EPA-540/1 -74-002
July 1974
Farmer's Pesticide Use Decisions
and
Attitudes on Alternate
Crop Protection Methods
Office of Pesticide Programs
Office of Water and Hazardous Materials
Environmental Protection Agency
-------
EPA REVIEW NOTICE
This EPA Report has been revie.wed by the Office of Pesticide
Programs 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.
-------
FARMERS PESTICIDE USE DECISIONS
AND ATTITUDES ON
ALTERNATE CROP PROTECTION METHODS
U. S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF PESTICIDE PROGRAMS
STRATEGIC STUDIES UNIT
401 M STREET, S.W.
WASHINGTON, D.C. 20460
Dr. Jay Turim, Project Officer
Mr. Charles D. Reese, Project Officer
Mr. Jeff Kempter, Project Member
And
COUNCIL ON ENVIRONMENTAL QUALITY
722 JACKSON PLACE, N.W.
WASHINGTON, D.C. 20460
Dr. Warren Muir, Project Officer
1974
Tf.B. "Environmental Prrt-cf:
Kegion 5, ! v ---'" ; - '
£;. ' S, Pcr:>' -.-- -"
Chic-30, -1. c ^
-------
PREFACE
The study on "Farmers' Pesticide Use Decisions and
Attitudes on Alternate Crop Protection Methods" was conducted by
RvR Consultants as Project No. 53, under contract to the Council
on Environmental Quality and the U. S. Environmental Protection
Agency (Contract No. EQC 325). Dr. Warren R. Muir was Project
Officer for the Council on Environmental Quality, and Dr. Jay Turim
and Mr. Charles D. Reese represented the Environmental Protection
Agency.
The study was initiated in July of 1973, and its infor-
mation gathering phase was concluded in January of 1974. The
program has been directed by Dr. Rosmarie von Rttmker, Managing
Partner, RvR Consultants, who also served as principal investiga-
tor. Mrs. Freda Horay, RvR Partner, served as project associate.
She assisted in all phases of the study and handled the tabulation
and processing of the results of a comprehensive survey of Iowa
and Illinois farmers conducted in the project. Mr. L. E. Bailey,
project associate, assisted in field work and led the team that
conducted the personal farmer interviews in Iowa under Dr. von
Rflmker's direction.
Dr. J. C. Headley, Dr. R. L. Metcalf, Dr. W. H. Luckmann,
Dr. H. J. Stockdale and Dr. D. W. Staniforth served as consultants
to the project. Many other persons made valuable contributions,
including 297 farmers in Iowa and Illinois who cooperated in pro-
viding answers to a comprehensive set of questions about their
farming and crop protection practices and information sources.
The final report draft was submitted to the sponsoring
agencies and to several independent reviewers. It has been re-
viewed by 18 experts affiliated with the Council on Environmental
Quality, the U. S. Environmental Protection Agency, the U. S.
-------
Department of Agriculture, the Federal/State Cooperative Exten-
sion Service, and several State Universities.
The authors gratefully acknowledge the project officers'
guidance throughout the study, and the many constructive comments
received from reviewers that were very helpful to the finalization
of this report.
RvR CONSULTANTS
By_
Dr. Rosmarie von Rumker
Managing Partner
10 July 1974
11
-------
TABLE OF CONTENTS
Page
Preface i
Table of Contents iii
I. Summary and Recommendations 1
A. Scope of the Study and Resources Employed 1
B. Pesticide Use Patterns, Side Effects and
Alternatives 1
C. Pesticide Information Flow Patterns 5
D. Pesticide Information Messages 6
E. Applicability of Findings to Other
Crops and Areas 8
II. Introduction 11
III. Production of Corn and Soybeans in the U. S
and in Iowa and Illinois 14
A. Past Developments, Future Trends 14
B. General Characteristics of Farms and
Farmers Interviewed 21
C. Corn and Soybean Production Costs and Prices .... 24
IV. Uses and Costs of Pesticides in the Midwest ...... 31
V. Corn Insects 37
A. Major Insect Pests 37
B. Losses Due to Insects and Benefits
from their Control 38
C. Use Patterns of Insecticides on Corn 42
D. Side Effects from the Use of Corn Insecticides ... 56
E. Alternatives to Chemical Control of
Corn Insects 60
F. Summary 64
VI. Soybean Insects 66
VII. Corn Weeds 69
A. Major Weeds 69
B. Losses Due to Corn Weeds and Benefits
from their Control 69
C. Use Patterns of Herbicides on Corn 74
D. Side Effects from the Use of Herbicides
on Corn 78
iii
-------
TABLE OF CONTENTS (Continued)
E. Alternatives to Chemical Control
of Corn Weeds 80
F. Summary gi
VIII. Soybean Weeds 83
A. Major Weeds '.'.'. 83
B. Losses Due to Soybean Weeds and
Benefits from their Control 85
C. Use Patterns of Herbicides on Soybeans 91
D. Side Effects from the Use of Herbicides
on Soybeans 95
E. Alternatives to Chemical Control of
Soybean Weeds 97
F. Summary 99
IX. Farmers' Sources of Information on Pesticides 101
A. Previous Studies 101
B. This Study 107
1. Receivers' Use and Perception of
Pesticide Information Sources 107
2. Senders of Pesticide Information 114
3. Public Agency Channels 114
4. Pesticide Trade Channels 118
5. Flow Patterns of Pesticide Information 120
6. Pesticide Information Messages 123
a. Information on pesticide selection,
use, costs, and profits 124
b. Information on pesticide side
effects 127
7. Individualized Crop Protection
Information 134
C. Summary 137
X. Literature References 141
XI. Resources and Methods 147
A. Project Consultants 147
B. Survey of Iowa and Illinois Farmers 148
C. Previous Studies 152
D. Other Contacts 153
Appendix A - Question form used in the Iowa and Illinois
farmer surveys.
Appendix B - Notes for interviewers.
Appendix C - Letter from Dr. S. R. Aldrich of 10-22-73.
iv
-------
TABLE OP CONTENTS (Continued)
Table List of Tables Page
1 U. S. Corn Acreage, Production and Value, 1969-1985 . . 15
2 U. S. Soybean Acreage, Production and Value, 1969-1985 . 16
3 Land Use and Major Field Crops in the U.S. and In
Iowa and Illinois, 1972 20
4 Total Acreage Farmed, Tillage Practices, and Corn
and Soybean Acreage Grown by Farmers Interviewed
in Iowa and Illinois, 1973 23
5 Cost of Producing Corn at 110 bu./acre on 320 - 440
Acre Farms in North Central Iowa, 1972 25
6 Cost of Producing Soybeans at 35 bu./acre on 320 - 440
Acre Farms in North Central Iowa, 1972 26
7 Direct Crop Costs and Hours of Han Labor and Tractor
Use Per Acre for Growing and Harvesting Crops
on 260 - 359 Acre Farm 28
8 Farm Prices and Value/Acre of Corn and Soybeans
by Months, 1973 29
9 Quantities of Pesticides Used on Farm Crops in
the Corn Belt in 1964, 1966 and 1971 32
10 Recommended Rates of Application and Approximate
Grower Costs of Selected Corn and Soybean
Insecticides and Herbicides in Iowa and Illinois, 1973 34
11 Iowa and Illinois Farmers' Crop Protection
Practices, 1973 35
12 Acres of Field Crops Treated With Insecticides and
Profit From Treatments, Illinois, 1973, Estimated
From Reports by County Extension Advisers 39
13 Estimated Use and Profitability of Soil Insecticides
for Corn Rootworm Control in Illinois, 1964-1973 ... 40
14 Thousands of Acres Treated With Soil Insecticides in
Illinois, a Comparison of Three Methods of Measuring . 46
15 Comparison of Corn Yields in Bushels per Acre and
Percent of Total Acreage Treated With Chlorinated
Hydrocarbons, 1966, 1968-1969, 1971-1972 47
-------
TABLE OF CONTENTS (Continued)
Table List of Tables
Page
16 Quantities of Insecticides Used on Corn in the
U.S., and on Farm Crops in the Corn Belt in
1964, 1966 and 1971, By Chemical Groups 50
17 Use of Soil Insecticides on Corn in Iowa
and Illinois, 1966-1973 53
18 Use of Major Corn Soil Insecticides in Iowa and
Illinois by Products in 1970, 1972 and 1973 55
19 Five Most Important Corn Weeds in Iowa
and Illinois, 1968 70
20 Average Annual Costs and Returns from Different
Methods of Controlling Weeds in Continuous Corn
in Illinois Over a Six-Year Period, 1966-1971 .... 71
21 Use of Major Corn Herbicides in Iowa and Illinois
by Products in 1970, 1972 and 1973 76
22 Five Most Important Soybean Weeds in
Iowa and Illinois, 1968 84
23 Average Annual Costs and Returns from Different
Methods of Controlling Weeds in Soybeans in
Illinois Over a Six-Year Period, 1966-1971 86
24 Weed Losses in Soybeans in the U.S. and in
Iowa and Illinois, 1970 and 1971 88
25 Summary of Soybean Weed Losses in the U.S.
and in Illinois and Iowa, 1970 and 1971 89
26 Use of Major Soybean Herbicides in Iowa and
Illinois by Products in 1970, 1972 and 1973 92
27 Distribution of the Weekly Iowa and Illinois Insect,
Weed and Plant Disease Newsletter/Survey Bulletin . . 117
VI
-------
TABLE OF CONTENTS (Concluded)
Figure List of Figures Page
1 Corn Harvested For All Purposes, 1964 18
2 Soybeans Harvested For All Purposes, 1964 19
3 Sources of Information on Pesticides and Extent
of Their Use by Iowa and Illinois Farmers, 1973 . . . 109
4 Sources of Information on Pesticides by Extent of
Use and Usefulness as Perceived by Iowa and
Illinois Farmers, 1973 Ill
5 Sources and Routes of Information on the Use of
Agricultural Pesticides in the Midwest 121
Vll
-------
I. SUMMARY AND RECOMMENDATIONS
A. Scope of the Study and Resources Employed.
Farmers' reasons for using pesticides, their knowledge
of alternate crop protection methods, and their sources of
information on both chemical and nonchemical crop protection
methods were studied. The corn/soybean production system in
the states of Iowa and Illinois was selected as a "study system"
because (1) corn and soybeans are the two leading U. S. crops
in terms of farm value; (2) the use of chemical pesticides on
these crops is heavy and increasing; and (3) Iowa and Illinois
are the two leading states in the production of corn and soybeans
in the U. S.
Resources employed in this project included an out-
standing panel of consultants; literature studies; the results
of several previous surveys; and numerous field contacts with
members of the federal/state agricultural research and extension
system, state universities, state governments, the pesticide
industry, and other knowledgeable persons. In addition, a
field survey was conducted, involving about 300 farmers in Iowa
and Illinois, each of whom provided replies to a question form
that included 149 information items, grouped in four sections
and 46 master questions. About 45,000 individual information
items were processed, providing extensive information on the
respondents' farming and crop protection practices and on their
pesticide information sources.
B. Pesticide Use Patterns, Side Effects and Alternatives.
Chemical pesticides, especially herbicides and insecti-
cides, are used extensively in the production of corn and soybeans
in the midwest.
-------
Herbicides are used by close to 100% of all corn and
soybean growers in Iowa and Illinois, and close to 90% of the
total acreage of these crops is treated with herbicides. The use
of herbicides on corn and soybeans is more profitable and conven-
ient to growers than the control of weeds by cultivating or other
means. In spite of the availability and use of an array of
effective herbicides, weeds still cause considerable yield losses,
especially on soybeans. Growers are familiar with a number of
alternatives to chemical weed control, but none of these are
nearly as attractive as herbicides in regard to efficacy, con-
venience and profitability.
Among the three major pesticide uses studied, soybean
herbicides are considered most essential by farmers. Almost one-
quarter of the farmers interviewed stated that they would quit
growing soybeans if no herbicides were available, while only 3-6%
of them said they would not grow corn without herbicides or
insecticides.
Three herbicides, i.e., atrazine on corn, and trifluralin
and chloramben on soybeans, have been used more extensively than
all others combined. Presence and persistence of atrazine residues
in the soil and carryover to the next season have been reported,
especially in Iowa. Trifluralin soil residues have also been found
in some samples.
Weed populations in corn and soybeans are gradually
changing; more difficult-to-control weeds are becoming more
prevalent as those species that are easily controlled recede.
The cost of chemical herbicides has increased somewhat
during the last five years, but this is not a major concern to
growers because the prices of corn and soybeans have increased
much more, especially during the last two years.
-------
Insecticides were used on corn at an increasing rate
during the 1960's. In 1969 and 1970, close to 70% of the total
acreage in Illinois was treated. Since that time, the use rate
has declined slightly. Until about 1970, chlorinated hydrocarbon
insecticides (80-90% aldrin) were used in larger quantities than
other products. The less persistent organic phosphate and carbamate
insecticides have increasingly replaced chlorinated
hydrocarbons during the last few years, especially in Illinois
where the extension service has recommended against the use of
chlorinated hydrocarbon insecticides for soil insect control since
1969. In addition, Illinois appears to have a more vigorous pro-
gram of monitoring for pesticide residues and enforcing established
tolerances in farm products. Iowa still recommends aldrin,
heptachlor and chlordane for the control of soil insects.
Close to 6 million acres of corn in Illinois were treated
with soil insecticides in recent years, primarily against corn
rootworms. Entomologists estimate that only about 40% (2.5 million
acres) of this acreage needed treatment. Concerning control of
soil insects other than corn rootworms, it is estimated that of
4.5 - 5.0 million acres/year treated with chlorinated hydrocarbon
insecticides in both states in recent years, at least 2.5 million
acres did not need the treatment. However, diagnostic and predic-
tive methods available to growers are not adequate, and it is often
difficult for them to know whether or not to use an insecticide.
Thus, from an overall standpoint, a substantial portion of the
corn soil insecticide uses appear to be unnecessary or wasteful,
while most growers consider their individual decisions to us a
preventive treatment a necessary protection against possible yield
losses.
Residues of aldrin, the most widely used soil insecti-
cide, are widespread in Iowa and Illinois soils and have also been
-------
found in milk, meat, poultry, eggs, and soybeans produced in
the area, as well as in wildlife, fish, rivers, lakes and
streams. Residues of heptachlor and heptachlor epoxide were
also found in a number of soil samples from Iowa and Illinois,
but less frequently than aldrin and dieldrin. These findings
are in line with the use patterns of these insecticides.
Several target insects including corn rootworms, seed-
corn beetles and seedcorn maggots have developed resistance to
chlorinated hydrocarbon insecticides.
Regarding alternatives, the effects of crop rotation on
the occurrence of corn insects are recognized by most corn growers.
However, crop rotation decisions are affected by many factors, most
of them overriding crop protection considerations. Other non-
chemical methods for the control of soil insects are currently being
researched, but none of them are ready for field use. Better
methods to diagnose and predict corn insect infestations are urgent-
ly needed to identify those areas and fields that really need
treatment.
On midwestern soybeans, insecticides have been required
only sporadically in the past. There are no soil insects requiring
control, and foliar insects have been a problem only occasionally.
An outbreak of green cloverworms, a foliage feeding insect, occurred
in 1973. Iowa and Illinois issued somewhat divergent treatment
recommendations, and producers and sellers of soybean insecticides,
naturally enough, gave greater publicity to the Illinois version
that recommended a lower treatment threshold than Iowa.
Experiences in other soybean areas of the U. S. indicate
that injudicious use of insecticides on soybeans may result in
progressive destruction of natural control factors, need for more
chemical insect control, etc. An effective management program for
soybean insects in the midwest is therefore most desirable at this
-------
time where regular use of insecticides on this crop has not
yet begun.
Recommendations:
-- Promote development and use of better methods for
diagnosis of corn soil insect problems and for pre-
dicting treatment needs in order to eliminate un-
necessary pesticide uses.
-- Promote development and implementation of insect
management programs for corn and soybeans.
C. Pesticide Information Flow Patterns.
Farmers in the midwest receive information on pesticides
primarily from pesticide sellers, labels, and other farmers.
University extension specialists, area extension agents and county
agents (farm advisers) are regarded as very useful sources of
information on pesticides by farmers. They are very effective
communicators, considering their small numbers in relation to the
large number of farmers they serve. However, these public servants
are outnumbered by pesticide industry representatives and pesticide
sellers by wide margins, and their messages reach only a small
percentage of growers directly. Extension publications likewise
do not reach a significant percentage of growers directly. Exten-
sion publications are also sent to news media including farm maga-
zines, newspapers, radio and TV and are reproduced by these media
in whole or in part, but this does not appreciably increase the
information flow to farmers because farmers do not think highly of
these media as sources of pesticide information and do not use
them much for this purpose. The pesticide trade is by far the
largest direct clientele for pesticide information from state uni-
versities and extension services outside of the university-extension
system itself.
-------
These pesticide information flow patterns developed
during a period when the objectives of the pesticide trade were
essentially in harmony with those of federal and state agencies.
In the past, pesticide development and increased use of pesticides
generally meant progress to both groups. Messages recommending
reduced or no use of pesticides do not flow well through this
system.
Many of the farmers interviewed expressed interest in
receiving more specific, individualized crop protection advice.
Some of this information is available from public sources, some
of it would have to be adapted to local conditions. However,
there are currently no effective, unbiased channels through which
growers could receive such information regularly and in a timely
fashion from the public agency originators of the information.
Recommendation:
-- Promote development and use of unbiased channels
of communication between public agencies that
generate crop protection information and growers
who need that information.
D. Pesticide Information Messages.
Most farmers are businessmen who apply crop protection
measures for economic reasons, i.e., to prevent yield losses that
occur if pests would not be controlled. Most often, pesticides
are the tools of choice because, based on the information avail-
able to farmers, they are more effective and convenient and,
especially, more profitable than other alternatives.
Profit incentives will be far more effective than any
others in prompting growers to adopt more judicious crop protect-
ion strategies. As businessmen, farmers are naturally interested
I
-------
in increasing or at least preserving the productivity of their
assets, including the fertility of their land and the effective-
ness of their tools, including crop protection tools.
There is increasing evidence that in the long run, only
those crop protection strategies that are ecologically sound will
also be economically sound. However, the fact that current crop
protection decisions may entail hidden future costs is generally
not known to farmers, and no effort is being made to bring it to
their attention. Both farmers and those advising them on crop
protection base their choices and their views on the profitability
of available alternatives on comparisons between the cost of the
treatment and the value of the crop yield loss to be prevented.
Two important types of side effects are generally neglected.
Firstly, surprisingly little information is available on
the interactions between different pesticides, and between pesti-
cides and all other elements of crop production systems. For
instance, chemical herbicides, insecticides, fungicides, and fertil-
izers are often applied to the same land year after year. Most
of these chemicals remain in the upper 1-3 inches of the soil.
Little is known about their routes and rates of degradation under
field conditions, on their individual and collective effects on
the soil microflora and microfauna, and on the long-term fertility
of the topsoil.
Secondly, the past history of the use of pesticides
teaches that the usefulness of most or all of these chemicals is
gradually eroded by the development of resistance in the target
pest(s), the selection of pest populations that are increasingly
more difficult to control, the destruction of beneficial organisms,
and other factors. No data are available on how current corn and
soybean crop protection practices might affect the future profit-
ability of these crops.
-------
Information on these (and other) side effects that are
currently largely disregarded would provide farmers and those
advising them with a better basis for making ecologically and
economically sound crop protection decisions.
Recommendations:
-- Provide growers with more information on comparative
advantages, disadvantages and costs of pesticides, and
on treatment thresholds and other details regarding
their most judicious use.
-- Promote more interdisciplinary studies on the present
and future biological and economic effects of different
crop protection strategies on the crop production
systems of which they are a part.
-- Promote greater awareness of the fact that current
pesticide uses may entail not only future adverse
ecological effects, but also adverse economic effects
on the user himself.
E. Applicability of Findings to Other Crops and Areas.
This study has provided a detailed analysis of the pests
and pesticide use patterns on corn and soybeans in Iowa and Illinois,
and of the pesticide information sources, channels and messages
that guide growers in making crop protection decisions. The extent
of use of different pesticide information sources, their degree of
usefulness as perceived by growers, and pesticide information flow
patterns were quantified, and interrelationships, strengths and
weaknesses within this system were identified.
Very few, if any similar studies have been reported thus
far in which all of these factors were investigatedf documented
and evaluated in a comparable, holistic fashion for other crops,
8
-------
including the interrelations between major elements of the production
system (e.g., land use patterns; farm sizes and number of farms;
crop rotation patterns; commodity prices; pest infestations; pesticide
costs, use practices, and side effects; alternatives to unilateral
reliance on pesticides), and the sources and content of, and the
delivery systems for information on crop protection and pesticides
that growers use in making crop protection decisions. Thus, in the
absence of similar studies on other crops for comparison, it is
difficult to know to what extent the findings of this study can be
extrapolated to other crops and areas. Different climates, soils,
crop production and rotation systems, land use and farm size patterns,
etc., generate different pest problems, crop protection needs and
pesticide use patterns. Public agencies, universities, state legis-
latures, commodity organizations, etc. differ in their philosophies
and approaches to crop protection and pesticides, and in the vigor
of their pesticide monitoring and enforcement activities, if any.
Very likely, different mixes of these factors produce somewhat
different problems, needs and opportunities in other regions
of the United States.
In addition to the important findings applicable to corn
and soybeans in Iowa and Illinois (and, probably, to neighboring corn
belt states), this project has provided a study approach, including
methods for the identification and quantification of a number of
critical parameters, that lends itself to the collection and analysis
of similar information for other areas and other crops, and to further
development and refinement.
Research successes in developing alternatives to sole
reliance on chemical pesticides, in integrated pest management, and
in other areas of crop protection will not improve agricultural pro-
duction or environmental quality in and of themselves, but only if,
and to the extent that they are implemented by growers. Growers'
-------
decisions and actions are based on the quantity and quality
(as perceived by them) of the information available to them. Thus,
knowledge of the sources, content and flow patterns of such infor-
mation, and of the effects of the information system on the crop
protection choices and practices resulting from it (as accumulated
in this study), is an important prerequisite to efforts to improve
the effectiveness and reduce the (monetary and ecological) costs of
crop protection.
Reaommendation:
-- Promote similar* holistic studies for other crops and
regions on farmers ' crop protection information, and
on the crop protection decisions and practices resulting
from that information, with a view to determining where
such information systems might need strengthening.
Efficient transfer of the best available crop protection
information to growers is an important element in assis-
ting them to make economically and ecologically sound
crop protection decisions.
10
-------
II. INTRODUCTION
Crop yield losses due to pests including insects, weeds,
plant diseases, and other organisms reduce farming profits. Modern
agricultural production techniques such as growing large, contin-
uous stands of one crop, use of high yielding crop varieties,
fertilizers, and other production inputs tend to increase potent-
ial crop losses due to pests and thus the incentive to prevent such
losses. Since the advent of synthetic organic pesticides, farmers
have increasingly relied on the use of chemicals for the protection
of their crops.
Sole reliance on chemical pesticides has failed as a
crop protection strategy in a number of instances because of the
development of resistant pest strains, selection of increasingly
resistant pest populations, destruction of natural control factors,
outbreaks of secondary pests, and other adverse effects. The dvelop-
ment of crop protection strategies alternative to sole reliance on
chemical pesticides has therefore become necessary, and substantial
research and development efforts are targeted toward this goal.
However, these programs will not affect agricultural production or
environmental quality unless and until they are reduced to practice
at the grower level. This study was undertaken to obtain first-hand
grassroots information on farmers' current pesticide use practices
and on the pesticide information sources, channels and messages that
guide them in their crop protection decisions, in particular, -
The basic factors motivating farmers to use pest
control systems;
The extent and source of farmers' knowledge of alterna-
tive pest control systems, especially those not
involving the use of chemical pesticides?
The factors influencing the decision of which control
system to select; and,
11
-------
where chemical pesticides are chosen as a control
system,, the factors influencing the decision of which
particular chemical pesticide to use, and the factors
influencing the farmers' determination of the manner,
timing, and level in which it should be aoolied.
The study proceeded in five stages:
(1) Review of the pertinent literature;
(2) analysis of the use patterns of pesticides on major
crops and selection of one or more major crop production
systems for detailed analysis;
(3) in-depth analysis of the selected crop system or systems
in terms of the framework set forth above;
(4) identification of wasteful and/or environmentally
objectionable pesticide use patterns and the availability
and practicality of alternatives;
(5) identification of factors or incentives that would
prompt growers to adopt alternatives.
The corn/soybean production system in the midwest was
selected as an appropriate "study system" for this investigation.
Corn and soybeans are the two leading cash crops in the United
States, and the two crops combined account for about 40% of the
total harvested cropland acreage in the U. S. Large quantities of
chemical pesticides, especially herbicides and insecticides, are
used on these crops. The study was centered in the states of
Iowa and Illinois, the two leading corn and soybean producing
states in the nation.
The results are presented by way of an introductory
discussion of the production of corn and soybeans in the study
area, and the uses and costs of pesticides applied to these crops.
Corn and soybean insects and weeds and their control are then
discussed in four separate chapters. Corn insect control patterns
were studied in the greatest detail because this is the area of
12
-------
greatest concern in regard to actual and potential wasteful uses
of chemicals and undesirable side effects. Also, many farmers
expressed interest in more specific, individualized advice on the
control of insects, while they were generally more confident of
their ability and competence to cope with weeds by the use of
herbicides or otherwise.
Findings in regard to farmers' sources of information
on pesticides are presented in terms of the four major elements
involved in a communication process, i.e., originating sources
or senders; channels through which the information is transmitted;
receivers and their use of the information; and content of the
information itself.
Literature references, and other resources and methods
employed in the study are listed and described in the last two
sections of the report, and in two appendices.
A summary of the findings of the study, and recommenda-
tions resulting therefrom were placed at the beginning of the report
to highlight them.
13
-------
III. PRODUCTION OF CORN AND SOYBEANS
IN THE U. S. AND IN IOWA AND ILLINOIS
A. Past Developments, Future Trends.
In terms of farm value, corn and soybeans are the two
leading crops in the United States. Corn also leads all other
crops in total acreage, while soybeans are in fourth place in
this regard, behind hay crops and wheat (U. S. Department of
Agriculture/ 1972a). in 1973, 71 million acres were planted to
field corn, that is almost 25% of the total U. S. harvested crop-
land acreage, and almost 3% of the total land area of the 50
states.
Tables 1 and 2 summarize acreage, production and value
of corn and soybeans in the United States for the 5-year period
1969 - 1973, and projections for 1980 and 1985. Worldwide as
well as domestic demand for corn and soybeans have increased
substantially during the last two years.
The corn acreage harvested for grain in the U. S. has
varied between 54.6 million acres in 1969 and 64.0 million acres
in 1971 (Table 1). 61.5 million acres of corn were harvested for
grain in 1973. The corn acreage for grain production is expected
to increase to 73.7 million acres by 1980, 75.5 million acres by
1985.
