state
is unknown. The cotton crop in Mississippi is more susceptible to
aerial application than the tobacco crop in Kentucky so the frequency
factor of usage is reflected in the accident statistics.
The period covered by Table F6 was a period of increased use of
aircraft. The regional accident total as a percent of the national total
has remained fairly even since 1964. Table F7 indicates the kinds of
operations in which the aerial applicators involved in the accidents were
engaged. It is obvious that the majority of the accidents occurred
while the applicator was engaged in dusting and spraying crops. Tables
F8 and F9 show that the aerial application accidents are concentrated among
the pilots whose ages fell in the 25-39 year bracket and with pilots having
more than 1000 hours flying experience.
The information in Tables F7 through F9 suggests that the most common
kinds of aerial application operations involving pesticides were being
performed by experienced and mature pilots. At this point a separate
investigation was initiated to ascertain the need for provisions in aerial
application laws to protect the pilot against the toxicological effects of
pesticides. In addition to the risk of accident associated with flying there
is also present the hazard of contact with the pesticide chemicals.
Tables F10, Fll and F12 provide information on chemical types and the
seriousness of toxicological effects and accident injuries on pilots
engaged in aerial applications.
263
-------
TABLE F6
Aerial Application Accidents - Southeastern Region
Analysis by State 1964-6854"58
JS
1964 | 12
i
1965 10
i
1966 ! 4
1967 11
1968 | 11
i
j
Five Year
Total
48
!
1
State Five
o
18
15
15
17
16
81
1 Year Total i
As Percent
Of Regional
Total
15. 0
25.3
rt
r- 1
18
13
10
14
•Jc
1
1
03
to
• i-H
U
14 10
15 2
; -
O
4
Tenn. *
1
1
S
5
2
28 1 9 1
3
6 ! 0
i
16
4
14 3
i
2
3
6 3
Regional
Total
National
Total
S
78 388
63
50
70
59
• j
, ( _____ j .__ __. f
61
19.0
7
67
20
i
j
;
2. 1
j
1
20.9
6.3
i
26
10
8.1 i 3.1
i
! !
1
320
i
i ;
341
323
405
369
1862
Region as
Percent of
National
20. 10
18.47
15.47
17.28
15.98
17.52 !
i
o.
States controlling aerial applicators
-------
TABLE F7
Aerial Application Accidents by Kinds of Operations
Southeastern Region 1964-6854"58
Kinds of
Operations
Dusting Crops
Dusting Other
Seeding Crops
Fertilizing (Dust)
Fertilizing (Liquid)
Defoliation (Dust)
Defoliation (Liquid)
Spraying Crops
Spraying Forest
Spraying Towns
Other
Unknown/Not Reported
Number of Accidents
1964
25
0
0
3
0
2
7
33
1
0
4
3
1965
17
0
0
5
0
1
4
30
0
1
2
3
1966
16
0
0
1
0
2
5
20
0
0
4
2
1967
15
1
2
6
0
0
2
28
2
1
2
11
1968
13
0
0
3
1
1
2
33
0
1
|
5
0
5 Year
Total
86
1
2
18
1
6
20
144
3
3
1 17
19
265
-------
TABLE F8
Pilot Age in Aerial Application Accidents
Southeastern Region 1964-6854'58
Pilot Age
Less than 20 years
ZO years but less than Z5 years
Z5 years but less than 40 years
40 years but less than 50 years
50 years or over
Unknown
Number of Accidents
1964
0
7
45
16
7
3
1965
0
6
34
18
5
0
1966
1
6
21
16
6
0
1967
0
9
43
14
2
2
1968
1
4
38
14
2
0
TABLET 9
Pilot Experience in Aerial Application Accidents
Southeastern Region 1964-6854-58
Number of Pilot Flying Hours
Less than 250 hours
250 hours but less than 500 hours
500 hours but less than 1000 hours
1000 hours but less than 2500 hours
i500 hours but less than 5000 hours
5000 hours or over
Unknown
Number of Accidents
1964
3
4
10
17
12
26
6
1965
0
9
7
15
12
19
1
1966
1
3
8
10
8
20
0
1967
2
9
8
19
13
17
2
1968
0
5
5
19
7
18
5
266
-------
TABLE F10
Aerial Application Accidents by Type of Chemical Used
Southeastern Region 1964-6854-58
Types of
Chemical Used
Dry Chemical, Toxic
Dry Chemical, Nontoxic
Liquid Chemical, Toxic
Liquid Chemical, Nontoxic
Unknown/Not Reported
Number of Accidents
1964
16
18
26
13
5
1965
11
12
31
4
5
1966
12
5
22
8
3
1967
13
12
27
6
12
1968
10
7
27
10
5
TABLEF11
Aerial Application Accidents by Toxic Effect on Pilots
Southeastern Region 1964-6854-58
Toxic Effect
on Pilot
Not Affected
Affected in Flight
Affected Prior to Flight
Unknown /Not Reported
Number of Accidents
1964
50
0
0
28
1965
36
0
0
27
1
1966
28
0
0
22
1967
42
0
0
28
1968
34
0
0
25
Most of the aircraft involved in aerial application accidents were
rigged with spray tanks containing toxic liquid chemicals (Table F10). The
Table Fll suggests that the chemical hazard is not a threat to pilot
health, although the number of accidents in which this type data was
unknown or not reported is sufficient that such an observation is only con-
jectural. Injuries statistics directly attributable to the accidents reflect
'that 76% of the pilot injuries were classed as minor or were not reported,
12% involved pilot fatalities and another 12% resulted in serious pilot
injury.
267
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TABLE F12
Aerial Application Accidents by Pilot Injury Seriousness
Southeastern Region 1964-6854'58
Pilot Injury
Seriousness
Fatility
Serious
Minor/Not Reported
Total
Number of Accidents
1964
6
10
62_
78
1965
8
6
47
63
1966
6
5
39_
50
1967
8
6
56_
70
1968
9
10
40
59
There are considerable differences among the four southeastern
states which regulate aerial applicators as to the scope and detailed
coverage included in the regulations implementing aerial applicator type
laws. All four states (Kentucky, Mississippi, North Carolina, Tennessee)
51,52,53,60
have regulations on the requirements for obtaining a license.
These requirements typically include a provision for an examination
of the applicant by a board to determine the applicant's ability and
knowledge to perform within limits and standards. These regulations
typically include information on requirements pertaining to license fees,
revocation, suspension, financial responsibility and penalties for violation.
The laws and regulations of the State of Mississippi provide the
most comprehensive controls of these four states. Their structure
consists of an agricultural aviation licensing act with regulations
administered by the Agricultural Aviation Board, and an act regulating
the application of hormone-type herbicides by aircraft with its regulations.
The latter is administered by the Commissioner of Agriculture
through his agent,the State Entomologist. Both acts contain provisions
linking the responsibilities of the two administering agencies.
The aspects of the aircraft, aircraft equipment, materials used
and methods of application are within the purview of one of the agencies.
268
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Despite what appears to be adequate statutory authority, none of
the four states controlling aerial applicators has promulgated a com-
plete set of environmentally-sensitive regulations. Environmental
factors which are not generally covered in present regulations are:
o Particle size (Mississippi regulations cover nozzle size
and PSI),
o Formulation (dust and spray),
(a) viscosity additives
(b) foam
(c) encapsulation
o Weather at the time of application (there are state exceptions
on this factor).
Another class of application and use laws are those designed to
control the time and condition of sale, the distribution and the use of
61, 62
particular pesticide chemicals. Also included in this class of laws are
other provisions for the handling, storage and disposal of pesticides,
control of unused pesticides and contaminated containers. The Council
of State Governments' 1971 suggested State Legislation, Volume XXX
63
contains a Model Pesticide Use and Application Act , Another
model statute, the State Pesticide Use and Applications Act, was pre-
64
pared in 1969 by the Public Health Service .
Application and use laws have been enacted in Alabama, Florida,
Kentucky and North Carolina. The Florida Pesticide Law on economic
poison registration was amended in 1969 to grant authority to the
Commissioner of Agriculture to establish rules and regulations to
designate chemicals as "restricted pesticides". In 1970 Kentucky passed
an act relating to the restriction of the use of DDT for pest control. This
act prohibits the use of DDT on agricultural croplands by prescription.
New laws were passed in the 1971 legislative sessions in Alabama and
North Carolina in September and July respectively. These laws repealed
the earlier economic poison laws, made new pesticide acts incorporating
269
-------
registration of economic poisons essentially as before, created a
Pesticide Advisory Board or Committee with membership including
conservation interest, and established a new chemical category entitled
"restricted use" pesticide. The regulatory trend in the three states with
restricted pesticides laws is to require the licensing of dealers who are
to sell restricted use pesticides and to require use permits for persons
to purchase and use restricted pesticides.
The State of Florida in 1970 further amended their basic pesticide
law to provide coverage in an area of environmental concern—the per-
sistency of the pesticide chemical in the environment. The Florida
statute defines a "persistent pesticide" as one which will persist in the
environment beyond one year from date of application. It makes it unlaw-
ful to broadcast persistent pesticides except under specified conditions.
The regulations implementing this act contain the names of a dozen
chemicals designated as persistent pesticides. The new 1971 North
65
Carolina law permits the Pesticide Board to designate a pesticide
after a public hearing, as a "restricted-use pesticide" either because
of its persistence, its toxicity or by other criteria. These new provisions
demonstrate recognition by legislatures of the public concern regarding
misuse and misapplication of pesticides and their environmental impact.
c. Residue Detection
The state food, drug and cosmetic acts or equivalents follow the
66-73
federal act closely. Food residues and tolerances established by the
Food and Drug Administration under the Miller amendment of 1959 are
immediately accepted and promulgated by states for intrastate regulation
of produce and feed. States do not attempt to establish these type standards
through their research and regulatory organizations. A comprehensive
discussion of tolerances and residue detection was prepared and published
in 1968 by the Food and Drug Administration.
270
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3. Effectiveness of Current Local Statutes
There are no established criteria for the evaluation of statutes
for effectiveness. For the purposes of this study four factors have been
isolated as indicators of the effectiveness. These are:
» Adequacy of statutory authority to control areas of potential
abuse of public health and the environment,
a Relative economic burden imposed on the private sector by
the statutes to achieve compliance,
• Relative ease of public administration, and
• Ecological sensitivity of present statutes.
The present registration laws for economic poisons are generally
adequate to achieve an inventory-type control of pesticide chemicals.
These laws also serve the purpose of insuring that the farmer who is not
skilled in chemical formulation receives a product approved by govern-
ment. This kind of consumer protection is essential to prevent
false gurantees and misleading or false advertising. The requirement for
specific testing to determine effectiveness is beyond the scope of the
average individual. This places the determinations of efficacy, toxicological
significance, residual amounts on agricultural crops and tolerance leVel
solely and properly within the purview of the institutions of government,
Table F4 indicates federal enforcement actions in the southeastern
states citing all types of violations, including labeling and failure to
register. These citations average only about 31 per month for the eight
states, or approximately four citations per state per month. This low
level of enforcement activity is one indicator that the provisions of the
registration statutes are generally under compliance. State-level
enforcement actions are also at a low level. Alabama's statistics
271
-------
indicate no seizures, approximately 75 "stop-sale orders" and approxi-
mately 150 administrative citations or notices annually. North
Carolina's 1970 "stop-sale orders" amounted to 315.
A cooperative spirit exists between the agricultural chemicals
industry and federal and state enforcement officials. This cooperation
is evidenced by the small number of enforcement actions which reach
the seizure category in the application of regulatory authority granted to
the administering agencies.
The statutes and regulations pertaining to label requirements
for economic poisons are generally adequate. In making this judge-
ment observations of the report of the General Accounting Office and
a part of the 1969 Congressional hearings, the Committee on Govern-
7 7
mental Operations eleventh report, the House of Representatives
hearings'" and the Senate hearings '' each were considered. Such a
judgement does not mean that administrative mistakes have not been
made. Rather it means that as a whole the labeling requirements of
the state statutes, which closely follow those of the FIFRA, are satis-
factory to warn and caution users of hazards.
There is evidence, however, labeling may not by itself be
sufficient warning when the age of individuals who come in contact with
pesticides is considered. Table F13 disclosed that nationwide pesticides
ingestion accounts for approximately 5.6% of the accidental ingestions
of children under five years of age and this statistic includes only those
cases reported by poison control centers to the National Clearinghouse.
Table F14 provides a tabulation of the accidental pesticides
ingestions by children in the southeastern states under 5 years of age
for a three and one-half year period. The incident rate in the State of
Florida appears disproportionate. This is probably because of the sub-
stantially higher number of reporting poison control centers in Florida
than in the other states. Florida in 1971 has 32 centers listed in the
directory to South Carolina's two centers and Kentucky's six centers.
272
-------
TABLE F13
Accidental Pesticide Ingestions by
Children Under 5 Years of Age
Reported by All Poison Control Centers 1965-6980' 81
Year
1965
1966
1967
1968
1969
Total No. of Cases
All Substances
63, 352
64,634
72,661
71, 563
76, 155
Number of
Pesticide.
Cases
3,856
3, 715
4,087
3,965
3,952
Pesticide Cases
As a % of Total
6.1
5.8
5.6
5.5
5.2
Source: Food and Drug Administration
TABLE F14
Accidental Pesticide Ingestion by Children
Under 5 Years of Age Southeastern States
Reported by Poison Control Centers 1968, 1969, 1970
and First Six Months 197182
1968
1969
1970
1971 (1st 6 mos.)
3 1/2 yr. Average
Source: Food and
Number of Accidental Ingestions Children Under 5 Yrs.
Ala.
19
24
13
4
17
Fla.
377
254
192
104
265
Ga.
61
43
57
28
54
Drug Administration
Ky.
7
13
12
2
9
Miss.
25
29
13
5
21
N.C.
77
69
82
32
74
S.C.
59
19
16
3
27
Tenn.
96
114
94
44
99
273
-------
The actual number of accidental pesticide ingestions occurring
is suspected to be much higher than the national or individual state
figures indicate. In 1969 a survey of South Carolina physicians was
83
conducted. Of 1157 queried, 667 reported they had seen 57Z cases
of pesticide poisoning during the year ending July 1969. The records
of the National Clearinghouse for Poison Control Centers indicate only
26 cases were reported for the calendar year 1969 and 72 cases for
1968. A similar survey was again conducted in South Carolina^ for
the year ending July 1971 and a total of 624 pesticide poisoning cases
were seen by physicians.
There is an absence of a completely reliable national reporting
system of the number of accidental ingestions of pesticide by children
under five years of age. However, the high incidence of such events
suggests that present packaging methods for pesticides may be creating
a condition in the home which is unsafe for small children. The state
registration statutes do not grant authority to the administering agency
to regulate product packaging.
Since application and use statutes are only found in four of the
eight southeastern states and these statutes are relatively new, their
adequacy cannot be assessed with the same completeness as the long-
standing registration statutes. For example, the Kentucky act relates
only to one of the organochlorine pesticides, DDT. There are many
other pesticides of related chemical composition. This and similar
statutes are deficient since they fail to provide adequate controls for the
range of products in a class and regulate only a single product within
the class.
Amendments to the registration statute in Florida provide the
statutory authority for application and use regulation. These amend-
ments commencing in 1969 are the oldest of this class of law in the case
study area. Authorities granted to the Commissioner of Agriculture
delegate responsibility for the classification of highly toxic and persistent
pesticides. These authorities also establish licensing of dealers and user
274
-------
permit requirements for restricted and persistent pesticides. The new
-Alabama and North Carolina laws provide similar authorities. The
significant difference in the application and use laws of these states is
that the North Carolina law calls for the licensing of ground equip-
ment used in pesticide application. As such, it is more extensive in
coverage than the laws of Alabama and Florida.
There is a hazard in writing laws with extensive regulatory
coverage. Unless adequate funding provisions for administration and
enforcement is assured, the law cannot be rendered effective. It is
estimated that there are 30, 000 pieces of ground application equipment
in North Carolina but the 1971 legislative session did not appropriate
adequate funds to permit staffing for ground equipment inspection.
The key economic significance associated with the state registra-
tion statutes in the southeast is threefold. First, the burden on chemical
formulators in terms of registration fees is nominal. Table F15 indicates
the statutory or regulatory annual license and fee requirements in the
eight states of the case study area.
Second, none of the southeastern states has required of
manufacturers and formulators any specialized labeling, or unique
requirements for information to be supplied as a part of the registration.
The requirements imposed on manufacturers and formulators are
essentially those imposed by FIFRA. In fact, many of the laws authorize
the state administering agency to accept the FIFRA registration without
protest.
Third, the type of agricultural crops and acreage involved in
the southeastern states is such that without pesticide chemicals the
farmer would not be able to achieve the production levels currently
being attained. A comprehensive discussion of the economic consequences
of restricting the use pesticides is beyond the purview of this study and
is adequately treated in a U.S.D.A. symposium.85The impact on
275
-------
TABLE F15
Statutory or Regulatory Annual License and Fees Requirements for
Pesticide Products and Applicator, Dealers and Consultant Services
Southeastern States
"X. Type of
State ^x^^
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Registration
Fee
Each Brand
$15
$10
$5 up to $200 annual
$5 ea up to $50 annual
$15 up to 10, then $5
$25
$20 ea up to 10, $10 ea add'l
$10 up to 10, $5 ea add'l
Dealers
License
NSC
"
NES
NSC
NSC
NSC
$25
NSC
NSC
Pesticide
Applications
License
NSC
NES
NSC
Aerial-$25
Aerial -DA
$25
NSC
$10
Pest
Control
Consultant
License
NSC
NSC
NSC
NSC
NSC
$25
NSC
NSC
Each
Aircraft
License
NSC
NSC
NSC
NSC
Up to $50
$10 .
NSC
NES
Each Piece
Ground
Equipment j
License
NSC
NSC
NSC
NSC
NSC
$5
NSC
NSC
ro
DA - Determined annually
NSC - No statutory coverage
- Not expressly stated
-------
cotton, corn, peanuts and tobacco have been studied by the Economic
of.
Research Service of the U. S. Department of Agriculture. These are
principal crops in the case study area.
The administration and enforcement of the state registration
statutes is being accomplished in the southeast without any apparent
difficulty. State chemists and pesticide laboratories have borne a significant
part of the total federal-state effort. Most of the administering agencies
and laboratories are operated with a modest staff. The level of staffing
of inspection personnel likewise has been modest.
The introduction of application and use statutes tends to increase
the administrative burden because of the inherent requirement to process
large numbers of dealer licenses and use permit applications. Currently
Florida has issued approximately 1400 licenses to dealers and 12, 000 user
permits. They needed four additional inspectors for the restricted and
persistent pesticide administration. Another four are to be added when the
law licensing of applicators is enacted. Adjustments were made in territory
size to be covered by a single inspector, and some responsibilities were
87
realigned. Forty-two persons are engaged as inspectors.
Ecological accidents in the southeast investigated by the En-
vironmental Protection Agency (formerly Agricultural Research Service)
staff for the years 1967 through October 1971 have involved injury to
humans, animals and plants. TableFl6 presents the number of invest!-
Q Q
gations conducted.
277
-------
TABLE F16
Ecological Accident Investigations
1967 - October 197188
State/Region
National
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
•
SE Regional Total
National Total
SE as % of National
Number of Investigations
1967
-
7
5
-
-
5
1968
3
5
4
-
5
3
1
3 j 1
i
j 1
20
95
21.1%
22
131
16.8%
1969
6
4
2
-
2
3
2
1970
4
12
5
2
-
28
6
[
i i 5
1
\
t
•
20
118
16.9%
62
197
31.5%
(10 mos)
1971
4
16
17
1
3
10
4
2
57
203
28.1%
5 Year
Total
17
44
33
3 i
r
10 !
49
16 i
9 !
181
744
24. 3%
Source: Environmental Protection Agency
278
-------
Of the 744 ecological accidents in the southeast 52. 5 percent
involved humans, 39 percent involved animals, 5. 5 percent involved
plants and miscellaneous accidents accounted for 3 percent. The
miscellaneous category includes such accidents as spills into -wells.
The increased number of investigations in 1970 and 1971 coincides
with the Congressional hearings on pesticide regulations and greater
public awareness attributed to news media coverage of major incidents
such as the parathion investigations in North Carolina in 1970. Many
incidences of ecological accidents involving pesticides are reported
to the national level. Only the more serious incidents are investigated.
The staff available is insufficient to check out each incident reported.
This investigative function should be expanded.
Current pesticide statutes rarely consider the need to protect
the environment. There is no reference to differentiate between
narmful and beneficial insects, magnification of toxicological components
via the food chain, or beyond the production of food and fiber is the need
to recognize other beneficial uses. To a large extent the void reflects
prior influence of the agarian element in our society and only a recent
awareness of the environmental implications.
The number of people living on farms has steadily declined.
Correspondingly, the new application and use statutes include controls
affecting both urban and farm dweller. For example, recent laws
address control of unused pesticides and contaminated containers.
Other provisions are concerned with the handling, storage and disposal
of pesticides. Recently enacted controls often emphasize environmental
awareness.
279
-------
4. Assessment of Important Litigation
There is a relative absence of litigation involving the registration
statutes of the southeastern states. The legal reporting services
document no cases for the region. A telephone survey of each of the
89
administering agencies verified that there has been no litigation.
Cases between private parties are generally settled out-of-court.
There have been no cases of private actions against public agencies
90-92
to compel environmental protection despite a legal trend elsewhere.
Such actions may occur as consumer knowledge and awareness of the
effects of pesticides increase.
Three explanations for the absence of litigation are suggested.
The first is that manufacturers and formulators have reacted as
responsible citizens to citations for violation of statutory provision
or regulation. For minor violations most of the statutes do not require
legal citation. Administrative citations are used generally for such
violations.
The second is that the nature of violations which are occurring
require only a limited action by the manufacturer or formulator.
Label violations are frequently handled by sending dealers new labels.
Discounts to invoices are given for the relabeling service. Violations
involving variance of active ingredient guarantees are typically handled
by the dealer returning the product to the manufacturer or formulator.
Then it is re-formulated to bring the levels and strengths of active
ingredients in compliance with the label and registration statements.
280
-------
The third reason is that 100% inspection of labels and laboratory
testing is not performed at either the federal level or in the southeastern
states. At the federal level approximately 5000-6000 samples are
taken annually for the 30, 000-40, 000 registered products to determine
variance from the registration statements on active and inactive
ingredients. This equates to federal inspection approximately once
every five years. In 1970 North Carolina reported 1743 inspections for
its 4854 registered products with the following results:
Samples analyzed 1074
Passed 855
Deficient 111
Excessive ingredient 6
Misbranded 1
Not registered 134
93
South Carolina's 1970 report indicates that 1139 samples were
analyzed and 133 or 11.69% were found deficient.
There is litigation on the application and use laws of two south-
eastern states. North Carolina has experienced 12 cases where litigation
resulted from the enforcement of its aerial crop-dusting laws. Briefs
of these cases are shown in Appendix . The fundamental issue in
each of these cases was engaging in custom application of pesticides
without a license as required by the 1953 statute. Litigants involve
three classes of persons: persons soliciting business for aerial appli-
cators, pilots operating aircraft engaged in aerial applications, and
owners of aircraft engaged in aerial applications. Theses cases were
litigated in county courts with no jury involved. Eight of the 12 cases
resulted in guilty pleas by defendants and three cases were nol-prossed.
281
-------
One case has been litigated in Florida challenging the legality of
regulating application and use in terms of the persistency of the chemical.
This case. Great Lakes Biochemical Co., Inc., v. Doyle Conner, as
94
Commissioner of Agriculture of the State of Florida was a civil
action in the Circuit Court of the Second Judicial Circuit, Leon County,
Florida. The court found that the state erred in failing to register the
plaintiff's products. The persistency of phenylmercuric acetate, was a
fundamental issue in the action. Subsequently, the Environmental Pro-
tection Agency cancelled registration in October of 1971 of three
products of the Great Lakes Biochemical Co. , Inc. 95 These were
included in the four products Great Lakes Biochemical sought to register
in the State of Florida.