Corn yields per acre have generally been on the uptrend
from 1969 to 1973, except for a dip in 1970, caused by the combined
effects of a fungus disease, the southern corn leaf blight
(Helminthosporium maydis), and drought in many of the corn produc-
ing regions in the United States. The U. S. Department of Agri-
culture projects further increases in corn yields, to about
110 bu./acre in 1980, and 120 bu./acre in 1985. These projections
appear to be attainable; the average corn yields in Iowa and
Illinois are already at or above 110 bu./acre today.
14
-------
Table 1 : U. S. Corn Acreage, Production and Value, 1969 - 1985.
Year
1969 1970 1971 1972 19731/ 19802/ 19852/
Acres planted, (000)
3/
Acres harvested, (000)
V
64,264 66,849 74,055 66,753 71,332
6/
6/
54,574 57,358 64,047 57,289 61,479 73,700 75,500
Production
- per harv.'d acre, bu.
- total, Million bu.
85.9 72.4 88.1 96.9 92.4 109.5 120.0
4,687 4,152 5,641 5,553 5,678 8,070 9,060
Av. price received
by farmers, $/bu.
Value of production
- per acre, $
- total, Million $
1.16
1.33
1.08
1.60 2.30
5/
6/
99.64 96.29 95.15 155.04 212.52 6/
5,437 5,522 6,092 8,885 13,059 6/
6/
^
6/
6/
I/ Preliminary
2/ USDA forecasts
3/ For all purposes
4/ For grain
5/ USDA estimate
6/ Not available
Sources: U. S. Department of Agriculture, 1973C. Feed
Situation, Fds-251, November. Economic Research
Service.
U. S. Department of Agriculture. 1973a. American
Agriculture, its Capacity to Produce. The Farm
Index 12(12): 8-14,16
-------
Table 2 : U. S. Soybean Acreage, Production and Value, 1969 - 1985.
Year 1969 1970 1971 1972 19731/ 19802/ 19852/
Acres planted, (000) 42,198 43,332 43,176 46,700 57,000 4/ 4/
Acres harvested, (000) 40,982 42,249 42,701 45,755 56,173 64,100 65,700
Production
- per harv.'d acre, bu. 27.5 26.7 27.5 28.0 28.0 32.0 34.5
- total, Million bu. 1,126 1,127 1,176 1,283 1,575 2,051 2,267
Av. price received
by farmers, $/bu. 2.35 2.85 3.03 4.75 5.003/ 4/ 4/
Value of production
- per acre, $ 64.63 76.10 83.33 133.00 140.00 4/ 4/
- total, Million $ 2,647 3,212 3,563 6,094 7,875 4/ 4/
I/ Preliminary Sources: U. S. Department of Agriculture. 1973b.
2/ USDA forecasts Fats and Oils Situation, FOS-270, November.
3/ USDA estimate Economic Research Service.
4/ Not available u. S. Department of Agriculture. 1973a.
American Agriculture, its Capacity to Produce.
The Farm Index 12(12): 8-14,16
-------
Increased corn acreage and yields combined are ex-
pected to boost total corn production to above 9 billion bu./year
by 1985, from the present level of around 5.6 billion bu./year
that was achieved during 1971, 1972 and 1973.
The average price for corn received by farmers has more
than doubled during the last two years, increasing the average
value of production per acre by 123% between 1971 ($95.15/acre)
and 1973 ($212.52/acre).
Recent developments in the production of soybeans are
equally dramatic (Table 2). The soybean acreage harvested for
beans in the U. S. varied between 41 and 46 million acres between
1969 and 1972. It jumped to 56 million acres in 1973 and is ex-
pected to reach 64.1 million acres by 1980, 65.7 million acres
by 1985.
Soybean yields per acre have hovered around 27 to 28
bu./acre during the last 5 years, but the U. S. Department of
Agriculture expects an increase to 32 bu./acre by 1980, 34.5 bu.
per acre by 1985. Average soybean yields in Iowa and Illinois in
1972 were 35 - 36 bu./acre.
Increased soybean acreage and yields combined are ex-
pected to raise the total U. S. soybean production from 1.6 billion
bu. in 1973 to 2.3 billion bu. by 1985.
The average price for soybeans received by farmers in-
creased from $3.03/bu. in 1971 to $4.75/bu. in 1972, and to an
estimated $5.00/bu. for the 1973 crop. As a result, the value of
production per acre of soybeans increased by almost 70% from 1971
($83.33/acre) to 1973 ($140.00/acre).
The regional distribution of the corn and soybean acreage
throughout the United States is shown in Figures 1 and 2. Iowa
and Illinois rank first and second in the nation in the production
of both corn and soybeans, Iowa being the leading corn state,
Illinois the leading soybean state.
17
-------
Fig. i : CORN HARVESTED FOR ALL PURPOSES, 1964
jltest mag~ava41amej geographical distribution still representative.)
oo
1 DOT - 10,000 ACRES
UNITH) STATES
TOTAL
63,514,906
MAP NO. 44A.M44
U.S. DEPARTMENT OF COMMERCE
BUREAU OF THE CENSUS
-------
2 : SOYBEANS HARVESTED FOR ALL PURPOSES, 1964
available; geographical distribution still representative.)
1 DOT - 10,000 ACRES
,0
<^~
~so
O
X-^-w'
V ^^Y
c^b»
c- 'jo
^ ^3
UNITED STATES
TOTAL
30,351,248
*J>
MAP NO 64A-M70
US. DEPARTMENT OF COMMERCE
BUREAU OF THE CENSUS
-------
to
o
Table 3 : Land Use and Major Field Crops in the U.S. and in Iowa and Illinois, 1972.
(In Thousands of Acres)
State
Iowa
Illinois
2 States
U. S.
2 States/U.S.
Corn
11,100
9,395
20,495
66,800
31%
Soybeans
6,070
7,500
13,570
47,000
29%
Hay
2,300
1,220
3,520
60,900
5.78%
Other
2,030
2,685
4,715
165,300
2.85%
All Field
Crops
20,800
20,800
41,600
340,000 1
12.2%
Total Land
in Farms
33,710
29,200
62,910
,063,346
5.92%
Total Land
Area
35,800
35,700
71,500
2,266,000
3.16%
Land in
Farms/
Total
Land Area
94.2%
81.8%
88.0%
46.9%
Sources: U. S. Department of Agriculture, 1972a, 1973b, 1973c.
Illinois Cooperative Crop Reporting Service, 1972, 1973a.
Iowa Crop and Livestock Reporting Service, 1973.
-------
Table 3 summarizes land use and major field crops in
Iowa and Illinois for 1972, compared to U. S. totals. The two
states combined raised 20.5 million acres of corn in 1972, that
is 31% of the total U. S. corn acreage (66.8 million acres).
The two states raised 13.6 million acres of soybeans in 1972,
equivalent to 29% of the U. S. total (47 million acres).
Iowa and Illinois combined cover only 3.2% of the total
U. S. land area, but account for 5.9% of total land in farms, and
12.2% of the total acreage of all field crops. 94.2% of Iowa's
total land area, and 81.8% of Illinois' total land area is land
in farms. Thus, Iowa and Illinois are among the most intensively
farmed land areas in the United States.
The use of chemical pesticides on corn and soybeans has
increased substantially in recent years. The projected further
increases in the production of both crops will undoubtedly result
in increased crop protection needs. In view of the leading position
of Iowa and Illinois in the production of corn and soybeans, it
was decided to center this study in these two states.
B. General Characteristics of Farms and Farmers Interviewed.
The great majority of farms in Iowa and Illinois are
relatively small in size. The number of farms and the average farm
size in both states are as follows:
Iowa Illinois
Number of farms 132,610 123,000
Average size farm 254 acres 237 acres
(Sources: Illinois Cooperative Crop Reporting Service, 1972.
Iowa Crop and Livestock Reporting Service, 1973.)
21
-------
As described in greater detail in the section on
"Resources and Methods", a comprehensive field survey of about
300 farmers in both states was one of the key methods employed
to accomplish the objectives of this study. The survey was focused
on farms of 320 acres or larger. Studies by Beal and Bohlen (1957)
indicate that larger farmers are usually the innovators and opinion
leaders who initiate the adoption of new ideas in agriculture.
Furthermore, a given number of larger farmers cover a larger share
of the total acreage than if all farm sizes were equally represented.
According to estimates by the Statistical Laboratory, Iowa State
University, about 25% of all farms in Iowa are larger than 320 acres,
and about 50% of the state's cropland area is in farms of this size.
The farm size distribution in Illinois is very similar. The size
of 320 acres is a logical break point because most farm sizes in
the midwest are fractions or multiples of one "section", that is
1 square mile, or 640 acres.
Table 4 summarizes a number of general characteristics of
the farms and farmers interviewed. The acreage operated by the
respondents averaged 520 acres in Iowa, 597 acres in Illinois. The
median farm size in the samples was 430 acres in Iowa, 505 acres
in Illinois; the range was 320 - 1,200 acres in Iowa, 320 - 1,560
acres in Illinois. ,
Practically all farmers reported using "conventional
tillage" practices, defined as "primary and secondary tillage
operations normally performed in preparing a seedbed for a given
crop; one of these operations usually being plowing". About
two-thirds of the Iowa respondents, and about one-third of those
in Illinois reported that they also used "minimum tillage", defined
as "the minimum soil manipulation necessary for crop production",
such as strip tillage or mulch tillage. (For more detailed de-
finitions, refer to Appendix B .) 52% of the Illinois respondents
also employed "no till" methods in 1973, defined as "a system
whereby a crop is planted directly into a seedbed untilled since
harvest of the previous crop".
22
-------
Table 4 : Total Acreage Farmed, Tillage Practices, and
Corn and Soybean Acreage Grown by Farmers
Interviewed in Iowa and Illinois, 1973.
State Iowa Illinois
Number of farmers interviewed
Average number of acres farmed
Median number of acres farmed
Range of number of acres farmed
Percent of farmers using -
- conventional tillage
- minimum tillage
- no till
Percent of farmers growing corn
Average number of acres of corn
58
520
430
320-1,200
100%
66%
0%
100%
210
239
597
505
320-1,560
98%
30%
52%
100%
254
per corn grower
Corn rotation: Corn following -
- corn 29% 37%
- soybeans 57% 50%
- sod or pasture 12% 10%
- another crop 2% 3%
Percent of farmers growing soybeans 97% 95%
Average number of acres of soybeans 176 224
per soybean grower
Soybean rotation: Soybeans following -
- soybeans 8% 16%
- corn 83% 74%
- another crop 9% 10%
Source: This study.
23
-------
The rate of use of minimum tillage and no-till methods
was unusually high in 1973 because an abnormally late and wet
spring prevented more extensive tillage operations that would
normally have been employed by many growers. Minimum tillage
or no-till save time and tractor fuel and reduce soil erosion,
but often require increased use of pesticides, especially
herbicides.
All farmers interviewed in both states raised corn, and
more than 95% of the interviewees also raised soybeans. The ro-
tation patterns of corn and soybeans were quite similar in both
states. In 1973, about one-half of all corn followed soybeans,
about one-third followed corn, about 10% followed sod or pasture,
and the balance another crop. About three-quarters of the soybeans
grown in 1973 followed corn in the rotation, the balance being
divided between soybeans on soybeans, and soybeans following
another crop.
C. Corn and Soybean Production Costs and Prices.
Farmers' costs of producing corn at 110 bu./acre and soy-
beans at 35 bu./acre in Iowa in 1972 are summarized in Tables 5 and
6. The production costs for these crops in Illinois would be very
similar. Stoneberg and Winterboer (1973) estimate the total pro-
duction costs for corn at $130.31/acre ($1.18/bu.), for soybeans
at $100.12/acre ($2.86/bu.).
A comparison of these production costs to the average
prices received by farmers for corn and soybeans in 1972 (Tables 1
and 2) indicates that corn yielded an average profit of $0.42/bu.,
equal to $46.20 for 110 bu./acre. Soybeans yielded an average pro-
fit of $1.89/bu., equal to $66.15/acre for 35 bu./acre.
The production costs given by Stoneberg and Winterboer
(1973) include $8.25/acre for herbicides and insecticides on corn,
and $6.00/acre for herbicides on soybeans.
24
-------
Table 5 : Cost of Producing Corn at 110 bu./acre on
320 - 440 Acre Farms in North Central Iowa, 1972
Cost Per Acre
I. Growing
Chopping 1
Disking 2
Plowing 1
Harrowing 1
Planting 1
Hoeing 1%
Cultivating 1
P & K bulk spread 1
Applying nitrogen 1
Wagons, etc.
Total growing
II. Harvesting and storage
Combining
Hauling l%C/bu.
Drying 6.5^/bu.
Storage 3<*./bu.
Total harvesting
.11. Seed, chemicals, etc.
Seed , ,
Fertilizer 140-60-601 + lime
Herbicides
Insecticides
Total seed, chemicals,etc.
IV. Farm Operating Overhead
V. Labor @ $3.00 per hour
Direct - growing 1.73
harvesting 1.26
Fixed
$ .89
1.04
1.68
.32
1.15
.69
.86
.46
1.15
$ 8.24
$ 6.58
.90
2.50
3.30
$13.28
« «
Variable
$ .44
.80
1.43
.20
.49
.39
.48
.60
1.07
.60
$ 6.50
$ 2.42
.75
4.65
$ 7.82
$ 7.50
$17.55
6.00
2.25
$33.30
Total
$ 1.33
1.84
3.11
.52
1.64
1.08
1.34
.60
1.53
1.75
$14.74
$ 9.00
1.65
7.15
3.30
$21.10
$ 7.50
$17.55
6.00
2.25
$33.30
Indirect (+30!',)
Total labor
VI. Land @ $600 per acre
1%7. for taxes
67. for interest
Total land
VII. Total cost - per acre
- per bushel
.90
3.89 hr. $11.67
$ 9.00
36.00
$45.00
$78.19
.71
$ 4.50
$52.12
47
$ 4.50
$11.67
$ 9.00
36.00
$45.00
$130.31
1.18
Hours Per
Acre
.17
.32
.40
.08
.21
.15
.20
.20
1.73 hrs
.56
.50
.20
1.26 hrs.
l/N @
C per pound
Source: Stoneberg and Winterboer, 1973
25
-------
Table 6 : Cost of Producing Soybeans at 35 bu./acre on
320 - 440 Acre Farms in North Central Iowa, 1972
I.
II.
III.
IV.
V.
VI.
VII.
Times
Over
Growing
Chopping 1
Disking 2
Plowing 1
Harrowing 1
Planting 1
Hoeing 2
Cultivating 1
P & K bulk spread 1
Wagons, etc.
Total growing
Harvesting and storage
Combining
Hauling 3c/bu.
Storage 3c/bu.
Total harvesting
Seed, chemicals, etc.
Seed
Fertilizer 0-40-40 + lime
Herbicides
Total seed, chemicals, etc
Farm operating overhead
Labor @ $3.00 per hour
Direct -growing 1.58
harvesting .64
Indirect (+30%) .67
Total labor 2.89
Land @ $600 per acre
1%% for taxes
6% for interest
Total land
Total cost - per acre
per bushel
Cost Per Acre
Fixed
$ .89
1.04
1.68
.32
1.04
.86
.86
1.15
$ 7.84
$ 3.95
.55
1.05
$ 5.55
$ 8.67
$ 9.00
36.00
$45.00
$67.06
1.92
Variable
$ .44
.80
1.43
.20
.49
.52
.48
.60
.60
$ 5.56
$ 1.30
.50
$ 1.80
$ 9.00
7.70
6.00
$22.70
$ 3.00
$33.06
.94
Total
$ 1.33
1.84
3.11
.52
1.53
1.38
1.34
.60
1.75
$13.40
$ 5.25
1.05
$ 7.35
$ 9.00
7.70
6.00
$22.70
$ 3.00
$ 8.67
$ 9.00
36.00
$45.00
$100.12
2.86
Hours per
Acre
.15
.32
.40
.10
.21
.20
.20
1.58 hrs
.44
.20
.64
Source: Stoneberg and Winterboer, 1973
26
-------
The Illinois Farm Management Manual (Hinton, 1972)
includes a tabulation (Table 7) of the direct costs (exclusive
of the cost of land, taxes, interest, indirect labor, and farm
operating overhead that are included by Stoneberg and Winterboer,
Tables 5 and 6) for growing crops on 260 - 359 acre farms at
different yield levels. The dollar costs allocated to "sprays
and other materials" for corn and soybeans appear to be unrealistic-
ally low, but the interesting point is that they increase by 150%
(from $2.00 to $5.00/acre) as the corn yield increases by 50%
(from 80 to 120 bu/acre). In the case of soybeans, Hinton1s costs
for "sprays and other materials" increase only by 14% (from $3.50
to $4.00/acre) as the yield increases by 52% (from 33 to 50 bu.
per acre). These figures indicate farm managers' expectations
that increased per-acre yields of corn and soybeans require in-
creased pesticide inputs, a finding that is especially significant
in the light of the projected substantial increases in the yields
and acreages of corn and soybeans in the next 10 years (Tables 1 & 2)
During 1973 when this study was in progress, farm prices
for corn and soybeans gyrated considerably (Table 8). Prices per
bushel of corn ranged from a low of $1.35 in February to a high of
$2.68 in August, settling back to $2.15 - $2.18 in September,
October and November. In February of 1974, market prices for corn
were quoted at around $3.00/bu.
Farm prices per bushel of soybeans varied by even wider
margins, from a low of $4.10 in January of 1973 to a high of $10.00
in June, settling back to $5.63 in October. In February of 1974,
market prices for soybeans were quoted at around $6.20 - $6.30/bu.
(February 1974 market prices for corn and soybeans quoted from the
Wall Street Journal of February 8, 1974.)
Table 8 also includes for both crops a computation of the
effects of the monthly commodity prices on the value of an acre of
27
-------
Table 7 : Direct Crop Costs and Hours of Han Labor and Tractor Use Per Acre for Growing
a/
and Harvesting Crops on 260-359 Acre Farm
Item
Preharvest
Power and machinery
Depreciation
Repairs and fuel
Custom machine hire
Seed or plants
:SfFrays and other materials
Seasonal hired labor
Harvest and condition
Seasonal hired labor
ro Power and machinery
00 Depreciation
Repairs and fuel
Custom machine hire
Other materials
Total direct costs
Total, excluding
Cost of fertilizer nutrient
removal per unit of yield
Farm man labor (hours)
Tractor and self-propelled
power (hours)
yield per acre (bushels}
£/ Adapted from 1964-1970 cost
80 bu.
$ 4.00
3.50
*
U.OO
2.00
*
10.00
3.10
1.60
.80
$31.00
$15.00
.14
4.4
3.7
80.0
data on
Corn
100 bu.
$ 6.00
3.50
6.00
3.50
. * .
10.00
3.60
2.00
1.00
$35.60
$19.60
.14
4.5
3.8
100.0
Soybeans
120 bu.
$ 6.00
3.50
....
8.00
5.00
....
10.00
U.10
2.40
1.20
$U0.20
$2U.20
.15
4.6
3.9
120.0
33
$ 6
3
'
3
3
0
U
1
$22
$12
i
4.
3.
bu.
.00
.50
.00
.50
.00
.30
.70
.00
.00
,18
,5
0
33.0
50 bu.
* 6. CO
3.50
*
4.00
4.00
....
U.OO
1.50
1.00
*
$2U.OO
$1U.OO
.17
4.6
3.1
50.0
Wheat
40 bu.
$ 3.00
1.40
....
2.80
.70
....
.U.OO
1.30
.80
*
$lU.OO
$ 7.00
.21
2.0
1.5
40.0
55 bu.
$ 3.00
1.40
3.50
.80
....
U.OO
1.50
1.10
....
$15.30
$ 8.30
.20
2.1
1.6
55.0
Oats
$ 3.oo
1.40
*
2.00
.50
*
U.OO
1.30
*
$12.20
$ 5.20
.11
2.0
1.5
67.0
Winter
barley
$ 3-00
1.40
2.20
.50
* *
*
u.oo
1.30
*
$12.UO
$ 5.40
.14
2.0
1.5
50.0
Grain
sorghum
$ 6.00
3.50
1.00
3.50
9.00
5.00
1.00
$ 29.00
$ lU.OO
.15
5.0
4.0
80.0
Illinois farms.
Source: Hinton, R. A. 1972
-------
Table 8 : Farm Prices and Value/Acre of
Corn and Soybeans by Months, 1973
Month
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Corn
Farm Price,
$/bu.
1.39
1.35
1.37
1.42
1.61
1.99
2.03
2.68
2.15
2.17
2.18
Value,, /
$/acre x/
153.60
149.18
151.39
156.91
177.91
219.90
224.32
296.14
237.58
239.79
240.89
Soybeans
Farm Price,
$/bu.
4.10
5.49
6.05
6.14
8.27
10.00
6.69
8.99
5.81
5.63
n.a.
Value , , .
$/acre *'
145.55
194.90
214.78
217.97
293.59
355.00
237.50
319.15
206.26
199.87
I/ Based on yield of 110.5 bu./acre.
Average 1972 yields were 110 bu./acre
in Illinois, 111 bu./acre in Iowa.
2/ Based on yield of 35.5 bu./acre.
Average 1972 yields were 35 bu./acre
in Illinois, 36 bu./acre in Iowa.
Sources: U. S. Dept. of Agriculture, 1973b, c.
Illinois Cooperative Crop Reporting Service, 1973a.
Iowa Crop and Livestock Reporting Service, 1973.
29
-------
corn at 110.5 bu./acre, and of an acre of soybeans at 35.5 bu.
per acre. The value of the crop as perceived by the grower at
the time when he has to decide whether or not to use a pesticide
will, of course, influence that decision. This became very apparent,
for instance, in the summer of 1973 when foliar soybean insects in
the study area started to feed on soybeans that were, at that time,
worth about $9.00/bu., or $320/acre. These events will be dis-
cussed in greater detail below in Section VI, Soybean Insects.
30
-------
IV. USES AND COSTS OF PESTICIDES IN THE MIDWEST
This section presents an overview of the use of pesti-
cides in the Midwest, including total quantities used, and rates
of application and grower costs of major corn and soybean insecti-
cides and herbicides, followed by an overview of the crop protection
practices of the Iowa and Illinois farmers interviewed in this
study. Many of these information items are discussed in greater
detail in other sections of this report, but it was felt desirable
to present them once in a manner that permits comparisons between
herbicides, insecticides and fungicides, and between weed and
insect control practices. This section of the report serves that
purpose.
According to estimates by the U. S. Department of Agricul-
ture 1968b, 1970b,1974), the use of herbicides and insecticides in
the "corn belt" region (Illinois, Indiana, Iowa, Missouri, and Ohio)
increased rapidly during the 8-year period, 1966 - 1971 (Table 9).
Corn herbicides accounted for more than one-half of the total
quantity of all pesticides used on all crops in this region in 1971,
followed by soybean herbicides and corn insecticides. All other
pesticide uses combined, including herbicides on crops other than
corn and soybeans, insecticides on crops other than corn, and
fungicides on all crops, make up only about 7% of the total quantity
of pesticides used.
Estimates from other sources on the quantities of pestici-
des used in the Midwest indicate that those by the U. S. Department
of Agriculture summarized in Table 9 may be too low (refer to pp. 49
below). However, the relative orders of magnitude evident in Table 9
are realistic.
This study was initially focused on the three major
pesticide uses in the area, i.e., the control of weeds in corn and
31
-------
Table 9: Quantities of Pesticides Used on Farm Crops in
the Corn Belt1/ in 1964, 1966 and 1971
(In Thousands of Lbs. of Active Ingredients).
Pesticide/Crop
Herbicides on
Corn
Soybeans
All Other Crops
All Crops
Insecticides on
Corn
Soybeans
All Other Crops2/
All Crops
Fungicides on
Corn
Soybeans
2/
All Other Crops '
All Crops
1964
12,590
3,024
1,381
16,995
10,812
516
3,030
14,358
0.1
0.2
7.9
8.2
1966
27,473
6,567
1,440
35,480
17,525
244
3,688
21,457
negl .
negl.
5.4
5.4
1971
54,069
18,875
3,407
76,351
15,314
117
2,993
18,424
negl.
negl.
5.3
5.3
I/ Corn Belt = Illinois, Indiana, Iowa, Missouri, and Ohio.
2/ Apples, vegetables, other field crops (mainly outside of
Illinois and Iowa)
Sources: U. S. Department of Agriculture, 1968b, 1970b, 1974.
32
-------
soybeans, and the control of insects on corn. An unexpected
infestation of foliar insects on soybeans developed while the
study was already in progress. It was too late at that time for
inclusion of this problem in the farmer survey, but other aspects
of the soybean insect situation were studied and are reported in
the section on "Soybean Insects".
The combined corn acreage of Iowa and Illinois accounts
for about two-thirds of all corn acres in the 5-state "corn belt".
The combined soybean acreage of the two states makes up close to
60% of all soybeans grown in the corn belt. Accordingly, it is
estimated that about two-thirds of all pesticides used on corn and
soybeans in the corn belt are used in Iowa and Illinois.
Table 10 lists the major corn and soybean herbicides and
insecticides used in Iowa and Illinois, their rates of application
as recommended by the Extension Service and by the pesticide trade,
and approximate grower costs based on the rates recommended by the
trade. There are no serious discrepancies between the rates recom-
mended by the different sources. The Iowa Extension Service does
not recommend rates of application for herbicides. Thus, those
listed in the Extension Service column are from Illinois only.
Conversely, Illinois Extension does not recommend the use of aldrin
(or other chlorinated hydrocarbon soil insecticides), and the rates
in the Extension column in this case are those recommended in Iowa.
In some instances, pesticides can be applied "piggyback"
in conjunction with tillage or cultivating operations. In this
case, application costs would be very small and are often not
counted. Otherwise, when the pesticide application requires a
special pass over the field (mostly by ground, sometimes by air
equipment), application costs are usually $1.00 to $1.50/acre, not
including the cost of the pesticide.
Table 11 summarizes the crop protection practices of the
33
-------
Table 10: Recommended Rates of Application and Approximate
Grower Costs of Selected Corn and Soybean Insecticides
and Herbicides in Iowa and Illinois, 1973
Rate Recommended By
Pesticide
Extension
Service
Lb.AI/Acre
Pesticide
Trade
Lb.AI/Acre
Approximate
Grower
Cost
$/Acre
Corn Herbicides
I/
I/
Atrazine (80WP)
Propachlor (65WP)
Butylate (6EC)
Soybean Herbicides
Trifluralin (4EC)
Chloramben (2EC)
Alachlor (4EC)
Corn Insecticides
Aldrin
Phorate (15G)
Carbofuran (10G)
Soybean Insecticides
Carbaryl (80WP)
Malathion(SEC)
Toxaphene(6EC)
0.8
4.0
0.5 -
2.5 -
2.0 -
4.0
4.9
4.0
1.0
3.0
3.0
1.0 -
2.0
4.0
3.0
0.75
2.0
2.0
2/
4.0 -' 1.0
1.0 0.75
0.75 0.75
1.6
1.0
2.0
3.2
6.0
4.0
1.0
3.0
3.0
3.0
1.0
1.0
1.6
1.0
1.5
6.10
8.75
5.80
4.70
9.75
6.70
1.60
1.85
3.30
9.80
13.15
7.75
6.25
14.60
10.00
4.80
2.40
4.40
2.00
2.00
0.80
I/ Iowa does not recommend rates of application for herbicides.
Rates given are from Illinois recommendations
2/ Not recommended in Illinois.
Sources: Illinois Cooperative Extension Service
1973 Field Crops Weed Control Guide, 11-72
1973 Suggested Insecticide Guides, Circ. 899, Dec. 1972
Iowa Cooperative Extension Service
1973 Herbicides for Weed Control in Corn and Soybeans,
WC-86 Rev., Nov. 1972
1973 Insect Pest Control Recommendations,
IC-328 Rev., Feb. 1973
Pesticide Trade Literature and Information
34
-------
Table 11: Iowa and Illinois Farmers' Crop
Protection Practices, 1973.
% Respondents
Iowa Illinois
Corn Herbicides.
100 99 used corn herbicides in 1973.
70 42 changed products at least once since 1970.
97 94 considered herbicide efficacy satisfactory or better
in 1972 and 1973.
88 82 believe all of their corn acres need herbicides each
year.
62 56 would not change herbicide use if cost would double.
97 97 would continue to grow corn if no herbicides were
available.
Corn Insecticides.
2/ 2/
53^ 70^', used corn insecticides in 1973.
52 . 43 . changed products at least once since 1970.
100 94 considered insecticide efficacy satisfactory or
. , better in 1972 and 1973.
559( 55_V\ believe all of their corn acres need insecticides
291/ 391/ each year<
~l~l-1 61 I would not change insecticide use if cost would double.
97 94 would continue to grow corn if no insecticides were
available.
Soybean Herbicides.
98 98 used soybean herbicides in 1973.
58 45 changed products at least once since 1970.
92 85 considered herbicide efficacy satisfactory or
better in 1972 and 1973.
96 86 believe all of their soybean acres need herbicides
each year.
72 67 would not change herbicide use if cost would double.
76 79 would continue to grow soybeans if no herbicides were
available.
I/ % of corn insecticide users
2/ % of corn growers
For general characteristics of farms and farmers interviewed, refer to
Table 4, page 23.
35
-------
Iowa and Illinois farmers interviewed in this study in 1973.
98 - 100% of the respondents in both states used herbicides on
corn and soybeans, and a high percentage of them consider this a
very essential practice. By contrast, only 53 (Iowa) to 70%
(Illinois) of the farmers interviewed used corn insecticides in
1973; and only 55% of this group, that is only about one-third
of all corn growers, believed that all of their corn acres need
insecticide treatments each year. Other aspects of the results
of the farmer survey will be reported and evaluated in greater
detail in the following sections of this report.
36
-------
V. CORN INSECTS
A. Major Insect Pests
Corn in Iowa and Illinois may be affected by soil as
well as by foliar insects. The soil insects are considerably more
detrimental. They consist of several species of corn rootworms,
and a number of other insects often referred to as the "soil insect
complex".
There are three species of corn rootworms in the area,
i.e., Diabrotica longicornis, the northern corn rootworm, D.
virgifera, the western corn rootworm; and D. undecimpuncata howardi,
the southern corn rootworm. The northern and western species pre-
dominate in Iowa and Illinois. The two species occur together and
have very similar life cycles and habits.
The "soil insect complex" includes seedcorn maggots,
Hylemya spp.; the seedcorn beetle, Agonoderus lecontei; the slender
seedcorn beetle, Clivina impressifrons; wireworms (order Coleoptera,
family Elateridae); cutworms (order Lepidoptera, family Noctuidae);
white grubs, Phyllophaga or Lachnosterna spp.; webworms, Crambus
spp.; billbugs, Calendra spp.; ants (order Hymenoptera, family
Formicidae); and the corn root aphid, Anuraphis maidiradicis.
These soil insects are most serious on first-year corn
following legumes, legume-grass or grass sods. They are seldom a
problem on corn following corn or soybeans in the rotation.
Corn rootworms are usually a problem only on corn follow-
ing corn, sorghum or sunflowers. Corn following soybeans or small
grains rarely suffers rootworm damage.
Foliar insects that may attack corn in the midwest include
corn borers, (order Lepidoptera, family Pyralididae); corn earworm,
Heliothis zea; and corn rootworm beetles, the adult forms of the
corn rootworms (Diabrotica spp.) discussed earlier. Foliar corn
37
-------
insects are generally much less of a threat to corn yields than
corn soil insects.
B. Losses Due to Insects and Benefits from their Control.
Entomologists at the University of Illinois have studied
insect infestations and potential yield losses in field crops since
1955 (Petty, 1974). An estimate of the acres of Illinois field
crops treated with insecticides, and of the profits obtained from
such treatments is compiled annually from reports by county exten-
sion advisors. Table 12 presents this estimate for 1973 as given by
Randell et al. (1974). According to these authors, Illinois field
crop growers realized an estimated net return of over $24 million
from the use of insecticides in 1973 ($23.8 million in 1972).
Table 12 indicates that about 84% of the total estimated
profit realized in 1973 ($20,083,186 of a total of $24,018,473)
resulted from the control of corn rootworms by insecticides. In re-
sponse to our request, one of Randell's co-authors, D. E. Kuhlman
(1973), provided further information on how these estimates were
derived. Table 13 summarizes the estimates by Randell, Kuhlman and
others on the use and profitability of soil insecticides for the
control of corn rootworms in Illinois during the 10-year period 1964-
1973. The methods by which these figures were obtained are outlined
in Footnote 2. According to these investigators, approximately 6
million acres of corn in Illinois were treated with soil insecticides
during the last 3 years, but only about 40% of these (2.5 million
acres) were treated profitably with corn rootworm insecticides. This
estimate is based on a survey of adult corn rootworm populations in
Illinois in 1971. On these 2.5 million acres of corn where rootworm
control was needed, the average yield loss prevented was estimated at
10% = 10 bu./acre. On the remaining 3.5 million acres (60%), the
use of soil insecticides yielded an estimated average profit of
only $1.00/acre over and above the cost of treatment.
38
-------
Table 12 Acres of Field Crops Treated With Insecticides and Profit From Treat-
ments, Illinois, 1973, Estimated From Reports by County Extension Ad-
visers
Crop and insect
Corn
Armyworms
Corn rootworm adults
Corn leaf aphids
Cutworms
European corn borers
Grasshoppers
Soil insects
Fall arm/worms
TOTAL
Soybeans
Green cloverworms
Grasshoppers
Cutworms
TOTAL
Wheat
Armyworms
Sorghum
Webworm, fall arm/worm, etc.
Clover and alfalfa
Alfalfa webworms
Alfalfa weevils
Pea aphids
Grasshoppers
Meadow spittlebugs
Potato leafhoppers
TOTAL
1972 TOTAL
1973 TOTAL
a/ Over and above treatment costs.
b/ Based on yield increase from use
Acres treated
19,593
24,642
137,292
93,781
108,284
12,829
5,738,053
124,063
6,258,537
735,917
2,435
8,490
746,842
12,870
28,496
478
105,461
3,800
33,261
539
4,334
147,873
6,768,851
7,194,618
of rootworm insecticides.
Estimated profit^/
$ 29 , 390
98,568
961,044
562,686
162,426
12,829
20, 083,1 86 £/
310,158
$22,220,287
$ 1,103,876
7,305
50,940
$ 1,162,121
$ 51,480
$ 42,744
$ 2,868
421,844
7,600
99,783
1,078
8,668
$ 541,841
$23,765,461
$24,018,473
From: Randell et al., 1974
39
-------
Table 13: Estimated Use and Profitability
of Soil Insecticides for Corn Rootworm
Control in Illinois, 1964 - 1973.
Year
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
10 Years
Corn Acres
Treated with
Soil
Insecticides
4,091,125
4,733,784
5,443,197
6,204,293
6,261,869
6,508,067
6,610,287
6,142,039
6,085,328
5,738,053
Average
Profit I/
$/Acre
4.00
5.00
5.00
5.00
5.00
5.00
3.75
3.502/
3.50
3.50
Total
Profit,
$
16,364,500
23,668,920
27,215,985
31,021,465
31,309,345
32,540,335
24,788,576
21,497,137
21,298,648
20,083,186
249,788,097
I/ Average return above cost of treatment for all corn soil
insecticide users.
2/ This estimate, $3.50/acre, based on following assumptions:
Cost of insecticide treatment = $3.00/acre. Farm price of
corn = $1.00/bu. Average saving in yield loss for 40% of
treated acres = 10% = $10.00/acre, less cost of treatment
= $7.00/acre net. 60% of treated acres obtained only
$1.00/acre net return above cost of treatment. Estimated
average return for all corn soil insecticide users = $3.50
per acre.
Higher average profit estimates for earlier years are based
on greater severity of the corn rootworm problem, resulting
in greater yield loss savings.
Sources: Randell et al, 1974; Kuhlman, 1973.
40
-------
Illinois corn growers realized estimated cumulative
profits of about $250 million from the use of corn rootworm insecti-
cides during the last 10 years. Estimated annual profits reached a
high of $32.5 million in 1969, declining steadily thereafter, to
about $20 million in 1973. This downward trend is attributed to
a lessening of the corn rootworm problem since 1970. Prior to 1970,
corn rootworm populations were considerably higher and thus more
damaging, and the return from using insecticides to control them
was greater. Whether this downward trend will continue in the
future will depend, among other things, on future corn rotation
patterns. Entomologists expect that corn rootworm problems will
continue to exist in continuous corn; if soybean acreage increases,
continuous corn acreage will decrease, and so will rootworm problems.
Foliar (above ground) insects of corn are not nearly as
important from the standpoint of economic damage potential as the
soil insects. Randell et al. (1974) estimated that Illinois corn
growers profited about $1.6 million from the use of insecticides
against foliar corn insects (armyworms, corn rootworm adults, corn
leaf aphids, European corn borers, grasshoppers, fall armyworms),
compared to estimated profits of $20.6 million from using insecti-
cides against soil insects, including cutworms (Table 12). Control
of corn leaf aphids on 137,000 acres accounted for $961,044, almost
two-thirds of the total estimated profits from using foliar corn
insecticides. In 1972, corn leaf aphids were controlled profitably
on 55,669 acres in Illinois, yielding an estimated profit to growers
of $389,683 (Kuhlman et al. 1973), while armyworms, corn rootworm
adults, European corn borers, and grasshoppers were of minor economic
importance.
The figures on the estimated economic benefits from the
use of insecticides on field crops in Illinois discussed in this
section are presented and quoted exactly as given in the sources
cited. One might question whether estimates can possibly be
41
-------
accurate to single acres or dollars. One might also question the
methodology and assumptions outlined by Kuhlman (Table 13, Footnote 2);
and perhaps other details whose pursuit would be beyond the scope of
the present study. The information in Tables 12 and 13 was rendered
"as is" despite these reservations because it is widely accepted and
used by entomologists, extension personnel, pesticide sellers, and
by farmers themselves, i.e., by the people whose collective opinions
and actions govern the use of pesticides and/or other crop protection
measures in the study area.
Furthermore, it is pointed out that the Illinois entomolo-
gists' estimates assume a farm price of corn of $1.00/bu. The actual
average farm price per bu. of corn was $1.08 in 1971, $1.60 in 1972
(Table 1). In 1973, it reached as high as $2.68 in August (Table 8),
while the average for the year was estimated at $2.30. The costs of
insecticides may have increased somewhat, but not nearly at the same
rate. Thus, the cost of insecticide treatment in 1973 was equivalent
to the value of less than 1.5 bu. of corn, compared to 3.0 bu.
assumed by Kuhlman (1973), making the insecticide use relatively
more attractive.
Comparable estimates on profits from the use of insecti-
cides on corn are not available for Iowa. However, a comparison
between Iowa and Illinois insect control recommendations, as well as
discussions with entomologists in both states indicate that the
relative economic importance of corn insects in Iowa is very similar
to that in Illinois.
C. Use Patterns of Insecticides on Corn.
In the early days of the use of soil insecticides on corn,
chlorinated hydrocarbon insecticides controlled both corn rootworras
and the complex of other soil insects. Today, western corn
rootworms are completely, and northern corn rootworms almost
completely resistant to the cyclodiene insecticides in Iowa
42
-------
and Illinois. Thus, it has become a widely adopted practice to
use chlorinated hydrocarbon insecticides against the soil insect
complex, and organic phosphate and/or carbamate insecticides against
resistant corn rootworms.
One vexing problem with the soil insects other than corn
rootworms is that they occur rather erratically and only in spots,
even in situations where they would be expected to be a problem
because of the rotation pattern. For instance, entomologists wish-
ing to conduct insecticide performance trials against these insects
find it very difficult to obtain meaningful field test results
because infestations are so unpredictable. Oftentimes, no insects
are present in nine out of ten trials. These field experiences in-
dicate that in all probability, only a small percentage of the corn
acreage in Iowa and Illinois that is currently treated with chlorin-
ated hydrocarbon insecticides against these soil insects really needs
the treatment. The problem is that at the present state of the art,
it is impossible to predict which field or which part of a given
field may or may not be damaged by soil insects. Since preventive
insecticide treatments are relatively inexpensive (Compare Tables
8 and 10), many growers apply them.
Because of increasing insect resistance to chlorinated
hydrocarbon insecticides and mounting residue problems (see section
on "Side Effects" below), Illinois began advising against the use
of these insecticides on dairy farms in 1965. In 1970, Illinois
discontinued the state recommendations for the use of chlorinated
hydrocarbon insecticides on corn altogether. The "1971 Suggested
Insecticide Guides/Insect Control for Field Crops" issued by the
University of Illinois Cooperative Extension Service in December of
1970 states in part as follows:
"The previous history of use (of aldrin and heptachlor)
in Illinois indicates that in about 5 million acres to
be planted to corn, residues of dieldrin/aldrin or
heptachlor epoxide-heptachlor may exert such a depress-
ing effect on the general pest population that continued
applications would not be needed.
43
-------
Selecting fields that warrant the use of aldrin or
heptachlor .is important. A few hundred thousand acres
of corn could be profitably treated broadcast with
aldrin or heptachlor to control black cutworms, but these
fields cannot be selected until the damage has already
occurred. To prevent this damage, it would be necessary
to apply one of these insecticides to 3 or 4 million
acres in Illinois. It is cheaper to apply control
measures when cutworms appear."
The last sentence of this quotation is probably undebatable
considering the state as a whole. However, many indiyidual growers
are left with the uncertainty whether or not their particular fields
would be among those where cutworm treatments would be profitable,
and many of them opt for preventive treatment. From an overall
standpoint, this results in a considerable amount of unnecessary and
thus wasteful insecticide use. At the same time, most growers con-
sider their individual use of the insecticide a protection against
possible yield losses and thus a necessary and prudent investment.
This dilemma is further illustrated by the fact that in
the current legal proceedings in connection with the proposed cancel-
lation of many registrations of aldrin, widely divergent views have
been presented in court in sworn testimony by expert witnesses on
whether the use of aldrin as a soil insecticide on corn and other
crops is wasteful or essential. No generally accepted definitions
or criteria have been established on what constitutes a wasteful
pesticide use, and very few, if any studies have been undertaken to
delineate and quantify wasteful pesticide use practices.
Petty (1974) monitored the use of corn soil insecticides
in Illinois during the period 1966-1972 by three different survey
methods (Table 14). The total acreage treated with soil insecticides
remained relatively constant during this period, but the number of
acres treated with chlorinated hydrocarbons decreased remarkably,
while the use of other insecticides, primarily organic phosphates
44
-------
and carbamates, increased from a very small acreage treated in
1966 to 3 to 4 million acres in 1972.
In view of the intense current debate on the need for
continued availability of aldrin for control of corn insects. Petty
also compared corn yields in southern, central and northern Illinois
with the use of chlorinated hydrocarbon insecticides in these areas
in 1966, 1968-1969, and 1971-1972 (Table 15). In all three areas,
corn yields continued to increase while the use of chlorinated
hydrocarbon insecticides (primarily aldrin) decreased from 66 to
39% in southern Illinois, from 64 to 14% in central Illinois, and
from 57 to 8% in northern Illinois. Petty's comments on these
figures are as follows:
"Some people ask about average yields and the effect of
decreasing use of chlorinated hydrocarbons. These com-
parisons are difficult to make with great reliability,
but some data are available by sections. When we compare
yields in bushels per acre and percent of acres treated
with chlorinated hydrocarbons, we find an inverse re-
lationship. As use has decreased, yields have increased
since 1966 (Table 15). That this positive correlation
can be drawn is open to question, but it is not questio-
able that a conclusion can be drawn that this decrease
in use did not affect yields adversely."
The Iowa Cooperative Extension Service has continued to
recommend aldrin, heptachlor and chlordane for use against corn
soil insects, except on dairy farms, up to and including 1973. We
understand that these recommendations will be continued in 1974.
Stockdale (1971, 1973) estimated that in 1971, about 6.5 million
acres of corn in Iowa were treated with soil insecticides, 2.75
million of these (42%) with chlorinated hydrocarbons (aldrin 90%;
heptachlor 8%; chlordane 2%), the balance with organic phosphates
and carbamates. In 1973, an estimated 5 million acres of corn in
Iowa were treated with soil insecticides, 2.5 million of these (50%)
with chlorinated hydrocarbons (aldrin 80%; heptachlor 16%;
chlordane 4%).
45
-------
Table 14; Thousands of Acres Treated With Soil Insecticides in Illinois,
a Comparison of Three Methods of Measuring^/
Total acres treated
Year
1966
1967
1968
1969
1970
1971
1972
EA
5,443.2
6,204.3
6,261.8
6,508.0
6,610.2
6,142.0
5,785.3
RS
6,648.1
. . .
5,775.7
6,018.8
6,314.8
5,894.1
5,522.2
ICR
...
7,071
5,770
5,488d/
5,511d/
Acres treated with
chlorinated hydrocarbons
EA
5,116.6
5,601.6
5,170.7
4,517.9
3,844.7
1,881.6^
2,051.7-/
RS
6,473.3
4,347.0
4,111.2
3,576
2,154.9^
1,820.7-
ICR
...
4,631
3,214
2,777
2,376d/
Acres treated with
other insecticides
EA
326.6
602.7
1,091.1
1,990.1
2,765.5
3,418.9
3,852.2
RS
174.8
1,428.7
1,907.6
2,738.8
3,739.2
3,701.5
ICR
. . .
*
2,440
2,556
2,711d/
3,135d/
a/ Methods used included questionnaires submitted to county extension advisers for their estimates (EA); ran-
~~ dom surveys of 22 counties and 10 fields per county for corn rootworm adult populations with a follow-up
and field histories, obtained by interviews (RS); and interviews by Illinois Crop Reporting Service employ-
ees (ICR).
b_/ Published figure, 2,723,000 acres, was adjusted because of distributor and dealer sales reported to us.
c/ Published figure, 1,933,100 acres, was an average of RS and EA.
d/ These figures added to Petty's original table.
From: Petty, 1974
-------
Table 15: Comparison of Corn Yields in Bushels per Acre and
Percent of Total Acreage Treated With Chlorinated
Hydrocarbons, 1966, 1968-1969, 1971-1972^1
Area
Southern
Illinois
Central
Illinois
Northern
Illinois
Bushels per acre
Percent of acres treated
Bushels per acre
Percent of acres treated
Bushels per acre
Percent of acres treated
1966
67.7
65.8
85.1
63.9
73.2
56.8
1968-1969
84.8
57.9
97.7
35.3
97.5
34.3
1971-1972
94.2
39.1
116.3
13.7
103.7
7.8
a/Data for 1967 were incomplete; southern corn blight interfered with yields
in 1970.
From: Petty, 1974
47
-------
We queried entomologists in both states about this
situation. There was consensus that from the standpoint of insect
infestations and damage potential, there is no greater or lesser
need for chlorinated hydrocarbon soil insecticides in Iowa than in
Illinois. In fact, if there are any differences in this regard,
they would be in the direction of a somewhat greater need for these
persistent insecticides in Illinois. The decline in the use of
chlorinated hydrocarbon insecticides in Illinois was attributed
primarily to the recommendations against their use by the Illinois
Cooperative Extension Service, probably supported by more vigorous
monitoring for aldrin/dieldrin residues, and the expectation of more
vigorous law enforcement in cases of illegal residues.
Iowa extension entomologists feel that aldrin is still
needed on about 1 million acres of corn in their state (that is
about one-half of the acreage actually treated with aldrin in 1973),
primarily for the control of the black cutworm, Agrotis ypsilon,
an insect whose occurrence is difficult to predict in areas gen-
erally known to be susceptible to infestations. In untreated fields,
black cutworm infestations are usually not detected until after
considerable damage has already occurred, and emergency spray or
bait treatments are too late, Iowa entomologists point out.
Illinois entomologists treat the black cutworm problem
as follows in their "1973 Suggested Insecticide Guides/Insect
Control for Field Crops":
"Black cutworms have been controlled adequately with
apple pomace-carbaryl pelleted baits, but early de-
tection and application are essential. Late application
kills the cutworms but much of the damage has already
been done. Baits are less successful with extreme
drouth or excessive rainfall. Carbaryl or trichlorfon
liquid sprays or spray baits are also effective, but
must be directed at the base of the plants."
48
-------
According to the estimates by the U. S. Department of
Agriculture (1968b,1970b, 1974) mentioned in Sec. IV above, the use
of insecticides on corn in the "corn belt" (Illinois, Indiana, Iowa,
Missouri, and Ohio) was 10.8 million Ibs. in 1964; 17.5 million Ibs.
in 1966; and 15.3 million Ibs. in 1971 (Table 9). A comparison of
these figures to the quantities of insecticides used on corn in the
entire U. S. (Table 16) indicates that 69% of all corn insecticides
were used in the five corn belt states in 1964; 74% in 1966; and
60% in 1971.
The USDA1s estimate of the quantity of insecticides used
on corn in the corn belt states in 1971 (15.3 million Ibs.) is
surprisingly low, and difficult to reconcile with the data reported
by Petty (1974) and Stockdale (1971). Combining Petty's and
Stockdale's well supported estimates on the corn acreage treated
with insecticides in Iowa and Illinois in 1971 with the corresponding
rates of application, the quantities used would be as follows:
Soil insecticides:
Chlorinated
hydrocarbons
Other insecticides
Subtotals
Totals, both states
Foliar insecticides
corn borers, cutwoi
grasshoppers) :
Totals
Acres Treated (000)
Iowa
2,750
3,750
Illinois
2,200
3,800
6,500 6,000
J 12,500
against
rms and
3,000
15,500
Rate
Lbs. AI
/Acrel/
1.3
1.0
1.5
Total
Quantity
Lbs. AI (000)
6,435
7,550
13,985
4,500
18,485
I/ Table 10; Wiersma et al. 1972; Carey et al. 1973
49
-------
Table 16:
Quantities of Insecticides Used on Corn in the U.S., and
on Farm Crops in the Corn Belt in 1964, 1966 and 1971,
By Chemical Groups.
Chemical
Group
Chlorinated
Hydrocarbons
Organic
Phosphates
Carbamates
Others2/
All Insecticides
Corn/United States
1964 1966
12,160 16,226 10
3,390 6,733 7
107 669 7
11 1
15,668 23,629 25
1971
Ibs. of
,046
,515
,905
65
,531
All Crops/Corn
1964 1966
active ingredients -
11,790 15,599
1,709 3,568
547 2,290
312
14,358 21,457
Belt1/
1971
9,651
4,313
3,815
645
18,424
Ul
o
I/ Corn Belt = Illinois, Indiana, Iowa, Missouri, and Ohio.
2/ Primarily inorganic insecticides.
Sources: U. S. Department of Agriculture, 1968b, 1970b, 1974.
-------
According to these estimates, the quantities of insecti-
cides used on corn in Iowa and Illinois alone in 1971 exceed the
USDA estimate for the entire corn belt (Table 9) by more than
3 million Ibs. Iowa a*nd Illinois raised 64% (21.8 million acres)
of all corn acres in the corn belt (33.9 million acres) in 1971
(U. S. Dept. of Agriculture,(1972a). Based on these figures, it
would appear that at least 25 million Ibs. of insecticides must
have been used on corn in the corn belt in 1971.
The U. S. Department of Agriculture (1968b, 1970b, 1974)
estimates do not include breakdowns of quantities of insecticides
by regions, individual crops, and types of insecticides, herbicides
and fungicides. However, breakdowns by types of pesticides are
given by crops for the nation, and for all crops by regions.
Table 16 summarizes the quantities of insecticides by (chemical
groups) used on corn in the U. S. (left part of table) and on all
farm crops in the corn belt (right part of table), for the years
1964, 1966, 1971.
The five corn belt states (Illinois, Indiana, Iowa,
Missouri and Ohio) raised 53% (33.9 million acres) of the total
U. S. corn acreage (64.0 million acres) in 1971. Again, the
USDA's estimate of the quantity of insecticides used on corn in
the entire U.S. in 1971, 25.5 million Ibs., appears to be
unrealistically low. As pointed out in the preceding paragraphs,
there is good reason to believe that at least that quantity of
insecticides was used on corn in the corn belt states alone in
1971.
51
-------
The right part of Table 16 lists all insecticides used
on all crops in the corn belt by years and by chemical groups.
Again, the quantities at least for 1971 appear to be unrealistically
low. The USDA estimates total use of all insecticides on all crops
in the 5-state region in 1971 at 18.4 million Ibs., whereas other
data indicate that more than 25 million Ibs. of insecticides were
used on corn alone.
Thus, there are some questions regarding the quantitative
aspects of these USDA pesticide use estimates. However, the trends
that they reflect (both parts of Table 16) agree well with data
from other sources, indicating a substantial increase in the use
of insecticides on corn in the mid- and late 1960's, and a slowing
down or levelling off of this trend beginning about 1970 (see also
Tables 13 and 14). The share of chlorinated hydrocarbon insecticides
in the total use is declining, with a proportional increase in the
use of organic phosphate and carbamate insecticides.
The use of insecticides on corn in Iowa and Illinois
during the last three years appears to continue on the same general
trend. Table 17 reports the corn insecticide use practices of the
Iowa and Illinois corn growers surveyed in this study in 1973 and
correlates our findings with the estimates by Petty (1974) and
Stockdale (1971, 1973) already cited, and with four other previous
surveys (identified in the explanations to Table 17).
These data indicate that during the last four years,
50-60% of the growers in Iowa and Illinois used insecticides on
corn, and that roughly the same percentage of the total corn
acreage in both states was treated. In our survey of Iowa and
Illinois farmers in 1973, it was found that 57% of the corn acres
in Iowa and 50% of those in Illinois followed soybeans in the
rotation (Table 4). These figures agree well with those in Table 17
and suggest that many growers believe, along with Iowa and Illinois
52
-------
Table 17: Use of Soil Insecticides on Corn
in Iowa and Illinois, 1966 - 1973
Year
1966
1967
1968
1969
1970
1971
1972
1973
Percentage of
Growers Using Soil
Insecticides on Corn
Iowa
54% (7)
57% (9)
53% (11)
Illinois
56% (8)
48% (10)
70% (11)
Percentage of
Corn Acres Treated
with Soil Insecticides
Iowa
56% (2, 5)
42% (2)
Illinois
53% (1, 3)
58% (1, 4)
62% (1, 4)
67% (1, 5)
66% (1, 5)
60% (1, 5)
54% (1, 6)
I/ Corn acres harvested for grain.