Private lawsuits involving implied or expressed warranties of
pesticides and negligence in the application of pesticides are few.
62
Rohrman cites six such cases. These cases raised no significant
issues not presently covered by the guarantee provisions in the registration
statutes, or the negligence aspects in common law.
5. Conclusions
The provisions of registration statutes of the southeastern states
are quite similar to the statutory provisions of the original FIFRA. All
states have not kept pace in modifying their statutes to comply with
changes in the FIFRA in terms of coverage of categories of pesticides.
The states took an excessive amount of time to enact comparable legis-
lation to the FIFRA to regulate ontrastate commerce of pesticides.
Amendments have required several years before enactment.
282
-------
It is questionable whether states should be permitted such time
period because of the potential environmental damage which could occur
during the interim. It is similarly doubtful or even logical to expect
states to invest sufficient funds to initiate research on the short and
long-term impacts on human health and the environment so that effective
and timely legislation can be enacted. The monitoring activities are
chiefly performed in the states by the state officials, land-grant colleges,
county farm agents, and water and air pollution authorities. Because
of their proximity to the physical environment and the agricultural crop-
lands, a fairly effective state surveillance program of pesticides does
exist with respect to annual registration of pesticides. This affords
protection of the farmer, the food supply, and to a lesser extent, the
protection of public health. The present state registration statutes
modeled after the FIFRA are inadequate to protect the environment,
but their annual registration requirement exceeds FIFRA requirements.
There are significant differences in scope of coverage in some
states pesticide laws compared to the coverage of the amended FIFRA.
There are also considerable differences in the enforcement authorities
granted to the state administering agencies. The penalties enacted for
violations are weak and are not deterrents to violations. On the other
hand the volume of litigation does not indicate that a strong penalty
deterrent is required.
Two major loopholes exist in the present registration statutes:
First, the exemption of officials of state and federal agencies from
registering products used in their official activities provides an opportunity
for the aquatic environment to be subject to pesticide'contamination.
This occurs without any possibility of assessing the type and volume of
chemicals entering the waters. Second, the registration statutes do not
Provide coverage of an important consumer protection need. This relates
*o the packaging aspect of pesticide containers to provide for child safety.
283
-------
The level of enforcement of the state registration statutes is
comparable to the level of enforcement of the FIFRA. Federal recall
and seizure actions in the southeastern states have been infrequent and
several states have made liberal use of their authority to issue "stop-
sale orders". Enforcement cooperation between the state and federal
levels of government has been high.
Some of the southeastern states are ahead of the federal govern-
ment in the enactment of pesticide application and use controls. Until
recently these controls have been limited to regulation of aerial applicators
in only four of the eight states. There is no federal statute governing
aerial applicators despite the fact that the aircraft are regulated by the
Federal Aviation Administration. The bulk of the current application
and use litigation has been concerned with aerial application licensing.
Aerial applicators frequently engage in interstate operations which require
separate licensing for each of the states served. Farmers needing
an urgent pesticide application are not prone to investigate whether or
not an applicator is licensed in his state.
Two information systems used, or which should be used, for
decisions affecting the federal pesticide program are either woefully
inadequate or warrant some improvement. Only a small number of the
incidences of pesticide poisonings which occur are being reported
(alledgely 10-15 percent) to the National Clearinghouse for Poison Control
Centers. This level of reporting is inadequate to base federal or state
policy decisions. The South Carolina community pesticide surveys for
two separate years would indicate that the 10-15 percent figure for the
nation is a reliable estimate of the situation in the southeastern states.
One aspect of the National Transportation Safety Board's reporting
system on aerial application accidents needs improvement. This relates
to the toxicological effects on pilots. The high incidence of "unknown or
not reported" for this data category limits the usefulness of this system.
This is a crucial consideration which could be used in health research
and pesticide program policy decisions.
284
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The inclusion in state application and use laws of provisions re-
quiring the inspection and licensing of ground application equipment is
commendable from the viewpoint of environmental protection. On the
other hand it is doubtful if an effective enforcement program can be
initiated and operated within the present and anticipated funding con-
straints. There is also the inherent implication that this area of control
and enforcement could create chaos for equipment manufacturers if
each state adopts different inspection standards for licensing.
None of the southeastern states have enacted legislation requir-
ing the posting of signs for fields which have been treated with pesticides.
The employment of migratory workers often of limited education
throughout the southeast makes any such future practice questionable
Unless a standardized program is established.
In summary, the southeastern states registration statutes are
slightly less adequate than the FIFRA. There are some states with
application and use controls offering limited protection of the aquatic
environment. The pesticide laws and common law principles applicable
to the use of pesticides do a reasonably adequate job of protecting
Persons and property from injury. There is a need for improvement
in the administration of present controls. Present state registration
laws are inadequate with respect to protection of the environment. On
the whole, envrionmental protection is just now being written into the
statutory language of the southeastern states in the form of application
and use laws.
6. Recommendations
1. The Southeastern states must reduce the time required to formulate
Pesticide legislation, enact legislation and implement pesticide programs
as technical advances elucidate the complex interaction between man and
the other factors affecting the environment. Alternatives available include
(a) pre-emption of registration and use controls by the federal government,
285
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(b) adoption of federal standards for compliance by states under new
federal legislation, (c) improved education to develop an informed public,
and (d) combinations of these.
2. Annual registration of pesticide products as practiced by the states
should be adopted for federal registration thus providing a more frequent
review of ingredient statements and the mechanism for readily challenging
efficacy statements as new scientific findings are made available. A no-
change registration form would facilitate administration of annual regis-
tration processes.
3. The national data collection systems supporting the federal pesticide
program should be improved. The federal government should encourage
legislation at the state and federal levels to make mandatory reporting
by physicians of treatment of pesticide poisonings. The U. S. Public
Health Service should promote effective diagnosis and reporting of pesti-
cide poisonings among its physicians and physicians at large. The
National Transportation Safety Board should cause improved reporting of
the toxicological effects on pilots by requiring investigation and re-submission
of future reports where this data category is improperly completed. The
Department of Commerce should expand it's annual reporting requirements.
Information should be collected from manufacturers and distributors on
the quantity of pesticides shipped as final sales to retailers or direct to
consumers by county.
4. The registration procedures on pesticides should include an assess-
ment of packaging adequacy from the viewpoint of child safety. Partici-
pation by the Office of Consumer Protection, by the Federal Trade
Commission, and the Food and Drug Administration might be necessary
to avoid duplicate staffing of qualified specialists.
5. An Executive Order should be issued by the President which would
cause all federal agencies introducing pesticide substances into public
waters and onto public lands to file with state water pollution agencies
the chemicals used, the amount, the time of use and the purpose. This
286
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recommendation accepts the Congressional intent that states have pri-
mary responsibility for water pollution control.
6. The federal government should encourage state water pollution control
agencies to issue regulations requiring all state government agencies using
pesticides in state waters and on public lands to file similar statements.
7. The focus of the federal pesticide program should be shifted to provide
incentives for the states to enact and enforce a high quality state pesticide
program. Federal standards on registration, inspection, and enforcements,
etc. should be established. States should be provided with federal grant
assistance to operate and administer their pesticide programs which satisfy
the federal standards. The grants could cover planning, inspection, labo-
ratory services, enforcement and personnel training similar to the type
policies being adopted to implement the Occupational Safety and Health Act
of 1970. Reduction of federal inspection and enforcement staffs could be
accomplished when state programs attain a satisfactory level. Other
federal programs such as the Wholesome Meat Inspection Act and the
Atomic Energy Commission's state radiation agency agreements provide
adequate precedent for states meeting federal standards to manage both
the state and federal program within their geographical boundary.
8. The FIFRA should be amended to provide for a joint comprehensive
federal-state pesticide program and to grant federal officials authority
to issue "stop-sale" and "stop-use" orders,
9. The investigative function performed by the Accident Investigation
Section in the Pesticides Office of the Environmental Protection Agency
should be expanded.
287
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7. References
1. Federal Insecticide, Fungicide, and Rodenticide Act, (61 Stat
163;7U.S.C. 135-135K) June 25, 1947.
2. Federal Food, Drug and Cosmetic Act, Miller Amendment, (Sec.
404 (d) (2), 68 Stat. 512; 21 U.S.C. 346a (d) (2)), 1959.
3. South Carolina Economic Poison Law, 1953.
4. Kentucky Economic Poisons Law, 1956.
5. Insecticides, Fungicides, and Other Economic Poisons, Article
20, Title 2, Section 337, 1958 Recompiled Code of Alabama, 1951.
6. Florida Pesticide Law, Chapter 487, 1953 (Revised).
7. The Georgia Economic Poisons Act, Georgia Laws 1950, Pg. 390
and Georgia Laws 1958, Pg. 389, 1949.
8. Mississippi Economic Poisons Act, Chapter 509* Senate Bill No.
2145, Laws of Mississippi, 1971.
9. North Carolina Insecticide, Fungicide, and Rodenticide Act of 1947.
10. Insecticide, Fungicide, and Rodenticide Law (Pesticide Act)
Tennessee Code Annotated, Title 43, Chapter 7, Sections 43-701-
703 as amended, 1951.
11. Alabama Pesticide Act of 1971.
12. Gimble, A. F. , Letter, Environmental Protection Agency, Region
IV, Pesticides Regulation Division, September 17, 1971.
13. North Carolina Department of Agriculture, North Carolina Pesticid6
Report for 1970.
14. Regulations for the Enforcement of the Federal Insecticide,
Fungicide, and Rodenticide Act (Title 7, Ch. Ill, Pt. 362 of the
Code of Federal Regulations), as amended, August 29, 1964.
15. Joint Regulations of the Secretary of Agriculture and the Secretary
of the Treasury for the Enforcement of Section 10 of the Act (Title
7, Ch. Ill, Pt. 362 of the Code of Federal Regulations), October 1*
1964.
288
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16. Regulations on Advisory Committee and Hearings under the Act
(Title 7, Ch. Ill, Pt. 364 of the Code of Federal Regulations),
August 29, 1969.
17. Rules of the Department of Agriculture (Florida) Chapter 7E-2
Pesticides, Revised January 23, 1967.
18, State of Tennessee Department of Agriculture Rules, Regulations,
Definitions and Standards for Pesticides, November 1962.
19. Rules and Regulations for the Enforcement of the Georgia Economic
Poisons Act, July 1, 1965.
20. Regulations, Mississippi Economic Poisons Act of 1950, Revised
September 9, 1970.
21. Rules and Regulations for the Enforcement of the Alabama
Economic Poison Law, Undated.
22. North Carolina Department of Agriculture, Rules, Regulations,
Definitions and Standards, Chapter XXIII, Pesticides, June 2, 1970.
23. Pesticide Fertilizer Regulation (South Carolina), July 1, 1955.
24. Huffman, W. J. , Letter explaining absence of published regulations
on Kentucky Economic Poison Law, July 1971.
25. Agricultural Research Service, Interpretation of Applicability to
Pest Control Operators, Interpretation No. 1, FIFRA, May 1965.
26. Agricultural Research Service, Interpretation of Terms, Interpre-
tation No. 3, FIFRA, November 1964.
27. Agricultural Research Service, Interpretation of Names of Products,
Interpretation No. 4, FIFRA, January 1965.
28. Agricultural Research Service, Interpretation on Ingredients,
Interpretation No. 5, FIFRA, March 1965.
29. Agricultural Research Service, Interpretation of Net Contents,
Interpretation No. 6, FIFRA, February 1965.
289
-------
30. Agricultural Research Service, Interpretation on Direction for
Use, Interpretation No. 7, FIFRA, May 1965.
31. Agricultural Research Service, Interpretation on Advertising,
Interpretation No. 9, FIFRA, July 1965.
32. Agricultural Research Service, Interpretation on Labels for Large
Containers, Interpretation No. 10, FIFRA, July 1965.
33. Agricultural Research Service, Interpretation on Guaranty,
Interpretation No. 11, FIFRA, May 1965.
34. Agricultural Research Service, Interpretation on Analyzing and
Testing, Interpretation No. 12, FIFRA, May 1965.
35. Agricultural Research Service, Interpretation of Liquid and
Pressurized Household Insecticides, Interpretation No. 15, FIFRA,
November 1964.
36. Agricultural Research Service, Interpretation of Warning, Caution,
Antidote Statements, Interpretation No. 18, FIFRA, November 1965-
37. Agricultural Research Service, Interpretation of Household
Containers Containing Chlordane, Interpretation No. 19. FIFRA,
April 1965.
38. Agricultural Research Service, Interpretation on Labeling Claims
for Hard Water Areas, Interpretation No. 21, FIFRA, July 1965.
39. Agricultural Research Service, Interpretation on Registration of
Thallium Products for Household, Interpretation No. 22, FIFRA,
August 1965.
40. Agricultural Research Service, Interpretation on Household
Insecticides Depositing Chemical Residues, Interpretation No. 23,
FIFRA, November 1964.
41. Agricultural Research Service, Interpretation on Claims for Safety
and Non-Toxicity Labeling, Interpretation No. 24, FIFRA,
September 1965.
42. Agricultural Research Service, Interpretation on Sodium Arsenite
and Arsenic Trioxide, Interpretation No. 25, FIFRA, August 1968-
290
-------
43. Agricultural Research Service, Interpretation on Labeling
Phosphorus Paste Products, Interpretation No. 26, FIFRA, March
1969.
44. Agricultural Research Service, Interpretation on Labeling Using
"Germ Proof", Interpretation No. 27, FIFRA, September 1969.
45. Environmental Protection Agency, Office of Pesticides Programs,
Digest of State Pesticide Use and Application Laws, May 1971.
46. North Carolina Aerial Crop-Dusting Law, 1953.
47. North Carolina Rules, Regulations, Definitions and Standards
Application of Pesticides by Aircraft, June 22, 1953.
48. Tennessee Pest Control Act, 1961.
49. Act Regulating the Application of Hormone-Type Herbicides by Air-
craft, Chapter 475, Senate Bill 2135, Laws of Mississippi 1971, 1971,
50. Agricultural Aviation Licensing Act of 1966 (Mississippi), Section
5011-01 through 5011-15, Mississippi Code of 1942.
51- Regulations, Mississippi Agricultural Aviation Licensing Act of 1966,
Amended March 13, 1970.
52. Regulations Governing the Application of Hormone-Type Herbicides
by Aircraft (Mississippi), as amended June 22, 1966.
53. Regulation of Aerial Applicators, KAV-5, Kentucky Department of
Aeronautics, 1954.
54. Civil Aeronautics Board, Briefs of Accidents Involving Aerial
Application, 1964.
55. National Transportation Safety Board, Briefs of Accidents Involving
Aerial Application Operations, 1965.
56. National Transportation Safety Board, Briefs of Accidents Involving
Aerial Application Operations, 1966.
57. National Transportation Safety Board, Briefs of Accidents Involving
Aerial Application Accidents, 1967.
291
-------
58. National Transportation Safety Board, Briefs of Accidents Involving
Aerial Application Operations, 1968.
59- Reich, George A. and Bemer, William H. , Aerial Application
Accidents, 1963 to 1966, Arch Environ Health, 17, 776-784,
November 1968.
60. Tennessee Department of Agriculture, Rules and Regulations
Governing Pest Control Operators, 1961.
61. Council of State Governments, Suggested State Legislation, Volume
XXV, Safe Use of Pesticides, 1966.
62. Rohrman, Douglas F. , Pesticide Laws and Legal Implications of
Pesticide Use, An undated publication of the National Communicable
Disease Center, Pesticides Program Training Guide, approximately
1967.
63. Council of State Governments, Suggested State Legislation, Model
Pesticide Use and Application Act, 1971.
64. U. S. Department of Health, Education and Welfare Public Health
Service, Guide for Drafting Pesticide Legislation Model Statute,
State Pesticide Use and Application Act, March 1969.
65. North Carolina Pesticide Law of 1971, Article 52, Chapter 143,
General Statutes of North Carolina, 1971.
66. State of Alabama, Detection of Pesticide Residues Statute, Title 2,
Section 337, Code of Alabama, 1940, 1965.
67. Florida Department of Agriculture, Food, Drug and Cosmetic Act,
1939.
68. Georgia Food Act, as amended, March 25, 1968.
69. Kentucky Food, Drug and Cosmetic Act, 217.005 to 217.215,
217.992, KRS, I960.
70. State of Mississippi, Mississippi Food Law, 1910.
71. State of North Carolina, Food, Drug and Cosmetic Act (1939 C, 320,
s. 1), January 1, 1940.
292
-------
72. South Carolina Department of Agriculture, Pure Food and Drug
Law, Chapter 10, Article 4, S. C. Code of Laws 1962, May 3, 1940.
73. Tennessee Department of Agriculture, Food, Drug and Cosmetic
Act and Regulations Including Soda Water Standards and Inhaling
Glue Act, January 1, 1969.
74. U.S. Department of Agriculture and U.S. Department of,Health,
Education and Welfare, Food and Drug Administration, The
Regulation of Pesticides in the United States, March 1968.
75. Kirkpatrick, John H. , Alabama Department of Agriculture,
Unpublished Data on Pesticide Enforcement, 1971.
76. Hearings, Deficiencies in Administration of Federal Insecticide,
Fungicide and Rodenticide Act, Subcommittee of the Committee
on Government Operations, House of Representatives, 91st
Congress, 1st Session, 1969. ,
77. Eleventh Report by the Committee on Government Operations,
Deficiencies in Administration of Federal Insecticide, Fungicide
and Rodenticide Act, House Report No. 91-637, 1969.
78. Hearings, Federal Pesticide Control Act of 1971, Committee on
Agriculture, House of Representatives, 92nd Congress, 1st
Session, Serial No. 92-A, 1971.
79. Hearings, Federal Environmental Pesticide Control Act, Senate
Subcommittee on Agricultural Research and General Legislation,
92nd Congress, 1st Session, March 23-26, 1971.
80. Food and Drug Administration, National Clearinghouse for Poison
Control Centers, Bulletin, Tabulation of 1968 Reports, September-
October 1969.
81. Food and Drug Administration, National Clearinghouse for Poison
Control Centers Bulletin, Tabulation of 1969 Reports, September- ,
October 1970.
82. F*ood and Drug Administration, National Clearinghouse Poison
Control Centers, Unpublished data on pesticide poisonings in
southeastern states 1968 - 1st half. 1971.
83. Keil, J. E. , Sandifer, S. H., and Gadsden, R. A. , Pesticide
Morbidity in South Carolina, The Journal of the South Carolina
Medical Association, 69-70, March 1971.
293
-------
84. Keil, J. E. , et al, Unpublished data on community pesticide study
in South Carolina furnished by Medical University of South
Carolina, 1971.
85. Economic Research Service, U.S.'D.A. , Economic Research on
Pesticides for Policy Decision-making, Proceedings of a
Symposium, April 27-29, 1970.
86. Economic Research Service, U. S. D. A. , Economic Consequences
of Restricting the Use of Organochlorine Insecticides on Cotton,
Corn, Peanuts and Tobacco, March 1970.
87. Giglio, Vincent, Unpublished data on Florida staffing experience
of new pesticide program, 1971.
88. Environmental Protection Agency Pesticides Office, Summary of
Pesticide Accidents, January 1967-November 1, 1971.
89. Teledyne Brown Engineering, Telephone survey of Southeastern
states pesticide program administrators on litigation, August
1971.
90. Grad, Frank P. and Rockett, Laurie R. , Environmental Litigation-
Where The Action Is?i Natural Resources Journal, 10, No. 4,
742-762, 1970.
91. Anonymous, Pesticides: Consumer Fear of 111 Effects Grows,
Chemical and Engineering News, 16-18, August 9, 1971.
92. Anonymous, PCB's Leaks of Toxic Substances Raises Issue of
Effects, Regulation Science, 173, 899-902, September 3, 1971.
93. South Carolina Agricultural Experiment Station, Annual Report of
Economic Poisons Analysis, July 1, 1969 - June 30, 1970.
94. Great Lakes Biochemical Co. , Inc. , v. Doyle Connor as
Commissioner of Agriculture of the State of Florida, May 21, 1971-
95. Environmental Protection Agency, Cancels Registration of Three
Products of Great Lakes Biochemical Co. , Inc. , I. F. and R.
Dockets Nos. 14 and 53, October 7, 1971.
294
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G. ALTERNATIVES TO PESTICIDES IN SOUTHEASTERN
UNITED STATES
1. Int r o du c ti. o n
Pest management should be predicated on the totality of
knowledge of all pest control methods and the ecological impact.
Effective control measures should be those which consider the long
term ecological and economic aspects. The indiscriminate use of
any single control method may produce undesirable and unintended
side effects.
On balance., the introduction of chemicals such as pesticides
to agricultural practice was beneficial. However, not all the effects
are positive. Problems have arisen, some quite serious, which
detract from the benefits.2' 3 This is attributed in a large measure
to the disregard of ecological considerations. Only chemical, toxio-
logical and economic criteria were used. Pest control has
consequently engendered serious problems through disruptive impact
on the ecosystem.
The benefits of pesticides were so evident that alternatives
were not evaluated with equal vigor. All practices, whether chemical,
cultural, physical, genetic or biological, must bring about the most
effective, least ecologically disruptive, pest control possible. The
objective is to reduce the impact of pesticides upon the aquatic
environment by critically analyzing the available alternatives.
Although alternative methods are sought, it is generally
conceded that pesticides will be used to control pests into the
foreseeable future. 4 Subsequent to the discovery of organic pesticides
295
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in the early forties, major research effort was not devoted to
alternatives. This accounts for continued and often excessive
reliance on pesticides.
Methods of control are effective because they either directly
affect the pest species or adversely modify environmental conditions
for its survival (Fig. G-l). Principles and examples of current and
proposed methods are considered.
2. Cultural Methods of Pest Control
Cultural methods are routinely utilized in agriculture to
reduce pest problems. These usually involve adjusting the time or
manner of performing operations for the production of crops or
animals, and in improved management procedures. Examples of
such cultural methods °~10 and the pest species against which it is
directed are:
• Sanitation
-Destruction of crop refuse (boll weevil, bollworm, corn
borer)
-Cleaning of field borders (weed control)
-Disposal of wastes (fly control)
• Rotations
-Crop rotation (specific pests for all crops, diseases,
fungal spores, bacteria, mites, insects and viruses, eg.
golden nematodes of potatoes, soybean cyst nematodes,
northern corn rootworm)
-Animal rotation (cattle tick control)
296
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METHODS OF CONTROL
EFFECT ON PESTS
INDUCED STERILITY
GENETIC MANIPULATION
AFFECT THE CHARACTERISTICS
OF THE SPECIES
ATTRACTANTS & REPELLENTS
INSECT HORMONES
HOST RESISTANCE
BIOLOGICAL AGENTS
PHYSICAL FACTORS
CHEMICAL AGENTS •
MODIFY ENVIRONMENTAL
CONDITIONS
QUARANTINES
SEED CERTIFICATION
SEED LAWS
•PREVENT SPREAD
Source: Rabb and Guthrie (Modified)5
FIGURE G-l. POSSIBLE METHODS OF PEST CONTROL
297
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• Farm Management
-Land bank and fallowing (cyst nematodes)
-Strip cropping (alfalfa aphid)
T Fertilizers (chinch bugs, weeds)
-Time of planting (southeastern corn borer, sugar-beet
nematode)
-Pest free seeds and seed certification (weed control,
wheat nematode control)
-Destruction of volunteer plants (potato aphids)
-Destruction of alternate hosts (wheat and apple rusts,
beet leaf hoppers, sweet potato weevils)
-Destruction of early blooms (sorghum midge)
-Tillage (grape berry moths)
-Crop spacing (weeds)
-Cleaning of farm equipment (weed control)
• Trap crops (citrus red mite)
• Regulation of plant stands (citrus pests)
• Selection of site (various forest insects)
• Thinning, Topping, Pruning and Defoliating
(Tobacco hornworm, mite, and control of dutch elm disease)
• Water Management
-Irrigation and flooding, (root knot and white tip
nematodes)
-Impoundment and improved pond management (acquatic
weeds, mosquitoes, biting midges)
-Drainage (nematodes)
298
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a. Cultural Control of the Southwestern Corn Borer
This southwestern corn borer, Diatrea grandiosella, is
primarily a pest in the western U. S. However, it has slowly moved
eastward and is found in western Tennessee and Alabama.11 Cultural
practices which increase exposure of the larvae of this insect to the
environment and to predators are effective in increasing overwintering
mortality. Burying is not detrimental to the larvae but the moths are
unable to emerge from the soil. Early-planted corn escapes some
of the damage. The primary advantage for early planting is reduction
in girdling. Although corn planted in Tennessee before May 1 is dam-
aged less by girdling in all years and locations, infestation and
lodging are not consistently reduced. It has been established that
the use of an early maturing hybrid is not an acceptable substitute
for early planting as a means of reducing damage caused by this
borer.11
b. Cultural Control of Cotton Pests
(1) Insect Control
The pink bollworm provides a classic example of a major
cotton pest controlled by cultural practices. The feature of the
control program includes stalk destruction and deep plowing of the
residue after the crop is harvested. Two factors, namely, over-
wintering as larvae and a single host plant (cotton), makes it highly
susceptible to this method of control. Cultural measures in
conjunction with good agronomic practices provide a means by which
the pink bollworm population may be reduced to extremely low levels.