Sources:
(1) Petty, 1974. (2) Stockdale, 1971, 1973.
(3) U. S. Dept. of Agriculture, 1968a.
(4) U. S. Dept. of Agriculture, 1970a.
(5) U. S. Dept. of Agriculture, 1972a.
(6) Illinois Cooperative Crop Reporting Service, 1973a,
(7) Wallaces Farmer, 1970; responses from 702 Iowa corn growers.
(8) Prairie Farmer, 1970;. responses from 636 Illinois corn
growers.
(9) Wallaces Farmer, 1972; responses from 667 Iowa corn growers,
(10) Prairie Farmer, 1972; responses from 608 Illinois corn
growers.
(11) This study, 1973; responses from 58 Iowa and 239 Illinois
corn growers farming more than 320 acres.
53
-------
University research and extension entomologists, that corn
following soybeans in the rotation rarely requires insecticide
treatments.
A list of the major insecticides used on corn in Iowa
and Illinois in 1970, 1972 and 1973 is given in Table 18. It is
interesting to note that during this four-year period, the use
of the chlorinated hydrocarbon insecticides, aldrin and heptachlor,
remained essentially unchanged or perhaps even increased slightly
in Iowa, whereas their use showed a downtrend in Illinois. These
divergent trends in the two states parallel the divergent policies
of the Iowa and Illinois extension agencies concerning the need
for continued use of chlorinated hydrocarbon insecticides on corn.
The use of organic phosphate insecticides (phorate,
diazinon and Dyfonate) is on a slightly increasing trend according
to Table 18. Among the carbamates, the use of carbofuran is
increasing strongly, while the use of metalkamate seems to be
rapidly declining in both states.
Concerning cost of corn insecticides, 50% of the corn
insecticide users in both states in our 1973 survey reported that
they had experienced a cost increase during the last 5 years; 9% in
each state reported a decrease; the remaining respondents felt
that costs had remained about the same. Those growers that reported
cost increases stated that they ranged from 2 to 200%; the average
increase reported was 28% in Iowa, 25% in Illinois.
Most corn soil insecticide users were well satisfied with
the effectiveness of the products they used during the last two years,
All of the Iowa respondents reported satisfactory or better suppres-
sion of insects in both years. Only 4% of the Illinois corn insecti-
cide users felt that control was unsatisfactory in 1973; 8% were
dissatisfied in 1972. More than 90% of the corn soil insecticide
users in both states felt that their money for these products was
well spent. Some 6% of the respondents in both states felt they
54
-------
Table 18: Use of Major Corn Soil Insecticides in Iowa and Illinois
by Products in 1970, 1972 and 19731/
Insecticide
Aldrin
Heptachlor
Phorate
Diazinon
Dyfonate
Carbofuran
Metalkamate (Bux)
Iowa
19702/
19723/
1.9736/
Illinois
19704/
19725/
19736/
Percent of Corn Soil Insecticide Users
41
17
23
6
4
4
38
35
8
29
4
7
15
32
49
18
30
negl.
6
24
12
49
25
18
14
2
4
10
43
11
19
21
8
12
10
32
14
18
18
13
13
5
I/ Totals do not add up to 100 because minor products are not
included, and because many growers used more than one product.
Sources:
2/ Wallaces Farmer, 1970; responses from 377 Iowa corn soil
insecticide users.
3/ Wallaces Farmer, 1972; responses from 375 Iowa corn soil
insecticide users.
4/ Prairie Farmer, 1970; responses from 341 Illinois corn soil
insecticide users.
5/ Prairie Farmer, 1972; responses from 292 Illinois corn soil
insecticide users.
6/ This study, 1973; responses from 33 Iowa and 157 Illinois
corn soil insecticide users farming more than 320 acres.
55
-------
should have spent more money for corn insecticides in 1972. In
both years, about 6% of the Illinois respondents felt that their
money for corn insecticides was wasted, while none of the Iowa
respondents felt that way in either year.
D. Side Effects from the Use of Corn Insecticides
The data presented in the preceding sections of this
chapter, especially in Tables 14, 15, 16 and 18, document that
chlorinated hydrocarbon insecticides have been used extensively in
Iowa and Illinois during the last two decades. It is estimated that
aldrin accounted for 80 to 90% of the total use of chlorinated hydro-
carbon insecticides in the area during that period. Thus, aldrin
has been used in both states in much larger quantities cumulatively
than any other insecticide.
Aldrin residues are metabolized to its more stable epoxida-
tion product, dieldrin, after application. In the 1969 National Soils
Monitoring program for Pesticides (Wiersma et al. 1972), Illinois had
the highest aldrin-dieldrin soil residues of any state. Dieldrin
residues were found in 61.3% of the 142 samples from the state that
were analyzed, ranging from 0.01 - 1.42 ppm; the mean level was
0.11 ppm. Aldrin residues were present in 42.2% of the Illinois
samples, ranging from 0.01 - 2.24 ppm; the mean level was 0.13 ppm.
In Iowa, dieldrin residues were found in 53.6% of 151
samples analyzed; they ranged from 0.01 - 0.42 ppm, the mean level
was 0.60 ppm. Aldrin residues were present in 31.8% of the Iowa
samples, ranging from 0.01 - 1.37 ppm, the mean level was 0.04 ppm.
By comparison, dieldrin residues were found in 27.8% of
1,729 samples collected nationwide; they ranged from 0.01 to 1.60 ppm,
and the mean level was 0.03 ppm. Aldrin residues were present in
10.9% of the samples from all states, ranging from 0.01 - 3.06 ppm;
the mean level was 0.02 ppm.
56
-------
In a follow-on study by Carey et al. (1973), 400 soil
samples were obtained in 1970 from 12 states in the corn belt region.
Illinois again had the highest dieldrin residues among all 12 states
included in this survey. Dieldrin residues were found in 66.7% of
69 soil samples from Illinois that were analyzed; they averaged
0.14 ppm, and ranged from 0.01 - 1.08 ppm. In Iowa, dieldrin resi-
dues were found in 55.3% of 76 samples analyzed, averaging 0.10 ppm
and ranging from 0.01 to 1.03 ppm.
In the same study, Carey et al. also found dieldrin resi-
dues in 9.7% of 145 samples of cornstalks, and in 56% of 75 soybean
samples that were analyzed. 2.7% of the soybean samples also con-
tained residues of heptachlor epoxide, the metabolite of heptachlor.
No heptachlor epoxide residues were found in any of the cornstalk
samples. No tolerances have been established for residues of these
products in soybeans.
During 1969-70 in Illinois, a total of 27 dairy farms were
found to be producing milk containing illegal amounts of chlorinated
hydrocarbon insecticide residues and, in 1971, the Illinois Depart-
ment of Public Health found dieldrin residues approaching an illegal
level in a sample of cheese taken from a northern Illinois manufact-
urer.
Moore et al. (1973) recently reported on a study
conducted to determine the sources of this chlorinated hydro-
carbon insecticide contamination. They concluded that the chances
of dieldrin residues in milk exceeding the administrative guide-
line of 0.3 ppm (fat basis) were greatest on dairy farms where
aldrin soil treatments were applied within the last six or seven
years. They predict that additional dairy herds, but in lessening
numbers, will be found producing milk with illegal residues for
about 4 to 6 more years.
Hay and oat straw were found to supply significant amounts
of dieldrin to dairy cattle. In addition, roasted soybeans, a
relatively new dairy cattle feed, appeared to be an important poten-
57
-------
tial source of dieldrin contamination. Corn silage, commercial feeds,
and well water usually were not important sources of dieldrin con-
tamination. Overall, there was a definite correlation between the
dieldrin soil residues on each farm and the level of dieldrin found
in the milk.
The Iowa State Cooperative Extension Service warned Iowa
dairymen in several news releases during the summer of 1973 against
using home-roasted or raw soybeans grown on soil treated with chlor-
inated hydrocarbon insecticides in dairy rations. It was pointed out
that soybeans grown on soil treated with aldrin, heptachlor or
chlordane within the last four years may contain residues of these
insecticides.
In both Iowa and Illinois, dieldrin residues have also been
found in meat animals, poultry, and eggs; and in wildlife, fish,
rivers, lakes and streams.
A voluminous literature deals with the problems of residues
of aldrin and dieldrin in humans, foods, feeds, and in many elements
of the environment including soils, water, air, wildlife, etc., and
with their significance. A detailed discussion of these complex
problems would be beyond the scope of the present study; suffice
it to refer to the comprehensive reviews of the subject by Mrak
(1969) and by Pimentel (1971), the latter with special reference
to the ecological effects on nontarget species.
Residues of heptachlor, heptachlor epoxide, chlordane
and DDT were also found in a relatively high percentage of soil
samples from Iowa and Illinois in the studies by Wiersma et al.
(1972) and Carey et al. (1973). DDT was used on corn in the midwest
against the European corn borer in the past, but that use subsided
when resistant corn hybrids became available.
It is thus evident that the heavy use of chlorinated
hydrocarbon insecticides, especially aldrin, in Iowa and Illinois
58
-------
has resulted in widespread persistent residues in the environment.
How soon actual soil residue levels will reflect the declining
use of these chemicals in Illinois remains to be seen. It is well
known and documented that due to their persistence, these residues
degrade very slowly, and that they bioaccumulate and build up in
food chains. The significance of these findings is widely debated,
and many divergent opinions have been presented in the course of
the current nationwide hearings on aldrin and dieldrin. The de-
tection of dieldrin residues in milk, soybeans and other produce,
the resulting bad publicity, adverse reactions on the part of
buyers of farm products, and the possibility of legal actions
against farm products bearing illegal pesticide residues are pro-
bably more real and comprehensible to Iowa and Illinois farmers
than the more subtle environmental effects. The actual and poten-
tial economic consequences of the widespread presence of these
chlorinated hydrocarbon insecticide residues thus have undoubtedly
contributed to grower compliance with the Illinois Extension
Service's recommendations against the further use of these products.
Such compliance is likely to be further encouraged by the widely
publicized detection of dieldrin residues in chicken feed in
Mississippi and other states that occurred recently.
The development of resistance to aldrin and other chlor-
inated hydrocarbon insecticides in target insects, another undesirable
side effect, has already been covered above in Section C of this
Chapter and is mentioned again here only for completeness1 sake.
The organic phosphate and carbamate insecticides used on
corn have not produced any major undesirable side effects, as far
as is known to date. They are generally much less persistent in
the soil and in other elements of the environment, and their resi-
dues decline during the growing season. They do not biomagnify in
59
-------
food chains. Phorate and carbofuran are highly toxic to humans
and other mammals in highly concentrated form. Liquid concen-
trates of these products require appropriate safety precautions
and care in handling, while granular formulations are somewhat
less hazardous to operators.
There are indications that some target insects are
becoming more difficult to control with organic phosphate or
carbamate insecticides.
E. Alternative to Chemical Control of Corn Insects.
In the farmer survey conducted in this project, 53%
(31 of 58) of the Iowa respondents and 70% (165 of 237) of those
in Illinois used insecticides on corn in 1973. Only slightly
more than one-half of the corn insecticide users (18 of 33 in
Iowa; 93 of 170 in Illinois) believed that all of their corn acres
need insecticide treatments each year, that is only about one-third
of all corn growers interviewed. Apparently, the use of corn
insecticides is considered essential by a much smaller percentage
of growers than the use of herbicides on corn or soybeans
(Table 11). Consistent with this finding, 97% of 33 corn insect-
icide users in Iowa, and 94% of 172 in Illinois would continue to
grow corn if no insecticides were available. In reply to the
question what they would do in this event to minimize insect
damage, responses from 31 Iowa and 150 Illinois farmers were as
follows:
60
-------
Iowa Illinois
% Respondents
Rotate crops 58 65
Till and/or cultivate more 19 4
Nothing 10 9
Other alternatives, each mentioned by less than 10% of
the respondents in either state, included growing fewer acres of
corn; planting thicker, later, or resistant varieties; treating
seed with livestock dip (I); harvesting earlier; fertilizing more;
seeking advice from the university; writing to politicians; and/or
praying.
Corn insecticide users in this survey were also asked if
they would change their insecticide use patterns if the cost of in-
secticides were twice as high as what they actually paid. Those
respondents (8 = 24% in Iowa; 68 = 40% in Illinois) who answered yes
were asked what changes they would make. This question served to find
out how growers might reduce their use of insecticides on corn if
need be. Replies from 8 Iowa and 66 Illinois respondents were as
follows:
Iowa Illinois
% Respondents
Grow fewer acres of corn 38 9
Treat fewer acres with insecticide 25 26
Change crop rotation 25 9
Use lower rate of insecticide 13 21
Use insecticide only if and when
loss occurs 13 0
Other alternatives mentioned by fewer than 10% of the
respondents in either state included using a less expensive product;
spraying corn rootworm adults; asking county agent; cultivating more;
and/or praying.
61
-------
As mentioned earlier, only about one-third of all corn
growers interviewed in both states felt that all of their corn acres
need chemical insecticides each year. Those growers (15 in Iowa;
77 in Illinois) who felt that only some of their corn fields need
insecticides were then asked: "How do you decide which corn acres
to treat and which not?" Responses from 15 Iowa and from 73 Illinois
growers were as follows:
Iowa Illinois
% Respondents
Treat only corn on corn 73 33
Treat only corn on sod 20 18
Treat all corn acres regardless 20 4
Treat only corn on soybeans 0 5
Treat only the seed 0 4
Additional responses, each mentioned by only a few respon-
dents, included considering crop history, weather, last year's insect
infestation level, neighbors' crops, soil type, etc. One respondent
summed up a common dilemma: "Don't know how to tell if I need
control chemicals, so I apply to all acres".
No effective, commercially feasible nonchemical methods
for the control of soil insects are currently available other than
those perceived by the growers themselves, and already practiced by
many of them. Substantial research efforts are in progress toward
the development of alternative insect control methods, and of inte-
grated insect management programs for corn. Development of better
and more reliable diagnostic and predictive methods with a view to
the reduction of unnecessary treatments is one important objective.
Other avenues that are currently being pursued by re-
searchers include the use of insect growth regulators, and of micro-
bial agents including Bacillus thuringiensis and nuclear polyhed-
rosis viruses. However, neither insect growth regulators nor micro-
bial agents have thus far shown much promise for the control of soil
62
-------
insects and thus are not realistic alternatives to the use of
chemical insecticides at the present time (Diekman, 1974;
Maddox, 1974).
Breeding of resistant corn varieties is another approach
being pursued at the research level. Traits being sought include
greater plant tolerance to corn rootworm feeding, greater regener-
ative power of the corn root system, and corn silks that may
adversely affect the fecundity and longevity of corn rootworm
adults. However, improved corn varieties with one or more of these
desirable features are not available to growers as yet.
Both the University of Illinois and Iowa State University
participate in a multi-state corn pest management project supported
by the U. S. Department of Agriculture and the Environmental Protect-
ion Agency. Work under this project was started in 1973.
In Iowa, a pilot scouting program was set up in Hamilton
County, in the central part of the State. 25 corn growers partici-
pated. Throughout the growing season, one scout made surveys of
wireworm, cutworm, European corn borer, corn rootworm, aphid, and
beneficial insect populations. All populations surveyed were deter-
mined to be below economic thresholds. Consequently, no control
measures were recommended or applied. In addition, weeds were
surveyed twice during the growing season, the first time in June
to determine approximate levels of herbicide efficiency, the second
time in July. Soil samples were taken from the project area to be
analyzed for pesticide residues, and plans were made for a data
storage and retrieval system (Hintz et al. 1973).
For 1974, Iowa plans to continue the program in Hamilton
County, and to add a survey of green cloverworms in soybeans. In
addition, surveys are to be started in Henry and Lee Counties on
corn, soybeans (green cloverworms) and alfalfa (alfalfa weevil).
Similar efforts are in progress in Illinois (Luckmann
et al. 1974).
63
-------
F. Summary.
Corn in I'owa and Illinois is attacked by three species
of the corn rootworm (at least two of them resistant against
chlorinated hydrocarbon insecticides); by a complex of additional
soil insects; and by some foliar insects. The foliar insects are
economically much less important than the soil insects.
Soil insecticides are currently used on SO to 60% of all
corn acres in Iowa and Illinois. This use has declined somewhat
from a peak in 1969/1970. It is estimated that more than one-half
of the corn acres currently being treated with soil insecticides
do not need the treatment. However, diagnostic and predictive
methods available to growers are not adequate, and it is often
difficult for them to decide whether or not to treat. Thus, this
insecticide use appears to be a partially wasteful practice from
the overall standpoint while to many individual growers, it is a
necessary protective measure. According to estimates by Illinois
entomologists, Illinois corn growers realized cumulative net profits
from the use of corn soil insecticides of the order of about $250
million during the ten year period, 1964-1975.
Until about 1970, chlorinated hydrocarbon insecticides
(80-90% aldrin) were used on about two-thirds of all corn acres
treated with soil insecticides. Since that time, the less persistent
organic phosphate and carbamate insecticides have increasingly re-
placed chlorinated hydrocarbons. The latter presently account for
almost two-thirds of the total corn acreage treated with soil
insecticides in the two states.
Aldrin residues (including dieldrin, a principal metabolite
of aldrin) were found in a high percentage (54 to 67%) of soil
samples from Iowa and Illinois. Aldrin/dieldrin residues have also
been found in milk, meat, poultry, eggs and soybeans produced in
the area, as well as in wildlife, fish, rivers, lakes and streams.
64
-------
A number of target insects have developed varying degrees of
resistance to chlorinated hydrocarbon insecticides. The organic
phosphate and carbamate insecticides used on corn have not produced
any major undesirable side effects to date, as far as is known,
except for the development of resistance in target insects in some
instances.
Among the farmers surveyed in this study, 53% of the
Iowa respondents and 70% of those in Illinois used corn insecticides
in 1973. Only slightly more than one-half of the corn insecticide
users in both states, that is only about one-third of all corn
growers interviewed, believed that all of their corn acres need
insecticide treatments each year. Consistent with this finding,
97% of the corn insecticide users in Iowa and 94% of those in
Illinois would continue to grow corn if no insecticides were
available.
Crop rotation is the most effective currently available
nonchemical method to suppress corn soil insects. However, growers'
crop rotation decisions are governed primarily by factors other
than crop protection considerations. No effective, commercially
feasible nonchemical methods for the control of corn soil insects
are currently available. Substantial research efforts are in pro-
gress toward the development of better corn insect prediction and
control methods, and of integrated insect management systems, but
these have not been perfected at the grower level as yet.
65
-------
VI. SOYBEAN INSECTS
Until recently, soybeans had fewer economically important
insect problems than most other field crops. For instance, the
widely used textbook on insects by Metcalf, Flint and Metcalf (1962)
contains a little more than one page of text on soybean and cowpea
insects, compared to 58 pages on insects injurious to corn.
Soil insects are generally not a problem on soybeans.
Foliar insects, especially the green cloverworm, Plathypena scabra,
build up to serious proportions on soybeans in the midwest only
occasionally, last in 1966 and 1968. However, 1973 was another
such year, and green cloverworms caused considerable concern to
entomologists as well as to soybean growers in Iowa and Illinois.
Randell et al. (1974) estimate that about 736,000 acres of soybeans
in Illinois were treated against this insect in 1973, and that
growers realized a profit of $1.1 million above the cost of treat-
ment from using insecticides (Table 12).
The Illinois insect control recommendations for 1973
advised treating against the green cloverworm when 6 or more worms
per foot of row are present. As the 1973 growing season progressed,
soybean prices skyrocketed (Table 8). In its "Insect, Weed and
Plant Disease Survey Bulletin" that is issued weekly during the grow-
ing season, the Illinois Extension Service advised on July 20, 1973
(No. 18, page 3):
"Normally, 6 (green clover) worms per foot of row are
considered damaging. We will reduce that to 3 or 4 this
year."
This recommendation was reiterated in subsequent issues of
Illinois' Insect, Weed and Plant Disease Survey Bulletin.
By contrast, Iowa's "Insect Pest Control Recommendations
for 1973", IC-328 (Rev.), February, 1973, contained the following
66
-------
advice on the control of soybean insects:
"The importance of treatment for the insects listed
(bean leaf beetle, green cloverworm, thistle cater-
pillar, garden webworm, grasshopper) depends on the
number of insects present and the stage of growth of
the soybeans. At Stage 7 (pods filling) 50% defolia-
tion reduces yield 18%. A population of 10 grass-
hoppers per square yard in field edges will defoliate
beans completely; 20 to 25 green cloverworms per
linear foot of row will cause 25 to 30% defoliation."
The Iowa Insect, Weed and Plant Disease Newsletter of
July 23, 1973, IC-405 (12) stated that the economic injury level of
green cloverworms (when yields are reduced by more than the cost of
treatment) is 18 to 20 worms per foot of row at Stage 7 (pod fill)
of the soybeans, based on experimental data. Growers were further
advised that green cloverworm populations are subject to parasites,
predators and weather conditions.
In the Newsletter of August 20, 1973, IC-405 (16), a treat-
ment threshold of 15 to 20 green cloverworms per foot of row was
reiterated, along with the statement:
"Green cloverworms are parasitized by wasp and fly
parasites and also victimized by insect pathogens
so treatment of fields at subeconomic levels not only
wastes money, it also slows the buildup of these
natural control agents."
Not surprisingly, pesticide salesmen made more use of the
Illinois than of the Iowa soybean insect control recommendations.
Their efforts received considerable support from the fact that an
insecticide treatment costs only $2.00 - 3.00/acre (including cost
of application), equal to the value of less than one-half bushel of
soybeans during the summer of 1973 (Tables 8, 10).
Recent experiences in southeastern and southern soybean
growing areas of the U. S. indicate that increased use of insecticides
on soybeans may well lead to progressive destruction of natural
control factors, need for more insecticides, etc. An effective
67
-------
insect management program for soybeans would thus seem to be
most desirable for the midwest at this time where this develop-
ment has not started as yet.
68
-------
VII. CORN WEEDS
A. Major Weeds
In the midwest, several major weeds compete with corn
for water, nutrients, sunlight, and other growth factors, and
threaten to reduce yields, interfere with planting, tilling and
harvesting operations, and result in the further propagation of
weeds through the spreading of weed seeds. Table 19 lists the
five most important corn weeds in Iowa and Illinois by percent
of the total corn acreage infested, based on information provided
by Federal and State weed specialists in a nationwide survey on
weeds conducted in 1968 (U. S. Dept. of Agriculture, 1972b).
Foxtails, velvetleaf and smartweed were considered
serious corn weeds in both states. Fall panicum and nutsedge
rated among the five most important weeds only in Illinois, and
cocklebur and sunflower only in Iowa.
B. Losses Due to Corn Weeds and Benefits from Their Control
Weed scientists in Iowa and Illinois estimate that weeds
reduce corn yields by up to 10 bu./acre in many "ordinary", not
catastrophically weedy fields.
Slife (1973) studied annual net profits from the use of
herbicides as compared to cultural practices for continuous corn,
and for different corn rotations over a 6-year period, 1966 to 1971,
Table 20 summarizes Slife1s results for continuous corn. The treat-
ments compared were (1) broadcast application of the same herbicide
(atrazine) each year with one cultivation, (2) broadcast applica-
tion of a different herbicide each year with one cultivation, and
(3) no herbicide with three timely cultivations. Cost figures per
acre were assigned to each crop for all production and harvesting
operations. Each cultivation was charged at the rate of $1.50/acre.
69
-------
Table 19 : Five Most Important Corn Weeds
in Iowa and Illinois, 1968
Percent of Total Soybean
Acreage Infested
Weeds
Giant foxtail, Setaria faberi
Foxtails, Setaria spp.
Smartweed, Polygonum spp.
Velvetleaf, Abutilon theophrasti
Fall panicum, Panicum dichotomif lorum
Nutsedge, Cyperus spp.
Cocklebur, Xanthium spp.
Sunflower, Helianthus spp.
Iowa
I/
90%
50%
60%
2/
2/
50%
10%
Illinois
50%
I/
25%
25%
15%
10%
2/
2/
I/ Not available.
2/ Not included among five most important problem weeds
in the state.
Source: U. S. Department of Agriculture, 1972b.
70
-------
Table 20 : Average Annual Costs and Returns from Different
Methods of Controlling Weeds in Continuous Corn
in Illinois Over a Six-Year Period, 1966 - 1971
Average Annual
Costs and Returns
Per Acre
Atrazine
Plus One
Cultivation
Different
Herbicide
Plus One
Cultivation
No
Herbicide,
Three
Cultivations
Cost of production
except weed control
Cost of cultivation(s)
Cost of herbicide
Cost of herbicide
application
$ 90.13
1.50
8.43
1.50
Total average production cost 101.56
Total average gross return 130.76
Total average net return
29.20
$ 90.13
1.50
8.93
1.50
102.06
136.47
34.41
$ 90.13
4.50
94.63
102.94
8.31
Source: Adapted from Slife (1973).
71
-------
Each of the herbicide treatments were charged with one cultiva-
tion, the cost of the.herbicide, and the cost of application of
the herbicide ($1.50/acre). The figures reported in Table 20 are
the average net returns per acre under the three weed control
systems over the 6-year period.
In 1967 and in 1969, the corn plots treated with herbi-
cide produced enough net income over the plots receiving cultivation
only to just cover the cost of the herbicide and its application,
but no more. In these two years, the cultivated plots did not suf-
fer great yield reductions because weeds were adequately removed
by cultivation only. In the other four years, cultivation alone
did not control weeds sufficiently, and yield reductions were
substantial.
Slife concludes from these results that over the 6-year
period covered by his study, three timely cultivations were gener-
ally not adequate to prevent yield reduction from weeds, and that
there is a direct economic return from the use of herbicides on
corn whenever moderate or heavier infestations of weeds can be ex-
pected. Rotation of herbicides was more advantageous than the
continuous use of atrazine.
Slife1s 6-year experiment also included a corn-corn-
soybeans and a corn-soybeans-wheat rotation. Average net return
data were obtained in the same manner as described for the contin-
uous corn. For the corn-corn-soybeans rotation, the average net
returns per acre were $49.01 for the same herbicide plus one culti-
vation; $55.62 for a different herbicide each year plus one culti-
vation; and $35.46 for three cultivations without herbicide.
For the corn-soybeans-wheat rotation, average net returns
per acre were $40.77 for the same herbicide plus one cultivation;
$45.47 for a different herbicide each year plus one cultivation;
and $33.82 for three cultivations without herbicide.
72
-------
All of these dollar returns from weed control were
computed on the basis of farm prices for corn that prevailed dur-
ing the period when the tests were conducted. These returns would,
of course, be even greater in terms of the corn prices of 1972 and
1973 because the costs of producing corn and of corn herbicides
have not increased nearly as much as the average corn prices re-
ceived by farmers, which doubled from 1971 to 1973 (Table 1).
The Iowa and Illinois corn herbicide users interviewed
in this study in 1973 were asked what benefits they obtain from
the use of herbicides. Replies from 58 Iowa and 230 Illinois re-
spondents to seven check-off-type questions were as follows:
Iowa Illinois
% Respondents
Control weeds 100 96
Save cultivating 95 70
Good-looking fields 93 52
Save labor 78 65
Save tilling operations other 2 9
than cultivating
Facilitate planting 0 8
No benefits 0 0
Additional, unstructured write-in replies under "addi-
tional benefits" included the following, in decreasing order of
frequency mentioned: Increased yield; facilitates harvesting,
sleep sounder; saves time; prevents spreading of weeds; facili-
tates fall plowing; controls erosion; produce weed-free seed.