Often damaging populations do not develop the following year.
299
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A modification of this approach is quite effective in reducing
boll weevil populations. The great majority of the dispausing boll
weevils leave the cotton fields for hibernation sites during the harvest
period of late September and October. Further, the adult requires a
feeding period of 1 to 3 weeks to accumulate sufficient fat reserve to
attain diapause or overwintering stage. Any practice which eliminates
either food or breeding sites during this critical period will be
detrimental.
The most important practice that can be effected during the
fall to reduce populations of diapausing boll weevils is defoliation or
desiccation of the cotton plants. This eliminates squares and young
bolls necessary for development of the diapausing population. The
next most important practice for reducing overwintering populations
is to harvest the crop as quickly as possible and then destroy the
stalks.
Attacking the boll weevil and pink bollworm during the fall
of the year is a biologically and operationally sound practice aimed
at destruction of the diapausing population. Only bollworms that are
in diapause are able to survive the winter. This is the weakest link
in its life cycle. A factor in the success of this method is that these
two major cotton pests do not develop large populations on wild or
alternate host plants.
(2) Disease and Nematode Control
The principal cotton diseases and their control with cultural
and other control methods are presented in Table G-l.
300
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TABLE G-l. Various cotton diseases and their control by
cultural and other methods.13
Name of Disease and
Causal Organism
Control
Measures
Anthracnose (the fungus
Glomeralla gossypii).
(South.) Edg.
Seed treatment; destruction of
diseased plant residues; suit-
able crop rotations
Ascochyta, or wet
weather, blight (the
fungus Ascochyta
gossypii). Syd.
Seed treatment; destruction of
diseased plant residues; suit-
able crop rotations
Bacterial blight (the
bacterium Xanthomonas
malvacearum).
Dows.
(E. F. Smi.)
Seed treatment; use of resistant
varieties; destruction of
diseased plant residues
Fusarium with (the fungus
Fusarium oxysporum Schlecht.
f, yasinfectum). (Atk.) Snyder
and Hansen.
Use of resistant varieties; suit-
able rotations; fumigation to
reduce nematodes; addition of
humus to soil; use of fertilizers
high in potash
Root-knot (the nematode
Meloidogyne incognita).
Chitwood.
Fumigation with locally recommended
fumigants; suitable crop rotations;
tolerant varieties
Root rot (the fungus Phymato-
trichum omnivorum).. (Shear)
Dug.
Fall plowing with phosphate add-
itions; use of Hubam clover as
cover crop; suitable crop rota-
tions; heavy applications of
organic manures in irrigated areas
Seedling diseases (several
seedborne and soil-inhabiting
fungi and bacteria).
Seed treatment; destruction of
diseased plant residues; use of
bacterial-blight resistant
varieties
Verticillium wilt (the fungus
Verticillium albo-atrum).
Reinke and Berth.
Use of tolerant varieties; rotation
with grain crops in irrigated areas;
planting on high beds; increasing
of plant population; avoiding heavy
irrigation that lowers soil tem-
peratures for prolonged periods
Source: Presley and Bird (Modified),
301
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(3) Weed Control
Cultural methods of controlling weeds in cotton are important.
Production practices which promote rapid emergence and growth tend
to control weeds by shading. Crop rotation or fallowing sometimes
offer another practical solution. These two practices permit the use
of alternate herbicide on weeds that are difficult to control in any
single crop. For example, cocklebur is very difficult to control in
cotton fields but relatively easy to control in corn. Disking or plowing
six to eight times during a single growing season effectively reduces
the number of viable Johnson grass rhizomes present at the beginning
of succeeding growing season. Plowing or disking every four weeks
for two successive growing seasons has been reported to eradicate
nutsedge essentially.
Cultural practices tend to create adverse conditions during
the pest's active or overwintering stage and result in reduced pest
infestation. Expansion of such agronomic practices together with
integrated control programs could reduce the use of the pesticides.
3. Physical and Mechanical Methods of Pest Control
Physical and mechanical methods differ from cultural methods
since they are intended specifically to control the pest and are not
routine agricultural practices. They may either be preventive or
corrective. Their effectiveness lies in the fact that all biological
species exhibit thresholds of tolerance with regard to extreme
temperature, humidity, sound, physical durability and response to
various regions of the electromagnetic spectrum. Among central
approaches, the possibilities inherent in the spectrum of radiant
energy and devices such as light traps are especially promising.15'16
302
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Temperature is utilized in the control of soil-borne diseases
caused by bacteria, viruses, fungi and nematodes.6 Fire has been
found to be an effective method of control of alfalfa weevil, Hypera
postica.17 In many cases stored seeds are protected by exposure to
temperatures 4 and 10°C, since most grain infesting insects are
inactive at these temperatures.
a. Inactivation of Plant Pathogenic Viruses by Heat in
Vegetatively Propagated Plant Materials
Temperature may affect the susceptibility of host plants to
virus infection, the time required for development of symptoms, and
the degree of damage. The principle may be extended to those cases
where the majority or all of the plants in a vegetatively propagated
clones are infected. A summary of viruses (Table G-2) that have
been inactivated in plants by heat illustrates the effectiveness of this
measure.
b. Disinfection of Plant Parasitic Nematodes by Heat
A hot water treatment, alone or together with a nematicidal
dip, is used to treat plants contaminated with ectoparasitic nematodes
such as Hemicycliophora sp. or Criconemoides sp. These pests are
difficult to dislodge by mechanical means because their long stylets
are inserted into the plant cells. Endoparasitic nematodes present
within plant tissues or enclosed within the protective layers of plant
parts require a penetrating chemical or physical agent to effect a
kill. Heat is most commonly used. Externally applied heat is
absorbed by the plant propagule and spreads within to reach the
pathogens. When a differential in heat susceptibility exists between
plant tissue and nematode and the latter is more sensitive, effective
heat treatment is possible.
303
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TABLE G-2. List of Viruses that Have Been Inactivated in Plants by Heat
18
Virus
Plant
Temperature
Treatment (°C.)
Length of
Treatment
Abutilon variegation
Apple mosaic
Aster yellows
Carnation ringspot
Cherry necrotic rusty
mottle
Cherry ringspot
Citrus tristeza
Cranberry false blossom
Cucumber mosaic
Little peach
Peach red suture
Peach rosette
Peach X-disease
(yellow-red virosis)
Peach yellows
Phony peach
Potato leaf roll
Potato witches' broom
Raspberry leaf mottle
Raspberry leaf spot
Raspberry unidentified
latent virus
Raspberry Rubus stunt
Strawberry j.eat burn
or X
Strawberry virus 1
(mottle)
Strawberry virus 3
(crinkle)
Strawberry virus 4
(vein chlorosis)
Strawberry virus 2
(mild yellow edge)
Strawberry nonpersis-
tant viruses
Abutilon striatum
Budded seedlings
Vinca rosea and
Nicotiana rustica
(plants)
Vinca rosea (plants)
Carnation (plants)
Cherry bud sticks
Cherry bud sticks
Potted plants
Cranberry and
Vinca rosea
(plants)
Cucumber, tobacco,
Datura stramonium
(plants)
Peach (bud sticks)
Peach (bud sticks)
Peach (bud sticks)
Peach (bud wood)
Peach (trees)
Peach (dormant
trees)
Peach (dormant
trees)
Potato (tubers)
Vinca rosea (plants)
Potato (tube.rs)
Raspberry (plants)
Raspberry (plants)
Raspberry (plants)
Raspberry (canes)
Strawberry (plants)
Strawberry (plants)
Strawberry (plants)
Strawberry (plants)
Strawberry (plants)
Strawberry (plants)
Hot air
Hot air
Hot air
Hot water
Hot air
Hot water
36
37
38-42
40-45
36
50
3-4 weeks
28-40 days
2-3 weeks
2 1/2-24 hr.
3-4 weeks
10 min.
Hot air 100 17-24 days
Hot air 95°F.+3° 121-360 days
Hot air
Hot air
Hot water
Hot water
Hot water
Hot water
Hot air
Hot water
Hot air
Hot water
42 8 days
36
50
50
50
50
35
3-4 weeks
3 min.
3 min.
8 min.
6-15 min.
24 days
50 10 min.
Hot water
Hot air
Hot air
Hot air
Hot air
Hot air
48
37
42
36
32-35
32-35
40 min.
15-30 days
13 days
6 days
1-4 weeks
1-4 weeks
32-35
45
1-4 weeks
1 1/2-2 hr,
Hot air
Hot air
Hot air
Hot air
Hot air
Hot water
37
37
37
37
37
43-48
7-11 days
7-11 days
7-11 days
7-11 days
16 days
1/2-7 hr.
304
-------
TABLE
G-2 (Continued)
Virus
Plant
Temperature Length of
Treatment <°c-> Treatment
Strawberry nonpersis-
tant viruses
Strawberry type 2
Strawberry viruses (un-
identified)
Sugarcane chlorotic
streak
Sugarcane ratoon stunt
Sugarcane ratoon stunt
Sugarcane sereh disease
Tobacco ringspot
Tomato aspermy
Tomato aspermy
Tomato bushy stunt
Strawberry (plants) Hot air
Strawberry (plants) Hot air
Strawberry (plants) Hot air
Sugarcane (cuttings) Hot water
Sugarcane (setts) Hot water
Sugarcane (cuttings) Hot water
Sugarcane (cuttings) Hot water
Tobacco (plants) Hot air
Tomato and tobacco Hot air
(plants)
Chrysanthemum (plants)Hot air
Datura stramonium Hot air
(plants)
36-38 8-12 days
38
37
52
50
50
52-55
37
36
36
36
8 days
10 days
20 min.
2 hours
20 min.
30 min.
3-4 weeks
3-4 weeks
3-4 weeks
3-4 weeks
Source: Carter, W.
305
-------
A few examples of recommended temperature-time combina-
A
tions found useful for control of parasitic nematodes include: Easter
lily bulbs with spring crimp nematode, Aphelenchoides fragariae,
1 hour at 44°C in a water and formalin bath; citrus rootstock with
borrowing nematode, Radopholus similis, 10 minutes at 50°C; seed
with bentgrass seedgall nematode, Anguina agrostis, 15 minutes at
52. 2°C in water containing a wetting agent; wheat seed with wheat
nematode, A_. tritici, 30 minutes at 49°C or 10 minutes at 50°C;
begonia with spring crimp nematode, treat by submerging pot and
contents for 1 minute at 49°C, 2 minutes at 47. 8°C, or 3 minutes
at 46. 8°C; sweet potatoes with root-knot nematodes, Meloidogyne
sp. , 65 minutes at 46. 8°C; and grape rootings with root-knot
nematodes, 30 minutes at 47.8°C, 10 minutes at 49°C, 5 minutes at
51.6°C, or 3 minutes at 53°C17'9.
c. Use of Light Traps in Insect Control
Light traps employing ultraviolet or blacklight lamps are being
used in experiments to determine their effectiveness for attracting
moths.19 In one 113-square mile area in North Carolina 370 traps
exterminated 50 to 60 percent of the adult tobacco hornworm moths
in one growing season. A trap density of three per square mile in
combination with stalk cuttings and insecticide treatment to prevent
late season breeding of hornworms, further reduced infestation in
tobacco about 80%. This reduction was measured in the center of
the test area during the second year. About 20 times more males
than females were captured. These results suggest the possibility
of using this means to decrease mating in the field.
Other uses of black-light traps for insect control include the
protection of cabbage from the attack of the cabbage looper, Tricho-
plusia ni (Hubner), and of celery from the celery looper, Anagrapha
306
-------
falcifera (Kirby) 8. The deleterious effects of both the European
corn borer and the cotton bollworm can be significantly reduced by
light traps if population pressure is not extremely high. Damage to
tomato fruit and foliage resulting from the attack of tobacco and
Q
tomato hornworms can be minimized . The increase in yield of
cucumbers from plants protected by light traps has been especially
encouraging; populations of the striped cucumber beetle and the
spotted cucumber beetle were reduced and the transmission of
bacterial wilt was minimized. The benefit of the light trap is that it
eliminates the need for chemical applications in those climatic areas
where light attraction is consistently good.
Light traps may be used to attract moths and bring them into
contact with chemosterilants. They can then be released. Not all
moths and flying beetles are sufficiently attracted to black-light
sources to affect control. Further, control over extensive areas is
not feasible. Recommendation of this approach must be made within
certain restraints. The limitations involve need for electrical power
and the presence of pests that are photosensitive. The advantages are;
no residues on crops; they detect moth emergence and can be used for
timing of control applications; attraction irrespective of the physical
condition of the field; integration with other control approaches (eg.
post season stalk cutting in tobacco) ' 19 and low operating cost.
Light attraction combined with chemical attractants is a
promising means of effective pest control.
307
-------
4. Use of Resistant Varieties of Crop Plants
Plants or animals that exhibit less damage or infestation by a
pest (disease, nematode or insect) than others under comparable
conditions in the field are considered to be resistant. Selection and
improvement results in a resistant variety which becomes an integral
part of the pest management program. One of the most important
contributions of agricultural programs of the pre DDT era was the
development of resistant varieties. This method of reducing pest
damage has been used extensively since the turn of the century.
Originally the case for natural resistance to plant pests was economic;
it added nothing to the grower's cost of production. Now, pollution
control is the consideration.
With alfalfa, small grains and tobacco, it is the availability
of resistant varieties which makes the difference between profit or
loss. In certain cases it is the resistance factor that makes culture
of a crop possible. In the Southeast, diseases such as stem rot of
peanuts; rusts and smuts of cereals; anthracnose of watermelon;
fusarium wilt, mosaic, black shank, and black root rot of tobacco are
only examples of the pathogens which are primarily controlled by
resistant varieties.10 At present, approximately 75 percent of the
total acreage in agriculture production in the United States utilizes
resistant varieties.
Varietal resistance to insects and other pests is classified
into three broad categories (Fig. G-2).
A classical example of the use of the plant genetics is the
control of grape phylloxera in Europe over the past 90 years. Highly
resistant American varieties saved the European viticulture. 5 An
308
-------
Preference
FOR OVIPOSITION
FOOD OR SHELTER,
Antibiosis
ADVERSE EFFECT OF
PLANT ON BIOLOGY OF INSECT
CO
o
vo
Tolerance
REPAIR, RECOVERY OR ABILITY
TO WITHSTAND INFESTATION
Source: Painter, R. H.
Fig. G-2. The Nature and Categories of Pest Resistance.
20
-------
early search for plants resistant to insects was made in California
over a period of 10 years beginning in 1881.20 By turn of the century,
programs were under way which were directed toward increased
disease resistance through breeding. Among the better known were
those programs concerned with mildew resistance in grapes in
France; late blight of potato in several European countries; rust
resistance in wheat in Australia, England and America; and, wilt
resistance in flax, cotton, watermelon and cow pea in United States.
These are still being pursued actively today along with scores of
others.21' 2Z In the 1953 Yearbook of the United States Department
of Agriculture there is a list of sources of resistance in crop plants
which occupies more than 24 pages. Many of these crops are grown
in the Southeastern states. 3 Each year many new resistant varieties
are added. Effort is being directed toward incorporating multiple
pest resistance into crop varieties.
The development of all the resistant varieties cannot be
considered within the scope of this review. The few cited exemplify
development and use of host plant resistance as one of the most
effective methods of economic pest management in agricultural
ecosystems.
a. Wilt Resistance in Tobacco
A bacterial disease known as Granville became a limiting
factor in flue cured tobacco producing counties in North Carolina
following the turn of the century. Losses in Granville County during
the period from 1920-40, one of the key tobacco growing areas, were
estimated at 30-40 million dollars.
310
-------
Intensive efforts to develop wilt-resistant tobacco were
initiated in 1935. This effort culminated in the release in 1944 of
a resistant tobacco variety of acceptable quality at a program cost of
about $150, 000. By 1948, the value of the tobacco in the area of
Granville was estimated as $2, 000, 000. In 1964, 416, 000 acres were
devoted to the tobacco crop in North Carolina and the value placed as
$520, 000, 000. Approximately 95 percent of this acreage was planted
to varieties which not only incorporated resistance to Granville wilt,
but also to black shank. If resistant varieties were not available
and only susceptible varieties were grown, it is estimated that yield
would be reduced to less than one-fourth.21' 23 These major diseases
involve soil-borne pathogens. No effective chemical controls would
have been available to control these diseases and the effectiveness or
practicality of other approaches, including rotation and related
cultural practices, would have been limited.
b. Varietal Resistance to Cotton Pests
Varietal resistance has been generally ignored as a possible
means of controlling cotton pests until recently. Research initiated to
screen available germplasm has proved to be highly rewarding.
The possibility of controlling Heliothis sp. and other lepidopterous
pests by incorporating high levels of gossypol and other pigments into
commercial varieties appears to be especially,promising. Plants
having a gossypol content of 1.5 percent or greater would cause both
larval mortality.and inhibition in development of Heliothis larvae.
Such levels have been attained in several lines.
High gossypol content is undesirable in cotton seed because of
its toxicity to non-ruminant animals. A considerable amount of effort
has been devoted to incorporating characteristics for low gossypol
311
-------
content into commercial varieties. This provides an excellent example
of the necessity for a cooperative approach in developing varieties of
cotton.12
The spread of the boll weevil, Anthonomus grandis (Boheman),
throughout the Cotton Belt around the start of this century brought
marked changes in the type of cotton grown. The late, vigorous, long-
staple upland varieties were rapidly replaced by early-maturing,
short-staple types which were less susceptible to damage by the weevil
because of their shorter exposure period and thicker carpel walls.
These short staple types tended to be inferior in quality; and breeding
efforts were directed toward increased quality and length of staple.
Knipling estimated that $75 million was expended annually for
control of the boll weevil. In spite of this expenditure, control was
far from complete and the annual loss from this insect was estimated
at $200 million. Indications of the weevil developing resistance to
insecticides renewed interest in the development of resistant types.
The U. S. Cotton Boll Weevil Research Laboratory was established in
1962 at State College, Mississippi, with the objective of finding new
approaches to boll weevil control or eradication with less emphasis
on use of insecticides. In addition to the search for resistance, other
alternative methods were also examined.
Extensive studies with cotton have demonstrated that several
factors contribute significantly to differences in relative resistance
and susceptibility to boll weevil attack. Some of these genetic factors
are complex and quantitative in their inheritance; others are simply
inherited. Frego bract is conditioned by a single recessive gene.
In this mutant type, the normally adherent bracts become flared and
twisted, leaving the squares relative exposed. Studies indicate that
312
-------
frego types are less attractive for oviposition (egg laying). In addition,
the exposed squares permit ready penetration of insecticides and
greater predation by birds and insects. Other simply inherited traits,
such as, red leaf and smooth leaf, contribute to reduce oviposition.
Combinations between certain of these traits appear to exhibit increased
non- preference.
A large portion of worl's germ plasm of cotton has been
screened at the U. S. Boll Weevil Research Laboratory, during
the period 1962 to 1968. An oviposition suppression factor causing
25 to 40 percent reduction in the number of eggs laid, by the weevil
has been found in Gossypium bardadense and successfully moved into
upland cotton, G. hirsutum. Research with five different genetic
lines each carrying a frego gene showed a significant degree of non-
preference for the oviposition to the boll weevil. Weevils were found
24
to avoid the exposed bud for feeding and oviposition.
Laboratory tests have been devised which permit the screening
of large numbers of plant types under controlled levels of exposure.
Marked differences in oviposition scores were obtained. Inheritance
studies, involving some of the less-preferred versus standard types,
indicated the oviposition factor to be under genetic control, but the
results could not be satisfactorily interpreted on a single gene basis.
More extensive studies involving backcross and Fj progeny provided
little additional information, due to difficulties in obtaining adequate
information on an individual plant basis. The fact, however, that ifche
resistance to oviposition can be satisfactorily transferred to other
strains is most encouraging.
313
-------
An extensive series of experiments has been conducted
establishing the existence of both plant attractants and repellants.
The attractants, still incompletely characterized, appear to be
alcohols and esters, while the repellants may be terpenoids.
Similarly, evidence exists for both feeding stimulants and deterrents.
In neither case have the causal constituents been adequately identified.
The combination of morphological traits, oviposition factors,
attractants, repellants and feeding stimulants to provide adequate
field resistance in the absence of chemical control, together with the
essential genetic factors for yield and fiber quality, poses a
formidable task. Continued progress may be expected, however,
as the intricacies are exposed.25 This is an example of a case where
considerable research effort over a long period has been directed
toward development of an alternative technology to pesticidal
control. Results from such efforts would ultimately be the basis
for reduced use of pesticides.
c. Control of Cyst-Nematode in Soybeans by Resistance
Discovery in 1954 of nematodes attacking soybeans in North
Carolina was the first report of this pest outside the Orient. z6
Damage to the crop posed a threat to the United States soybean
industry. Control of the soybean cyst nematodes has been difficult.
Multiple approaches have been necessary. Application of chemicals
to the soil has not been economically feasible. Crop rotation of
two to three years was effective, but resulted in limited production.
Federal and state quarantines were only partially successful.
In 1957, some 2, 800 soybean varieties were screened for
nematode resistance in heavily infested fields.2 Four varieties were
found on which the nematode did not reproduce. The desirable
314
-------
characteristic of resistance was transferred to a commercial variety
and the new combination was called Pickett. This variety was developed
cooperatively by the Agricultural Research Service and the Agricultural
Experiment Stations of Arkansas, Missouri, North Carolina, Tennessee,
and Virginia. 2
d. Breeding Vegetable and Fruit Crops for Resistance to Diseases
Disease resistant vegetable varieties are especially noteworthy.
A vegetable grower in the Southeastern states by proper selection of such
varieties can now reduce the damage caused by such destructive
diseases as fusarium wilt of cabbage, tomato, and watermelon;
common mosaic of beans; celery leaf blights; spinach blight, cucumber
scab; and many others. In many cases, the farmer will not sacrifice
the quality or productivity of his crop through use of a resistant
variety.27
Examples of vegetables and fruits grown in the Southeastern
states, which have shown resistance to fungus, nematode, virus or
bacterial diseases are listed in Table G-3.
e. Disease and Insect Resistance Research for Southern Forests
The greatest forest insect resistance research is presently
concentrated on the fusiform rust of southern pines. Agencies, both
governmental and private, are engaged. z8 In North Carolina, a
"rust nursery" approach is being used for mass screening of known
seed sources of southern pines. It also permits estimatation of the
heritability of resistance in a natural population of southern and
loblolly pine. Since 1954, a tree improvement program has been
underway in Florida. This involves screening of select slash pines
for reistance to fusiform rust. Selection and field testing of slash
and loblolly pines of one parent and controlled progeny are being
studied for their resistance.
315
-------
Table G-3. Classification of Representative Vegetable and Fruit Disease Resistance Cases According to
Causal Agent, Mode of Inheritance, and Field Experience
Disease
Original source
of resistance
Pathogen
Field
reaction
CO
o\
Monogenically controlled resistance
a. Proven susceptible to
races of prevalence
1. Potato late blight
2. Lettuce downy
mildew
3. Bean powdery
mildew
4. Cantaloupe powdery
mildew
5. Bean rust
6. Apple scab
7. Tomato leaf mold
I. Fungus Diseases
8. Bean anthracnose
b. Remaining resistant
to prevalent races
1. Spinach downy
mildew
2. Cucumber scab
3. Tomato leaf sopt
Solanum demissum
European Varieties
Several varieties
Indian varieties
Several varieties
Malus baccata
Lycopersicon pimpinelli-
folium
Several varieties
Iranian variety
Longfellow variety
Lycopersicon hirsutum
Phytophthoracinfestans Immune
Bremia lactucae Immune
Erysiphe polygon! Immune
Erysiphe cichoracearum Immune
Uromyces phaseoli typj.ca Immune
Venturia inaequalis Immune
C la do sjjorium fulvium Immune
Colletotrichum linde- Immune
muthianum
Peronospora effusa Immune
Cladosporium cucumerinum Immune
Septoria lyoppersj-cj^ Resistant
-------
Table G-3. (Continued)
Disease
Original source
of resistance
Pathogen
Field
reaction
4. Tomato gray leaf
spot
5. Tomato fusarium
wilt
6. Cabbage fusarium
wilt
7. Ceder-apple rust
L. pimpinellifolium
L^_ pimpinellifolium
American varieties
Several apple varieties
8. Apple scab Asiatic species of Malus
Polygenically3^ controlled resistance
a. Proven susceptible to
races of prevalence
1. Strawberry red stele
b. Remaining r esistant
to prevalent races
1. Potato late blight
2. Apple scab
3. Cabbage fusarium
wilt
Aberdeen and other
varieties
Selections of Solanum
demissum and other species
Antonovka
American varieties
II. Nematode Diseases
Monogenically3 controlled resistance
a. Proven susceptible to
races of prevalence
None
b. Remaining resistant
to prevalent races
1. Tomato root knot Lycopersicon peruvianum
2. Pepper root knot Santanka X S variety
Stemphylium solani
•p
F. oxysporum lyco-
persici
F_._ oxysporum " con-
glutianans
Gymno sporangium juni-
perivirginianoe
Venturia inaequalis
Phytophthora fragariae
Phytophthora infestans
Venturia inaequalis
F.. oxysporum F."con-
glotinans
Meloidogyne spp.
Meloidogyne spp.
Immune
Immune
Immune
Immune
Immune
Resistant
Resistant
Immune
Resistant
Resistant
Resistant
-------
Table G-3. (Continued)
Disease
Original source
of resistance
Pathogen
Field
reaction
Polygenically controlled resistance
a. Proven susceptible to
races of prevalence
None
to
•—*
CO
b. Remaining resistant
to prevalent races
1. Lima beam root know
2. Peach root knot
Hopi 5989 and Westan
Shalil and Yannan
varieties
Meloidogyne spp. Resistant
Meloidoevne incognita Resistant
Monogenically3 controlled resistance
III. Virus Diseases
a. Proven susceptible to
races of prevalence
1. Tomato spotted wilt
b. Remaining resistant
to prevalent races
1. Bean mosaic
2. Bean pod mottle
3. Bean southern Mosaic
4. Pepper mosaic
5. Spinach blight
Argentine variety
Corbett Refugee
Several varieties
Several varieties
Tabasco variety
Old Dominion; Va.
Savoy
Polygenically3 controlled resistance
a. Proven susceptible to
races of prevalence
1. Tomato spotted wilt
b. Remaining resistant
to prevalent races
1. Cabbage mosaic -
Lycopersicon p impinellifolium
Selections from varieties
Spotted wilt virus Resistant
Bean virus 1 Resistant
Bean pod mottle virus Immune
Bean mosaic virus 4 Immune
Tabasco mosaic virus Immune
Cucumber virus 1 Immune
Spotted wilt virus Resistant
Cabbage viruses A and B Resistant
-------
Table G-3 (Continued)
Disease
Original source
of resistance
Pathogen
Field
reaction
CO
ID
2. Cucumber mosaic
3. Lima bean mosaic
A. Bean curly top
5. Potato latent mosaic
Oriental varieties
Fordhook and others
Several varieties
S41956 variety
IV. Bacterial Diseases
Monogenically controlled resistance
a. Proven susceptible to
races of prevalence
None
b. Remaining resistant
to prevalent races
1. Bean halo blight
Several dry bean varieties
Polygenlcally controlled resistance
a. Proven susceptible to
races of prevalence
None
b. Remaining resistant
to prevalent races
1. Pear fireblight
Selections from Pyrus spp.
Cucumber virus 1
Cucumber virus 1
Curly top virus
Potato virus
Pseudomonas phaseo-
licola
Erwinia amylovora
Resistant
Resistant
Resistant
Immune
Resistant
Resistant
Resistances that have been found to be controlled by more than one factor pair are classified here as
polygenic.
In 1958, a race of Pernospora effusa developed extensively in California on this source of resistance.
Source: Shay, J. R.
-------
f. Insect Resistance to Corn Earworm
Heliothis zea (Boddie) is adapted to feed on a wide range of
hosts and has been given common names associated with the crop
attacked, e.g., the corn earworm, the cotton bollworm, and the
tomato fruitworm. The most widely used control has involved chemicals.
Several million pounds are being used annually. Considerable effort has
been devoted to corn and cotton to develop varieties which possess
some degree of tolerance or resistance.
The corn earworm may feed on the leaves, silks, or the
developing grains. Most studies on resistance have been concerned
with damage to the grain. The literature is extensive and variation
in earworm damage has been ascribed to variety, planting dates,
spacings, date of maturity, soil fertility, concentration of feeding
stimulant and nitrogen balance. Varietal differences have commonly
been associated with husk characteristics, either extension or tightness.
However, chemical differences also appear to be involved.
The effect of either husk extension or husk tightness are
explicable from knowledge concerning the feeding habits and cannibalistic
tendencies of the earworm. Either husk extension or tightness or their
combination may ensure minimizing damage to the developing grain,
but have little or no effect on population dynamics, and therefore,
represent a special case of tolerance rather than one of antibiosis.25
Extensive work should be under taken to find sources of resistance
(amtibiosis) to leaf feeding.
g. Resistance to Potato Leaf Hopper
The nonhardy and Turkestan alfalfa varieties are highly
susceptible to the potato leaf hopper while Me die ago falcata or cultivars
involving some degree of falcata introgression possess greater
320
-------
resistance. ^ Pubescent plants tend to be less attractive for oviposition
than glabrous plants, although resistant types may be found in each
category. After seven cycles of selection "cherokee" variety was
released from such pubescent resistant plant types. This variety
has been superior to 'Atlantic1 and 'Williamsburg1 in the area where
it was developed, North Carolina.2
Resistant varieties are one of the least expensive means of
avoiding pest damage. Such efforts however, do not and should not
cease after a new variety is developed for a given crop. New disease
strains develop for which further resistance needs to be incorporated.
Multiple pest resistance is also in need of greater study. For many
crop varieties, breeders have started to look for reduced weed competition.
The potential benefits of pest resistance have, as yet, not been fully
exploited.
5. Biological Agents for Pest Control
Biological control is the suppression of the reproductive poten-
tial of organisms through the actions of parasites, predators, or patho-
gens to restrict pest population at a lower average density than would
occur if these were absent.
The citrus industry in California once suffered a massive infes-
tation of a mealy bug, cottony cushion-scale (Icerya purchasi), intro-
duced from Australia on Acacia in 1868. The introduction of two
Australian species, the ladybirds, Radola cardinalig (vedalia ladybird)
and Cryptochetum iceryae, provided the necessary predator-prey regu-
lation. They first reduced the mealy bug populations to levels at which
they no longer constituted a major pest infestation. Unfortunately,
however, as is shown in Figure G-3, cottony cushion-scale again
reached major pest population levels when extensive use of DDT for
citrus spraying eliminated the vedalia ladybird locally.
321
-------
This recurrence emphasizes an inherent danger of pesticide use.
There may be a catastrophic effect on the natural regulatory mechanisms,
While they temporarily diminish the numbers of a particular pest, the
pesticides also reduce its natural enemies. The pest often undergoes
a population explosion before its natural enemies can recover.
Successful biological control programs have engendered world-
wide interest. The governments of several countries have established
facilities for such research.
The interest in microbial insecticides has intensified because
of such problems as development of resistant strains, emergence of
secondary pests, and toxic residues. These have developed with the
use of the broad spectrum chemical insecticides. Steinhaus
first to employ the term microbial control.
30
was the
introduction of
Crptochaetum iceryae and
Rodolia cardinalis
Resurgence produced by
DDT in San Joaquin Valley
4 — -^.Slpmic_injurv_ level/
'-.«..„ -L-- .Economic threshold
General
equilibrium
position
1868 1888-89 1892
1947
Figure 6-3 Cottony cushion-scale (Icerva
incidence on citrus in California.^
Source: Stern, V. M. et al.
322
-------
Insects, like animals, suffer from disease attacks. Under
favorable conditions, a disease may reach epidemic proportions for
an insect species. Within a few days or weeks it may reduce the
species from a point of great abundance to one of scarcity. Insect
diseases may be caused by protozoa, fungi, viruses and bacteria.
During the last two decades, there has been an increasing awareness
of the great potential of insect diseases as insect control agents. About
225 species of insect viruses have now been isolated. Of these, the
nuclear polyhedroses (107 species) and the granuloses (80 species) are
effective candidates for insect control.31 Greer32 reported over 300
insect viruses that can be utilized for control of specific pests.
The advantages offered by microbial pesticides are:
c Insect pathogens in general and viruses in particular,
are very discriminating and infect only one species
or members of closely related species.33
• Microbial control is a natural method of control and
it increases the effectiveness naturally after once
being introduced into an area. If conditions are
optimum, the introduced microorganisms may spread
of their own accord, resulting in widespread killing
of the host.
• Microbial insecticides are biodegradable and leave
no residue or buildup in the soil, as occurs with
many chemical pesticides.
• Most microbial pesticides are essentially harmless
to animals and plants and may be applied in heavy
doses without damaging these forms of life.30
• Microbial pesticides are generally compatible with
•other pesticides.
323
-------
Examples of pathogenic diseases associated with major economic
arthopod pests are listed in Table G-4. Selected examples of arthopod
pathogens used successfully to control arthropod pests are presented
in Table G-5. Table G-6 lists the arthropod pathogens commercially
or experimentally produced by commercial firms for use as microbial
insecticides.
All methods of pest control have disadvantages. The perfect
method of controlling pests is yet to be devised. The only intelligent
approach to the evaluation of any method of control is through an honest
acknowledgment of its limitations. Gaps may thus be filled by other
control procedures. Some of the limitations of microbial pest control
are:
e Perhaps the greatest single aspect not yet understood
in the use of microorganisms in the control of insect
pests has to do with the timing of application in
relation to environmental conditions. Some researchers
believe that high humidity has little effect on virus
diseases, others, however, have associated virus
epizootics with wet weather. In the laboratory, an
excess of moisture often leads to the outbreak of bac-
terial diseases. Low humidity is generally considered
a limiting factor in fungus diseases for the spore germ-
ination, infection and subsequent sporulation of the
fungus on the host. High temperature generally accel-
erates the course of a disease. Much remains to be
learned about optimum times to apply the microorgan-
isms.
• There is a necessity of maintaining the vitality and
virulence of the infecting agent especially for those
microorganisms not possessing a cyst or spore stage.
The possibility exists that resistant populations will
develop after prolonged use of microorganisms.30
This requires further study,
e The effect that heavily applied entomogenous micro-
organisms may have upon plants and higher animals
always needs to be considered. There appears to be
324
-------
TABLE G-4. Examples of Pathogenic Diseases Associated
with Major Economic Arthropod
Arthropod Pest Complex Pathogen Genus
Forest, Ornamental an
-------
TABLE
G-4
(Continued)
Arthropod Pest Complex
Pathogen Genus
Household, Stored Products, Man and Domesticated Animals
Cattle grubs-flies
Clothes moth
Cockroaches-termites
Lice-mites
Mosquitoes-midges-gnats
Stored products beetles
Stored products caterpillars
Entomophthora, Bacillus
Nosema, Bacillus, NPV, CPV
Entomophthora, Serratia
Aspergillus, Bacillus
Entomophthora, Aspergillus, Coelomo-
myces, Thelohania, Plistophora, No-
sema, Bacillus, Enterella, NPV
Nosema, Adelina, Mattesia, Farinocys-
tis, Ophyocystis, Bacillus
Nosema, Mattesia, Bacillus, NPV, CPV, GV
Source: Ignoffo, C. M. (Modified).
326
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TABLE G~^* Selected Examples of Arthropod Pathogens Used
Successfully to Control Arthropod Pests ^4
Pathogen
Pest Species
Viruses
Nuclear polyhedrosis
Cytoplasmic polyhedrosis
Granulosis
Non-Inclusion
Bacillus popilliae
Bacillus thuringiensis
Coccobacillus acridiorum
Serratia marcescens
Thelohania hyphantriae
Mattesia grandis
Malameba locustiae
Bollworm-budworm complex
European spruce sawfly
Alfalfa caterpillar
Cabbage looper
Pine processionary worm
Cabbageworm
Spruce budworm
Red-banded leaf roller
Codling moth
Citrus mite
Bacteria
Japanese beetle
Many caterpillar spp.
Grasshoppers
Termites
Protozoa
Fall webworm
Boll weevil
Grasshoppers
Entomophthora spp,
Beauveria spp.
Metarrhizium anisopliae
Aeschersonia spp.
Brown-tailed moth
Spotted alfalfa aphid
Chinch bug
Colorado potato beetle
Corn borer
Sugar beet curculio
Froghopper
White fly and Scale insects
Source? Tgnoffo, C. M. (Modified).
327
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TABLE G-6. Arthropod Pathogens Commercially or Experimentally
Produced by Commercial Firms for Use as Microbial Insecticides-
34
Disease Organism
Product Names
Susceptible Pests
Commercially Produced
Bacillus popilliae
Bacillus thuringiensis
Heliothis NPV
Trichoplusia NPV
Neodiprion NPV
Doom, Japidemic
Agritrol, Amdol-6000,
Bakthane L-69,
Bactospeine, Bathurin,
Biospor 2802, Biotrol
BTB, Dendrobacilin,
Entobakterin-3,
Parasporin, Sporeine,
Thuricide, Tribactur
Virex
Cabbage looper virus
Polyvirocide
Japanese beetle, Scarabaeids
Alfalfa caterpillar, Artichoke
plume moth, Bagworm, Cabbage
looper, Diamondback moth,
Fruit-tree leaf roller, Grape
leaf folder, Gypsy moth, Im-
ported cabbageworm, Lawn
moth, Linden looper, Oak moth,
Orange dog, Rindworm complex,
Saltmarsh caterpillar, Spring-
Fall cankerworm, Tent cater-
pillar, Tobacco budworm,
Tobacco budworm, Tobacco and
tomato hornworm, Webworm com-
plex, Winter moth
Corn earworm, Cotton bollworm,
Tobacco budworm, Tomato fruit-
worm
Cabbage looper
Pine sawfly
Experimentally Produced
Bacillus sphaericus
Beauveria bassiana
IMC,B_. sphaericus
Biotrol FBB, IMC-
B., bassiana
Metarrhizium anisopliae
IMC,+M. anisopliae
Nuclear Polyhedrosis Virus
Heliothis Biotrol VHZ:VIRON/H
Aquatic diptera, i.e., mosqui-
toes, midges, simulids
Alfalfa weevil, Cockroach, Codl-
ing moth, Coconut zygaenid,
Colorado potato beetle, Cutworm,
European corn borer, Grass-
hoppers, Horsefly, Japanese
beetle, Larch sawfly, Stored
products beetles, Websorms
Corn borer, Cutworm Frog hopper,
Leafhopper, Rhinoceros beetle,
Sugar beet curculio, Sugarcane-
borer, Wheat cockchafer
Corn earworm, Cotton bollworm,
Tobacco budworm, Tomato fruit-
worm
328
-------
TABLE G-6 (Continued)
Disease Organism Product Names Susceptible Pests
Prodenia Biotrol VPO, VIRON/P Cotton leafworm; Pacific,
Southern, and Yellow-
striped armyworm
Spodoptera VIRON/S Beet armyworm, Fall armyworm
Trichoplusia, Biotrol VTN; VIRON/T Cabbage looper
a Only Doom, Japidemic, Biotrol BTB, and Thuricide are currently
commercially available in U. S.
Source: Ignoffo, C. M. (Modified).
329
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little likelihood, however, that microorganisms
naturally pathogenic to insects could cause serious
injury to animals or plants.
• A microbial insecticide can be used against one
species only. Mixed formulations have not yet been
widely tested.
• Of considerable importance is the effect that patho-
genic microorganisms may have upon the insect para-
sites and predators of a pest. Only a few observations
have been made, but enough has been learned to sug-
gest that close attention must be paid to this relation-
ship whenever the artificial dissemination of micro-
organisms is contemplated. Sometimes the insect
parasites and the disease are related in a comple-
mentary or supplementary fashion. This has been
observed in alfalfa fields infested with caterpillars
of the alfalfa butterfly (Colias). In fields where the
polyhedral wilt disease is present but not abundant
among the caterpillars, the smaller larvae may be
parasitized by Apanteles while the larger larvae may
be killed by the polyhedral wilt disease.3
Herbicides have been used to control aquatic weeds. Aquatic
weeds obstruct water flow, increase evaporation and induce large
losses of water through transpiration. The management of aquatic
vegetation has been revitalized recently because of increased demand
on our fresh waters. Major aquatic weeds in the U.. S. are water
hyacinth, Eichhornia crassipes, water fern, Salvinia auriculata, water
lettuce, Pistia stratiotes; submersed weeds belonging to genera, Scipus,
or •if.
Typha, Nymphaea, Saggitaria, and Alternanthera. J> J0
The demand for a clean environment is bringing close public
and legislative scrutiny of all pesticides with the likely result of cur-
tailment of certain herbicides that are used in aquatic weed control.
This is forcing many state and federal research agencies to search for
alternate methods. Mechanical methods are costly, usually temporary
330
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in effect, and difficult to employ in canals. Biological control offers
a potential means of control over extensive areas where the cost of
chemical or mechanical practices would be prohibitive.
To date, biological control of weeds has been accomplished
mainly by insects; but use of mites, snails, pathogenic microorganisms,
fish, ducks and geese, manatees, and parasitic higher plants are under
investigation. Caution is necessary for thorough screening of all
animals which are introduced for control of weeds. In the absence of
their preferred food there is danger in their becoming pests of alter-
nate plant types. This caution is less necessary for agents introduced
for insect control.
a. Biological Control of Red Scale and
and Purple Scale in Florida
Florida red scale, Chrysomphalus anoidum (1.) and purple scale,
Lepidosaph.es beckii (Newman), were until recently the two most impor-
tant armored scales on citrus. Control of purple scale by the introduc-
3 7
tion of the parasite Aphytis lepidosaphes has been reported. Hymeno-
pterous parasites represent the critical control factors for the Florida
red scale. Pseudhomalopoda prima, the parasite attacking mature
female red scale, is highly important. The most important parasite
species appear to be Aspidiotiphagus lounsburyi and Phospaltella
38
aurantii which attack male and second-stage female scales. A special
survey of Florida red scale and parasites was made between February ,
and June 1967 in 104 groves. Parasites were identified as being either
P. prima or A. holoxanthus. Parasitism by A_. holoxanthus was very
high. This parasite, which was introduced from California in I960,
appears to have much greater ability to survive adverse weather condi-
tions than P. prima.39' 4° Partial to complete control has been
achieved using these parasites in most areas in Florida.
331
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b. Biological Control of Cotton Bollworm and Tobacco
Bud worm in Mississippi
Several species of parasitic insects were reared from field
collected larvae of the bollworm, Heliothis zea (Boddie); and the
tobacco budworm, HL virescens (F.), in Mississippi.41 The parasites
belong to the families Braconidae, Ichmeumonidae, and Tachinidae.
The predominant species were two Braconids, Microplitis croceipes
and Cardiochiles nigriceps. Parasites provided a high percent of
control on cranesbill, tomato, and spider flower. Observations were
also reported on the effectiveness of Cardiochiles nigriceps in control-
ling H. virescens on tobacco in areas of Florida and Georgia.42
c. Control of Pea Aphid by Aphidius smithi in Kentucky
Since 1962, Aphidius smithi was found to be parasitizing
increasingly large numbers of the pea aphid, Acyrtho siphon pi sum, in
clover and alfalfa fields in Kentucky.43 In a 6-hour parasitization
period, 60 pea aphids parasitization by Aphidius smithi was highest
(82 percent average) with first-instar aphids, and lowest (0 percent)
with post reproductive aphids. Such differences in degree of parasiti-
zation were not found in mixed groups of various instars. Progeny
production by pea aphid ceased after the fourth day if they were para-
sitized on the first day of parturition (birth). A., pi sum parasitized in
the third instar did not mature to the reproductive state. This parasite
was propagated and widely released in California and has since become
an important factor in the control of pea aphid in that area.
d. Introduced Wasps for the Control of Gypsy Moth in Alabama
Twenty-thousand tiny parasitic wasps were released in 1971 in
Russell County, Alabama, in an effort to prevent the spread of the
332
-------
gypsy moth, the world's most serious forest pest.44 These moths were
recently reported in Alabama. The wasps which are completely harm-
less to people, were shipped from New York, but are native to the
Mediterranean countries. The wasps seek out egg masses of the moth
and lay their eggs in the moth eggs. When the wasp eggs hatch, the
larvae feed on the eggs of the moth and destroy them. In this case a
biological agent prevents the establishment of this pest.
e. Field Control of the Nantucket Pine Tip Moth by the
Nematode DD-136 in South Carolina
Field investigations have demonstrated that the nematode DD-136
will kill Nantucket pine tip moth, Rhyacionia frustrana, larvae under
natural conditions.45 More first-generation tip moth larvae were killed
than secord or third generations. Nematode suspensions were aided in
effectiveness by addition of 10 percent glycerin and to a lesser degree
by addition of wetting agents or spreader-sticker, namely 2 percent
solution of Emgard 2050, Sole-Onic CDS, and Igepon AO-78.45 DD-136
did not provide sufficient control of the moth to recommend its use.
This case suggests that biological agents cannot be successfully
employed in all situations.
f. Heliothis Control with Virus
TM
Virus, Viron/H , attacks only species of the genus Heliothis
yiresjiens of which there are two major economic pests. One is H_.
virescens, the tobacco budworm and the other is H. zea commonly
known as cotton bollworm. This virus has performed equal to or
better than commonly used chemical insecticides in 80 to 90 percent
of the cases. Its greatest advantages lie in the fact that it is completely
specific and is absolutely safe and non-toxic. This virus is reasonably
compatible with some chemical insecticides. These can be sprayed in
333
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mixtures as long as the pH of the solution is neutral. The formulated
form contains 126 billion inclusion bodies per ounce and a quart will
control the bollworms on 10 acres of cotton with a light to moderate
infestation. The application of this virus in practically every cotton-
growing state was permitted by the Food and Drug Administration (FDA)
in 1970. 32
g. Integration of the Heliothis Nuclear Polyhedrosis Virus into
a Biological Control Program on Control in Mississippi
A biological control program for the control of bollworm, H..
zea, and tobacco budworm, H. virescens, was integrated into an over-
wintering boll-weevil control program on cotton in the Mississippi
Delta in 1965. 4* The Heliothis program was designed to utilize
biological control measures whereby chemical control would not be
required during the growing season. The factors utilized in the Helio-
this biological program consisted of the naturally occurring predator-
parasite complex and the application of the nuclear polyhedrosis virus.