It is thus apparent that growers believe that they de-
rive substantial benefits from the use of herbicides on corn.
73
-------
C. Use Patterns of Herbicides on Corn
The use of herbicides on corn in the five corn belt
states (Illinois, Indiana, Iowa, Missouri, and Ohio) increased
from 12.6 million Ibs. in 1964 to 27.5 million Ibs. in 1966 (in-
crease of 118%), and to 54.1 million Ibs. in 1971 (increase of
97% from 1966), according to the U. S. Department of Agriculture
(1968b, 1970b, 1974. Thus, the quantities of herbicides used on
corn in this area more than quadrupled during the 8-year period,
1964-1971 (Table 9).
In the survey of Iowa and Illinois farmers conducted in
this study, all of the Iowa corn growers and 99% of the Illinois
corn growers reported that they used herbicides on corn in 1973.
Additional data on the use of herbicides on corn in the two states
are available from surveys conducted by two farm magazines in 1970
and in 1972.
Wallaces Farmer (1970, 1972) surveyed Iowa corn growers..
Of the respondents who raised 100 acres or more of corn, 96% of
287 respondents in 1970, and the same percentage of 212 respondents
in 1972 used herbicides. In the same surveys, 77% of the total
corn acreage of 696 respondents was treated with chemical herbicides
in 1970, and 79% of the total corn acreage of 663 respondents in
1972.
In a survey of Illinois corn growers by Prairie Farmer
(1970, 1972), 97% of 306 growers who raised more than 100 acres of
corn in 1970, and also 97% of 289 growers who raised more than
100 acres of corn in 1972 used herbicides. In the same surveys,
85% of the total corn acreage of 633 respondents was treated with
herbicides in 1970, and 89% of the total corn acreage of 608
growers in 1972.
According to these findings, more than 95% of the larger
corn growers in both states use chemical herbicides, and between
74
-------
80 and 90% of all corn acres in Iowa and Illinois are treated with
chemical herbicides. Since some corn acres receive both pre- and
postemergence treatments (Illinois Cooperative Crop Reporting Ser-
vice, 1973b, U. S. Dept. of Agriculture, 1972b), the number of "gross"
corn acres (acres treated more than once counted for each treat-
ment) considerably exceeds the number of total corn acres harvested.
Table 21 summarizes the use of major individual corn herb-
icides in Iowa and Illinois in 1970, 1972 and 1973, as derived from
the farmer survey conducted in this project, and from Wallaces
Farmer's and Prairie Farmer's 1970 and 1972 surveys. All three sur-
veys indicate that atrazine is the most frequently used corn herbi-
cide in both states. In 1973, the two triazine herbicides, atrazine
and cyanazine, combined were used by more than 80% of the Iowa corn
growers interviewed, and by almost 70% of their counterparts in
Illinois. The two anilide herbicides, propachlor and alachlor, were
also used heavily in both states. Butylate, a thiocarbamate herbi-
cide, was first introduced in the late 1960's and has rapidly in-
creased in volume in Iowa and Illinois during the last four years.
2,4-D continues to be used by about one-third of the corn growers in
both states, primarily as a postemergence treatment against broad-
leaf weeds.
In our 1973 farmer survey, 97% of the Iowa and 94% of the
Illinois corn herbicide users considered efficacy of these products
during the last two years satisfactory or better. None of the Iowa
respondents, and only 2.2% (3.6% in 1972) of the Illinois respondents
felt that the money they spent for corn herbicides was wasted.
About 10% of the respondents from both states felt that they should
have spent more money for corn herbicides in 1972 and 1973. The
great majority of all corn herbicide users in both states (about 90%)
felt that their money for corn herbicides was well spent in both
years.
75
-------
Table 21: Use of Major Corn Herbicides in Iowa and Illinois
by.Products in 1970, 1972 and 1973
Herbicide
Atrazine
Cyanazine
Propachlor
Alachlor
Butylate
2,4-D
Iowa
19702/
19723/
19736/
Illinois
19704/
19725/
19736/
Percent of Corn Herbicide Users
48
negl.
33
6
4
43
61
5
29
21
8
29
62
21
40
17
33
33
60
negl.
38
6
8
27
59
2
29
22
15
22
60
8
43
20
34
33
I/ Totals do not add up to 100 because minor products are not
included in this table, and because many growers used more
than one product.
Sources:
2/ Wallaces Farmer, 1970; responses from 610 Iowa corn
herbicide users.
3/ Wallaces Farmer, 1972; responses from 552 Iowa corn
herbicide users.
4/ Prairie Farmer; 1970; responses from 537 Illinois corn
herbicide users.
5/ Prairie Farmer, 1972; responses from 523 Illinois corn
herbicide users.
6/ This study, 1973; responses from 58 Iowa and 217 Illinois
corn herbicide users farming more than 320 acres.
76
-------
About 69% of the Iowa corn herbicide users (40 of 58),
and 42% of those in Illinois (95 of 228) changed products at least
once since 1970. Those that did were asked why. The following
reasons were given by 40 Iowa and 88 Illinois respondents:
Iowa Illinois
% Respondents
Want to increase spectrum of
weed control 20 66
Concerned about carryover of
herbicide residues 35 9
Change to broadcast application 18 6
Weather 15 5
Changed to preplant application 8 0
Cost of herbicide 3 5
Change of, or difficulty with
equipment 3 5
Almost two-thirds of the corn herbicide users in both
states reported that their cost ($ per acre) for corn herbicides
had increased during the last five years; 5% of the respondents
reported a cost decrease; the remainder felt that the cost of herbi-
cides had remained about the same. Reported increases in the cost
of corn herbicides ranged from 5 - 100% in Iowa, from 3 - 400% in
Illinois, averaging 23% in Iowa, 38% in Illinois.
A high percentage of the corn herbicide users in both states
(88% = 51 of 58 in Iowa; 82% = 189 of 230 in Illinois) believe that all
of their corn acres need herbicide treatments each year. Of those who
did not think so, about 60% (3 of 5 in Iowa; 24 of 41 in Illinois)
stated that they treat only the weedy areas, whereas the remainder
treat all acres regardless.
Most of the corn herbicide users (93% = 5o of 54 in Iowa; 95%=
211 of 223 in Illinois) feel that the corn herbicides available today
give better weed control than those they used ten years ago. 62%
(36 of 58) of the Iowa growers and 56% (127 of 226) of those in Illinois
would not change their herbicide use patterns if the cost of herbi-
cides would double. 97% of the corn growers in both states (56 of 58
77
-------
in Iowa; 219 of 226 in Illinois) would continue to grown corn if
no herbicides were available. Among those few that would not grow
corn without herbicides, some stated they would grow grass, wheat,
soybeans and/or oats instead, some said they would retire.
D. Side Effects from the Use of Herbicides on Corn
The heavy use of herbicides, especially the relatively
persistent product atrazine, in Iowa and Illinois has resulted in
increasing evidence of persistence of herbicide residues in the
soil. In the nationwide survey of weed scientists conducted by the
USDA in 1968, both Iowa and Illinois answered "Yes" to the question
whether they had a herbicide persistence problem. Illinois reported
2%, Iowa 20% of the herbicide-treated corn acreage affected
(U. S. Department of Agriculture, 1972b).
No more recent data are available on this problem. However,
since the use of corn herbicides, especially atrazine, has continued
to increase in the interim, the persistence problem most likely has
also. In the 1973 farmer survey, 70% of the Iowa corn herbicide
users and 42% of those in Illinois changed products at least once
since 1970. Concern about residue carryover was the second most
important reason given (by 35% of the Iowa and 9% of the Illinois
respondents).
In the National Soils Monitoring Program for Pesticides,
1,729 samples of cropland soils were collected from 43 states in 1969.
Samples were analyzed for residues of atrazine only when pesticide
use records indicated that this herbicide had been applied. Atrazine
residues were found in 2 samples out of 43 (4.7%) from Illinois, and
in 13 of 48 samples (27.1%) from Iowa. Residues found ranged from
0.02 - 0.10 ppm (mean level less than 0.01 ppm) in Illinois, and
0.01 - 1.55 ppm (mean level 0.05 ppm) in Iowa (G. B. Wiersma et al.
1972). The report does not indicate whether atrazine metabolites
were included in these analyses, or whether the analytical method
employed registered only the parent compound.
78
-------
Soil residues of atrazine prevent growing of sensitive
crops following atrazine-treated corn in rotation. This is espec-
ially true if atrazine has been used by itself at the full recom- '
mended rate. Soybeans and oats are particularly sensitive to
atrazine and have sometimes been affected even in the second year
after atrazine use.
It is noteworthy that all three sources quoted on the
corn herbicide persistence problem, i.e., the 1968 USDA survey, the
1969 National Soils Monitoring Program for Pesticides, and our 1973
survey of farmers, indicate that the problem appears to be greater
in Iowa than in Illinois. This is not surprising since Iowa grows
more acres of corn than Illinois (Table 3) and therefore has probab-
ly had heavier cumulative inputs of persistent corn herbicides than
Illinois.
Cyanazine, while also a triazine chemical, is considerably
less persistent than atrazine and has, mainly for this reason, in-
creased in use, especially in Iowa, since its introduction a few
years ago (Table 21). However, its safety margin on corn is not as
good as that of atrazine.
No major persistence problems are known to be associated
with the use of any of the other major corn herbicides.
2,4-D may cause damage to susceptible crops or plants
(soybeans, cotton, many vegetables, etc.) outside of the target area
through spray drift, or if volatile forms of the product are used.
Development of resistance of corn weeds to chemical herbi-
cides has not generally been a problem to this date. However, weed
species that are more difficult to control are gradually becoming
more predominant as those species that are easily controlled recede.
Fall panicum, for instance, has become more abundant in Iowa and
Illinois corn fields in recent years.
79
-------
E. Alternatives to Chemical Control of Corn Weeds
In the survey of farmers conducted in this project in 1973,
97% of the corn herbicide users both in Iowa and Illinois indicated
that they would continue to grow corn if no chemical herbicides were
available. In reply to the question what they would do to control
weeds in this event, replies from 56 Iowa and 212 Illinois respond-
ents were as follows:
Iowa Illinois
% Respondents
Till and/or cultivate more 89 98
Rotate crops 25 10
Grow fewer acres of corn 16 5
Hoe and pull weeds by hand 7 11
Change planting time 5 9
"Check row" (cultivate between
rows and at 90 degree angle) 7 2
Other alternatives mentioned less frequently included
"fight, fight, fight"; "work like hell"; "raise hell"; "no way";
or simply "don't know".
Corn growers were also asked if they would change their
corn herbicide use practices if the cost of herbicides were twice as
high. Those respondents (38% = 22 of 58 in Iowa; 44% = 99 of 226 in
Illinois) who said yes were asked what they would do. The answers to
this question indicate what possibilities growers see to reduce use of
herbicides on corn. Replies from 22 Iowa and 97 Illinois respondents
were as follows:
Iowa Illinois
% Respondents
Cultivate more 50 43
Reduce corn acres 36 6
Use lower rate of herbicide 14 13
Band herbicide rather than broadcast 14 8
Treat fewer acres with herbicide 5 26
80
-------
Less than 5% of the respondents mentioned changing crop
rotation; changing planting date; changing corn variety; or being
undecided.
University weed scientists, extension specialists
and farmers agree that none of these nonchemical alternatives would
be comparable to herbicides in regard to cost, effectiveness,
efficiency, profitability and convenience.
F. Summary
Major corn weeds in the midwest include foxtails, velvet-
leaf', smartweed, cocklebur, fall panicum, nutsedge, and wild sun-
flower. Weed scientists in Iowa and Illinois estimate that weeds
reduce corn yields by up to 10 bu./acre in many average, not catas-
trophically weedy fields. Research data widely publicized and
accepted in the midwest indicate that over a six-year period, three
timely cultivations per year were not adequate to prevent corn yield
reduction from weeds, and that the use of herbicides on corn is
profitable whenever moderate or heavier weed infestations can be
expected.
The use of herbicides saves cultivating and labor and
facilitates harvesting. All of the Iowa corn growers and 99% of
those in Illinois interviewed in this study used corn herbicide* in
1973. Between 80 and 90% of all corn acres in Iowa and Illinois are
treated with chemical herbicides. Some of these acres receive both
pre- and postemergence treatments. The most frequently used corn
herbicides were atrazine and propachlor.
A high percentage of the corn herbicide users in both states
(88% in Iowa, 82% in Illinois) believe that all of their corn acres
need herbicide treatments each year. However, almost all (97%) of
the corn growers in both states would continue to grow corn if no
herbicides were available.
81
-------
Currently available monitoring data are not adequate to
evaluate whether and to what extent corn herbicide residues may be
building up in heavily treated soils. In a nationwide survey of
weed scientists in 1968, both Iowa and Illinois reported that they
had a corn herbicide persistence problem. Illinois reported 2%,
Iowa 20% of the herbicide-treated corn acreage affected. In the
1973 farmer survey conducted in this project, concern about residue
carryover was expressed by a number of corn herbicide users.
Development of resistance of corn weeds to chemical herbi-
cides has not been a problem to date. However, corn weed populations
are gradually changing; more difficult-to-control weeds such as fall
panicum are becoming more prevalent as those species that are easily
controlled recede.
Growers are familiar with a number of alternatives to
chemical weed control, mainly increased cultivation and/or crop ro-
tation. None of these are considered nearly as attractive as herbi-
cides in regard to efficacy, convenience, and profitability by
growers or weed specialists.
82
-------
SOYBEAN WEEDS
VIII.
A. Major Weeds
Table 22 lists the five most important species of weeds
infesting soybeans in Iowa and Illinois, based on a nationwide sur-
vey of state weed scientists and extension personnel conducted in
1968 (U. S. Department of Agriculture, 1972b). According to this
survey, cocklebur and wild sunflower were considered serious and
believed to infest about 50% of the total soybean acreage in Iowa.
In Illinois, these two species did not rate among the five most im-
portant weeds. Conversely, pigweed and morningglory were considered
serious in Illinois, but not in Iowa. Foxtails, velvetleaf and
smartweed were among the five most important weeds in both states.
Comparing this list against that of the five most important
corn weeds from the same survey (Table 19), it is evident that most
of the major weeds were common to both corn and soybeans. Exceptions
were fall panicum and nutsedge that were listed as serious only in
corn; and pigweed and morningglory that were considered serious only
in soybeans.
A comprehensive nationwide survey of yield losses due to
soybean weeds was conducted in 1970 and again in 1971 under the
sponsorship of the basic producer of one of the major soybean herbi-
cides. According to this source, the following five weed species
83
-------
Table 22 : Five Most Important Soybean Weeds
in Iowa and Illinois, 1968
Weeds
Giant foxtail, Setaria faberi
Foxtails, Setaria spp.
Cocklebur, Xanthium spp.
Velvetleaf, Abutilon theophrasti
Smar tweed, Polygonum spp.
Sunflower, Helianthus spp.
Pigweed, Amaranthus spp.
Morningglory, Ipomoea spp.
Percent of Total Soybean
Acreage Infested
Iowa
I/
50
50
30
20
50
2/
2/
Illinois
60
I/
2/
30
25
2/
30
25
I/ Not available.
2/ Not included among five most important problem weeds
in the state.
Source: U. S. Department of Agriculture, 1972b.
84
-------
were most damaging in Iowa (listed in decreasing order of loss
caused): foxtail/ pigweed, velvetleaf, smartweed, volunteer corn.
In Illinois, the five most damaging soybean weeds were foxtail,
pigweed, velvetleaf, smartweed, and ragweed.
These two soybean weed surveys thus are in good agree-
ment in regard to the weed species that are economically most
damaging to the production of soybeans in Iowa and Illinois.
B. Losses Due to Soybean Weeds and Benefits from Their Control
Soybean plots were included in the 6-year studies conduct-
ed by Slife (1973) in Illinois. Slife's plot design and the methods
by which he arrived at the total average net return for the different
treatments are described in the section on corn weeds, pp. ggf 72, and
will not be reiterated here.
Table 23 summarizes the average annual costs and gross
and net returns from three different methods of controlling weeds in
soybeans over a 6-year period, 1966 - 1971. Best results ($64.10
net return/acre) were achieved when a different soybean herbicide
was used each year, along with one cultivation. Annual use of the
same herbicide, chloramben, plus one cultivation yielded the next
best return, $58.25/acre; whereas three timely cultivations without
a chemical herbicide yielded an average net return of $47.86/acre.
The use of herbicides on soybeans was unprofitable only in 1969,
that is only one out of the six years studied.
Again, as in the case of the corn tests, the returns for
the different weed control methods are based on the commodity prices
that prevailed at the time. These returns would be greater for all
treatments, and the differences in terms of dollars per acre between
treatments would be greater, based on the greatly increased soybean
prices that growers realized in 1972 and 1973 (Table 1).
85
-------
Table 23: Average Annual Costs and Returns from Different
Methods of Controlling Weeds in Soybeans in
Illinois Over a Six-Year Period, 1966 - 1971
Average Annual
Costs and Returns
Per Acre
Chloramben
Plus One
Cultivation
Different
Herbicide
Plus One
Cultivation
No
Herbicide,
Three
Cultivations
Cost of production
except weed control
Cost of cultivation (s)
Cost of herbicide
Cost of herbicide
application
Total average production cost
Total average gross return
Total average net return
$ 51.
1.
13.
1.
67.
126.
58.
00
50
95
50
95
20
25
$ 51.
1.
7.
1.
61.
125.
64.
00
50
29
50
29
39
10
$ 51
4
55
103
47
.00
.50
.50
.36
.86
Source: Adapted from Slife (1973)
86
-------
In the soybean weed loss surveys conducted in 1970 and
1971 already mentioned in Sec. A above, weed losses were estimated
in 26 soybean growing states by a field rating system using a weed
loss chart. Five weed loss categories were established on the basis
of a large number of research studies in many soybean growing states.
In late August, 60 two-man survey teams rated weed infestation levels
in a total of 21,000 soybean fields. The five weed loss categories
are as follows:
1 - Fields free of weeds, or with only very few weeds -
no measurable losses;
2 - Slightly weedy - fields will usually suffer between
5 and 10% yield reduction;
3 - Moderately weedy - fields will yield 10 to 20% less
than weed-free fields growing under the same conditions;
4 - Heavy weeds - fields will suffer yield losses of
20 to 35%;
5 - Disaster - fields where soybeans are totally
dominated by weeds will suffer yield losses ranging
from 35 to 100%.
Table 24 presents the results of the 1971 survey for the
United States, and for Iowa and Illinois. The percentage of soybean
fields in each of the five weed infestation categories from the 1970
survey are included for comparison.
According to these estimates, the nationwide soybean yield
losses due to weeds in 1971 amounted to $428 million. Iowa losses
were $45 million, Illinois $71 million. In both states, the heaviest
losses were attributed to a relatively large share of fields in loss
categories 2 and 3. In addition, Illinois in 1971 had a higher per-
centage of fields in categories 4 and 5 and, since its total soybean
acreage was greater, it had a greater total loss.
Table 25 summarizes results of the 1970 and 1971 soybean
weed loss surveys in terms of percent of all soybean fields suffering
5% or more yield loss; average percent loss in all fields; and average
87
-------
Table 24: Weed Losses in Soybeans in the U.S. and in
Iowa and Illinois, 1970 and 1971
Degree
of
Loss
1971
Number
of
Fields
United States
1
2
3
4
5
Totals
4,412
7,353
5,421
2,803
1,138
21,127
Iowa
1
2
3
4
5
Totals
766
1,183
630
183
31
2,793
Illinois
1
2
3
4
5
Totals
843
1,379
858
286
137
3,503
Percent
of Fields
Surveyed
21%
35%
26%
13%
5%
27%
43%
23%
6%
1%
24%
39%
25%
8%
4%
Acreage
In Each
Category
(000)
8,994
14,991
11,136
5,568
2,142
42,830
1,496
2,382
1,274
366
61
5,540
1,730
2,811
1,802
577
288
7,208
Average
Loss
Per Acre
$
VB ^
5.82
11.64
21.61
41.55
^m ^m
6.72
13.44
24.96
48.00
««
6.72
13.44
24.96
48.00
Value
of
Loss
$ 000
__
87,545
130,321
120,922
89,379
$428,167
__
16,008
17,125
9,126
2,925
45,185
_ _
18,891
24,219
14,393
13,839
71,342
1970
Percent
of Fields
Surveyed
29%
26%
27%
13%
5%
35%
29%
23%
10%
3%
36%
28%
24%
9%
3%
Source: 1971 National Soybean Weed Loss Survey
Inter/Agriculture
Chicago, 111.
88
-------
Table 25 : Summary of Soybean Weed Losses in the
U.S. and in Illinois and Iowa, 1970 and 1971
'Type of
Loss
Fields suffering
5% or more loss
Average % yield loss
in all fields
Average loss
bu./acre
$/acre
United States
1970
71%
11.5%
3.1
7.75
1971
79%
12%
3.3
9.99
Iowa
1970
65%
9.3%
3.0
7.50
1971
73%
8.3%
2.9
8.65
Illinois
1970
64%
9.2%
2.9
7.25
1971
76%
10.3%
3.3
9.89
Source: 1971 National Soybean Weed Loss Survey
Inter/Agriculture
Chicago, Illinois
89
-------
losses in terms of bu./acre and $/acre. These losses occurred in
spite of soybean weed control methods available and practiced by
soybean growers in 1970 and 1971. The somewhat greater losses in
the U. S. and in Illinois in 1971 as compared to 1970 are attributed
to wet weather in 1971 which hampered weed control efforts and
stimulated heavy weed germination and growth in many areas. The
dollar loss figures are greater for 1971 because the 1971 soybean
crop was valued at $3.00/bu. for purposes of this survey, the 1970
crop at $2.50/bu.
The results of this survey for Iowa and Illinois agree
well with those reported by Slife (1973), as discussed above. In
Slife's 6-year studies (Table 23), the use of a soybean herbicide
with one cultivation increased average net returns from $10.39 to
$16.24/acre over the return from soybeans that received only 3
timely cultivations for weed control, but no herbicide.
The National Soybean Weed Loss Survey (1971) also included
a state-by-state weed census, an effort to break down the losses by
major weeds for each state. In Iowa and Illinois, the same four weed
species accounted for 76% (Illinois) and 87% (Iowa) of the total esti-
mated weed losses. These weeds, and the dollar loss attributed to
each, are as follows: Illinois Iowa
Estimated Loss/State in $000
Foxtail 23,777 14,725
Pigweed 13,524 10,007
Velvetleaf 9,110 7,102
Smartweed 7,483 7,477
Subtotals 53,894 39,311
All other weeds 17,106 5,689
All weeds 71,000 45,000
First four weeds/total 76% 87%
90
-------
These data indicate that weeds caused substantial
economic losses to soybean growers in Iowa and Illinois (as well
as in the entire nation) in 1970 and 1971. Foxtails, pigweed,
velvetleaf and smartweed were the four most damaging weeds in
Iowa and Illinois.
C. Use Patterns of Herbicides on Soybeans
The use of herbicides on soybeans in the five corn belt
states (Illinois, Indiana, Iowa, Missouri, and Ohio) increased from
3.0 million Ibs. in 1964 to 6.6 million Ibs. in 1966 (increase of
117%), and to 18.9 million Ibs. in 1971 (increase of 187% from 1966),
according to the U. S. Department of Agriculture (1968b, 1970b, 1974)
These estimates indicate that the quantities of herbicides used on
soybeans in the corn belt increased more than six-fold during this
eight-year period.
In the survey of Iowa and Illinois farmers conducted in
this study, 98% of the soybean growers in both states reported using
herbicides on soybeans in 1973. As in the case of corn herbicides,
results of two previous surveys are available for comparison.
Wallaces Farmer (1970, 1972) surveyed the extent of the
use of herbicides on soybeans by Iowa farmers raising 100 acres or
more of soybeans. In 1970, 88% of 148 respondents used herbicides,
96% of 140 respondents in 1972. In the same surveys, 71% of the
total soybean acreage of 546 respondents was treated with chemical
herbicides in 1970, and 79% of the total soybean acreage of 505
respondents in 1972.
In a parallel survey of Illinois soybean growers by
Prairie Farmer (1970, 1972), 89% of 237 soybean growers raising
more than 100 acres of soybeans used herbicides in 1970, and 94% of
227 such growers in 1972. 73% of the total soybean acreage of 523
respondents was treated with herbicides in 1970, and 85% of the
total soybean acreage of 541 respondents in 1972.
91
-------
Table 26: Use of Major Soybean Herbicides in
Iowa and Illinois by Products in 1970, 1972 and 1973.
Herbicide
Trifluralin
Chloramben
Alachlor
Chlorpropham
Metribuzin
Linuron
Vernolate
Iowa
19702/
19723/
19736/
Illinois
19704/
19725/
19736/
Percent of Soybean Herbicide Users '
37
48
16
5
-
2
-
40
44
22
5
-
4
2
62
42
26
9
7
4
2
30
52
18
3
-
9
5
34
42
29
2
-
19
5
59
53
20
5
7
11
11
I/ Totals do not add up to 100 because minor products are not
included in this table, and because many growers used more
than one product.
Sources:
2/ Wallaces Farmer, 1970; responses from 396 Iowa soybean herbicide
users.
3/ Wallaces Farmer, 1972; responses from 400 Iowa soybean herbicide
users.
4/ Prairie Farmer, 1970; responses from 391 Illinois soybean herbicide
users.
5/ Prairie Farmer, 1972; responses from 454 Illinois soybean herbicide
users.
6/ This study,1973; responses from 55 Iowa and 213 Illinois soybean
herbicide users farming more than 320 acres.
92
-------
The findings from these five surveys indicate that
80 to 85% of the total soybean acreage in Iowa and Illinois is
treated with chemical herbicides, and that almost all larger
soybean growers use chemical herbicides and treat close to 90%
of their soybean acreage.
Table 26 combines the results of the surveys by Wallaces
Farmer, Prairie Farmer and this project in regard to the most fre-
quently used soybean herbicides. Two products, trifluralin and
chloramben, dominate the scene. The use of trifluralin increased
from 1970 to 1973, while the percentage of growers that used
chloramben in either state showed no distinct upward trend. The
use of alachlor appears to be increasing more in Iowa than in
Illinois. All other soybean herbicides were used to a much smaller
extent than these three major products.
All of the soybean herbicides included in Table 26 are
used preplant or pre-emergence. The use of postemergence herbicides
on soybeans in Iowa and Illinois is very small, as indicated uni-
formly by all three surveys.
In the 1973 farmer survey conducted in this study, 92% of
the Iowa soybean herbicide users and 85% of their colleagues in
Illinois considered the efficacy of these products satisfactory or
better in 1972 and 1973. About 5% of the respondents in both states
felt that the money they spent for soybean herbicides was wasted,
while 12 to 14% of them felt that they should have spent more money
for soybean herbicides in the last two years. The great majority
of all soybean herbicide users (about 84%) felt that the money spent
for soybean herbicides was a good investment.
About 58% of the Iowa soybean herbicide users (32 of 55
respondents); and 45% of those in Illinois (98 of 217 respondents)
changed products at least once since 1970. The farmers that changed
soybean herbicides were asked why. 32 Iowa respondents and 81 from
Illinois gave the following reasons:
93
-------
Iowa Illinois
% Respondents
Want to increase spectrum of
weed control 58 74
Want to experiment 18 4
Change to broadcast application 12 9
- Weather 9 1
Crop damage 3 3
Changed application equipment 0 5
Cost was not mentioned as a reason for changing soybean
herbicides by any grower in Iowa, and only by a single respondent
in Illinois. By contrast, 2.3% of the corn herbicide users in Iowa
who changed products, and 5% of their Illinois colleagues indicated
cost as the reason for doing so.
Approximately two-thirds of the users of soybean herbi-
cides in both states indicated that their costs ($ per acre) for
them had gone up during the last five years, while 9% of the Iowa
respondents and 4% of the Illinois respondents reported a decrease.
The remaining persons in the group, close to 30% in each state, re-
ported no significant changes in the cost of soybean herbicides
during the last 5 years. Increases in the cost of soybean herbicides
ranged from 5 - 100% in Iowa, from 4 - 300% in Illinois, averaging
38% in Iowa, 33% in Illinois.
A very high percentage of the soybean herbicide users in
both states (96% = 53 of 55 in Iowa; 86% = 171 of 200 in Illinois)
feel that all of their soybean acres need a herbicide treatment each
year. The few Iowa soybean growers who did not think so stated that
they treat all of their soybean acres with herbicides regardless,
whereas about two-thirds of the Illinois growers (18 of 29) who felt
that not all of their soybean acres need herbicides each year stated
that they treat only the weedy areas.
94
-------
Most of the soybean herbicide users (92% = 43 of 47 in
Iowa; 96% = 179 of 186 in Illinois) feel that the soybean herbicides
available today give better weed control than those available in the
mid-1960's. 72% (39 of 54) of the Iowa soybean herbicide users and
67% (130 of 193) of those in Illinois stated that they would not change
their use of these products if their costs would double. 24% (13 of 54)
of the Iowa respondents and 21% (40 of 194) of the Illinois respondents
indicated that they would quit growing soybeans if no chemical herbici-
des were available. Instead of soybeans, they would grow corn, small
grains, alfalfa and/or forage crops.
Among the three major types of pesticides studied in this
project, Iowa and Illinois growers consider soybean herbicides most
essential, as indicated by the fact that over 20% of them said they
would not grow soybeans without herbicides. By comparison, only 3%
of the corn growers said they would not grow corn without chemical
herbicides, and only 2 - 4% of the corn growers would not want to
grow corn without insecticides.
D. Side Effects from the Use of Herbicides on Soybeans
The total soybean acreage in Iowa and Illinois is
about 2/3 the size of the total corn acreage in the two states
(Table 3). During the 1960's, a smaller percentage of the soybean
acreage was treated with herbicides as compared to corn. However,
during the last few years, the use of herbicides on soybeans has in-
creased at a steep rate, to the point where today, close to 90% of
all soybean acres in both states are treated with herbicides.
Two chemicals, trifluralin and chloramben, account for
70 to 80% of the total soybean herbicide use during the last few
years in terms of number of acres treated. Chloramben appears to be
degraded in the soil within a few months after application (Pimentel,
1971). Trifluralin is rapidly inactivated if exposed to atmospheric
conditions on the soil surface. Directions for use call for soil
95
-------
incorporation within eight hours of application, preferably
immediately. In the-soil, trifluralin is moderately persistent;
80 - 90% of an applied rate will normally degrade during the grow-
ing season. However, there have been some reports of injury to
corn or small grains following in the rotation after soybeans
treated with trifluralin.
In the nationwide survey of weed scientists conducted in
1968 by the USDA, Illinois answered "Yes" to the question whether
there was a persistence problem with soybean herbicides; 1% of treat-
ed acres were reported affected. Iowa reported no soybean herbicide
persistence problem in the same survey (U. S. Dept. of Agriculture,
1972b).
In the National Soils Monitoring Program for Pesticides,
1,729 samples of cropland soil from 43 states were analyzed for
residues of trifluralin. Nationwide, trifluralin residues were found
in 60 samples (3.5%). Residues detected ranged from 0.01 - 0.25 ppm,
the mean residue level was below 0.01 ppm. State by state, triflura-
lin residues were found in 2 samples out of 142 (1.4%) from Illinois,
and in 5 of 151 samples (3.3%) from Iowa. Residues found ranged
from 0.05 - 0.16 ppm in Illinois, and from 0.02 to 0.08 ppm in Iowa.
The mean trifluralin residue level found was less than 0.01 ppm in
both states.
In a follow-on study by Carey et al. (1973), trifluralin
residues were found in 5 samples out of 69 (7.2%) from Illinois,
ranging from 0.01 - 0.08 ppm; and in 3 out of 76 samples (3.9%) from
Iowa, ranging from 0.02 - 0.06 ppm. The average residue level for
both states was less than 0.01 ppm.
Chloramben was not included in these studies.
Comparing these results to those reported above for
atrazine, it appears that trifluralin residues in Iowa and Illinois
soils are not nearly as widespread as those of atrazine.
96
-------
Trifluralin is highly toxic to fish. However, to date
there have been no reports of fish kills due to the use of tri-
fluralin as a soybean herbicide in accordance with label directions.
There are no reports on the development of resistance of
soybean weeds to herbicides. However, both of the most frequently
used soybean herbicides, trifluralin and chloramben, control grass
weeds better than broadleaves. Consequently, weed populations in
soybeans are shifting towards higher percentages of more-difficult-
to-control broadleaf weeds such as cocklebur, velvetleaf, jimsonweed,
and morningglory.
E. Alternatives to Chemical Control of Soybean Weeds
In our survey of Iowa and Illinois soybean growers in
1973, 24% (13 of 54) of the Iowa respondents and 21% (40 of 194) of the
Illinois respondents indicated that they would quit growing soybeans
if no chemical herbicides were available. (By comparison, only about
3% of the corn growers in both states indicated that they would not
grow corn without chemical herbicides.)
The growers who indicated they would continue to raise soy-
beans if no herbicides were available answered the question how they
would control weeds as follows (41 respondents from Iowa, 153 from
Illinois):
Iowa Illinois
% of Respondents
Till and/or cultivate more 78 79
Hoe and pull weeds by hand 29 37
Rotate crops 22 9
~ Plant later 15 20
Grow fewer acres of soybeans 20 7
Increase seed rate, go to narrower
rows or solid planting 2 2
97
-------
Other alternatives mentioned less frequently include
"plant only clean fields to soybeans"; "don't know"; and "cry a
lot" .
Soybean growers were also asked if they would change their
soybean herbicide use practices if the cost of soybean herbicides
were tiwce as high as what they last paid. Those respondents (28% =
15 of 54 in Iowa, 33% = 63 of 193 in Illinois) who said yes were
asked what they would do. This question was intended to find out
what possibilities growers visualize for reducing their use of herbi-
cides on soybeans. Replies from 15 Iowa and 62 Illinois respondents
were as follows:
Iowa Illinois
% of Respondents
Reduce soybean acres 47 5
Till and cultivate more 33 34
Reduce herbicide application rate 27 18
Rotate crops 13 2
Use different herbicides 7 15
Hand labor 7 13
Band herbicide rather than broadcast 7 3
Treat fewer acres with herbicide 0 19
Small percentages of the respondents mentioned changing
soybean planting dates, or being unsure what to do.
University weed scientists and extension specialists do
not have alternatives to the use of chemical herbicides on soybeans
over and above those perceived by Iowa and Illinois soybean growers
themselves, and practiced by many of them. Scientists working in
this field as well as growers agree that growing soybeans in the
midwest without herbicides would be considerably less profitable,
and that there are currently no economically attractive alternatives
to the use of soybean herbicides. Furthermore, fields in soybeans
-------
are generally more susceptible to soil erosion than under most
other crops. Additional soil movements that would be caused by
more tilling and cultivating would further increase the already
high rate of soil loss from soybean fields.
F. Summary
Major soybean weeds in Iowa and Illinois include foxtails,
cocklebur, velvetleaf, smartweed, and wild sunflower (largely the
same species as those found in corn). Several field studies indicate
that weeds cause substantial soybean yield losses in spite of the
availability and use of soybean herbicides. In a six-year study, the
use of herbicides on soybeans was more profitable than three timely
cultivations. Herbicide use was unprofitable only in one out of the
six years studied.
Of the Iowa and Illinois soybean growers surveyed in this
project, 98% used herbicides on soybeans in 1973. An estimated 80
to 85% of the total soybean acreage in the two states is currently
treated with chemical herbicides. Almost all of the larger soybean
growers use herbicides and treat close to 90% of their soybean acreage.
The two most frequently used soybean herbicides were trifluralin and
chloramben.
Among the three major types of pesticides studied in this
project, Iowa and Illinois growers consider soybean herbicides most
essential. A high percentage of the soybean herbicide users (96% in
Iowa; 85% in Illinois) feel that all of their soybean acres need a
herbicide treatment each year. Over 20% of the soybean growers stated
that they would quit growing soybeans if no herbicide were available.
(By comparison, only 3% of the corn growers said they would not grow
corn without herbicides, and only 3-6% would not grow corn without
insecticides.)
99
-------
Environmental monitoring data currently available are
not adequate to evaluate whether or not a soybean herbicide soil
persistence problem exists. In a nationwide survey of weed scien-
tists in 1968, Illinois stated that there was a persistence problem
with, soybean herbicides in the state, 1% of treated acres were re-
ported affected. In the same survey, Iowa did not report a soybean
herbicide persistence problem.
There are no reports on the development of resistance of
soybean weeds to herbicides. However, both of the most frequently
used soybean herbicides, trifluralin and chloramben, are more
effective against grass tihan against broadleaf weeds. As a result,
soybean weed populations are shifting towards greater preponderance
of more-difficult-to-control broadleaf weeds such as aocklebur,
velvetleaf, jimsonweed, and morningglory.
Among alternatives to the use of soybean herbicides, in-
creased tillage and cultivation, hand-hoeing and -pulling of weeds,
and crop rotation were mentioned most frequently by the soybean
growers interviewed. Weed scientists and extension specialists do
not propose additional alternatives to the use of chemical herbicides
on soybeans. Weed scientists, extension specialists and growers
agree that the production of soybeans in the midwest without herbi-
cides would be considerably less profitable and more difficult, and
that there are currently no economically attractive alternatives to
the use of soybean herbicides.
100
-------
TX. FARMERS' SOURCES OF INFORMATION ON PESTICIDES
The data presented in Chapters IV - VIII of this
report amply document that chemical herbicides and insecticides
are used in large quantities on a high percentage of all corn and
soybean acres in Iowa and Illinois. The Illinois Cooperative Crop
Reporting Service (1973b) reports that in 1972, 77% of the corn
acres and 86% of the soybean acres treated with herbicides were
treated by the farmers themselves, the balance by custom applica-
tors. About 94% of the corn acres, and 71% of the soybean acres
that received insecticide treatments in 1972 were treated by
farmers. Thus, more than three-fourths of the pesticides used
on these crops are applied by growers.
There are more than 250,000 individual farmers in Iowa
and Illinois. The foregoing data indicate that most of them handle
and apply pesticides. Therefore, it is important to know how
farmers obtain information on pesticides, where this information
originates, and how it travels from the source to the receiver.
A major effort in this study was focused on these questions.
A. Previous Studies
Smith and Heady (1970) studied the characteristics of
commercial farm operators and their employees in Iowa. They inter-
viewed 114 farm operators on 98 farms. This group had an average
education of 11.8 years (range 6-19 years), just less than a high-
school education. Of the 114 operators interviewed, 65 (57%) had
completed highschool; 24 others (21%) had at least some college
education, but only 17 of the latter had studied agriculture. The
study further showed that of all 114 commercial farm operators
interviewed, -
101
-------
70 (61%) had no formal agricultural education;
20 (18%) had highschool vocational agriculture
training only;
10 (9%) had college agriculture training only;
4 (4%) had both vocational and college
agriculture training;
6 (5%) had veterans' training in agriculture;
3 (3%) had both veteran's training and college
agriculture.
A considerable number of authors have dealt with the
process of adoption of new ideas, new technologies and new farming
practices by farmers, including Beal and Bohlen (1957), Fliegel
(1956), Fliegel and Kivlin (1962, 1966), and Kivlin and Fliegel
(1968). However, none of these deal specifically with crop protec-
tion practices and pesticides.
Farm magazines including Wallaces Farmer and Prairie
Farmer survey farmers from time to time regarding their sources of
information on a variety of subjects, sometimes including crop pro-
tection. However, these surveys usually do not cover all of the
channels through which farmers may receive information, but are
limited to certain types of channels such as, for instance, compari-
sons between farm magazines, daily newspapers, radio, and TV. The
results of such studies are useful to actual and potential adver-
tisers.
Prior studies that were more directly applicable to the
objectives of this project include those by Beal et al. (1966) ,
Beal et al. (1969), Kerr (1970), and Hestand et al. (1971).
In 1965, Beal et al. (1966) conducted personal interviews
of 229 Iowa farmers who farmed at least 70 acres in 1964 and per-
sonally made the major management decisions for their farming
operations. One section of the survey dealt with what farmers
know about pesticides.
Respondents' knowledge of soil, crop and livestock
insecticides was tested by 16 statements with which the interviewee
102
-------
had to agree or disagree. Correct answers ranged from 10 - 83%,
averaging 43%. An average of 18% incorrect answers were given,
the balance (39%) were "don't know" or no-opinion answers.
A similar set of 14 agree/disagree statements dealt
with farmers' knowledge of herbicides ("weed, grass and brush
killers"). In this case, an average of 47% (range 10 - 73%) of
correct answers were given. Incorrect answers averaged 23%, no-
opinion answers 29%.
A set of questions on proper safety precautions and on
general knowledge about pesticides and their use scored somewhat
better, with correct answers averaging 71 - 85%.
When the responses to all 44 knowledge statements on
pesticides from all 229 participants in the survey were pooled,
the average number of correct responses was 24 out of 44, that
is 55%.
Another section of the study by Deal et al. (1966) dealt
with the information sources used by Iowa farmers. Respondents
were asked to indicate which of 29 specified sources of informa-
tion on pesticides they were presently using. Responses were as
follows:
% of Respondents
Farm magazines and farm papers 94.3
~ Pesticide label 90.4
Other farmers in the community 67.7
Local agricultural chemical dealers 60.7
Radio 48.9
County extension personnel 47.6
Veterinarian ^/ 43.7
Television 42.4
Agricultural chemical company 41.5
publications
Newspapers 35.8
Agricultural extension publications 34.9
Meetings sponsored by local 25.3
agricultural chemical dealers
(Continued on next page)
103
-------
(Continued) % of Respondents
Family members 25.3
Meetings'sponsored by ag. chemical 24.9
companies
U. S. Dept. of Agriculture publications 20.5
Agricultural chemical manufactuers' 17.9
or,wholesalers' salesmen
Meetings sponsored by the State University 16.6
and Extension Service
Vocational agriculture teacher 14.4
State University specialists 14.0
Iowa Farm Science publication 10.0
I/ Livestock insecticides were included in the survey
The remaining information sources (Farm Bureau; landlord;
community organization; banker; other publications; farm manager;
Iowa Institute of Agricultural Medicine; A.S.C. meetings; and past
experiences) were mentioned by less than 10% of the respondents.
Additional questions were asked to determine the most
useful source of information in regard to specific aspects of the
use of pesticides. The pesticide trade, especially local dealers,
and farm magazines and farm papers were rated most useful regard-
ing which chemical to use for a particular purpose. Pesticide
labels were rated most useful regarding methods and rates of appli-
cation, handling and safety precautions, and hazards and possible
harmful consequences of misuse.
Respondents in this survey also indicated from whom they
purchased pesticides. Pesticide suppliers were as follows:
104
-------
% of Respondents
Feed and seed store 62.0
Farmers co-op elevator 60.7
Veterinarianl/ 52.8
General farm supply store 27.9
Drugstores 24.0
Farm service companies 22.3
I/ Livestock products were included in the survey
All remaining sources of supply were mentioned by less
than 20% of the respondents.
Finally, farmers participating in this survey were asked
to express their opinions on pesticide dealers' qualifications as
sources of information on pesticides. 55% of the respondents
considered their dealers to be a "qualified source of information
on some aspects of agricultural chemicals and their use", while 27%
rated them a "highly qualified source of information on all aspects
of agricultural chemicals and their use". Of the remaining respond-
ents, 9% considered dealers not qualified, 7% considered them to be
poorly qualified, and 2% did not answer the question.
In a related question, 13% of the respondents expected
their pesticide suppliers to provide information only; 75% expected
them to provide information and make recommendations; 9% considered
dealers not qualified to give information, while 4% did not reply
to the question.
Thomas and Evans (1963) summarized the results of four
different studies on farmers' information sources that were carried
out by members of the Extension Editorial Office of the University
of Illinois, College of Agriculture, Urbana. Most of these surveys
dealt with problems other than pesticides, but one of them included
an item pertinent to our inquiry.
In a study by Jones in 1959 in which 100 farmers in
southern Illinois were personally interviewed, replies to the
105
-------
question "What one source would you probably look to for
information on how to control weeds with chemicals?" were as
follows: Seed and fertilizer dealer - 30%; county farm adviser -
24%; neighbors - 5%; local banker, past experience, university
specialist - 1% each. 2% of the respondents gave unspecified
miscelleanous answers, the balance (36%) said they did not know.
Kerr (1970) interviewed 44 farmers in Winnebago and
Boone Counties in northern Illinois in regard to their herbicide
use practices. Included in the scope of this study were character-
istics of the operators interviewed and of their farms; weed pro-
blems; application problems encountered in the use of herbicides
such as clogging of nozzles and strainers, water hauling, irri-
tation (operator? skin? mucuous membranes?), separation or settl-
ing of the spray mixture, foaming, pump breakdown, calibration,
spray drift, mixing difficulties, and safety precautions. Regard-
ing use of the information on herbicide labels, 22 respondents (50%)
reported that they read the product label before purchase; 12 (27%)
read it at the time of purchase; 32 (73%) read it before use of the
product; 35 (80%) read it at the time of use, and 4 (9%) reported
reading it after application had started.
Several questions in this survey pertain to the importance
of price in the selection and use of herbicides. In choosing be-
tween two herbicides of nearly equal performance, 61% of the respond-
ents would rate previous good experience with a product more
important than price; 52% of the respondents would prefer familiarity
with the product over price, while 27% would buy the lower-priced
material. Good crop tolerance and weed control were rated more
important than a lower price.
By way of general comments, some criticism was voiced of
farm magazines because of the relationship of their reporting to
advertising. Respondents expressed the view that farm magazines'
106
-------
reporting on herbicide performance was too general to be useful.
Respondents also said that the pesticide industry should reduce
prices if possible; improve products by increasing safety and
effectiveness; be honest and complete in informing the user; do
a better job of grading and packaging; and move from a profit
motive to a service motive.
Hestand et al. (1971), conducted a similar survey in
Wabash and Edwards Counties in southeastern Illinois, using a sli-
ghtly modified version of the survey form developed by Kerr (1970),
and following the same objectives. 43 farmers were interviewed in
this study. The results obtained were generally quite similar to
those reported by Kerr, except for variations in weed problems and
other factors due to the differences in geographic location between
the two survey areas. Regarding use of herbicide labels, 34 (79%)
respondents in this survey reported that they looked at it before
or at the time of purchase; 35 (81%) read it after purchase and
before use; 20 (47%) read it at the time of use; and 2 (5%) after
start of application.
B. This Study
Beal et al. (1966) have pointed out that the communica-
tion process contains four basic elements, i.e., the sender, the
channel, the message, and the receiver. The following discussion
will be structured accordingly, except for a somewhat different
order because the prime interest of this study centers on the
receiver, that is the farmer.
" Receivers' Use and Perception of Pesticide Information Sources
In the survey of Iowa and Illinois farmers conducted in
this project, respondents were asked which of 15 specified sources
of information they used in 1972 and 1973 in deciding if, when, and
107
-------
how to use pesticides, which product to use, and what rate of appli-
cation. All respondents (58 in Iowa, 239 in Illinois) answered this
set of questions very thoroughly. Figure 3 summarizes the results
regarding the extent of use of these sources by the Iowa and Illinois
respondents. In evaluating these results, it must be remembered that,
as outlined in the Methods section, Iowa farmers were interviewed in
person, Illinois farmers by mail.
Only 4 of the 15 information sources were used by more
than 50% of the respondents in both states, i.e., (in decreasing
order of extent of use) pesticide sellers; farm magazines; neighbors,
friends and relatives; and pesticide labels. 30 to 50% of the Iowa
interviewees obtained information on pesticides from trade meetings;
publications other than farm magazines, newspapers or sales pamph-
lets; state university meetings or field demonstrations; and the
radio. 30 to 50% of the Illinois respondents received pesticide
information from county agents (farm advisers) and pesticide manu-
facturers' representatives. All other sources of information were
used by less than 30% of the respondents in both states.
In the next step, respondents' perception of the useful-
ness of the pesticide information received from these sources was
examined. For each source that a respondent reported he used, he
was asked to indicate whether the information received was "very
good", "satisfactory", or "unsatisfactory". Usefulness ratings
were computed from these entries by averaging for each source the
"very good" ratings, then subtracting the averaged "unsatisfactory"
ratings.
The following four information sources were considered
most useful by the respondents and scored usefulness ratings higher
than 50 (rating following each source): pesticide labels (59);
pesticide sellers (56); neighbors, friends, relatives (53); and
university extension specialists (52). The following four infor-
mation sources were considered least useful: television (minus 8) ;
108
-------
Figure 3 : Sources of Information on Pesticides and Extent of their Use by
Iowa and Illinois Farmers, 1973
Use of Source
% of All Respondents
Iowa Farmers
(58 respondents)
Pesticide Sellers (95%)
Neighbors, Friends (84%)
Pesticide Label (81%)
Farm Magazines
Trade Meetings (41%)-
Other Publications (38%)-
University Meetings (36%)-
Radio (34%)-
County Agents (29%)
Extension Specialists (26%)
TV (26%)
Pesticide Mfr.'s Rep. (22%)
Sales Literature (21%)
Newspapers (19%)
Area Extension Agents (14%)
90
80
70
60
50
40
30
20
10
Illinois Farmers
(239 respondents)
-Pesticide Sellers (75%)
-Farm Magazines (59%)
Pesticide Label (50%)
'Neighbors, Friends (50%)
County Agents (34%)
Pesticide Mfr.'s Rep. (31%)
Extension Specialists (29%)
O-Trade Meetings (29%)
Sales Literature (28%)
University Meetings (26%)
Newspapers (15%)
^Other Publications (13%)
Area Extension Agents (13%)
'-Radio (10%)
TV (8%)
109
-------
newspapers (6); radio (10); and sales leaflets (10.5). All of
the remaining information sources scored usefulness ratings be-
tween 10 and 50.
Figure 4 summarizes the extent of use of the pesticide
information sources and their usefulness as perceived by the
participants in our survey. For each information source, frequency
of use (percentage share of all pesticide information impressions)
is plotted against the usefulness rating. The width x height = area
of each bar is thus an indication of the relative importance of
each source in farmers' pesticide use decisions.
Pesticide labels, pesticide sellers, and neighbors, friends
and relatives ranked high in usefulness as well as in frequency of
use. University extension specialists, area extension agents,
county agents (farm advisers), and university meetings also ranked
high in usefulness, but much lower in frequency of use. Among these
four sources of pesticide information supported by public funds,
university extension agents, county agents and university meetings
scored usefulness ratings between 40 and 50. Pesticide information
received at meetings or field demonstrations by pesticide producers
or sellers ("trade meetings") or from representatives of pesticide
manufacturers rated 34 and 33.5 on the usefulness scale, respectively.
Farm magazines are read by a high percentage of Iowa and
Illinois farmers. They accounted for 13% of all pesticide informa-
tion impressions, but scored relatively low (23) in regard to their
usefulness as pesticide information sources. This is not surprising
because such magazines generally do not attempt to convey specific,
detailed pesticide use information to growers.
As mentioned earlier, some of the respondents in the study
by Kerr (1970) expressed criticism of farm magazines, suggesting a
relationship of their reporting on pesticides to their advertising
revenue. In the report by Hestand et al. 1971), "suggestions for
110
-------
8^
»- <
oj n>
M
Oi *«
OQ
= O
C! O
0 0.
co =
01
rt H
p. CD
in rt
HI M.
Co 3
O OQ
rt CO
O
H M
^ (t)
- CO
CO
H
to *3
d C!
OQ 9
CO CO
» to
rt
H M-
(D CO
CO t-h
C IB
t-1 O
rt rt
H- O
OQ ^
0 H
IB
CD rt
0 £
(0 OQ
OQ CO
0] .
rt
£~
» 3
»-t
CD H
rt fD
H- O
0 ID
OQ H-
O (D
Hi O.
00 On
^_x (j,
Very good
rt I-1
O to
rt
P
I-1
CO
(D
OJ
O
O
a.
rt ui
O
O OJ
I,
H-
0
OQ OJ
O
H>
H)
to
Oi
TV
Usefulness Rating
ho
O
I/
OJ
o
I
Ui
O
ON
O
1
University Extension Specialists
Area Extension Agents
County Agents
University Meetings
Neighbors, Friends, Relatives
Farm Magazines
Other Publications
I Newspapers
Radio
Pesticide Labels
Sales Literature
Trade Meetings
Mfr.'s Representatives
Pesticide Sellers
M
O
6
ex
o
o
H-
CO
CU
It
II
CO
VO
»J
OJ
00
C
r(
(D
a.
(0
CO
w
x
rt
8
o
Hi
CO
(D
(a
3
a.
CO
(D
3
fO
CO
CO
p)
CO
rt>
S.
111
-------
farm magazines" read in part as follows: "Do features on proven
methods, require proof in advertising, cut the 'bologna'".
Other media including newspapers, radio, television,
sales literature, and other publications scored low on the use-
fulness scale and were not used extensively by the respondents as
sources of information on pesticides.
Comparing these findings to those of Beal et al. (1966),
it is noteworthy that the same four sources of information on pesti-
cides were used most frequently by the respondents in both surveys,
i.e., pesticide labels; pesticide sellers; farm magazines; and neigh-
bors, friends and relatives. In both studies, these were the only
four information sources that were used by more than 50% of the
respondents. Comparing extent of use of the remaining sources be-
tween the two surveys, it appears that university extension special-
ists and meetings and field demonstrations conducted by the university
reached farmers more frequently in 1973 than in 1965. Conversely,
newspapers, radio, sales literature and county agents were mentioned
less frequently as pesticide information sources by farmers in 1973
than in 1965.
To determine how well farmers use the pesticide informa-
tion they receive through these various sources, an analysis
was made of all responses to our 1973 farmer survey that might
indicate pesticide misuses.