Heliothis control with biological agents was compared with a toxaphene-
DDT-methyl parathion control program using 25 to 30 acre plots. The
virus was applied at 1.2 X 10" (20 LU, Larval Units). 3. 0 X 10" (50 LU),
and 6. 0 X 10" (100 LU) polyhedral inclusion bodies per acre. The
initiation of virus applications was varied to evaluate the effectiveness
of the virus against various ages of larvae. The Heliothis biological
control program compared favorably with the insecticide program when
virus application was initiated to coincide with hatch of egg populations.
h. Two-Spotted Spider Mite Control with Fungus in Alabama
A study was conducted in Alabama in 1968 to determine the
importance of Entomophthora sp. as a natural control factor for
334
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field populations of the two-spotted spider mite, Tetranychus urticae
Koch. Studies on the distribution of this fungus revealed its presence
in 14 of the 15 counties where collections were made, Average infec-
47
tion rate by this fungus was 25 percent. Five epizootics of the patho-
genic fungus were observed in two-spotted spider mite populations in
Lee County, Alabama. Each epizootic was characterized by a high
degree of infection by Entomophthora sp. accompanied by a rapid
decline in mite numbers. This was a preliminary study and no final
conclusions can be drawn. Further research work is needed.
i. Control of Aquatic Weeds by the Snail in Florida
Experiments were conducted in the state of Florida in 200-
gallon concrete tanks to evaluate the.effectiveness of large fresh-water
snails, Marisa cornuarietis, as a biological aquatic weed control agent.
The snails controlled Ceratophyllum demersum, Najas guadalupensis,
and Potamogeton illineonsis completely and Pistia stratiotes and
Alternanthera philoxeroides partially. Marisa preferred submersed
weeds to floating weeds. Little damage was done by Marisa to 4 and 5
week-old rice plants, but younger rice was killed when the snails had
no other source of food.48 Except for its possible deletarious effects
in rice-growing areas, Marisa was regarded as very promising within
Florida for the control of aquatic weeds at least in confined bodies of
water. 4*
j. Biological Control of Alligatorweed with Flea Beetle
in Southeastern States
Alligatorweed, Alternanthera philoxeroides, is an extremely
prolific plant which is most difficult to control and even more difficult
to kill. It does not pose a serious weed problem in South America,
where 40 to 50 species of insects act as suppressing biotic agents.
335
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Only one of these insects was known to occur in the United States and
this insect, a flea beetle, belongs to genus Agasicles. During the fall
of 1965 and spring of 1966, over 9, 000 beetles were transferred to
selected and approved locations throughout Florida, Georgia, South
Carolina, and Mississippi. * Frequent observations were made in the
vicinity of the release sites and at no time was there any evidence that
the beetle fed on any plant other than alligatorweed. The beetles pre-
fer the alligatorweed that is growing in the water. The results look
very promising and should be extended to pilot studies on larger areas. *
k. Control of Pond Weeds by the Use of Herbivorous Fish
The possible use of herbivorous fish has received little atten-
tion in the United States. Common carp, Cyprinus carpie, may control
some aquatic plants by keeping the water muddy and to a lesser degree
by rooting out plants. In China, Japan, Israel, and Thailand; the grass
carp, Ctenopharyngodon idellus, has been used successfully for the
control of rooted aquatics. 36
Species of fish that feed upon aquatic weeds and appear promising
in Alabama are listed in Table G-7. Since 1957 eight species of fish have
been field tested for effectiveness in aquatic weed control in Alabama.
The Congo tilapia, Tilapia melanopleura; grass carp, Ctenopharyngodon
idellus; and the Israeli carp, Cyprinus carpio have shown the best poten-
tial for weed control. In ponds, Congo tilapia, when stocked at rates of
approximately 1, 500 to 1, 000 per acre, controlled in three months
Pithophora sp., giant Spirogyra, E. acicularis, _E. densa, Hydrochloa
sp., tJ. biflora, and Rhizoclonium sp. Grass carp controlled Chara sp.,
P. oviersi folius and E_. acicularis in one month when stocked at a rate
of 20 to 40 per acre. Six to 9-inch Israeli carp, when stocked at rates
of 25 to 50 per acre, were effective in reducing or eliminating
336
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TABLE G-7 Species of fishes feeding upon filamentous algae and rooted
aquatics that appear of promise in the biological control of pond weeds in
Alabama.35
Common name
Common carp
Grass carp
Golden carp
Goldfish
Tawes
Nilem
Tilapia
Tilapia
Gourami
Sepat Siam
Milkfish
Scientific name
Cyprinis carpio (Lin.)
Ctenopharyagodon idellus (C. and
Carassium carassius (Lin.)
Carassius auratus Lin.
Puntius javanicus (Sleeker)
Osteochilus hasselti (C. and V.)
Tilapia mossambica Peters
Tilapia melanopleura (Dum.)
Osphronemus goramy (Lac,)
Trichogaster pectoralis (Regan)
Chanos chanos (Forskal)
Feeding upon
Filamentous Rooted
algae aquatics
X X
V.) x
X
X
X X
X
X X
X
X
X
X X
Source: Swingle, H. S,
337
-------
Pithophora sp., Rhizoclonium sp., and_E_. acicularis but in some
ponds required 2 to 3 years to effect control.5
The species of fish receiving.most of the attention in Georgia
are: Tilapia nilotica, Tilapia mossambica, T. melanopleura,
Cyprinus carpio, and Ctenopharyngodon idellus. All observations on
Chinese or grass carp, C. idellus, are most favorable.52 In the spring
of 1967, 2, 000 grass carp were stocked in a 20-acre pond in Georgia
that had a 5-year history of excessive growths of Najas. and
Potamogeton. Within 6 weeks, grass carp was able to consume most
of the rooted aquatic vegetation.
Table G-8 contains a list of insect parasites and predators
successfully colonized in the Continental United States. 53 Many of
the pests listed in the table are also of economic importance in the
southeastern part of the United States.
Many of the economic pests in the United States have come
from other countries without their biological parasites or predators.
Through lack of biological agents and abundance of food in agro-
ecosystems some of these pests have themselves become important
problems. Importation and release of biological agents have shown
promise as control programs. Considerable success has also been
achieved by the use of pest pathogens (bacteria and virus) in controlling
economic pests.
338
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Table G-8 Insect Pest and their Parasites and Predators Successfully
Colonized in Continental United States ^3
PEST
WHERE FOUND
PARASITE OR PREDATOR
Aphids, several species, Family
Aphidae (see Field and Garden
Insects)
Apple mealybug, Phenacoccus
aceris (Signoret)
Black scale,
Saissetia oleae (Bern.)
FRUIT INSECTS
Florida citrus
and papaya areas
Oregon, and Maine
to Vermont
California
California red scale,
Aonidiella aurantii(Mask.)
Chiefly Cali-
fornia, Arizona,
and Texas
Citrophilus mealybug,
Pseudococcus gahani Green
(see Tree and Shrub Insects)
Citrus mealybug,
Pseudococcus citri (Risso)
Tree and Shrub Insects)
(See
California
California and
Florida
Leis dimidiata 15-spilota
(Hope)
Allotropa utilis Hues.
Aphycus helyolus Comp.
Aphycus lounsburyi How.
Aphycus stanleyi (Comp.)
Coccophagus capensis Comp.
Coccophagus cowperi Git.
Coccophagus pulvinariae Comp.
Coccophagus rusti Comp.
Coccophagus trifasciatus Comp,
Diversinervus elegans Silv.
Lecaniobius utilis Comp.
Quaylea whittieri (Gir.)
Rhizobius debilis Blackb.
Rhizobius ventralis (Er.)
Scutellista cyanea Mots.
Ajphytis j-ingnanensjjs Comp.
Aphytis melinus DeBach
Chilocorus kuwanae Silv.
Comperlella fasciata How.
(red scale strain)
Cybocephalus sp.
Habrolepis rouxi Comp.
Lindorus j^ojh^ntae (Blaisd.)
Orcus chalybeus (Boisd.)
Prospaltella perniciosi Tower
(red scale strain)
Cleodiplosis koebelei (Felt)
Coccophagus gurneyi Comp,
Scymnus binaevatus (Muls.)
Tetracnemus pretiosus Tirob.
Allo_trgp_a c±tri_ Hues.
Cryptolaemus montrouzieri Muls,
Leptomastidea abnormis (Gir.)
Pauridia peregrina Timb.
339
-------
G-8 (Continued)
PEST
WHERE FOUND
PARASITE OR PREDATOR
FRUIT INSECTS.—Continued.
Coconut scale,
Aspidiotus destructor Sign.
Comstock mealybug,
Pseudococcus comstocki (Kuw.)
Cottony-cushion scale,
Icerya purchasi Mask.
Florida red scale,
Chrysomphalus aonidum (L.)
Gypsy moth,
Porthetria dispar (L.) (see Tree
and Shrub Insects)
Florida
Eastern apple
regions
California,
Arizona, and
Southeastern
seaboard
Florida,
Mississippi,
Louisiana,
California
New England, New
York, New Jersey
and Pennsylvania
Japanese beetle,
Popillia japonica Newm. (See Field
and Garden Insects and Tree and
Shrub Insects)
Long-tailed mealybug,
Pseudococcus adonidum (L.)
(See Tree and Shrub Insects)
Olive scale,
Parlatoria oleae (Colvee)
(See Tree and Shrub Insects)
The East
California
California and
Maryland
Azya trinitatis Mshll.
Cryptognatha nodiceps Mshll.
Allotropa burrelli Mues.
Pseudaphycus malinus Gahan
Cryptochaetum iceryae (Will.)
Rodolia cardinalis (Muls.)
Aphytis holoxanthus DeBach
Anastatus disparis Ruschka
Apanteles melanoscelus (Ratz-)
Blepharipa scutellata R.-D.
Calosoma sycophanta (L.)
Carabus auratus L.
Compsilura concinnata (Meig^)
Exorista larvarum (L.)
Monodontomerus aereus Wlkr.
Ooencyrtus kuwanai (How.)
Parasetigena agilis (R.-D.)
Phobocampe disparis (Vier.)
Dexilla ventralis (Aid.)
Hyperecteina aldrichi Mesnil
Prosena siberita (F.)
Tiphia popilliavora Roh.
Tiphia vernalis Roh.
Anagyrus fusciventris (Gir.)
Anarhopus sydeyensis Timb.
Tetracnemus peregrinus Comp-
Aphytis maculicornis (Masi)
(Egyptian strain)
(Indian strain)
(Persian strain)
(Spanish strain)
Aspidiotiphagus sp.
Chilocorus bipustulatus (L.)
340
-------
TABLE G-8 (Continued)
PEST
WHERE FOUND
PARASITE OR PREDATOR
FRUIT INSECTS.—Continued.
Oriental fruit moth,
Grapholitha molesta (Busck)
The East
California, and
scattered elsewhere
Agathis diversa (Hues.)
Agathis festiva Hues.
Pineapple mealybug,
Pseudococcus brevipes (Ckll.)
Purple scale,
Lepidosaph.es beckii (Newm.)
Scales, several species, Family
Coccidae (see Tree and Shrub
Insects)
South Florida
and Hawaii
California,
Florida to Texas
General in fruit
areas
Walnut aphid, Pacific Coast
Chromaphis ju alandicola (Kalt.) States, Utah and
(see Tree and Shrub Insects) Idaho
Western grape leaf skeletonizer,
Harrisina brillians B. & McD.
Woolly apple aphid
Eriosoma lanigerum (Hausm.)
Yellow scale,
Aonidiella citrina (Coq.)
Southwest, Utah
Colorado
General
California, Texas
and Florida
Hambletonia pseudococcina
Comp .
Aphytis lepidosaphes Comp .
Physcus fulvus C. & A.
Chilocorus sp. near distigma
Exochomus quadripustulatus
(L.)
Trioxys pallidus Hal.
Apanteles harrisinae Hues.
Sturmia harrisinae Coq.
Aphelinus mali (Hald.)
Exochomus quadripustulatus
(L.)
Comperiella bifasciata How
Alfalfa weevil,
Hypera postica (Gyll.)
FIELD AND GARDEN INSECTS
General
Aphids, several species, Family General
Aphidae (see Fruit Insects)
Asiatic garden beetle, The East
Maladera castanea (Arrow)
Clover leaf weevil General
Hypera punctata (F.)
Anaphes pratensis (Foerst.)
Bathyplectes curculionis
(Thorns.)
Microtonus aethiops (Nees.)
Tetrastichus incertus Ratz.
Tiphia asericae A. & J.
Biolysia tristis (Grav.)
341
-------
TABLE G-8 (Continued)
PEST
WHERE FOUND
PARASITE OR PREDATOR
FIELD AND GARDEN INSECTS.--
Continued
European corn borer,
Ostrinia nubilalis (Hbn.)
European wheat stem sawfly,
Cephus pygmaeus (L.)
Greenbug,
Schizaph_J8_ graminum (Rondani)
Hessian fly,
Phytophaga destructor (Say)
Imported cabbageworm,
Pieris rapae (L.)
Japanese beetle,
Popillia japonica Newm. (see
Fruit Insects and Tree and
Shrub Insects)
Pea aphid,
Acyrthosiphon pisum (Harris)
Rhodes grass scale,
Antonina graminis (Mask.)
Spotted alfalfa aphid,
Therioaphis maculata (Buckton)
Sugarcane borer,
Diatraea saccharalis (F.)
Yellow clover aphid,
Therioaphis trifolii (Monell)
The East and the
Midwest
Eastern wheat
areas and North
Dakota
General
All small-grain
areas
General
The East
General
Gulf States, New
Mexico, Arizona
and California
General
Gulf States
Chelonu.8 annulipes Uesm.
Horogenes punctorius (Roman)
Lydella thompsoni Herting
Macrocentrus gifuensis Ashm.
Phaeogenes nigridens Wesm.
Sympieais viridula (Thorns.)
Collyria calcitrator (Grav.)
Aphidus testaceipes (Cresson)
Hippodamia convergens Guer.
Pedobius metalicus (Nees)
Apanteles glomeratus (L.)
The East
Aphidus srnithi S. & A.
Hippodamia convergens Guer.
Anagyrus antoninae Timb.
Dusmetia sangwani Rao
Aphelinus semiflavus How.
Praon palitans Hues.
Agathis stigmatera (Cress.)
Lixophagji diatraeae (Tns.)
Paratheresia claripalpis
(V.d.W.)
f
Trioxys utilis Mues.
342
-------
TABLE G-8 (Continued)
PEST
WHERE FOUND
PARASITE OR PREDATOR
TREE AND SHRUB INSECTS
Balsam woolly aphid,
Chermes piceae Ratz.
Barnacle scale,
Ceroplastes cirripediformis
Cornst.
Birch leaf-mining sawfly,
Heterarthrus nemoratus (Fall.)
Browntail moth,
Nygmia phaeorrhoea (Donov.)
Browntail moth,—Cont.
Nygmia phaeorrhoea (Donov.)
Citrophilus mealybug,
Pseudococcus gahani Green
(see Fruit Insects)
Citrus mealybug,
Pseudococcus citri (Risso)
(see Fruit Insects)
Elm leaf beetle,
Galerucella xanthomelaena
(Schr.)
European earwig,
Forficula auricularia L.
(also general-nuisance pest)
European elm scale,
Gossyparia spuria (Mod.)
European pine sawfly,
Neodiprion sertifer (Geoff.)
East and West
Coasts
Southern coastal
areas, California,
and Hawaii
Northern New
England
New England
New England
California
California
Pacific States
and the East
Eastern
Seaboard and the
West
The East and
California
New England,
New Jersey
Aphidoletes thompsoni Mohn.
Cremifania nigrocellulata Cz,
Laricobius erichsonii Rosen.
Leucopis obscura Hal.
Scymnus impexus Muls.
Scutellista cyanea Mots.
Chrysocharis laricinellae
(Ratz.)
Phanomeris phyllotomae Mues.
Apanteles lacteicolor Vier
Carabus auratus L.
Carcelia laxifrons Vill.
Eupteromalus nidulans
(Thorns.)
Exorista larvarum (L.)
Meteorus versicolor (Wesm.)
Monodontomerus aereus Wlkr.
Tjjwnsendicellomyia nidicola
-------
TABLE G-8 (Continued)
PEST
WHERE FOUND
PARASITE OR PREDATOR
TREE AND SHRUB INSECTS.—Continued
European pine shoot moth,
Rhyacionia buoliana (Schiff.)
European spruce sawfly,
Diprion hercyniae (Htg.)
Gypsy moth,
Porthetria dispar (L.)
(see Fruit Insects)
Japanese beetle,
Popillia japonica Newm.
(see Fruit Insects and Field
and Garden Insects)
Larch casebearer,
Colephora laricella (Hbn.)
Long-tailed mealybug,
Pseudococcus adonidum (L.)
(see Fruit Insects)
Nigra scale,
Saissetia nigra (Nietn.)
Olive scale,
Parlatoria oleae (Colvee)
(See Fruit Insects)
Oriental moth,
Cnidocampa flavescens (Wlkr.)
Satin moth,
Stilpnotia salicis (L.)
Walnut aphid,
Chromaphis juglandicola (Kalt.)
(see Fruit Insects)
Northeast,
North Central
States, and
Washington
Upper New
England
New England,
New York, New
Jersey, and
Pennsylvania
The East
Eastern half of
U.S.
Citrus-growing
areas
California
California
Massachusetts
New England
Washington, and
Oregon
Pacific Coast
States, Utah,
and Idaho
Temelucha interrupter Grav.
Orgilus obscurator (Nees)
Tetrastichus turionum (Htg.)
Dahlbominus fuscipennis
(Zett.)
Agathis pumila (Ratz.)
Chrysocharis laricinellae
(Ratz)
Aphycus helvolus Comp.
Chaetexorista javana B. &
Apanteles solitarius (Ratz.)
Meteorus versicolor (Wesm.)
Source: Agricultural Research Service, U.S.D.A. (Modified).
344
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6. Sterility Approach to Insect Control
The use of insect sterilization to control and eradicate pest
populations is one of the revolutionary departures of modern
54-57
entomology. There are two ways by which the sterility principle
might be used to help control or eradicate insects. One involves
rearing, sterilization and release into the natural population so that
the sterile members will compete with normal ones and thus lower the
reproduction rate. Early experiments in sterilizing insects employed
x-rays, but the first attempts at sterilizing insects as a control
measure utilized irradiation with gamma rays from a cobalt-60
source. A theoretical model involving such a release, procedure is
given in Table G-9. It is assumed that the natural population exists
in an isolated area containing a stable population of 2 million insects
with a 1:1 ratio of males to females in equilibrium with the environ-
ment and with the biotic potential canceled out by environmental
resistance. Each generation, 2 million sterile males would be
released in this area to compete equally for mates. By the fourth
generation, the ratio of sterile to fertile males competing for each
virgin female would be 1, 807 to 1; with equal competition 99. 95% of
these matings would be sterile.
The other method is to treat and sterilize insects in the
natural population to reduce reproduction. The chemical compounds
which reduce or entirely eliminate the reproductive capacity are
called chemosterilants. Chemosterilants may affect only one sex
(male sterilants, female sterilant) or both sexes (male-female
sterilants). United States Department of Agriculture entomologists
and chemists have screened 3, 000 materials and have found that at
least 50 of them produce sterility in insects. Apholate and Aphoxide
are among the most active chemosterilants currently under
345
-------
Table G-9 Theoretical Population Decline in Each Subsequent Generation When a Constant Number of Sterile Males
Are Released Among a Natural Population of 1 Million Females and 1 Million Males -
54
generation
Number of virgin
females in the area
Number of sterile males
released each generation
Ratio of sterile to
fertilf males competing Percentage of
for each virgin females mated
female to sterile males
Theoretical popu-
lation of fertile
females each sub-
sequent generation
Fl
F2
F3
F4
1; 000, 000
333,333
47,619
1,107
2,000,000
2,000,000
2,000,000
2,000,000
2
6
42
1,807
: 1
: 1
: 1
: 1
66.7
85.7
97.7
99.95
333,333
47,619
1,107
Less than 1
Source: Knipling, E. F.
en
-------
investigation.55 When administered orally or by contact these compounds
produce irreversible sterility without apparent adverse effects on the
mating behavior and length of life of the insects.
Insects on which sterility information is available57 and which
are ready for field testing are listed in Table G-10.
a. Eradication Program of the Screw Worm Fly in the
Southeastern States
Screw worms were brought to the vanishing point by the release
of 100 sterile males per square mile per week on Sanibel Island near
Fort Myers, Florida, but eradication could not be proved because the
test area was not sufficiently isolated to prevent immigration of a few
fertilized females from nearby untreated areas. The other experiment
was performed on the island of Curacao where eradication was
achieved on that isolated 170 square mile island. The apparent
eradication of the screw worms from Curacao supported the theory
that screw worms could be eradicated from the southeastern states by
by releasing sterilized flies. In July 1958, a huge sterilized fly
production facility was completed at Sebring, Florida. This establishment
produced 50 million sterilized flies per week, which were distributed
over all infested areas in the Southeast (Florida, Georgia, Alabama,
Mississippi, South Carolina, North Carolina). By 1958, the screw-
worm had been eliminated from the Southeastern states, the major
part of the'Continental United States in which this pest can overwinter,
and no infestations of screw worms have since occurred.58
The screw worms were irradicated with gamma-rays using a
cobalt 60 source.59 The 7500 roentgens dose was adopted as standard
for eradication programs. In laboratory experiments, the radiation-
induced sterility was permanent and the sterilized males were
competitive with normal males in cage-mating experiments.
347
-------
TABLE G-10 Insects on which sterility information is available
and which are ready for field testing.
Scientific Name
Common Name
Anastrepha ludens (Loew)
Ceratitis capitata (Wied)
Dacus cucurbitae Coq.
Dacus dorsalis (Hendel)
Anastrepha suspensa
Anastrepha fraterculus Wied.
Dacus tryoni (Froyg.)
Drosophila spp.
Dacus oleae (Gmelin)
Glossina roorsitans (Westwood)
Glossina austeni (Newstead)
Hylemya antiqua (Meig)
Aedes aegypti
Aedes scutellaris
Culex pipiens fatigans Wied.
Anopheles gambiae
Dermatobia hominis (Linnaeus)
Haematobia irritans (Linnaeus)
Musca domestica (Linnaeus)
Authonomus grandis (Bol.)
Oryctes rhinoceros L.
Acanthoscelides obtectus Say
Melolontha vulgaris F.
Carpocapsa pomonella L.
Diatraea saccharalis (F.)
Leucoptera coffeella
Heliothio virescens (F.)
Heliothio zeae (Boddie)
Chilo suppressalis Walker
Pectinophera gonypiella (Saunders)
Dysdercus peruvianus C.
Popillia japonica (Newm.)
Protoparce sexta (Ich.)
Trichoplusia ni
Mexican fruit fly
Mediterranean fruit fly
Melon fly
Oriental fruit fly
Carribean fruit fly
South American fruit fly
Queensland fruit fly
Vinegar flies
Olive fly
Tsetse fly
Tsetse fly
Onion fly
Yellow fever mosquito
Vector of filariasis (mosquito)
Vector of filariasis (mosquito)
Vector of malaris (mosquito)
Torsalo, human bot fly
Hornfly
House fly
Boll weevil
Rhinoceros beetle
Bean weevil
Cockchafer
Codling moth
Sugar cane borer
Coffee leaf miner
Tobacco budworm
Cotton bollworm
Rice-stem borer
Pink bollworm
Cotton red stainer
Japanese beetle
Hornworm
Cabbage looper
Source: International Atomic Energy Agency (Modified).
348
-------
Further applications of the same techniques are now being tried
with other pests. These are being combined with chemosterilants and
genetic male sterile forms.
b. Eradication of the Cotton Bollworm From St. Croix,
U. S. Virgin Islands
Eradication of the cotton bollworm, Heliothis zea (Boddie). from
St. Croix, U. S. Virgin Islands, was attempted in 1968 and 1969, using
the sterile-male release method. Although both attempts failed in the
primary objective of eradicating the species, the reasons were the
high ratios of sterile to natural males which caused the elimination of
oviposition, and high degree of locking between the released population
and the native females.
c. Eradication of Cotton Boll Weevil in the Southeast
A truly effective chemosterilant for the boll weevil has not yet
been discovered. Some of the aziridinyl compounds, particularly
apholate, induce a rather high degree of sterility in the males, but the
mortality of treated insects is high and their competitiveness is
reduced.61 During 1962, Apholate sterilized male boll weevils
Anthonomus grandis, normal males and virgin untreated females were
released in three experimental one acre plots of cotton in Virginia,
Tennessee, and Louisiana in the ratio of 20:1:1 in each of five uniformly
distributed points. A total of 8, 850 sterile males released over an
eight we"ek period, prevented matings between the ensuing Fj, males
and females. On the seventeenth week of the experiment, no egg or
feeding punctures were found in two examinations of all the squares
and bolls on plants in the field. Only in the Louisiana experiment
was eradication of the population achieved. 2 The successful eradication
in 1962 of an artificially induced infestation of boll weevils prompted
349
-------
further studies. From June 17 through August 26, 1964, eleven
weekly releases of apholate sterilized male boll weevils were made in
nine cotton fields that had been treated with insecticides in the fall
of 1963, to reduce the population of diapausing weevils. An average
of 8, ZOO males were released per acre. This was done in Baldwin
County, east of Mobile, Alabama. This release program reduced the
number of oviposition punctured squares. Also, the percentage of
infertile eggs, the number of live immature and adult weevils per
acre in fruit, numbers of over-wintered adults and the levels of
infestation during the second year were considerably lower in the
release zone than in the zone treated intensively with insecticides.
Effectiveness of apholate in decreasing the sperm viability of
the male boll weevil was determined 3 in Mississippi by allowing the
weevils to feed on a diet containing from 0. 001 to 0. 020 percent of the
chemosterilant and on plants sprayed with 0.5 and 2.5 percent solutions.
After both treatments, virgin females mated to treated males oviposited
eggs with decreased hatchability and emergence of the Fj, progeny.
At the higher levels of treatment, longevity of males was reduced.
Repeated spray applications of the chemosterilant to plants, especially
at the higher levels, caused phytotoxicity manifested by leaf necrosis,
stunting of growth and cessation of square production. The male
boll weevil can also be sterilized with TEPA, either by feeding 1, 500 ppm
in the diet for two days or by an injection of 3. 5 mg.64 Lower levels
of TEPA produced transitory sterilization. At the effective levels,
mortality was significant.
d. Control of House Flies with Chemosterilant Baits in Florida
Three compounds, aphoxide, aphomide, and apholate caused
sterility in male and female house flies at concentrations of 1 percent
350
-------
to 0.5 percent in food given to the adults. Of 97 percent compounds
administered in granulated sugar or in fly food tested in Florida, only
27 percent caused sterility in adult house filies, Musca domestica L.6*
Corn meal baits containing 0.5 percent of aphoxide (1-Aziridinyl
Phosphine Oxide), a chemosterilant, were applied on an isolated refuse
dump in the Florida Keys for the control of house flies, Musca
domestica L. Applications were made each day during the second week.
House fly populations were reduced from 47 per grid to zero within
four weeks and the percent hatch among all eggs laid was reduced to
one percent within five weeks, 7 House fly baits containing 0.5 percent
of metepa (methaphoxide tris-(2-methyl-1-aziridinyl) phosphine oxide)
were applied to the droppings in a poultry house in the suburbs of
Orlando, Florida, for the control of. house flies. Applications were
first made at weekly intervals for nine weeks, then semi-weekly.
Granular baits with corn meal as a carrier were the most effective
and vermiculite granules, were unsatisfactory.68
A corn bait containing 0.75 percent of Apholate was applied on
a dump at Pine Island, Florida for the control of house flies.
Applications were made over a week for seven consecutive weeks,
then five times each week for seven consecutive weeks, then five
time each week for five weeks. The fly population decreased from
68 per grid to 5 to 20 during the first seven weeks and remained
between 0 and 3 per grid the following five weeks.69
e. Preliminary Work with Chemosterilants for Important
Noctuids in Georgia
The corn earworm, Heliothis zea (Boddie); the armyworm,
Pseudaletia unipuncta (Haworth); and the granulate cutworm,
Feltia subterranea (F.), can be sterilized with TEPA. Males of each
351
-------
species are sterilized when they are fed 53 mg of TEPA in a 10 percent
sucrose solution. A dose in excess of 106 mg is required to sterilize
female corn earworms and a dose of more than 53 mg to sterilize
female army worms and granulate cutworms.70 Sterilization of the fall
armyworm by a apholate and TEPA has also been reported.7
Insect sterility, a new technique is offering promise for many
major agricultural pests of southeastern U. S. including the boll weevil,
bollworm, budworm, and pink bollworm. Much research and field
experiments must be conducted on each pest problem to determine if
this approach will be useful in an expanded practical control program.
7. Insect Attractant and Repellants
Many insects find their food, their partners for mating and favor-
able sites in which to deposit their eggs by means of automatic response
to various scent clues. Male moths for example, can smell potential
sexual partners at a considerable distance. Not surprisingly, each spe-
cies tends to have its own distinctive odor which facilitates the meeting
of partners capable of mating. The survival and adaptation of many insect
species depend on these odors. Frequently they can be attracted by means
of a chemical attractant to a trap for pest detection purposes or to a toxi-
cant that destroys them, or to a substance which makes them incapable of
72
fertile mating.
Attractants have been classified into three categories; sex, food,
and oviposition lures. The type of lure is inferred or deduced from insect
behavior and the designation given to such response is frequently uncer-
tain. If exposure to a chemical causes a male insect to assume a mating
posture, the chemical is probably a sex attractant, even if it is a synthe-
tic and unrelated to any natural lure. Some entomologists believe that
methyleugenol, the attractant for the oriental fruit fly (Dacus dorsolis
Hendel), is a sex attractant because the chemical attracts only the male.
352
-------
However, it appears to be a food lure, because the-flies avidly devour
the chemical. '* The insects in which female lures male and conversely,
males lure or excite the females are presented in Table G-ll and Table
G-12 respectively. "^
The use of food-based or fermenting lures has a definite place in
control operations. Disadvantages include lack of specificity (traps fill
with many kinds of insects), attraction over only a short distance, rapid
deterioration (especially of fermenting lures), and frequently inconsistent
performance. In regard to oviposition lures, females have been induced
to lay their eggs on, or in the vicinity of, certain chemicals. Materials
that release ammonia are known to encourage oviposition in house flies.
•7 ^
The apple maggot is attracted to decomposing proteins, such as egg albumin.
Chemical attractants and associated agents, such as stimulants and
assertants have been widely used for many years in studies of insect be-
havior. They have served many useful purposes as lures in traps, for ex-
ample:
• To sample insect populations, to determine relative densities
from time to time and from place to place.
• To trace the movement of marke.d insects in dispersion and mi-
gration studies.
• To study survival of insects in their natural environments.
• To study behavior associated with the search for mates and ovi-
positions sites.
lathe search for selective methods of insect control, many entomio-
logists and plant protection personnel are seeking chemicals which elicit
repellence. A repellent is a chemical that causes an insect to make
oriented movements away from its source. 8 The distance the insect need
move, however, is usually much shorter than the distance it does move in
response to an attractant. Ordinarily, it need only leave or avoid a
treated surface or at most move a few centimeters out of the effective
concentration of repellent vapor. Less use has been made of repellents
353
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TABLE G-ll INSECTS IN WHICH FEMALES LURE THE MALES
74
Order
Scientific Name
Common Name
Orthoptera
Lepidoptera
Blaberus craniifer
(Burmeister)
Blaberus giganteus (L.)
Byrsotria futnigata (Guerin)
Leucophaea maderae (F.)
Mantis religiosa (L.)
Nauphoeta cinerea (Olivier)
Periplaneta americana (L.)
Periplaneta australasiae
(Fabricius)
Periplaneta brunnea
(Burmeisterl
Periplaneta fuliginosa
(Serville)
Achroea grisella (Fabricius)
Achroea sp.
Acronicta psi (L.)
Actias caja (L.)
Actias selene (Hiibner)
Actias villica (L.)
Agathymus baueri (Stallings
& Turner)
Agathymus polingi
(Skinner)
Aglia tau (L.)
Agrotis fimbria (L.)
Agrotis ypsilon (Hufnagel)
Antheraea pernyi
(Guerin-Meneville)
Antheraea (Telea) poly-
phemus (Cramer)
Aphomia gularis (Zeller)
Argynnis adippe (L.)
Argynnis euphrosyne (L.)
Argynnis latonia (L.)
Argynnis paphia (L.)
Giant death's head
roach
Cockroach
Cockroach
Praying mantis
Cockroach
American cockroach
Australian cockroach
Lesser wax moth
Garden tiger moth
Cream-spot tiger moth
Nailspot
Black cutworm
Polyphemus moth
Pearl-bordered
fritillary
Emperor's cloak
354
-------
TABLE G-ll (Continued)
Order
Scientific Name
Common Name
Lepidopetra
(Contd.)
Autoerapha californica
(Speyer)
Bombyx mori (L,)
Cacoecia murinana (Hb.)
Caligula japonica (Butler)
Callimorpha dominula (L.)
Callimorpha dominula per-
sona (Hbn.)
Callosamia promethea
(Drury)
Carpoeapsa pomonella (L.)
Celaena haworthii (Curtis)
Chaerocampa elpenor (L.)
Clysia ambiguella (Hubner)
Colocasia coryli (L.)
Colotois pennaria (L.)
Cossus robiniae (Pek.)
Cucullia argentea (Hufnagel)
Cucullia verbasci (L.)
Dasvchira fascelina (L.)
Dasvchira horsfieldj^ (Saund.)
Dasvchira pudibunda (L.)
Dendrolinus pini, (L.)
Diatrae saccharalis (F.)
Endromis versicolora (L.)
Ephestia, cautella (Walker)
Ephestia elutella (Hubner)
Eohestia kuhniella (Zeller)
Euroeta crameri (Westw.)
Euproctis chrysorrhoea (L.)
Eupterotida fabia (Cram.)
Eupterotida undulata (Blanch.)
Galleria mellonella (L.)
Graphotitha rnolesta (Busck)
Harrisima brillians
(B. & McD.)
Heliothis virescens (F.)
Alfalfa looper
Silkworm moth
Scarlet tiger moth
Promethea moth
Codling moth
Haworth's minor
Grape berry moth
Silver monk
Brown monk
Pale tussock moth
Sugarcane borer
Kentish glory moth
Almond moth
Tobacco moth
Mediterranean
flour moth
Gold tail moth
Greater wax moth
Oriental fruit
moth
Western grape
leaf skeletonizer
Tobacco budworm
355
-------
TABLE G-ll (Continued)
Order
Scientific Name
Common Name
Lepidoptera
(Contd.)
Heliothis zea (Boddie)
Heterusia cingala (Moore)
Hyalophora cecropia (L.)
Hyalophora colleta
Hyalophora euryalus
(Boisduval)
Hypocrita jacobaeae (L.)
Hypogymna morio (L.)
Laphygma frugiperda
(J. E. Smith)
Lasiocampa quercus (L.)
Lasiocampa trifolii (Schiff.)
Lobesia (Polychrosis)
Botrana (Schiff.)
Lymantria ampla (Walker)
Mahasena graminivora
(Hampson)
Malacosoma neustria (L.)
Metopsilus porcellus (L.)
Micropteryx spp.
Orgyia antiqua (L.)
Orgyia ericae (Germ.)
Orgyia gonostigma
(Fabricius)
Parasemia plantaginis (L.)
Pectinophora gossypiella
(Saunders)
Phalera bucephala (L.)
Plodia interpunctella
(Hiibner)
Porthesia similis (Fuessly)
Porthetria (Lymantria)
dispar (L.7
Porthetria dispar japonica
(Motsch)
Porthetria (Lvmantria)
monacha (L.)
Bollworm, corn
earworm, to-
mato fruitworm
Cecropia moth
Ceanothus silk
Moth
Cinnabar moth
Fall armyworm
Oak eggar moth
Grass eggar moth
Bagworm
Lackey moth
Vapourer moth,
rusty tussock
moth
Wood tiger moth
Pink bollworm
moth
Moonspot
Indian meal moth
Gypsy moth
Gypsy moth
Nun moth
356
-------
TABLE G-ll (Continued)
Order
Scientific Name
Common Name
Lepidoptera
(Contd,)
Prodenia litura (Fabricius)
Prodenia ornithoealli
(Guene'e)
Protoparce sexta (Johannson)
Pierostoma palpina (L.)
Ptiloohora plumigera
(Schiff.)
Pygaera curtula (L.)
Pygaera pigra ;(Hufn.)
Rhyacionia buoliana
(Schiff.)
RhyacJLonia Lfrustrana
(Comstock)
Rothschildia orizaba
(Westwood)
Samia cynthia (Drury)
Sanninoidea exitosa (Say)
Saturnia carpini (Schiff.)
Saturnia pavonia (L.)
'Saturnia pavonia minor (L.)
Saturnia pyri (L.)
Smerinthus ocellatus (L.)
Solenobia Jumosej.la (Hein.)
Solenobia lichenella (L.)
Solenobia seileri (Sauter)
Solenobia triquetrella (Hbn.)
Sphinx ligustri (L.)
Spilosoma lutea (Hufn.)
Spodoptera exigua (Hiibner)
Stilpnotia salicis (L.)
Synanthedon pictipes
(Grote & Robinson)
Tineola biselliella (Hummel)
Trabala vishnu (Lef.)
Trichoplusia ni (Hiibner)
Egyptian cotton
leaf worm
Yellow-striped
armyworm
Tobacco hornworm
Snout spinner
Pine shoot moth
Nantucket pine
tip moth
Orizaba silk moth
Cynthia moth
Peach tree borer
Emperor moth,
peacock moth
Lesser peacock
moth
Eyed hawk moth
Privet hawk moth
Buff ermine moth
Beet armyworm
Satin moth
Lesser peach tree
borer
Webbing clothes
moth
Cabbage looper
357
-------
TABLE G-ll (Continued)
Order
Scientific Name
Common Name
Lepidoptera
(Contd.)
Coleoptera
Vanessa uritcae (L.)
Zygaena filipendulae (L.)
Agriotes ferrugineipennis
(LeConte)
Ctenicera destructor (Brown)
Ctenicera sylvatica
(Van dyke)
Diabrotica balteata
(LeConte)
Dytiscus marginalis (L.)
Hemicrepidius morio
(Leconte)
Hylecoetus dermestoides
Limonius californicus
(L . )
Limonius sp.
Melolontha vulgaris
(Fabricius)
Pachypus cornytus (Olivier)
Phvllophaga lanceolata (Say)
-Rhopaea maenicornis
(Blackburn)
.Rhopaea varreauxi
(Blanchard)
Telephorus rufa (L. )
Tenebrio roolitor (L.)
Six-spot burnet
moth
Click beetle
Click beetle
Click beetle
Banded cucumber
beetle
Sugar-beet wire
worm
Wireworm
June beetle
Yellow mealworm
Hymenoptera
.Apis mellifera (L.)
Bracon hebetor (Say)
(=Habrobracon juglandis)
Crabro cribrarius (L.)
Dasymutilla spp.
Diprion similis (Hartig)
Jforytes campestris (L.)
Honey bee
Wasp
Wasp
Velvet ant
Introduced pine
sawfly
Wasp
358
-------
TABLE G-ll (Continued)
Order
Scientific Name
Common Name
Hymenoptera
(Contd.)
Diptera
Gorytes mystaceus (L . )
Macroeentrus ancvlivora
(Rohwer)
Macrocentrus gifuenals
(Ashraead)
M^cropis labiate (Fabricius)
Megarhyssa atrata
(Fabricius)
Megarhyssa inquisitor^ (Say)
lunator (L.)
N^odiprion lecontqi (Fitch)
Neodiprion pratti pratti
(Dyar)
Praon palitans (Muesebeck)
Pristiphora conjugate
(Dahlb.)
Culiseta inornate (Williston)
Drosophila melanogaster
(Meigen)
Musca domestica (L.)
Phytophaga destructor (Say)
Red-headed pine
sawfly
Virginia-pine
sawfly
Sawfly
Mosquito
House fly
Hessian fly
Isoptera
Reticulitermes arenincola
(Coellner)
Reticulitermes flavipes
(Kollar)
Termite
Eastern subter-
ranean termite
Source: Jacobson, M.
359
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TABLE G-12.
INSECTS IN WHICH MALES LURE OR
EXCITE THE FEMALES.74
Order
Scientific Name
Common Name
Orthoptera
Byrsotrla fumigata (Guerin) Cockroach
Eurycotls floridana (Walker)
Leucophaea maderae (F.) Cockroach
Hemlptera
Lethocerus Indlcus (Lepetier &
Serville) (=Belostoma_ Indlca)
Rhoecocorls sulclventris (Stal.)
Giant water bug
Bronze orange bug
Lepldoptera
Achevontia atropos (L . )
Achroca gr is el la. (Fabricius)
Aphomia gularls (Zeller)
Argynnis adippe (L)
Argynnis aglaja (L.)
Argynnis paphla (L.)
Callgo arlsbe (Hbn . )
Collas edusa (Fabricius)
Danaus plexippus (L. )
Ely mn las undularls (Dru.)
Ephestia cautella (Walker)
Ephestla elut ella (Hiibner)
Erynnls tages (L.) :
semele (L.)
Lesser wax moth
Emperor's cloak
Monarch butterfly
Almond moth
Tobacco moth
Euploca phaenar; eta (Schall. )
Euploca sp.
Eury tides protesilaus (L) .
Gallerla mellonella (L.)
Heplalus behrensl (Stretch.)
Hepialus hectus (L.)
Hlpparchla semele (L.)
Lethe rphria (F.)
Lycaena spp.
Mvcalesls suaveolens
(W.-M. & N.)
Opslphanes Invlrae Isagoras (Fruhst.)
Otosema odorata (L. )
Panlvmnas chrvslppus (L. )
Papllip arlstolochlae (F. )
Pechlpogon barbalis (CL.)
Phassus schamyl (Chr . )
Phlogophora metlculosa (L.)
Pierls napl (L. )
Plerls rapae (L.)
Plod la interpunctella (Hiibner)
Sphinx ligustri (L. )
Greater wax moth
Grayling butterfly
Angleshade moth
Mustard white
Imported cabbage worm
Indian meal moth
Privet hawk moth
360
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TABLE G-12 Continued.
Order
Scientific Name
Common Name
Lepidoptera
(Contd.)
Stichophthalma camadeva
(Westw.)
Syrichtus malvae (L.)
Terias hecabe fimbriata (Wall.)
Tineola biselliella (Hummel)
Xvlophasla monoglypha
(Hufn.)
Webbing clothes
moth
Dark arch moth
Coleoptera
Anthonomus grandis
(Boheman)
Boll weevil
Malachiidae bettles
Hymenoptera
Diptera
Bombus terrestris (L.)
Ceratitis cap.it.ata (Wied.)
Drosophila melanogaster
(Meigen)
Drosophila victoria
(Sturtevant)
Bumble bee
Mediterranean
fruit fly
Mecoptera
flajrpobittacus australis (Klug)
Harpobittacus nigriceps (Selys)
Scorpion fly
Scorpion fly
Neuroptera
Osmvlus chrysops (L.)
Source: Jacobson, M.
361
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for the protection of animals and plants than for the protection of man.
For humans these have been skin repellents, systemic repellents, and
repellents for clothing treatment.
Ultimately the best attractants (based on laboratory findings) must
be tested in the field where they must prove effective despite a multitude
of natural odors, colors, light conditions, and weather. ?3, 75, 76 Examples
of some potent synthetic attractants are listed in Table G-13
a. Use of Synthetic Attractants in Control and Eradication
of the Mediterranean Fruit Fly in Florida
In 1956, the Mediterranean fruit fly (med-fly) reappeared in Florida
after an absence of 26 years. Following its initial eradication in 1929-30,
the on-tree annual value of the citrus crop had climbed to about 250 million
dollars and that of all other commercial hosts of this pest was many
77
million dollars more. It was estimated that if these flies were not eradicated
the combined annual cost of control efforts, fumigation of exported fruit,
and maintenance of quarantine and road blocks would approximate 20 million
dollars exclusive of crop losses and decrease of consumer acceptance of
the state's citrus products.
Quick action by state and federal agencies (Plant Pest Control and
Entomology Research Branch, U. S. Department of Agriculture) and in-
dustry, along with good public support, made it possible to establish effec-
tive curtailment and eradication programs in a minimum of time. The
eradication effort was a complete success (Table G-14).
The general plan for state-wide eradication was to apply aerial
sprays to known infested areas and strips one-half mile adjacent to these
areas. The spray contained 1 Ib. of protein hydrolysate and 2 Ibs. of 25%
malathion per acre. The spray was applied on a 10-day schedule, but later
the coverage was on at a 7-day schedule because of rainy conditions.
362
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Lures and detection methods comprised of angelica oil, Siglure
and esters of cyclohexene carboxylic acid on cotton dental roll wicks with
3% DDVP (another phosphorus insecticide). A 25% lindane and 40% chlor-
dane wettable powder was applied bi-weekly at 1/4 teaspoon per trap to
prevent ant and spider depredation and to assist in fly kill. The traps were
placed at the rate of 10 to 40 per square miles preferably in med-fly hosts.
The number of traps was increased after a larval or adult find. The trap
servicing was done on two to three weeks schedules. Traps aided in
determining the effectiveness of the bait spray.
The cost of the program was $11 million. Among the most impor-
tant results of this research were the development:
• Of highly effective lures for use in bait traps. These served
as indicators of the presence of the flies in a given location
and as a measure of the progress toward eradication.
• Of attractive materials which could be combined with insecti-
cides in bait sprays.
363
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TABLE G-13 Potent Attractants Made Synthetically
73
Common Name
Species Attracted
Other Species Attracted
Methyleugenol3
Anisylacetone
Cue-lurea
Siglure
Medlure
Frontalure
Trimedlurea
Natural lure of
gypsy moth3
Gyplure
Bombykol
Butyl sorbate3
Methyl
linolenate3
Oriental fruit fly
(Dacus dorsalis)
Melon fly (Dacus
cucurbitae)
Melon fly (Dacus
cucurbitae)
Melon fly (Dacus
cucurbitae)
Mediterranean fruit fly
(Ceratitis capitata)
Mediterranean fruit fly
(Ceratitis capitata)
Southern pine beetle
(Dendroctrotonus fron-
talis)
Mediterranean fluit fly
(Ceratitis capitata)
Gypsy moth (Porthetria
dispar)
Gypsy moth (Porthetria
dispar)
Silkworm worth
(Bombyx mori)
European chafer
(AmphimalIon majalis)
Bark beetles
(Ips typographus)
(Hylurgops glabratus)
Dacus umbrosus
Queensland fruit fly
(D. tryoni)
(jD. ocbrosiae)
Queensland fruit fly
(£.• tryoni)
(D. ocbrosiae)
Walnut husk fly
(Rhagoletis completa)
Western pine beetle
(I), brevicomis)
Douglad fir (D.
pseudotsuge)
Natal fruit fly
(Pterandrus rosa)
364
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TABLE G-13 (Continued)
Common Name Species Attracted Other Species Attracted
Grandlure Cotton boll weevil
Anthnomous grandis Boheman
effective lure for insect under "Sp'ecies Attracted" column.