In the survey, 217 Illinois corn growers made a total of
460 product entries in response to the question which corn herbicides
they used in 1973 or 1972. Five times, products were mentioned
(1.1% of all responses) that are either not herbicides, or herbicides
that are not registered for use on corn and would, most likely,
damage corn, i.e. (numbers in parentheses = times mentioned),
carbaryl, an insecticide (1) ; and the herbicides metribuzin (1),
dinitramine (1) and trifluralin (3).
112
-------
In response to the question which soybean herbicides
they used in 1973 or 1972, 213 Illinois soybean growers made 371
product entries. Products that are not registered for use on
soybeans were mentioned 5 times (1.3% of all responses); they were
atrazine (1), paraquat (1)/ and propachlor (3).
Replying to the question which insecticides they used in
1973 or 1972 for the control of corn insects, 157 Illinois farmers
made 194 product entries. Products that are either not insecticides,
or that are not registered for use on corn were mentioned 8 times
(4.1%). These included the herbicides atrazine, butylate, 2,4-D,
linuron, and propachlor; the fungicide captan; and the nonregistered
products Counter and ID 2570.
In the surveys of Iowa farmers by Wallaces Farmer (1970,
1972) , there were comparable percentages of wrong products mentioned.
Soybean growers reported using as soybean herbicides atrazine
(0.5% in 1970; 1.0% in 1972); 2,4-D (1.5% in 1970; 0.3% in 1972); and
propachlor (registered for use on soybeans for seed only; 1.0% in
1970; 1.8% in 1972).
In the 1972 survey of Illinois farmers by Prairie Farmer
(1972), soybean growers reported using as soybean herbicides atrazine
(0.2%) and propachlor (0.4%).
If these percentages of reported misuses would be indica-
tive of actual misuses of pesticides in the field, there would be
reason for concern. It is possible, of course, that at least some
of them were cases of misreporting rather than actual misuse. How-
ever, extension personnel as well as pesticide sellers report that a
certain amount of misuse of pesticides does occur. This is not sur-
prising, considering the findings by Smith and Heady (1970) regarding
the educational level of commercial farm operators, those of Beal
et al. (1966) on their knowledge of pesticides, those of Kerr (1970)
and Hestand et al. (1971) on the reading c^ pesticide labels, and
113
-------
the fact that about 200,000 individual farmers apply pesticides
Ln Iowa and Illinois alone (see pp. 84-86 and 89-90).
2. Senders of Pesticide Information
There are two major originating sources (or senders) of
information on pesticides, i.e., the basic manufacturer, and federal
and state agencies. The basic manufacturer of a pesticide usually
accumulates all chemical, physical, analytical, toxicological,
physiological, efficacy, safety and other data required for regis-
tration of the product. The research and development work necessary
to obtain these data is often carried out in part in the commercial
company's own facilities, in part through contrcicts or other arrange-
ments on the outside.
Many federal and state crop protection scientists work on
pesticides, especially in situations where certain products will be
useful to agriculture in a given area, where regional or local
directions for use may have to be developed, and/or where there may
be concern about residues or undesirable side effects.
Information from both of these basic sources, pesticide
manufacturers and public agencies, is used in the writing of pesti-
cide labels. Such labels are then registered by the U. S. Environ-
mental Protection Agency. In addition, state registrations are re-
quired in many states.
3. Public Agency Channels
Federal and state crop protection scientists and extension
workers convey the results of their work on pesticides primarily
through publications, including papers in the scientific litera-
ture; popular articles, bulletins and leaflets; weed, insect, and
disease control recommendations and newsletters; and meetings and
field demonstrations.
114
-------
The results of the farmer surveys discussed earlier in
this chapter, especially the 1973 survey conducted in this project,
indicate that state university extension specialists, area exten-
sion agents, county agents and university meetings and demonstra-
tions were not among the most frequently used sources of information
on pesticides. All four of these sources combined accounted for
only 19% of the total pesticide information impressions (Figure 4).
We therefore examined to what extent extension publications, espec-
ially weed, insect and disease control recommendations and news-
letters, might extend the outreach of federal/state crop protection
research and extension specialists.
One example selected were the Illinois pest control recom-
mendations. Weed control recommendations (but not the insect or
disease control recommendations) are included in the "Illinois
Agronomy Handbook", a publication by the University of Illinois'
Department of Agronomy that is issued annually. About 13,000 copies
of this handbook were printed in 1973. Additional copies of the
weed control recommendations (as well as copies of the insect and
plant disease control recommendations) are included in the Illinois
Custom Spray Operators' Training School Manual of which about 1,300
copies are printed annually. An additional 3 - 4,000 copies of
these recommendations are distributed at various meetings and
"clinics" throughout the state, and about 1,000 copies are sent out
in response to mail requests. Thus, it appears that about 19,000
copies of the Illinois weed control recommendations are distributed
each year. Of the approximately 6,000 copies distributed via the
custom spray operators' training school manual and as single copies,
we estimate that less than 1,000 reach growers directly, based on
the percentage of growers attending the meetings at which these
manuals and single copies are made available. If 11,000 copies of
the Agronomy Handbook would reach growers directly, about 12,000
115
-------
Illinois farmers would receive the State weed control recommenda-
tions, that is approximately 10% of all farmers in the state. The
insect and plant disease control recommendations probably reach a
much smaller number of growers directly because they are not in-
cluded in the Agronomy Handbook which appears to be the prime
vehicle by which weed control recommendation reach the growers.
The Federal/State Cooperative Extension Service at Iowa
State University publishes an "Insect, weed and plant disease news-
letter" at weekly intervals throughout the crop growing season, for
a total of about 20 issues per year. The Illinois Cooperative
Extension Service has a very similar publication, called "Insect,
weed and plant disease survey bulletin", that had 24 issues in 1973.
Both of these publications are very similar in format and
content. They convey timely information on weed, insect and disease
problems and methods on how to cope with them week by week throughout
the growing season, along with notes on regulatory and similar
actions that may be of importance to growers. Table 27 gives a
breakdown of the distribution of both publications. The distribution
pattern in both states is quite similar; only about 2% of the copies
in Iowa, and 10% of the Illinois copies go to farmers directly. By
far the greatest percentage of the newsletters in both states go
to the pesticide trade, the next largest share to state university
and cooperative extension service personnel within the state and, in
the case of Iowa, to surrounding states.
The number of personnel involved in generating and trans-
mitting pesticide information was also examined, using the situation
in Iowa as an example. At Iowa State University, there are 7 ex-
tension specialists dealing full-time with crop protection problems,
i.e., 3 in entomology and 2 each in weed science and plant pathology.
There are 12 area extension agents and 100 county agents, the latter
also sometimes referred to as "farm advisers". Area extension
116
-------
Table 27: Distribution of the Weekly Iowa and Illinois
Insect, Weed and Plant Disease
Newsletter/Survey Bulletin, 1973
Recipients
Distribution
Number of Copies per Issue
Iowa
Illinois
State University and Cooperative
Extension Service Personnel
Surrounding States' Extension
Personnel
Pesticide Producers, Sellers,
Fieldmen, Commercial Applicators
Newsmedia (Newspapers, Radio and
TV Stations)
Vocational Ag. and Area Schools
State and District Foresters
Farmers
Totals
215 (18%)
100 (9%)
600 (51%)
I/
225 (19%)
15 (1%)
20 (2%)
1,175 (100%)
199 (20%)
I/
695 (70%)
I/
I/
99 (10%)
993 (100%)
I/ Not mentioned
Sources: Stockdale, 1973; Luckmann, 1973.
117
-------
agents and county agents, however, have to cover all crop, live-
stock and horticultural problems of their farm and/or urban
clientele and thus deal with crop protection and pesticide problems
only part-time.
4. Pesticide Trade Channels
One of the prime channels transmitting pesticide informa-
tion from pesticide producers to farmers is the pesticide label.
In addition, pesticide producers convey information on their products
through sales pamphlets and other literature, advertisements, and
through personal contacts between their representatives and all other
parties involved in distributing pesticides and pesticide informa-
tion, especially pesticide wholesalers and retailers.
To obtain information on the number of personnel involved
in transmitting pesticide information through pesticide trade channels,
we contacted the Iowa State Department of Agriculture to determine the
number of pesticide retail outlets in the state. That information is
not available as such. However, the Department advised that fertil-
izer outlets have to be licensed in the State of Iowa, and that there
are 1,274 such outlets licensed at present. It is estimated that
most of these (more than 90%) also sell pesticides. In addition,
pesticides are also sold by commercial pesticide applicators. In-
cluding urban operators, there are about 1,500 licensed pesticide
applicators in the state. The great majority of these are farm
pesticide applicators.
We were further advised that there are currently about
4,750 individual pesticide products registered in the State of Iowa
by about 600 individual registrants (more than 95% of these products
on Federal, rather than intrastate labels).
The State of Illinois Department of Agriculture was also
contacted for information on the number of sales outlets for
118
-------
agricultural pesticides in Illinois; the number of salesmen
selling such products in Illinois; and the number of agricultural
pesticides registered in Illinois intrastate and/or on national
labels. Illinois advised that they currently have 4,895 pesticides
registered, but that breakdowns by national versus intrastate
labels, or by agricultural versus nonagricultural pesticides are
not available. In response to the first two questions, we were
informed that the state does not have any information or estimates
on the number of salesmen or sales outlets selling agricultural
pesticides in Illinois.
Trade sources finally proved more fruitful in rounding
out the picture. Combining information received from the Iowa
State Department of Agriculture and from several trade sources, the
following estimate on the number of personnel involved in promoting
and selling pesticides and distributing information on pesticides
in the state of Iowa resulted:
At least 28 basic pesticide producers develop,
advertise and sell their products in Iowa.
These firms employ about 130 field representatives
who engage full-time in the development, demonstra-
tion, promotion and selling of pesticides.
Additional field representatives are employed by
the larger wholesalers.
There are approximately 1,800 retail outlets for
agricultural pesticides in the state, including
5 - 600 custom applicators.
There are over 4,000 persons involved in retail
selling of agricultural pesticides in Iowa. The
great majority of the persons in this group also
handle other agricultural supplies and therefore
deal with pesticides and pesticide information
only part-time.
The last two of these estimates were obtained as follows.
In a survey of Iowa agricultural chemical dealers by Beal et al.
(1969), it was found that the number of employees (including
119
-------
the manager) of 126 dealers interviewed ranged from 1 to 27.
The majority of the businesses had between 1 and 5 employees,
in addition to the manager. We estimate (conservatively) that
there are about 1,250 agricultural pesticide retailers with an
average staff of three persons each, including the manager. We
further estimate that there are at least 550 commercial applica-
tors who dispense pesticides and information. The total number
of personnel involved in retail selling of agricultural pesticides
would thus be 4,300, hence our estimate of "over 4,000".
5. Flow Patterns of Pesticide Information
Figure 5 shows the flow patterns of pesticide information
from the originating sources to growers, based on all data and sur-
veys discussed in the preceding sections of this chapter. For the
key information conveyors, the approximate numbers of workers
involved in transmitting pesticide information in the State of
Iowa have been included.
The important findings are as follows:
Pesticide labels and pesticide retailers are the
two prime channels that convey pesticide informa-
tion to growers.
Pesticide information from extension specialists,
area agents and county agents reaches only a small
percentage of growers directly.
Extension publications (pesticide use recommenda-
tions, newsletters, etc.) reach only a small per-
centage of growers directly; they are used primar-
ily by the pesticide trade.
Extension publications sent to media (farm magazines,
newspapers, radio, TV) may be reproduced or other-
wise used by these media, but this does not produce
a significant pyramiding effect because growers do
not use these media extensively as sources of infor-
mation on pesticides and do not consider them to be
very useful in this regard.
Growers communicate extensively with other growers.
120
-------
Figure 5 : Sources and Routes of Information on the Use of
Agricultural Pesticides in Iowa and Illinois I/ 2/.
Federal Agencies
Pesticide
Manufacturers
Field
Representatives
( 130
State Governments
State University
Extension
Publications
Extension
Specialists
( 7 )
Wholesalers
t
Retailers
(>4,000*
Area Ext. Agents (12*)
*
County Agents (100*)
(Farm Advisers)
Media
(Farm Magazines,
Newspapers,
Radio, TV,
Other Publications)
Growers
* Growers (130,000)
* Deal with pesticide problems only part-time.
I/ Heavy lines indicate predominant routes.
2/ Numbers in parentheses indicate approximate number of workers
in specified category in the State of Iowa.
3/ Assumptions: There are about 1,250 sellers of agricultural pesticides
in Iowa, and an average of 3 persons per outlet selling pesticides,
plus about 550 commercial applicators retailing agricultural pesticides,
121
-------
The pesticide information flow patterns in Illinois
are very similar to those in Iowa. Illinois also has an area
extension structure between the university and the counties, and
an almost identical number of counties. The basic structure of
the pesticide trade is very comparable. The numbers of persons
involved in sending and transmitting pesticide information at
different stations in the flow pattern may vary somewhat between
the two states, but the basic situation is very similar. In
Illinois as well as in Iowa, pesticide specialists and extension
workers in public service are outnumbered by those in the pesticide
trade by wide margins.
Comparing the data in Figures 3, 4 and 5, it is interest-
ing to note that university extension specialists, despite their
small numbers, managed to reach 26% of the Iowa growers and 29%
of the Illinois growers directly (Figure 3), and to produce 5% of
all pesticide information impressions (Figure 4). Pesticide manu-
facturers' representatives, outnumbering extension specialists by
a margin of almost 20 to 1, reached 22% of the Iowa growers and
31% of the Illinois growers directly, and accounted for 5% of all
pesticide information impressions. This comparison speaks very
well for the efficiency and effectiveness of university extension
specialists.
Area extension agents and county agents likewise seem to
be very efficient conveyers of pesticide information, considering
their numbers. Nevertheless, even though pesticide trade represen-
tatives seem to be less efficient per caput than their public
servant counterparts by these comparisons, they outnumber the latter
by such wide margins that overall, they reach a much higher per-
centage of farmers in both states directly and produce a much higher
percentage of all pesticide information impressions than the public
servants.
122
-------
The information flow pattern depicted in Figure 5
worked very well as long as the objectives of the pesticide trade
were essentially in harmony with those of federal and state
agencies, i.e., as long as pesticide development and increased use
of pesticides meant progress to both groups. There are indications
that problems may arise in situations where this congruity of
objectives no longer exists such as, for instance, if the extension
service issues messages that may reduce the use of pesticides. A
case in point from within the study area is the soybean insect
situation briefly discussed in Chapter V of this report. More
serious problems in this regard have arisen, for instance, in the
state of Arizona, according to verbal reports at a recent scienti-
fic meeting (Carl, 1974; Good, 1974).
6. Pesticide Information Messages
Farmers who have pest problems in their crops need the
following information:
What pest or pests are causing the problem?
Should I use a pesticide?
If not, what other choices are there?
If so, what products are available? Which is the
best, considering effectiveness, use rates, safety
to crops and to operators, price, etc.?
When and how should I use the product of choice
(rate of application, equipment, timing, safety
precautions, etc.)?
How much will it cost, and how much profit will it
return?
Will there be side effects? Now? Later?
To determine to what extent the pesticide information
messages reaching growers in Iowa and Illinois answer these quest-
ions, several aspects were studied.
123
-------
a. Information on pesticide selection, use, costs, and profits.
All but the. last one of the farmer questions listed above
fall into this category and, since they are interrelated, they will
be considered together.
First, the weed and insect control recommendations pub-
lished annually by the Iowa and Illinois Cooperative Extension
Services were examined. Neither the Iowa nor the Illinois weed or
insect control recommendations include information on the cost of
the products whose use is recommended or "suggested". The Iowa
weed control recommendations do not include dosage rates. The re-
commendations do not include all products federally registered and
legally available for use within the state, but they do not indicate
which individual product or products may be the best for a given
purpose.
Crop protection scientists in both states with whom we
discussed this question stated that they do have more specific in-
formation on the advantages and disadvantages of the herbicides and
insecticides included in these recommendations. They would gladly
make such information available in response to direct, individual
questions, but would not want to "go out on a limb" by making their
written recommendations more specific. Some also opined that reper-
cussions from the suppliers of products that might not receive top
rating were a deterrent to publishing more specifics, and to grading
products by their advantages and disadvantages. It was also pointed
out that sometimes, comparable data pertinent to the situation in
the state are not available for all products, and that conditions
within the state may vary, resulting in variations in product per-
formance from place to place.
Pressing the point further, research and extension workers
were asked to assume that they had valid data and were convinced
124
-------
of the existence of genuine differences between pesticides. Most
of them felt that even then, they would rather not publish more
specifics that would differentiate between individual pesticides
to a greater degree.
All entomologists and weed scientists interviewed felt
quite strongly that they should not become involved with the cost
and profit aspects of individual pesticides, admitting that this
would leave growers without an unbiased source of advice on the
economics of their pesticide choices.
It thus appears that there is a reservoir of detailed
and specific information on the performance and relative usefulness
of individual pesticides at the university level that is not pub-
lished. (However, as pointed out in Section 5, of this chapter,
even the information that is published reaches growers only to a
limited extent, and most of it not directly, but through the chan-
nels of the pesticide trade.)
Next, we examined whether Iowa and Illinois farmers them-
selves might feel a need for more specific crop protection advice
than they are currently receiving. Several questions along these
lines were included in the farmer survey.
The first question in this series asked how many weed and/or
insect control demonstration tests the respondent personally visited
during the last three years, and whether the tests were conducted by
federal, state, university or county personnel; or by pesticide compan-
ies or sellers. 48% (28 of 58) of the Iowa and 42% (99 of 238) of the
Illinois respondents reported that they had visited insect and
weed control field tests and/or demonstrations in person during the
last three years. The number of tests visited ranged from 1 to
more than 10; most respondents (79%) had seen between 1 and 3 tests.
43% of the tests visited by Iowa respondents, and 65% of those
visited by Illinois respondents were put on by public agencies,
the balance by the pesticide trade.
125
-------
Concerning use of the results of such tests beyond the
visual impressions, 57% of the Iowa farmers and 31% of the Illinois
farmers received test results in written form. 21% of the Iowa
and 52% of the Illinois growers stated that they had not received
such written reports in the past, but would like to receive them
in the future. Only about 20% of the respondents in both states
felt that such data would not be of value to them.
The next question asked:
"Assume a competent crop protection advisory service
would give you precise information (by mail, telephone,
radio, etc.), based on insect and weed counts, soil
properties, etc., on which herbicides and insecticides
to use (by product name); the amount to use per acre;
and the date the product or products should be applied
for best results, would you follow the advice?"
Replies from 58 Iowa and 239 Illinois respondents
were as follows:
Yes No Undecided
Iowa 81% 17% 2%
Illinois 69% 18% 13%
Next, growers were asked if they would refrain from using
a pesticide if the advisory service would inform them that some or
all of their fields did not need treatment because of low weed or
insect infestations. 85% of the Iowa and 63% of the Illinois
growers said they would follow the advice and not treat.
About one-half of all respondents stated that they would
be willing to pay a fee for such a service, ranging from $0.05 to
$5.00/acre, averaging $0.76/acre in Iowa, $0.70/acre in Illinois.
A surprisingly large number of respondents made additional,
unsolicited comments on this question. A sampling follows:
126
-------
"You don't need anyone to tell you whether you need
herbicides or not, you can tell by the looks of your
fields. As far as insects, no one can predict very
accurately what damage they will do regardless seemingly
large build-ups. Weather and parasites turn things
around".
"Would be interested in the insecticide portion but I
feel I know the weed problem as well as anyone on this
farm".
"Extension is good enough and it is free".
"I get most of this information from my chemical dealer".
"Would pay fee if soil test was also included".
These responses indicate that there is a good deal of
interest in individualized, specific advice on crop protection
among Iowa and Illinois farmers, especially in regard to insect
control. Growers were about equally divided concerning possible
charges for such service. About one-half of them said they would
be prepared to pay a fee, while others felt that the information
now available for free from pesticide sellers and from the exten-
sion service was sufficient.
Some of the more specific information desired by growers
may be available at the state university, but is not published.
Information on costs and profits of specific pesticides is not
available from the university.
b. Information on pesticide side effects.
Side effects from the use of pesticides may occur and be-
come apparent immediately or soon after the use of the pesticide, or
they may occur slowly, through sometimes complex chains of events,
in such a way that they become apparent only later, often long after
the causative pesticide use.
127
-------
An example of the first type would be damage to a
neighboring, susceptible crop from the use of a herbicide. An
example of the second type would be the gradual build-up, bio-
accumulation and biomagnification of residues of persistent pesti-
cides that, after a period of time, may result in the appearance
of high residues in organisms at the tops of food chains, as has
been demonstrated in the case of some of the persistent chlorinated
hydrocarbon insecticides. There is no clear-cut delineation be-
tween these two types of effects and sometimes, both overt and
delayed effects may result from the same pesticide use.
Side effects from the use of pesticides that are of
concern to farmers include possible interactions between various
insect, weed and disease control measures, crop rotation, tillage,
cultivation and other soil management practices, soil erosion,
profits, and, a newly added concern, farm fuel requirements.
To determine to what extent state universities can or
do assist growers in assessing these interactions and in coping with
them, we directed the following inquiry to the Deans of the College
of Agriculture of the University of Illinois and Iowa State Uni-
versity, respectively:
"Under a contract funded jointly by the Council on
Environmental Quality and the U. S. Environmental Pro-
tection Agency (Contract #EQC-325), we are currently
studying use patterns of insecticides and herbicides
on corn and soybeans in the midwest. We are interested,
among other things, in the interactions between the use
of insecticides and herbicides, weed and insect damage
thresholds, tillage practices, crop rotation sequences,
and profit to growers. We are wondering if any tests
have been conducted in your state in which these factors
may have been studied jointly, in the same field tests,
by agronomists, weed scientists, entomologists, and
economists. If so, could you please arrange for us to
receive copies of reprints or reports on the results?
Regardless of whether or not such multidisciplinary
studies have been conducted, we would be interested in
128
-------
your views on the feasibility and merits of such an
approach. Many agricultural scientists seem to feel
that it is best for each discipline to work on its
own problems in its own, separate tests, leaving it
up to the farmer to put it all together. We wonder to
what extent this attitude may arise from traditions,
and the organizational structure and teaching responsi-
bilities of land-grant colleges. In any event, we
would be very grateful if we could have your comments
on the relative merits and demerits of multidisciplinary
approaches to the crop protection problems in your
state".
A very constructive and thoughtful reply to this inquiry
was received from Dr. S. R. Aldrich, Assistant Director of the
University of Illinois Agricultural Experiment Station. Among other
things Dr. Aldrich describes the problems encountered by researchers
in dealing with large numbers of variables in a single experiment.
Directly to the point, Aldrich states:
"In the final analysis, the individual farmer must
assume considerable responsibility for fitting pieces
together because pre-tailored packages of practices
will always have to be too general to fit his partic-
ular system".
It appears from other parts of his letter that the uni-
versity is aware of additional opportunities for interdisciplinary
approaches, especially in the field of environmental studies, and
that efforts are made to promote more interdisciplinary research and
teaching. Interestingly, Dr. Aldrich did not take up the question
of studies on the economic consequences of crop protection measures.
Nevertheless, his letter presents an excellent overview of the pro-
blems at the university level, and of the many steps that are taken
to better assist farmers in coping with theirs. For this reason,
Dr. Aldrich1s letter has been included in its entirety in this report
as Appendix C.
129
-------
Iowa State University replied to the same inquiry in
a nutshell format, saying essentially the same as the much more
detailed reply from Illinois, including the following:
"Multidisciplinary research is being increased.
One-third of agronomy research projects involve
personnel from other disciplines. Ag-engineering
and weed science are cooperating on some research
this year. Members of the entomology department are
working with agronomy on some phases of their research".
Iowa further stated that "no large multidisciplinary
research" was underway which would involve agronomists, weed scient-
ists, entomologists and economists in a planned effort. "This
probably should be done, but it would be difficult."
These replies indicate that at the present time, there is
not much, if any information available to growers from state univer-
sities in regard to the interactions between crop protection mea-
sures, other agronomic practices, and resulting profits.
Concerning delayed side effects from the use of pesticides,
many authors have dealt with the biological and environmental aspects
of this problem. Much less attention has been given thus far to the
effects of various crop protection strategies on the future profit-
ability of the crop production systems involved or, in other words,
to the economic aspects of the problem.
A review of the past history of the use of chemical pesti-
cides indicates that the usefulness of most or all of them is eroded
by the development of resistance in the target pest(s), the selection
of pest populations that are more difficult to control, and/or the
destruction of natural control factors. This erosion process proceeds
slowly with some chemicals and some of their uses, quite rapidly with
others. Sometimes groups of related chemicals are affected, and a
new chemical in such a group may run into resistance problems even
before it ever reaches the market.
130
-------
The typical progression of this erosion process is all
to well known. Following highly successful initial use of a given
pesticide, succeeding applications begin to work less well. Rates
and frequency of application of the pesticide(s) are increased.
Next, more potent pesticides are used, but they soon experience the
same problem. Costs of controlling target pests rise steadily.
Often, problems of residues in treated crops and/or in the environ-
ment, and side effects on nontarget organisms also develop and in-
crease. Eventually, the reservoir of still more potent chemicals
becomes exhausted, or costs become prohibitive. At this stage, un-
less alternate control methods are available, growers are left with
an unmanageable problem, and the pesticide industry without customers.
A classical case demonstrating this sequence of events
has been described by Adkisson (1971). In northeastern Mexico,
cotton was intensively dusted and sprayed wiht chlorinated hydro-
carbon insecticides, mainly for control of the boll weevil, Anthonomus
grandis. In the late 1950's, the boll weevil became resistant to
chlorinated hydrocarbons, and growers switched to organophosphorus
insecticides, primarily methyl parathion. DDT was added to control
the bollworm, Heliothis zea, and the tobacco budworm, H. virescens.
Within a few years, the bollworm and tobacco budworm became more
important than the boll weevil and, at the same time, both species,
especially the tobacco budworm, became increasingly resistant to all
insecticides. By the late 1960's, many cotton growers had to treat
their fields 15 to 18 times with high rates of methyl parathion and,
even then, suffered great yield losses. By 1970, the tobacco budworm
had developed such a high level of resistance that severe outbreaks
could not be controlled, regardless of the insecticide used. In
1960, about 700,000 acres of cotton were grown in the Matamoros-
Reynosa area of northern Mexico. When cotton insect problems first
became severe in this area, approximately 500,000 acres of cotton
131
-------
were moved from Matamoros to new land somewhat further south,
in the Tampico-Mante area. By 1970, less than 3,000 acres of
cotton were raised in both of these areas combined. Adkisson
comments on these developments as follows:
"The seeds for the destruction of the Mexican cotton
industry were planted when the producers decided that
their insect pest problems could be best solved by
the unilateral use of regularly scheduled applications
of broad-spectrum insecticides. Hindsight shows that
this method of pest control was bound for failure since
the genetic diversity of insects is such that they
appear capable of evolving strains resistant to all
insecticides. Once the tobacco budworm became resist-
ant to all available insecticides, the system failed
in Mexico. Thus, it is evident that a different
strategy for the control of insect pests of cotton
must be devised if the industry is to survive".