Source: Beroza, M. and Green, N. (Modified).
365
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Table G-14. Status of Bait-Spray and Trap Operations for Eradication
of the Mediterranean fruit fly in Florida.77
Acres Sprayed by Air
Date or
Period
Ending
1956
June 30
July 31
Aug. 31
Sept. 30
Oct. 31
Nov. 30a
Dec. 31 b
1957
Feb. 28
Apr. 30
June 30C
Aug. 31
Oct. 31
Dec. 31
1958
Feb. 28
Counties
Being
Sprayed
19
24
23
19
16
14
14
11
5
6
2
1
1
0
Currently
328,309
602,381
239,646
215,506
168,485
106,820
38,055
24,580
11,530
31,100
3,500
1,400
4,600
0
Cumulative
Coverage
495,541
1,996,000
3,321,091
4,022,141
4,921,715
5,510,613
5,787,193
6,168,696
6,324,529
6,572,925
6,723,052
6,747,592
6,787,653
6,805,000
No. of
Traps
In use
4,000
17,000
18,100
34,157
39,503
45,060
45,801
45,026
47,810
48,760
36,978
27,757
23,722
25,197
Flies
Per 1,000
Trap-Days
122,500
7,490
3,780
0,882
0,475
0,161
0,027
0,037
0,051
0,033
0,002
0,001
0,004
0
aHernado (last county found infested) added.
Insecticide applications completed in all eastern and southern counties.
cFinal eradication in all counties except Hillsboro, Lake, Manatee, Orange,
Pasco, Pinellas, and Polk.
Source: Steiner, L. E. et al.
366
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The bait sprays greatly suppressed house flies and mosquitoes
also. Some species of tropical fish in very shallow water were susceptible
to the small amounts of malathion in the bait spray. Apart from this draw-
back, the eradication program was relatively safe compared to conventional
aerial sprays, and was very effective. ''
b. Synthetic Pheromone of the Boll Weevil
Two terpene alcohols and two terpene aldehydes from male boll
weevils, Anthonomous grandis Boheman.were isolated and identified at the
Mississippi State University in 1969. ° These compounds are the compo-
'!•
nents of the pheromone to which only female boll weevils respond in labo-
ratory tests. In bioassays, mixtures containing all four compounds elicited
a response by females equivalent to or better than that elicited by live
males. ?9 Absence of either alcohols or the two aldehydes from the mix-
ture resulted in almost complete lack of response. The response to mix-
tures of synthetic compounds was identified to that obtained from corresr
ponding mixtures of natural compounds. The extract of fecal material
of boll weevils (both male and mixed sexes) produced a material highly
attractive to females but not to males.
The synthesized pheromone was names Grandlure. This compound,
however, had a very short life. Polyethylene glycol increased its life.
Rfi
This stable product became a tool in surveying boll weevil infestation.
c. Virgin Female Traps for Introduced Pine Sawfly
The Pine Sawfly (Diprion similis) is a pest of eastern white pine.
Once it was observed that large numbers of males swarmed toward females.
Investigations were conducted to determine whether a sex attractant was
involved. The wooden traps used consisted of a box (12 X 6 X 1 inches)
with a 2 I/2-inch screened opening in the center, A virgin female was
placed in the screened portion and Tanglefoot was spread over the. wooden
portion. The traps were suspended from trees in infested areas. An
average of 1, 000 males were attracted in each of the eight traps. Large
367
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numbers of males also fell to the ground. Some females did not attract
males for an unknown reason. The male response was rapid. Many
approached within 30 seconds after the traps were set-up. Traps set-
up at an angle of 90 degrees to the wind direction at the edge of the woods
were consistently more attractive than those set in dense woods. Greatest
activity took place from midmorning to sunset. One trap with a virgin
female exposed from 11 a.m. to 4 p.m. attracted more than 7, 000 males.
She continued attracting males at approximately 1, 000 per day until she
died on the fifth day, after which small numbers were caught for the next
three days. Males were lured 200 feet from the forest over an open field.
Chernosterilant-attractant mixtures can be effective in reducing or eradi-
cating a field population of this insect. ?4
d. Sex Pheromones of the Southern Pine Beetle
and Other Bark Beetles
Epidemics of the southern pine beetle, Dendrochonus frontalis Zimm.,
have occurred periodically throughout the outheast and in parts of Texas.
The standard procedure developed in response to this problem involved
aerial detection of infested pines over intervals of several weeks, followed
by confirmation on the ground and actual control. The control techniques
consisted of cutting and spraying infested trees with benzene hexachloride
(BHC) in water or oil. The trees most recently infested were cut and
sprayed first. This was to interrupt the otherwise continuing aggregation
of the southern pine beetle population in response to the attractants emanating
from such standing, freshly attacked trees. The control effect on individual
infestations appeared satisfactory but research revealed that although the
southern pine beetles did not aggregate on sprayed and felled timbers, their
predators did. Despite very diligent and persistant efforts the BHC-con-
trol failed to affect the overall population level. The results of further
research suggested that the prescribed control method was in fact, more
effective against predators, parasites and competitors of the souther pine
beetle than the target insect; so BHC-control was largely abandoned in
early 1969. The subsequent rapid decline of the southern pine beetle
368
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epidemic undoubtedly had a complex cause. The elimination of insecticides
may account for subsequent resurgence of predators.
A method presently being tried uses Frontalure [l, 5-dimethyl-6,
8-dioxabicyclo (3. 2.1) octane, the sex pheromone and 2 parts of d-pinene]
to aggregate southern pine beetle populations on the trees to be harvested
and/or treated with cacodylic acid, which checked brood development but
does not harm non-target insects. In fact, the simultaneous aggregation
and survival of predators and competitors has become an integral part of
this method.
The new method depends, like prior measures, on aerial survey
detection of southern pine beetle activity. Infestations, however, can be
treated immediately by the crew performing the ground check. Few tools
are needed and the amount of chemicals deployed does not surpass gram
quantities per acre. The reduction in labor in comparison with former
control measures is considerable and environmental pollution is avoided.
The recommended technique involves the following steps:
• The cause, extent of damage, and the number of pines contain-
ing an active brood of southern pine beetle are determined.
• Two to ten non-infested pine trees, near the most recently at-
tacked trees in active infestations, are selected for baiting
with Frontalure. Two pines seem to be adequate for small
infestations, but at large spots of infestations, up to ten trees
are baited. Six caps containing 1 ml. of Frontalure are at-
tached on each tree around the circumference at a convenient
height. The large trees are preferred.
• The brood is destroyed by injecting cacodylic acid into baited
trees and the adjacent trees within 15 to 25 ft., provided these
are 6" or more in size (Diameter at breast height of DBH).
Cacodylic acid is applied in closely spaced frills made with an
ax, at least one foot above the ground. The total number of
trees present in the spot.
• This treatment is followed after two or three weeks with either
salvage of the treated and infested timber or re-check of the
infestation, and repetition of the procedure where necessary.
This 'ground-checking control1 is a typical example of the point
application of population attractants and especially suits the forestry prac-
tices of the large pulpwood industry in southeast. ^
369
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Attractants and related agents may be used in several ways for con-
trolling insects, as well as for gathering fundamental information about
pest population, which might lead to their control. By their use in prac-
tical control programs, insects may be lured into traps and then killed by
an insecticide or by adhesive, etc. , or a culture of pathogens may be
mixed with an attractant or feeding stimulant to destroy the pest. A
chemical may also be used to attract large numbers of insects that can be
sterilized and released among the native population to reduce pest numbers.
Attractants are increasingly finding such uses.
8. Insect Hormones
Scientists are looking for new chemicals to control pests. These
should be specific to only a given pest species, non-toxic to man and domes-
tic animals, biodegradable, and of such a nature that pests will not be able
to develop resistance.
One approach involves our rapidly expanding knowledge of how
insects rely upon hormones to regulate their growth, feeding, mating, repro-
duction and diapause or over-wintering. '" The primary candidate is the
Juvenile hormone that all insects secrete at certain stages in their lives. 82
Therefore, the potential utilization of this information for insect control
depends upon the ingenuity with which man can supply a Juvenile hormone
to the insect at an unfavorable stage. The contact of a last-stage nymph,
larva or pupa with a Juvenile hormone induces morphogentic damage. This
results in the development of intermediates or monsters which are unable
to mature and die in a short time.
Subsequent investigations have revealed other important function
of the Juvenile hormone in insects such as, diapause, reproduction, embryo-
ijf
genesis, sex attractant production, and lipid metabolism.
The synthetic Juvenile hormone analogue, Trans, Trans 10, 11-
Epoxy farnesenic acid methyl ester successfully terminated adult diapause
in several species of Hemiptera, including the box elder bug and the red
370
-------
linden bug. ®^ Juvenile hormones are unquestionably deeply involved in
the regulation of diapause and the possibility exists that more research
may result in the development of antihormones which can prevent or
even induce diapause.
A male pyrrhocoris treated topically with 1 mg of dichloride com-
pound, synthetic Juvenile hormone, is able to transfer enough of this
chemical to females by contact during mating to induce sterility. This
novel method of transmitting sterility should have interesting field applica-
tions if similar chemicals affecting insects other than Pyrrhocoris are
developed.
Williams 82 believes that synthetic Juvenile hormone eventually
will prove to be most effective as an egg killer (ovicide).
Ecdysone is another insect hormone which has the potential of
becoming a selective insecticide. This substance initiates ecdysis (shed-
ding of skin) or metamorphosis from one stage to another in the larval or
nymphal development of insects. Over stimulation with ecdysone results
in repeated metamorphosis without sufficient time for the accumulation
of food reserves so that eventually the larva or nymph becomes exhausted
and dies.
From the foregoing it is obvious that the application of morphogene-
tic compounds to immature insects can kill them by upsetting their develop-
ment. The practical utilization of these compounds becomes attractive
with the realization that these hormonal effects are specific to insects.
In addition, these chemicals have no effect on other forms of life. '"' °^
A further advantage is that insects cannot develop immunity against the
compounds for if they did, they would become immune to the hormone
that is essential to part of their life cycle. Since this discipline of pest
control is still little explored, specific case studies are not available.
371
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9. Integrated Control
Integrated control combines several agronomic practices and
pest control methods. The total effect of these combined methods is
synergistic rather than additive; not only does it reduce the pesticide
pollution problem, but the control obtained is more effective. Integrated
QC
control is predicated on fundamental ecological principles. The con-
cept includes appropriate combinations of pesticides, natural enemies,
29
insect pathogens, and cultural treatments, etc.
The first principle emphasizes the ecosystem which includes
the complex of organisms, the culture of the crop or animal and the
environment. The second principle stresses economic levels. It
concerns the population levels at which the pest species cause harm,
damage or constitute a nuisance, and measures directed to keep them
below detrimental economic levels. The third principle emphasizes
the importance of avoiding disruptive actions. Measures must be designed
to give adequate control in a manner which does not upset some other part
86
of the ecosystem.
a. Integrated Control of Cotton Boll Weevil in Southeastern States
A large scale experiment is currently underway to eradicate
the cotton boll weevil, a meanacing and costly pest of cotton, in the
southeast. The test area is 150 miles in diameter and is located around
Gulfport, Mississippi. This two-year study runs to July 1, 1973.
At that time researchers will have determined if eradication is feasible,
and what the cost will be. Presently it is estimated that the total cost
of eradication might be about $275 million.
For the first time treatment involves at least six simultaneous
operations. These include in-season spray as needed; a series of repro-
duction - diapause sprays in the fall to prevent overwintering; defoliation;
stalk shredding; and pheromone traps for males to prevent reproduction
372
-------
by surviving males. In addition, continued experiements with Frego-bract
weevil resistant cotton, and temik systemic insecticide will be part of
the research. The chief weapon will be diapause control by a series of
up to seven fall sprays applied mainly by five helicopters in the core
zone, Columbia, Mississippi, and the first buffer zone, spilling over
slightly into Alabama and Louisiana. Properly timed, this treatment
can kill up to 99 percent of weevils entering hibemat ion. Chemicals
used will be ultra-low-volume Guthion or Malathion, depending upon
the environmental hazard involved. Next spring, adhesive-coated traps
baited with Grandlure will be placed on fencelines. These traps should
catch about 80 percent of emerging weevils. A single application of
insecticide before square drop should kill about half of the surviving
weevils, without permanently suppressing beneficial insect popullations.
The sterile males will then be released at 50 to 200 per' acre for several
generations, and theoretically should reduce the native population by
4 87
98 percent with each generation. ' If the eradication of the boll weevil
should eventually be possible at a cost comparable to the annual losses
for just 1 year, such a program w uld be one of the best investments the
cotton industry could make. Perhaps even more important, the elimination
of this insect would be the greatest single contribution that could be made
in the foreseeable future toward the goal of reducing environmental
pollution caused by the use of broad spectrum insecticides.
b. Integrated Control of Heliothis
Recent theoretical studies not yet published suggest that the mass
production and programmed releases of one or more species of selective
Heliothis larval parasites coxild also provide an effective and highly
selective means of managing Heliothis populations. Relatively little
is known about the numerical relationship between parasites and their
hosts. However, based on a theoretical appraisal, there is good reason
to believe that it is well within the realm of feasibility to mass produce
and release sufficient selective parasites to truly manage insect populations
373
-------
like the Heliothis species. This system of insect population management
should have its maximum efficiency when the host insect population is
high and should have diminished efficiency when it is low. This is just
the reverse of the potential efficiency of the genetic approach. Therefore,
the parasite release technique and the genetic technique may eventually
prove to be highly complementary when they are integrated into one system
4
of suppression. Insect pathologists are making considerable progress
in developing microbial agents which may further strengthen their integrated
approach.
c. Integrated Control System for Tobacco Horn
North Carolina
Control of Hornworms on Tobacco, Protoparce sexta (Hohan),
and P. quinquemaculata, with insecticides is not completely satisfactory
in North Carolina. When Polistes wasps were induced to nest in shelters
erected around the field, populations of fifth-instar hornworms were re-
duced by about 60 percent and damage by 76 percent. One-fifth the
recommended rate of insecticides TDE or Endrin, applied as top sprays
gave reliable and adequate control of both hornworms and budworms.
This was true whether applied every two weeks on a preventive schedule
88
or only when counts indicate treatment was needed. Such an integrated
program would be more economical than present systems and would
reduce residues to a fraction of the present levels.
d. Integrated Control of Muscid Flies in Poultry Houses in
Kentucky
Control of the house fly, Musca domestica 1. , and little house
fly, Fannia canicular is (L. ),in poultry houses was studied in an integrated
control system in Kentucky employing the predator mites, Macrocheles
musaedoemsticae (Scopoli) and Fuscuropoda vegetans (De Geer), fly
374
-------
larvicides and fly poisbned baits. Baccilus thuringiensis Berliner was
the most harmless to the mites. Diazinon gave consistent reduction
of fly larvae and was relatively harmless to the mite populations. A
parasite nematode, Neoplectana carpocapsae Weiser, was ineffective
largely because of its succeptibility to desiccation. Adult flies were
89
effectively controlled with the use of liquid poisoned diazmon baits.
e. Integrated Biological and Chemical Control of Aquatic Weeds
in Florida
The introduction of the beetle (Agasicles sp.) as a biological
control agent has been an added deterrent to the growth of alligatorweed
(Althernanthera philoxeroides Mart. Griseb.) through the Atlantic Coast
states. However, floating mats have been controlled in only very small
local areas where herbicides have not been used. The recommended
chemical control of alligatorweed is 2 or more treatments of silvex
£2-(2, 4, 5-trichlorophenoxy) propionic acid] at 8 Ib/A. Alligatorweed
may be controlled with less herbicide in the presence of large populations
of alligatorweed flea beetles. A dense mat of alligatorweed was treated
with 6 Ib/A of silvex and a beetle population of one adult per 2-sq ft
of mat was introduced when regrowth was 2 to 5" high. The beetles
showed a feeding preference for the young regrowth over the more mature
nontreated alligatorweed and maintained sufficient feeding pressure to
90
eliminate the floating mat growth.
Integrated .control today has acquired a wider interpretation than
was proposed 15 years ago. Broadly, it refers to integration of all
crop protection procedures. The acceptance of such an approach of
pest control is widely accepted by agriculturists and environmentalists.
Integrated control programs in general required a higher level
of scientific background when compared to chemical control. At least
a minimum level of information is usually needed regarding the following
points: the general biology, distribution and behavior of the key pests;
an approximation of the pest population levels that can be tolerated without
375
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significant crop loss; a rough evaluation of the times and places of
occurrence, and the significance of the major predators, parasites,
and pathogens present; information on the impact of the use of pesticides,
insecticides, herbicides, and fungicides, as well as other control
measures on natural enemies, and on natural and agroecosystems.
10. Miscellaneous Methods
a. Seed Laws
One of the methods by which weeds spread is through their in-
clusion with crop seeds. As early as 1821, Connecticut passed a law
prohibiting the sale of grass seed containing Canada thistle and other
weeds. The earliest vegetable seed laws were adopted by Florida in 1889.
91
By 1941 all 48 states had seed laws. The federal seed act requires
in part that the following information be provided on seed labels in
interstate commerce: percentage of pure seed of the named crop,
percentage of other crop seeds, percentage of weed seeds, and the
rate of their occurrence. Crop seeds cannot be sold for seeding purposes
in most states if they contain noxious weeds in exceed of a specified
percent by weight of weed seeds, generally two or three percent.
The model state seed law, used as a guideline for legislation
by many states, provides a typical example of state regulations.
Noxious-weo;d seeds are separated into two classes: prohibited (generally
annuals) and restricted (seeds of perennial weeds).
Seed laws at state and federal levels have been important in
91
reducing the spread of weed species and in improving seed quality.
b. Seed Certification
Seed certification is the system used to keep pedigree records
for crop varieties and to make available sources of genetically pure,
disease-free seeds and propagating material for general distribution.
Without such a system, seeds tend to become contaminated and mixed
and lose identity. Certified seeds contain relatively fewer weed seeds.
376
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Drill-box surveys of the quality of field crop seeds planted by
farmers has indicated that seed suppliers have not kept pace wi th the
strides that have been made in developing better seed-cleaning machinery
and knowledge of seed processing. Only about five percent of seeds were
certified and they were found to contain 1. 2 weed seeds per pound, in
comparison with 160 weed seed per pound for non-certified seeds
purchased from dealers or taken from farmers bins. Although seed
certification programs have direct control over only a small percentage
of the small grain that is planted, their beneficial effect on quality of
seeds planted by farmers will grow through continuing seed certification
92 7
and educational program. '
c. Disease Control through Virus-free Stock
There are at present no practical and economical treatments
to cure virus-infected plants in the fields. Methods of control, therefore,
are generally directed toward preventing infection by eliminating the
source of inoculum, by preventing spread of virus, or by developing
varieties immune to the virus or immune to disease they cause. The
production abd distribution of "virus-free" propagating material
has proved highly successful in controlling virus diseases in many
crops. The term virus-free can be defined as free from the known and
specified viruses for which tests have been conducted.
The tactics of virus control depend upon integration of several
distinct activities:
• The recognition and characterization of the virus diseases in
each crop
• The development of reliable indexing methods to retrieve any
existing healthy stock, to sort plants that have been treated
to eliminate virus, and to detect any symptomless carriers
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* The development of techniques to rid a few selected plants of
virus and establish clones of virus-free foundation stocks
•where no healthy material is found.
• The enactment of measures such as certification program to
maintain the health of foundation stocks, and to secure
effective distribution of their progeny to growers and
nurserymen.
In the United States certification programs are individual state
functions. A certification program for virus-free citrus stocks is
presently used in Florida. Such programs tend to keep a control on the
18
known viruses of crops propagated from vegetative stocks.
d. Quarantine and Regulatory Controls
In agriculture, quarantine refers to the restraints or restrictions
placed upon the transportation of animals, livestock, poultry, plants,
fruits and vegetables, plant and animal products or other materials which
are suspected of being carriers of agricultural pests. Such precautions
are necessary as many of the worst plant pests came from other countries
and thrieved here because of abundant food and few natural enemies.
The tempo of international travel has greatly increased and with it the
danger of spreading pests has greatly increased. Quarantine system is,
as such, a necessary element of overall national preventive pest control
93
programs.
Domestic quarantines between states, combined with treatment
programs , have eliminated several pests from the United States.
For example Japanese beetle, Popillia japonic a Newman has been under
continuous regulation in the United States since 1919. Established
infestation still doesn't exist west of the Mississippi River, and occurs
only in siolated areas in the southeast. Control and quarantine programs
have confined the gypsy moth, Prothetria d Is par (Linn.) to a few north-
eastern states although there are some 100 million acres west of the
8
Mississippi River known to be susceptible to attack.
378
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Publicly supported regulatory programs are an essential part
of the overall effort to protect crops and livestock from pests. Various
methods are used in eradication, containment and suppression programs;
there include chemical, cultural and biological measures. Greater
merit is indicated for large scale alternative control programs as
compared to region-wide chemical spraying. Many of the alternative
techniques of pest control are employed on larger areas than individual
farms. Programs of state and federal agencies in cooperation with
private agencies and farmers will be required in pest control.
e. Pest Surveillance
The detection of pests and surveys of their distribution and
abundance are essential prerequisites to rational control programs. The
first principle of pest detection and surveys as related to control is
that no control measures should be undertaken against a pest unless it
is known that the pest is actually present. In many instances, this
principle is not followed. Many farmers often follow a strict schedule
without bothering to determine whether the pest is actually present. This
is partly attributed to the lack of appreciation of the merits of pest
assessment. The second principle of pest detection is that no control
f ' •
measures should be undertaken unless it is known that the pest is
present in sufficient numbers to cause economic loss.
In 1971, cotton insect scouting programs have been conducted
in ten states (Alabama, Arkansas, Georgia, Mississippi, Missouri,
North Carolina, South Carolina, Texas and Louisiana). A total of 628
scouts were trained. They scouted 877,225 acres out of 10,421,000
acres under cultivation. Scouting programs have been in operation for
nine years in Alabama. Scouted cotton fields have averaged 200 more
pounds of lint per acre than fields not scouted. A scout who has received
special training by an extension service entomologist can keep growers
informed of the following;
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• When the infestation count is great enough to warrant starting
a control program
• When to expect hatchout of boll weevils or bollworms
• How long to continue the control program into the fall
Scouts give farmers weekly written insect reports and also send
infestation reports to county extension chairmen and to extension entomo-
logists. Each week, reports are summarized and a copy sent to all
94
county extension chairmen and other agriculturists in the state. Although
no data are available about the actual percent reduction in the pesticide
used, it is estimated that a considerable number of unnecessary pesticide
applications can be avoided without loss in economic returns. This
can only be effective if large areas are brought under surveillance.
Sufficient understanding of pest ecology and biology exists so that such
programs can be initiated now. Extension services and agricultural
universities can play an important role in such activities.
f. Genetic Manipulations
The first attempt at control by the application of genetics to
decrease fitness involved the tsetse flies, Glossina sp. Interspecific
crosses were made of Glossina swynnertoni and the reproductively
but not sexually isolated G, morsitans. Viable but sterile offspring
were obtained from such crosses, which competed with normal individual
57
for survival in the environment.
Many lethal genes exist in populations of insect species that have
been subjected to genetic analyses. Deleterious genes need not be lethal
nor act immediately for effective control. Drastic reductions in insect
numbers can be obtained theoretically by constant low-level mortality
factors superimposed on populations already exposed to the stress of
380
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adverse environmental conditions as, for example, low temperature
during hibernation. Three requirements are essential to the success of
control measures utilizing the release of strains carrying unfavorable
genetic characters: the factors must not prevent rearing under laboratory
conditions; they must not interfere with mating ability; and they should
act at particular times, such as during hibernation or immature stages.
It has been postulated on theoretical grounds that the eradication of
the boll weevil, Anthonomus grandis, could be achieved in a few years
if males carrying two lethal genes were repeatedly released into field
populations. It should be considered that such additional release of
pests could temporarily increase the loss of the crop until lethal genes
are inherited and come into effect.
Although genetic methods seem to offer promising leads, considerable
work is needed before such techniques can be incorporated at a practical
level.
g. Development of Safer Pesticides
It is widely accepted that although alternative technology exists,
conventional chemicals will remain the chief means of insect pest
control for the foreseeable future". ' An explanation for this lag in the
use of alternative methods merits explanation. There has been a growing
concern over certain known and potential threats to the quality of our
environment because of the use of the broad-spectrum pesticides. This
concern however, has not been fully translated into increased commitment
of resources toward search, development or large-scale testing of alter-
native methods. The United States must be prepared to support substantially
larger expenditures from its resources if there is to be great progress
in correcting or alleviating many pesticidal pollution problems, utilizing
and boradening our knowledge of alternative pest control technology and
development of safer pesticides. The time factor is also involved
as regards ecological aspects, alternatives need to be developed soundly
381
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after elaborate trials. It requires several years to perfect these techniques
prior to use at a national or regional level. Such practices in a strict
sense, must not be considered as alternatives to total pesticide usage,
but rather, means for the more effective use of pesticides.
Most of the chemicals widely used for agricultural pest control
have been selected on the basis of optimum effectiveness against the
pest and for maximum persistence. The original DDT patent of 1939
covered a number of insecticidal analogs. ' These included methoxychlor,
ethoxychlor and methychlor. All of these compounds are persistent
insecticides effective against a wide spectrum of insect pests and they are
relatively inexpensive. However, DDT is the most stable and has had
extensive use, whereas methoxychlor has been used on a modest scale,
and ethoxychlor and methylchlor not at all. These DDT-related compounds
are rapidly degraded by the multifunction oxidases of higher animals
and converted to water soluble compounds. DDT is not. Similarly, the
related compounds are less toxic to fish. Ethoxychlor, methychlor and
other biodegradable derivaties of DDT merit further investigation as
replacements for DDT and other persistent and non-biodegradable
chlorinated hydrocarbons. Similar safer analogs (fenthion, ronnel,
dicapthon) exist for methyl parathion, the most commonly used organic
phosphate insecticide. 'Attention is being given to the effect on wildlife
of pesticides. Further consideration should also be directed toward
the effect of these pesticides on the natural enemies of pests.
A questionnaire survey was conducted by the 1970 National
Agricultural Chemicals Association.9 ^This is a trade organization
representing most of the U. S. pesticide industry. When asked to
reply in their words as to the most important obstacles to the develop-
ment of safer, less persistent and more selective pesticides, the following
reasons were listed (the number in parehtheses indicating the number of
382
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times each item was cited): high cost of research and development in
terms of money and time (11); lack of knowledge of basic plant and animal
biochemistry (4); competition from existing, non-selective, relatively
inexpensive pesticides (4); lack of grower interest, high cost of selective
products that grower is unwilling to pay (3); cumbersome government
registration procedures, especially slowness and procrastination in
handling of petitions (1), unscientific approach (1), and stringent
requirements (1); fear of consumer complaints and litigation (1); lack
of interest, support, and experience on part of agricultural workers (1).
The next question was also unstructured and asked what steps
might be taken to remove the restraints described under the preceding
question. The following suggestions were made (the numbers in
parentheses again indicating the number of times each item was cited):
design better and more efficient screening, testing, and development
methods to reduce development time and cost (4); modify registration
requirements to reduce development time and cost, speed up processing
of registration applications (3); create a less emotional, more objective
public attitude toward pesticides (3); provide for a patent life of pesticides
more in line with their commercial usefulness, recognizing the long
time required for research, development, and initial registration
(2); provide economic incentives to manufacturers (2); increase basic
physiological, biochemical, and ecological know-how (1); educate
agricultural workers, and regulatory agencies that the purpose of pest
control is not destruction of pests, but protection of crop yield (1);
define levels of pesticide persistence that are necessary and safe (1);
limit manufacturers' liability to proven fault in his product (1); cease
97
diverting manpower to the defense establishment (1).
383
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If chemicals are to be used in a harmonious manner in the agro-
ecosystem then we must have materials that are inherently selective
or we must learn how to use them so that their effects are selective.
All pesticides have some selectivity but the range in degree of selectivity
is very great. Much effort has been expended in seeking materials
with relatively high toxicity to invertebrates and low toxicity to mammals.
We must also seek differential toxicity within the arthropods (insects).
We do not need the ultimate in specificity that would permit us to prescribe
a specific chemical for each pest species. However, we do need materials
that are specific for groups of pests such as aphids, locusts, lepidopterous
larvae, weevils, and so forth. As shown above, there are some indications
that we can have some materials with such specificity and still have
them economically feasible from the viewpoint of the chemical industry.
98
Also, there are indications that safer chemicals can be synthesized.
Somehow, the imperative need to replace older and obsolescent agents
with substances having more desirable properties has not been forcefully
transmitted to the agricultural and pest control industries. At least
development and widespread use of selective pesticides has not been
encouraged. There is an increasingly regrettable tendency to develop
and market nonselective insecticides which are more and more toxic
to higher animals and man, as well as beneficial and harmful insects.
There is always likely to be a need for some chemical pesticides
if we are to provide for the needs of the human society. Risks of their
usage must be minimized and supplemented with other pest control
methods.
Through greater cooperation between public and private sectors
and by legislation of adequate laws, excessive reliance on broad spectrum
pesticides can be reduced. Creation of a situation where voluntary
information and resource exchange exists can solve the problem of
384
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erratic and short term pesticidal control. Only in such an atmosphere
can alternative methods be further developed and utilized. As with other
pollution problems, solution of pesticidal dilemna will require a carefully
chartered course, consolidated effort and a national commitment. The
magnitude of this problem should motivate the country toward an intensive
action program at the grass-roots level.
385
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11. Conclusions
Cultural methods of control (sanitation, tillage, dates of planting
etc. ) along with the use of resistant crop varieties is the farmers first
line of defense against pests. These practices considerably reduce but
do not eliminate the need for other pest control methods. For certain
pests, such as many plant viruses and nematodes, chemical treatment
is neither feasable nor economical. In such cases, physical, mechanical
and regulatory (quarantine and certification) methods are utilized to
reduce or prevent pest populations.
Many major economic pests in the United States have been
introduced from other countries without their natural parasites and
predators. Importation and release of these natural enemies have
proved to be effective in suppression of pests in some cases. Broad
spectrum pesticide applications have the adverse effect of destroying
the natural enemies of insects thus eliminating a natural check on
pest populations in agricultural ecosystems.
Efforts toward the development of biological control agents
(virus, bacteria, protoza, fungi, nematodes attacking insects) may
result in safer and specific pest control practices. Similarly numerous
insect hormones (e. g. juvenile and ecdysone) have the potential of being
utilized as selective insecticides.
Many insect attractants have been characterized and developed to
lure insects into traps containing pesticides, pathogens and
chemosterilants. Chemical and electromagnetic radiation (light traps)
attractants also provide for early detection and location of insect-
infestation. This is an important component in integrated and pest
surveillance programs.
386
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Eradication of selected insect species has been achieved by
releasing sterile males to compete with the fertile ones in the natural
environment. This method of pest eradication is successful only if the
natural insect population is low. In such cases, the sterile males
"overwhelm" the fertile males. Expanded use of this technique has been
restricted by high cost and logistic factors. Sterilization of the natural
pest population by chemosterilants could reduce such time and cost
factors.
Integrated control is a pest population management system that
employs several suitable techniques to reduce pest populations and
maintain them at levels below those causing economic injury. This
method provides the best solution to a pest problem because all possible
controls are first evaluated. This approach requires ecological
information, pest threshold and economic injury levels.
To date, public and private efforts in pest control have been
directed toward development of pesticides with little effort being
directed to alternatives. There is little inducement for industry to
develop alternative methods until large-scale pilot studies have been
proven successful. Pesticides will continue to be used in the foreseeable
future. Alternative methods, if further developed and applied, can
reduce excessive dependence on broad spectrum pesticides.
12. Recommendations
1. A set of national priorities must be established by 'the U. S.
Department of Agriculture for developing alternative methods of pest
control beginning with those situations which utilize the largest
quantities of broad spectrum, persistant pesticides.
2. U. S. Department of Agriculture, through its Extension Service,
should expand its role of judicious use of pesticides. A complementary
activity and one of the methods which could considerably reduce the
amount of pesticides applied is increased crop surveillance.
387
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3. The Agricultural Research Service of U. S. Department of
Agriculture should receive greater support for large scale field
testing to determine the effectiveness of promising alternative methods
of pest control. Successful programs can then be adopted regionally
to eradicate,, reduce or maintain pest populations below economic
injury thresholds. Pest control at the farmer level should be
reevaluated in order that part of the pest management programs can be
conducted on the entire pest infestation region.
4. Fundamental research should be supported by U. S. Department of
Agriculture and the Environmental Protection Agency which elucidates
basic life processes. Such understanding is to provide the basis for
improved pest management with minimum disruption of the ecosystem.
5. Educational training at the farm level in pest surveillance, integrated
control, population dynamics and ecological aspect must be expanded.
6. Federal and state governments must drastically increase their
financial support if alternative methods are to emerge as effective
methods of control and management.
7. Protocols for safety tests of microbial.pesticides and hormones
should be defined by the Food and Drug Adminstration so that researcher
as well as prospective producers will be guided by common requirements
8. The U. S. Department of Agriculture in conjunction with other
governmental agencies and scientific organizations should seek greater
international cooperation in minimizing pest migration and in developing
biological control and alternatives to pesticides.
388
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13. Ref e rences
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Physical and Selected Chemical Methods, New York, Academic
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2. Rudd, R. L. , Pesticides and the Living Landscape, Madison,
University of Wisconsin Press, 320, 1966.
3. DeBach, Paul, The Scope of Biological Control, Biological Control
of Insect Pests and Weeds, New York, Reinhold Publishing,
3-18, 1964.
4. Knipling, E. F. , Use of Organisms to Control Insect Pests, J.
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10. Johnson, H. W. , Development of Crop Resistance to Diseases and
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References (continued)
12. Newsom, L. D. and Brazzel, J. R., Pests and Their Control,
Advances in Production and Utilization °£ Quality Cotton, Ames,
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13. Presley, J. T. and Bird, L. S. , Diseases and Their Control in
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14. Holstun, J. T., Jr. and Wooten, O. B., Weeds and Their Control
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15. Hartsock, J. G., Deay, H. D. , Barrett, J. R. , Jr., Practical
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References (continued)
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29. Stern, V. M. , Smith, R. F., Van Den Bosch, R. , Hagen, K. S. ,
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38. Muma, M. H. , Natural Control of Florida Red Scale on Citrus in
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39. Clancy, D.W., Shelhime, A. G. , and Muma, M. H., Establishment
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47. Garner, G. R. and Canerday, T.D. , Entomophthora Species as
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72. Jacobson, M. and Beroza, M. , Chemical Insect Attractants,
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74. Jacobson, Martin, Insect Sex Attractants, New York, Interscience
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76. Jacobson, M. and Crosby, D. G., Naturally Occurring Insecticides,
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A. C., Hedin, P. A. and Minyard, J. P. , Sex Phermones Produced
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Isolation Studies, J. Econ. Entomol. j6J_, 470-4, 1968.
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Studies of an Integrated Control System for Hornworms on
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396
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Certification in United States, U.S. Department of Agric. Yearbook,
394-401, 1961.
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D.C., President's Science Advi. Comm. , 230-91, 1965.
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97. Rumker, R. von, Quest, H. R. and Upholt, W.M., The Search
for Safer, More Selective and Less Persistent Pesticides,
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272, 644-47, 1971.
397
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APPENDIX
398
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BRIEF OF
STATE OF NORTH CAROLINA
SCOTLAND COUNTY COURT
State of North Carolina vs. Stanley Svrlin o, 1953
The defendant, Stanley Svrlingo, a resident of the State of Florida,
was charged with engaging in the custom application of pesticides within
Scotland County, North Carolina without a license issued by the Com-
missioner of Agriculture as required by North Carolina General Statutes,
Chapter 106, Article 4B, Section 65. 14. The term, "custom application
of pesticides" is defined in the law to mean any application of pesticides
by aircraft.
The defendant was the operator of a Steerman aircraft. He was
warned by the enforcement officer that he could not engage in the custom
application of pesticides without a license. The following day the enforce-
ment officer who had warned the defendant personally observed that the
aircraft operated by the defendant was dusting a cotton field.
Evidence collected by the State of North Carolina included the
eye witness testimony of the enforcement officer, farmers who had con-
tracted for service by the defendant and cancelled checks of farmers who
paid earlier for dusting services by the defendant.
Conclusions
A warrant was issued for the arrest of the defendant. Bond in
the amount of $25 was set and posted. At the time of the trial, the
defendant did not appear. The defendant was observed in North Carolina
the following year but the Scotland County solicitor refused to reopen the
case.
399
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BRIEF OF
STATE OF NORTH CAROLINA
MARTIN COUNTY COURT
State of North Carolina vs. Walter Ray Griffin, 1956
The defendant, Walter Ray Griffin of RFD Greensboro, North
Carolina, was charged with engaging in the custom application of pesticides
without a license issued by the Commissioner of Agriculture. The
defendant was charged with violating Chapter 106, Article 4B, Section 65.14
of the General Statutes of the State of North Carolina.
Private-individuals advised enforcement authorities that an
advance agent (spotter) was contacting farmers in Martin County to
arrange business contracts for the aerial application of pesticides by
the defendant.
Evidence was obtained by subpoena of the advance agent and sev-
eral farmers. The records of several farmers were obtained which
indicated the number of acres sprayed by the defendant using a J-3 Cub
aircraft and the amount of dollars paid to the defendant.
Conclusions
The defendant entered a plea of guilty and was convicted. The
sentence required the defendant to pay a fine of $100 plus the court cost.
400
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BRIEF OF
STATE OF NORTH CAROLINA
WASHINGTON COUNTY COURT
State of North Carolina vs. Delmar Owens, 1957
The defendant, Delmar Owens of Washington City, North Carolina
was charged with violation of Chapter 106, Article 4B, Section 65. 14 of
the North Carolina General Statutes by operating a J-3 Cub aircraft in
Washington County and engaging in the custom application of pesticides
without a license from the Commissioner of Agriculture.
The evidence obtained by the enforcement officials included the
bills sent by the defendant to several farmers, their cancelled checks
and the testimony of several farmers. The defendant was hired by the
farmers to apply pesticides to tobacco and soybean crops.
Conclusions.
The defendant entered a plea of Guilty. The Clerk of the Court
permitted the defendant to satisfy the misdeamor by payment of the court
cost only.
401
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BRIEF OF
STATE OF NORTH CAROLINA
ROCKINGHAM COUNTY COURT
State of North Carolina vs. Jack Reynolds, 1958
The defendant, Jack Reynolds, a native of Candor, North
Carolina, was charged with violation of Chapter 106, Article 4B,
Section 65. 14 of the General Statutes of North Carolina. Specifically,
he engaged in the custom application of pesticide in Rockingham County
by operating a Steerman aircraft in the aerial application of pesticides
without the license required by the cited statute.
The defendant was warned of the requirement for a license by
enforcement officials several times prior to the indictment. Farmers in
the area who had engaged the defendant were subpoenaed by the State.
The records of the farmers and their cancelled checks showing payment
to the defendant were offered in evidence.
Conclusions
The defendant pleaded Not Guilty. He was convicted of violating
the cited statute. The sentence was a fine of $100 plus the court cost.
402
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BRIEF OF
STATE OF NORTH CAROLINA
BEAUFORT COUNTY COURT
State of North Carolina vs. Tom Stancill, 1965
The State of North Carolina indicted Tom Stancill for violation
of Chapter 106, Article 4B, Section 65. 14 of the General Statutes of
North Carolina. The defendant, Mr. Stancill, was charged with en-
gaging in the aerial application of pesticides in Beaufort County,
specifically operating a Piper-Pawnee PA 18 aircraft.
The defendant was a chronic violator who was warned by en-
forcement officials numerous times. Mr. Stancill operates a business
known as Tom Stancill Flying Service.
Several eye witnesses saw him spraying. On indictment he
posted a $200 bond. Evidence included the bills of services rendered
from several farmers, photostats of cancelled checks of farmers who
paid for the services. The defendant was subsequently involved in an
aerial accident during an application flight.
Conclusions
The defendant entered a plea of Guilty with the Clerk of the
Court and exercised his right to a waiver of appearance for a misdeamor.
The Clerk of the Court accepted settlement of $15 fine plus court cost.
403
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BRIEF OF
STATE OF NORTH CAROLINA
BEAUFORT COUNTY COURT
State of North Carolina vs. Merrill Mayo, 1969
The defendant, Merrill Mayo, was charged with engaging in the
custom application of pesticides without a license as required by
Chapter 106, Article 4B, Section 65. 14 of the General Statutes of
North Carolina. Specifically, the defendant as the aircraft owner
failed to obtain a license.
The aircraft was found by investigators in Newburn, North
Carolina as being without a proper license. Both the defendant and
the pilot, Richard Nanney, were informed by the investigators of the
law requiring a license. The following day the investigators found the
aircraft on a dirt strip in the farming area. A farmer informed the
investigator that Mayo's aircraft had sprayed his fields that morning.
Again the pilot was instructed. He subsequently engaged in application
operations witnessed by the investigator.
Conclusions
The defendant entered a plea of Not Guilty. The eyewitness
testimony of the investigator resulted in a conviction. The sentence was
a $100 fine plus the court cost.
404
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BRIEF OF
STATE OF NORTH CAROLINA
BEAUFORT COUNTY COURT
State of North Carolina vs. Richard Nanney, 1969
The defendant, Richard Nanney, was charged under Chapter 106,
Article 4B, Section 65. 14 of the North Carolina General Statutes of
operating an aircraft engaged in the custom application of pesticides
without a license.
The circumstances and testimony in this case are recorded
in the earlier case entitled: State of North Carolina versus Merrill
Mayo, 1969.
Conclusions
This case was tried subsequent to the case of Merrill Mayo.
The defendant pleaded Guilty. The conviction carried a sentence of
a $50 fine plus the court cost.
405
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BRIEF OF
STATE OF NORTH CAROLINA
BEAUFORT COUNTY COURT
State of North Carolina vs. Rodney Godley, 1969
The defendant, Rodney Godley, a native of Beaufort, North
Carolina was charged under Chapter 106, Article 4B, Section 65. 14
of engaging as a contractor for the custom application of pesticides
without a license.
A farmer was prepared to testify that Rodney Godley had con-
tracted for spraying his crops. He had engaged Godley's firm and sub-
sequently witnessed the actual spraying. At the time of arrest, the
defendant posted a $200 bond.
Conclusions
The defendant could not be found at the time of trial. The State
of North Carolina subsequently elected to nol pros the case.
406
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BRIEF OF
STATE OF NORTH CAROLINA
BEAUFORT COUNTY COURT
State of North Carolina vs. Thomas E. Stancil, Jr., 1969
The defendant, Thomas E. Stancil, Jr. , of Beaufort County,
doing business as Stancil Flying Service was charged with violation of
Chapter 106, Article 4B, Section 65. 14 of the North Carolina General
Statutes.
Specifically, Mr. Stancil was charged with operating a Cal-Air
aircraft in the aerial application of pesticides without a license. The
evidence collected by the investigators included bills to farmers sub-
mitted by Stancil for services, cancelled checks of farmers paying for the
custom application of pesticides. In addition, several farmers were
willing to testify that they engage Stancil for custom application ser-
vices and that he did perform these services.
Conclusions
The defendant entered a plea of Guilty. He was convicted and
sentenced to pay a fine of $100 plus the court cost.
407
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BRIEF OF
STATE OF NORTH CAROLINA
HENDERSON COUNTY COURT
5
State of North Carolina vs. Ernest Marshall, 1969
The defendant, Ernest Marshall, a resident of the State of
Florida, was charged with operating an aircraft engaged in the custom
application of pesticides without a license from the Commissioner of
Agriculture. The statutory authority for the charge was cited as
Chapter 106, Article 4B, Section 65. 14 of the North Carolina General
Statutes.
Mr. Jack Atkinson complained to the state investigators that
the defendant did on numerous occasions, spray his land in an in-
tentional discharge from aircraft. These nuisance incidents resulted
in an investigation. The defendant operated a Steerman aircraft and
engaged without proper license in the custom application of pesticides.
Conclusions
The defendent entered a plea of Guilty. An attorney for the
complainant, Jack Atkinson, sat at the trail as a friend of the State.
The judgement of the court was six months sentence of imprisonment
suspended for five years on the conditions that: (1) the defendant not
fly over the property of Jack Atkinson, (2) the defendant not spray within
two miles of the City of Hendersonville, North Carolina, (3) the defendant
not spray within one mile of Jack Atkinson's property, (4) the defendant
not apply any pesticides without a valid license from the Commissioner
of Agriculture and (5) the defendant pay the court cost.
408
-------
BRIEF OF
STATE OF NORTH CAROLINA
BEAUFORT COUNTY COURT
State of North Carolina vs. James Clark, 1969
The defendant, James Clark, a resident of Iowa was charged with
operating an aircraft engaged in the custom application of pesticides
without a license. The charge was a violation of Chapter 106, Article 4B,
Section 65. 14 of the North Carolina General Statutes.
A warrant was issued and bond posted in the amount of $200. A
farmer testified he had been contacted by Rodney Godley, an advance
agent (spotter) and had engaged the services of the firm represented
by Godley. He also testified he had witnessed the actual spraying per-
formed by the defendant.
Conclusions
The defendant entered a plea of Guilty. He was convicted. The
sentence imposed was a $100 fine plus the court cost.
409
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BRIEF OF
STATE OF NORTH CAROLINA
CLEVELAND COUNTY COURT
State of North Carolina vs. James E. Ellis, 1969
The defendant, James E. Ellis, a native of Cleveland, Nqrth
Carolina, was charged with violating the General Statutes of North
Carolina, specifically Chapter 106, Article 4B, Section 65.14.
Several farmers informed the investigator that the defendant had
been engaged by them and did perform the custom application of pesti-
cides. A warrant was issued for the defendant. The case was continued
three times. At the time of the trial the first witness expressed a loss
of memory. At the suggestion of the prosecutor, the investigator
obtained two new warrants. These warrants cited that violation occurred
on the particular lands of each of the two farmers.
Conclusions
The case was continued nine times. The State of North Carolina
enforcement officials informed the county prosecutors they would appear
when the parties were present. Substantial time has passed and the
case has since been nol pressed.
410
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BRIEF OF
STATE OF NORTH CAROLINA
PAMLICO COUNTY COURT
State of North Carolina vs. Daniel Emery Jones, 1970
The defendant, Daniel Emery Jones, a pilot was charged with
engaging in the custom application of pesticides without a license in
violation of Chapter 106, Article 4B, Section 65. 14 of the General
Statutes of North Carolina.
This charge arose from an incident in which the defendant
operated an aircraft for Mr. R. E. King, the aircraft owner. The
defendant sprayed a pesticide containing methyl parathion on a field of
sweet corn belonging to Sam Jones, a farmer, adjacent to a housing
project. It was reported that the spray also landed on several black
residents of a family living in the housing project. The residents got
sick but would not go to a doctor after the investigator requested them
to do so.
Conclusion
The defendant entered a plea of Guilty. The judgement was
that the defendant pay the court cost.
*US. GOVERNMENT PRINTING OFFICE: 1972 723-851/44 1.3
411
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