This unfortunate experience of Mexican cotton growers
is one of the more dramatic, but not the only example of failure
of a unilateral chemical pest control strategy. For instance, pro-
blems of mites, aphids and other insects on fruit and vegetable
crops in certain parts of the United States (as well as in other
countries) have taken a very similar course, except that in most
instances, disaster was averted by timely adoption of more judicious
crop protection strategies, including more judicious use of
chemical pesticides.
In the midwest today, failure of the strategies currently
employed for the control of corn and soybean insects and weeds does
not appear imminent, but several warning signals are in evidence.
These include:
The use of ever increasing quantities of herbicides
and insecticides;
The ongoing selection of more resistant target weed
and insect strains, species and populations;
The continuing increase in the cost of chemical
crop protection;
Pesticide residue and persistence problems.
132
-------
These symptoms indicate that corn and soybean insecti-
cides and herbicides are not exempt from this erosion process. The
question arises if this escalator cannot be stopped, or at least
slowed down, before a crisis stage is reached, and what might be
done now to preserve and prolong the usefulness of presently avail-
able crop protection tools, including the chemical pesticides
currently in use.
Most midwestern farmers are businessmen who are naturally
interested in preserving the productivity of their assets. Chemical
pesticides are among these assets. However, few if any farmers,
and few of the persons advising them on the use of pesticides appear
to be aware of hidden future costs inherent in present pesticide use
decisions. Greater awareness on the part of pesticide users of how
their present crop protection decisions might affect their future
profits would appear to be desirable.
For instance, those midwestern farmers to whom we "experi-
mentally" mentioned the Mexican cotton growers' experience were
intensely interested in it. Data or projections on how current corn
and soybean pesticide use practices might affect the future profit-
ability of these crops would undoubtedly be of even much greater
interest. Such data are not available at present, but it may be
worthwhile to attempt to generate them. This type of information
would probably be a much greater incentive to farmers to use pesti-
cides more judiciously than warnings about ill-defined actual or
potential environmental damage.
Returning to the farmers' questions enumerated at the
beginning of this discussion (p. 123), the findings and considerations
presented in this section suggest that farmers are not adequately
informed about side effects that may result from their pesticide
use decisions. The term "side effect" is used in a broad sense in
133
-------
this discussion/ including especially overt and delayed economic
effects. Such information does not appear to be available, at
least not in regard to the corn and soybean production systems.
7. Individualized Crop Protection Information
The question how the apparent interest on the part of a
substantial number of growers in individualized advice on crop pro-
tection might be met was explored with agricutlural research and
extension workers, pesticide industry representatives, and other
knowledgeable persons both in the midwest and elsewhere. The sub-
ject was also discussed at length during the meeting with project
consultants from Iowa, Illinois and Missouri at Davenport, Iowa,
in January of 1974. Considerable uncertainty and differences of
opinion were evident in these discussions.
Pesticide industry representatives are caught in a dilemma.
As documented in other parts of this report, the pesticide trade has
thus far been the predominant source of pesticide information for
growers. Many individuals in all echelons of the pesticide industry
are very receptive to the idea of shifting emphasis from the selling
of pesticides to the selling of crop protection. However, the pro-
position to provide services instead of chemicals, rather than in
support of the sale of chemicals, is quite foreign to the basic
policies and philosophies of many chemical companies. For most re-
presentatives of the pesticide indsutry who work where the "rubber
hits the road", rewards such as raises, promotions, Christmas bonuses
and/or commissions still appear to be geared to sales volumes in
terms of quantities.
Most (but not all) extension workers believe that it is
beyond the scope of the federal/state cooperative extension service
to furnish specific crop protection advice to individual growers on
a regular basis. They point out that the extension service does
134
-------
not have the personnel to check more than a limited number of
fields on an irregular basis and suggest that there may be a need
for independent, private-enterprise crop protection consultants.
The question is whether such enterprises would find sufficient
economic incentives in working on insect and weed problems of
midwestern field crops.
Farmers in our survey expressed more interest in advice
on insect than on weed control. As pointed out in Chapter IV, corn
soil insecticides are applied only once per season in the majority
of cases, and the cost of the insecticide is only about $2.00 to
4.00/acre (Table 10). Thus, avoidance of unnecessary insecticide
applications will not result in large dollar savings, while the
use of an insecticide when needed is quite profitable (Table 13).
Control of soybean insects has not been a regular problem in Iowa
and Illinois in the past. Here again, the insecticide cost is only
about $1.00 to 2.00/acre/treatment.
Under these circumstances, handling of corn and soybean
insect control problems alone would probably not offer a viable
economic basis for private crop protection entrepreneurs. One
solution suggested was that individualized crop protection advice
might be provided as part of a "package deal" that would also include
advice on fertilizers, seeds, irrigation, etc., at least in the
beginning.
These opinions are supported by the fact that up to the
present, no private crop protection consultants are known to be
operating in Iowa or Illinois. We therefore extended a search for
such enterprises to neighboring states and discovered only one, i.e.,
a company serving growers in southwestern Nebraska and, through
another office, in Arizona. Services offered are as follows:
135
-------
Feed lot and materials handling systems design;
Irrigation pump and well evaluation;
Soil fertility services;
Foreign consulting;
Data processing service;
Irrigation scheduling services;
Insect and disease control;
(Note: Weed control not mentioned!)
Research and development.
The professional staff of this organization includes five
engineers, one soil scientist, one data processing manager, and
four "agricultural specialists" with training and experience in ag-
ronomy or general agriculture.
The company hires scouts to survey clients' fields to
determine irrigation and soil fertility needs and, at the same time,
insect and disease levels.
Private-enterprise crop protection (or pest management)
consultants who specialize in crop protection alone are operating
successfully in other parts of the country, especially in California
and the Southwest, some also in the "Cotton South". In addition to
cotton, crops serviced include citrus and pome fruits, grapes,
walnuts, almonds, tomatoes; and fly and/or bird problems in cattle
feed lots, dairies, poultry farms, etc. All of these situations
differ from the current problems of weed and insect control on mid-
western field crops in at least two important aspects:
(1) They involve crops whose cash value is much
higher than that of corn and soybeans;
(2) Target pests (especially insects and phytophagous
mites) developed such high degrees of resistance
that control by "conventional" use of chemical
insecticides became increasingly impractical or
impossible, making the adoption of other crop
protection strategies an economic necessity.
In these areas, crop protection or pest management con-
sultants, being a part of the alternate crop protection strategies
136
-------
required, provided and continue to provide a service for which
there is a clear economic need.
In the midwestern field crop situation, comparable
economic incentives for private-enterprise crop protection advisers
do not exist at present because chemical crop protection methods
are still quite economical, especially if possible hidden future
costs are disregarded. This situation may change if the cash value
of corn and soybeans continues to increase, and/or if the useful-
ness and economy of the presently used chemical pesticides continues
to erode.
It would seem highly desirable to attempt to slow down
this erosion process before it reaches critical proportions. Pro-
viding growers with the type of specific, individualized advice on
the use (or nonuse) of pesticides in which many of them expressed
interest would appear to be one important step in this direction.
As more information on economic and other side effects from the
unilateral use of pesticides becomes available, this should also
be made available to growers speedily in order to provide them with
a better base for crop protection decisions.
C. Summary
Farmers in Iowa and Illinois receive information on
pesticides primarily from pesticide sellers, pesticide labels, and
other farmers. University extension specialists, area extension
agents and county agents (farm advisors) are regarded by farmers as
very useful sources of information on pesticides. They are very
effective communicators, considering their small numbers in relation
to the large number of farmers they serve. However, these public
servants are outnumbered by pesticide industry representatives and
sellers by such wide margins that their messages reach a much smaller
percentage of growers directly.
137
-------
Extension publications, meetings and field demonstrations
likewise do not reach a significant percentage of growers directly.
The pesticide trade is the largest clientele for these communications
outside of the university and extension system itself. Extension
publications are also sent to news media such as farm magazines, news-
papers, radio, and TV stations and are reproduced by these media in
whole or in part. However, this does not significantly increase the
flow of information to farmers because they do not think highly of
these media as sources of pesticide information.
These pesticide information flow patterns developed during
a. period when the objectives of the pesticide trade were largely in
harmony with those of federal and state agencies. In the past, the
development and increased use of pesticides were generally promoted
by both groups. Messages recommending reduced or no use of pesti-
cides will not flow well through this communications system.
Insect and weed control recommendations published by the
Iowa and Illinois extension services provide growers with little in-
formation on the specific advantages and disadvantages of individual
pesticides, and with no information on costs or profits. The Iowa
weed control recommendations do not include dosage rates. Entomolo-
gists and weed scientists interviewed realize that this leaves growers
without an unbiased source of advice on the economics of their pesti-
cide choices, but feel strongly that they (public agency personnel)
should not become involved with the cost and profit aspects of in-
dividual pesticides.
Many of the farmers interviewed expressed interest in
receiving individualized, specific advice on crop protection, espec-
ially in regard to insect control. About one-half of the respondents
stated that they would be willing to pay a fee for such a service
(ranging from $0.05 to $5.00/acre, averaging about $0.75/acre), while
the other half felt that the information now available without charge
138
-------
from pesticide sellers and from the extension service was sufficient.
Practically no information is available to growers on
possible side effects from the use of pesticides over the long term,
or on interactions between various insect, weed, and disease control
measures; crop rotation, tillage, cultivation and other agronomic
practices; soil erosion; profits; and (a newly added concern) farm
fuel requirements. Tackling these problems would require systematic
interdisciplinary studies which, at least up to the present, univer-
sities or other agricultural agencies in the area have not mounted.
In this connection, it is important to consider that in
intensive agriculture such as the midwestern corn/soybean production
system, heavy applications of chemical pesticides and fertilizers
are made to the same land year after year. Most of these chemicals
remain in the upper l-S inches of topsoil, and their routes and
rates of degradation under field conditions are often not known.
It is surprising and somewhat alarming how little information is
available on the individual or collective effects of these chemicals
on the soil microflora and -fauna and on the long-term fertility of
the topsoil, one of our most important resources.
The history of the use of chemical pesticides in other crop
production systems indicates that the usefulness of most or all of
them is eroded by the development of resistance in the target pest(s),
the selection of hardier pest populations, the destruction of natural
pest suppression factors, etc. In the midwest today, biological or
economic failure of unilateral reliance on corn and soybean pesti-
cides does not appear imminent, but there are warning symptoms, in-
cluding the use of steadily increasing quantities of pesticides; the
progressive selection of more resistant target pest strains, species
and populations; the continuing increase of the cost of chemical crop
protection; and pesticide residue and persistence problems.
One important step toward slowing this erosion process may
139
-------
be to provide growers with more specific, individualized advice on
the more judicious u&e (or nonuse) of pesticides. Some of the in-
formation needed by growers is available from public agency sources,
some of it would have to be adapted to local conditions. However,
there are currently no effective, unbiased communication channels
through which growers could receive such information regularly and
in a timely fashion.
Private enterprise crop protection (or pest management)
consultants operate successfully in other parts of the country on
crops whose cash value is much higher than that of corn and soybeans
(for instance, cotton; fruit, nut and vegetable crops). At the
present time, it is questionable whether private entrepreneurs spec-
ializing in crop protection only would find a sufficient economic
base in the midwestern corn/soybean economy. The pesticide industry
does not appear to be actively interested in providing crop protection
services instead of chemicals, rather than in support of the sale
of chemicals. Most extension workers believe that it would be beyond
the scope of their system to provide specific crop protection advice
to growers on a regular basis. It thus appears that the question on
how crop protection information can be communicated from state uni-
versities to midwestern growers more effectively and without bias
merits attention.
140
-------
X. LITERATURE REFERENCES
Adkisson, P. L. 1971. Objective Uses of Insecticides in
Agriculture. In: Agricultural Chemicals - Harmony or
Discord. University of California, Division of Agri-
cultural Sciences. Symposium Proceedings, p. 43-51.
Beal, G. M., and J. M. Bohlen. 1957. The Diffusion Process.
Special Report No. 18. Agricultural Extension Service,
Iowa State College, Ames, Iowa.
Beal, G. M., J. M. Bohlen, W. A. Fleischman. 1969. Behavior
Studies Related to Pesticides/Agricultural Chemicals and
Iowa Agricultural Chemical Dealers. P-Bulletin-139.
Iowa State University. Ames, Iowa.
Beal, G. M., J. M. Bohlen, and H. G. Lingren. 1966. Behavior
Studies Related to Pesticides/Agricultural Chemicals and
Iowa Farmers. Special Report No. 49. Iowa State University
of Science and Technology. Ames, Iowa.
Carey, A. E., G. B. Wiersma, H. Tai, and W. G. Mitchell, 1973.
Organochlorine Pesticide Residues in Soils and Crops of the
Corn Belt Region, United States - 1970. Pesticides Monitor-
ing Journal 6(4)369-376.
Carl, S. 1974. Contribution to the Panel Discussion on Pest
Management in Perspective. Weed Science Society of America,
Fourteenth Meeting. Las Vegas, Nevada.
Diekman, J. D. 1974. Insect Control with Growth Regulators.
Twenty-Sixth Illinois Custom Spray Operators Training School,
University of Illinois, Urbana, Illinois. Summary of
Presentations, pp. 75-77.
Fliegel, F. C. 1956. A Multiple Correlation Analysis of
Factors Associated with Adoption of Farm Practices. Rural
Sociology 21(3-4)284-292.
Fliegel, F. C., and J. E. Kivlin. 1962. Farm Practice Attri-
butes and Adoption Rates. Social Forces 40(4)364-370.
Williams and Wilkins Company.
141
-------
Fliegel, F. C., and J. E. Kivlin. 1966. Attributes of
Innovations and Factors in Diffusion. The American
Journal of Sociology 72(3)235-248.
Good, J. M. 1974. Integration of Pest Management Systems.
Contribution to the Symposium on the Weed Science Phase of
Pest Management. Weed Science Society of America,
Fourteenth Meeting. Las Vegas, Nevada.
Hestand, K., C. Shupe, and C. Koenig. 1971. Herbicide Use
Practices Among South Eastern Illinois Farmers. Department
of Agronomy, University of Illinois, Urbana. Unpublished
Manuscript.
Hinton, R. A. 1972. Farm Management Manual. AE-4281. Depart-
ment of Agricultural Economics, University of Illinois, Urbana,
Illinois.
Hintz, S. D., H. J. Stockdale, J. R. DeWitt, and E. P. Sylwester.
1973. Iowa Pilot Corn Pest Management Project, Summary of
1973 Results. Iowa State University, Ames (Presented at the
meeting of the Entomological Society of America at Dallas,
Texas, November, 1973; and at the meeting of the Weed Science
Society of America at Las Vegas, Nevada, February, 1974.
Illinois Cooperative Crop Reporting Service. 1972. Illinois
Agricultural Statistics. Annual Summary. Bulletin 72-1.
Springfield, Illinois.
Illinois Cooperative Crop Reporting Service. 1973a. Corn and
Soybeans - Acreage, Yield, and Production, Illinois, by
Counties, 1972. Preliminary Report. Springfield, Illinois.
Illinois Cooperative Crop Reporting Service. 1973b. Illinois
Pesticide Use by Illinois Farmers 1972. Bulletin 73-3.
Springfield, Illinois.
Inter/Agriculture. 1970. Results of the First National Soybean
Weed Loss Survey. Chicago, Illinois.
Inter/Agriculture. 1971. Weed Losses in Soybeans. Chicago,
Illinois.
Iowa Crop and Livestock Reporting Service. 1973. Iowa Annual
Farm Census 1972 (Preliminary). Iowa Department of Agriculture,
Division of Agricultural Statistics. Des Moines, Iowa.
142
-------
Kerr, R. G. 1970. Herbicide Use Study. Department of
Agronomy, University of Illinois, Urbana. Unpublished
Manuscript.
Kivlin, J. E., and F. C. Fliegel. 1968. Orientations to
Agriculture: A Factor Analysis of Farmers' Perceptions of
New Practices. Rural Sociology 33(2)127-140.
Kuhlman, D. E. 1973. Personal Communication.
Kuhlman, D. E., R. Randell, and T. A. Cooley. 1973. Insect
Situation and Outlook, 1973. Twenty-Fifth Illinois Custom
Spray Operators Training School, University of Illinois,
Urbana, Illinois. Summary of Presentations, pp. 109-126.
Luckmann, W. H. 1973. Personal Communication.
Luckmann, W. H., S. Evrard, and J. Shaw. 1974. Managing Corn
Rootworm Populations. Twenty-Sixth Illinois Custom Spray
Operators Training School, University of Illinois, Urbana,
Illinois. Summaries of Presentations, pp. 51-55.
Maddox, J. V. 1974. Present Status and Future Prospects of
Insect Diseases as Control Agents. Twenty-Sixth Illinois
Custom Spray Operators Training School. University of
Illinois, Urbana, Illinois. Summaries of Presentations,
pp. 78-82
Metcalf, C. L., W. P. Flint, and R. L. Metcalf. 1962. Destruct-
ive and Useful Insects, Their Habits and Control. McGraw-Hill
Book Company. Fourth Edition. New York, San Francisco,
Toronto, London.
Moore III, S., W. N. Bruce, D. E. Kuhlman, and R. Randell. 1973.
A study of the Sources of Insecticide Residues in Milk on
Dairy Farms in Illinois - 1971. Pesticides Monitoring Journal
6(4)233-237.
Mrak, E. M. (Chairman). 1969. Report of the Secretary's
Commission on Pesticides and their Relationship to Environmental
Health. U. S. Department of Health, Education, and Welfare.
U. S. Government Printing Office, Washington, D. C.
143
-------
Petty, H. B. 1974. Soil-Insecticide Use in Illinois Corn
Fields, 1966-1972:- A Comparative Summary of Survey Methods
Used. Twenty-Sixth Illinois Custom Spray Operators Training
School, University of Illinois, Urbana, Illinois. Summaries
of Presentations, pp. 24-32.
Pimentel, D. 1971. Ecological Effects of Pesticides on
Non-Target Species. Executive Office of the President,
Office of Science and Technology. U. S. Government Printing
Office, Washington, D. C.
Prairie Farmer. 1970. Indiana and Illinois Agricultural
Chemicals Survey Report No. 6. Research Department.
Chicago, Illinois.
Prairie Farmer. 1972. Illinois and Indiana Agricultural
Chemical and Fertilizer Survey Report. Research Department.
Chicago, Illinois.
Randell, R., T. A. Cooley, and D. E. Kuhlman. 1974. Insect
Situation and Outlook, 1974. Twenty-Sixth Illinois Custom
Spray Operators Training School, University of Illinois,
Urbana, Illinois. Summary of Presentations, pp. 85-102.
Slife, F. W. 1973. Costs and Benefits from Weed Control.
Twenty-Fifth Illinois Custom Spray Operators Training
School. University of Illinois, Urbana, Illinois.
Summaries of Presentations, pp. 160-162.
Smith, R. B., and E. O. Heady. 1970. Characteristics of
Commercial Farm Operators and Their Employees. Iowa Farm
Science 25(3)20-23. FS-1379. Iowa State University of
Science and Technology. Ames, Iowa.
Stockdale, H. J. 1971, 1973. Personal Communications.
Stoneberg, E. G., and R. Winterboer. 1973. Cost of Crop
Production in North Central Iowa. FM 1565 (Rev.) Iowa
State University Cooperative Extension Service, Ames,
Iowa.
Thomas, S. A. J., and J. F. Evans. 1963. Where Farmers Get
Information. Agricultural Communications Research Report - 14,
Extension Editorial Office, University of Illinois College of
Agriculture. Urbana, Illinois.
144
-------
U. S. Department of Agriculture. 1968a. Agricultural
Statistics. U. S. Government Printing Office, Washington,
D. C.
U. S. Department of Agriculture. 1968b. Quantities of Pesticides
Used by Farmers in 1964. Agricultural Economic Report No. 131,
Economic Research Service.
U. S. Department of Agriculture. 1970a. Agricultural Statistics.
U. S. Government Printing Office, Washington, D. C.
U. S. Department of Agriculture. 1970b. Quantities of Pesticides
Used by Farmers in 1966. Agricultural Economic Report No. 179,
Economic Research Service.
U. S. Department of Agriculture. 1972a. Agricultural Statistics.
U. S. Government Printing Office, Washington, D. C.
U. S. Department of Agriculture. 1972b. Extent and Cost of Weed
Control with Herbicides and an Evaluation of Important Weeds,
1968. Economic Research Service, Extension Service, and
Agricultural Research Service. ARS-H-1. U. S. Government
Printing Office, Washington, D. C.
U. S. Department of Agriculture. 1973a. American Agriculture,
Its Capacity to Produce. The Farm Index 12 (12):8-14,16.
U. S. Department of Agriculture. 1973b. Fats and Oils
Situation, FOS-270, November. Economic Research Service.
U. S. Department of Agriculture. 1973c. Feed Situation..
Fds-251, November. Economic Research Service.
U. S. Department of Agriculture. 1974. Quantities of Pesticides
Used by Farmers in 1971. Economic Research Service, National
Economic Analysis Division. In press.
University of Illinois. 1972. Illinois Agronomy Handbook 1973.
College of Agriculture/Cooperative Extension Service.
Circular 1069. Urbana, Illinois.
Wallaces Farmer. 1970. Iowa Agricultural Chemicals Survey
Report No. 6. Research Department. Des Moines, Iowa
145
-------
Wallaces Farmer. 1972. Iowa Agricultural Chemical and
Fertilizer Survey Report. Research Department.
Des Moines, Iowa.
Wiersma, G. B., H. Tai, and P. F. Sand. 1972. Pesticide
Residue Levels in Soil, FY 1969 - National Soils Monitoring
Program. Pesticides Monitoring Journal 6(3)194-228.
146
-------
XI. RESOURCES AND METHODS
A. Project Consultants
An outstanding panel of consultants assisted the
RvR project team in this study. Members of this panel were:
Dr. Joseph C. Headley
Professor, Production Economics
Department of Agricultural Economics
University of Missouri
Columbia, Missouri
Dr. Robert L. Metcalf
Professor of Entomology, Biology, and
Veterinary Physiology & Pharmacology
University of Illinois
Urbana-Champaign, Illinois
Dr. William H. Luckmann
Entomologist and Head
Section of Economic Entomology
Illinois Natural History Survey
Professor of Agricultural Entomology
University of Illinois
Urbana-Champaign, Illinois
Dr. Harold J. Stockdale
Associate Professor, Extension Entomologist
Department of Zoology & Entomology
Iowa State University
Ames, Iowa
Dr. David W. Staniforth
Professor, Weed Investigations
Department of Botany and Plant Pathology
Iowa State University
Ames, Iowa
Advice and assistance from these consultants were sought
and obtained frequently throughout the duration of this study in
personal visits, by telephone, and by mail. In addition, "Prelim-
inary results and conclusions" of the study in a nutshell format
147
-------
were mailed to all consultants early in January of 1974, for their
review and critique. All consultants except Dr. Metcalf who was
unfortunately prevented from attending, then convened for a project
meeting with Dr. von Rtimker at Davenport, Iowa on January 24-25,
1974. At that meeting, the preliminary results and conclusions and
all other aspects of the project were reviewed and thoroughly dis-
cussed.
All comments and leads received from all consultants
throughout the study and at the Davenport meeting have been care-
fully considered, followed up, and, where appropriate, incorporated
into the final report.
Thus, these consultants made major contributions to the
project and, in addition, provided considerable encouragement to
the project team. We acknowledge these contributions with much
appreciation and gratitude.
B. Survey of Iowa and Illinois Farmers
The backbone of this study is a survey of farmers in Iowa
and Illinois that was carried out in several phases.
1. Development of the Question Form.
Firstly, a question form for the farmer interview was
drafted, tried out on a grower, re-drafted, and submitted for
critique to £he project consultants. Written, verbal or telephone
comments were received from all of them except Dr. Headley who was
still abroad at that time. In addition, helpful comments and advice
on the draft form were received in discussions of the form with
Dr. H. B. Petty, Jr., Extension Entomologist; Dr. E. L. Knake,
Extension Weed Specialist; Dr. J. F. Evans, Agricultural Communi-
cations Specialist; Dr. F. C. Fliegel, Rural Sociologist;
148
-------
Mr. F. M. Sims, Farm Management Extension Specialist; Dr. C. R.
Taylor, Agricultural Economist; all at the University of Illinois,
Urbana; and from Dr. R. D. Hickman, Associate Professor of Sampling
and Survey Methods, Iowa State University, Ames. All of these
comments from eleven experts, representing both Iowa and Illinois,
and a variety of disciplines and viewpoints, were incorporated
into the final version of the question form, Appendix A. In addi-
tion, three pages of "Notes for Interviewers" (Appendix B) were
prepared to provide interviewers with necessary background informa-
tion, definitions, etc.
,2. The Iowa Farmer Survey
In cooperation with Dr. R. D. Hickman, Statistical Labor-
atory, Iowa State University, and members of the Department of
Entomology and Agronomy at Iowa State University, it was decided
to center the Iowa phase of the farmer survey in four counties in
northcentral Iowa (Cerro Gordo, Franklin, Hancock, and Wright), an
area of intensive corn and soybean production. It was further de-
<
cided to limit the survey to farmers operating at least 320 acres.
About 25% of all farms in Iowa are larger than 320 acres, and more
than 50% of the state's cropland area is in farms in this category.
Thus, by focusing the survey on larger operators, we obtained infor-
mation on a larger share of the total cropland acreage than would
have been obtained otherwise. Furthermore, studies by Beal and
Bohlen (1957) and others indicate that larger farmers are the inno-
vators and opinion leaders whose attitudes and actions are subse-
quently followed and adopted by smaller operators. This was a
second important reason for focusing the survey on larger operators.
A total of 50 to 60 interviews were desired for the Iowa
phase of the farmer survey, in keeping with the financial, manpower
149
-------
and time resources available for the entire project.
Using materials especially constructed for the purpose
of sampling in rural areas, personnel of the Statistical Labora-
tory at Iowa State University selected an area sample expected to
yield about 70 eligible farm operators, thus allowing a margin
for sampling error and for nonresponse. The overall sampling rate
was approximately 1 out of 22.6. This rate was applied separately
to the sampling materials in each county.
In each county, the sampling was carried out in three
stages. In the first stage, two "blocks" (a technical term relat-
ing to the sampling materials but roughly equivalent to a township)
were selected with probabilities proportional to their sizes in
terms of estimated total number of farms. Within each sample block,
four so-called count units were selected in a systematic manner
with probabilities proportional to their sizes. Finally, by means
of dot maps, sample count units were subdivided into smaller areas.
These were sampled at a rate such that the product of the selection
probabilities at all three stages was equal to the desired overall
sampling rate of 1 out of 22.6.
The areas selected at the final stage of sampling were
shaded in color on county highway maps. To the extent possible,
identifiable boundaries (such as roads or section lines) were used
to define the areas. In some cases it was necessary for the field
worker to follow prescribed procedures utilizing automobile odometers
in order to determine the boundary. Once the boundaries were
located, all eligible operators living within the specified area
were to be included in the sample. Every eligible farm operator
living in the open country (that is, living outside the corporate
limits o.f towns and cities) in the four counties cited previously
had the same chance of being selected in the sample .
150
-------
In late August of 1973, farm operators in the designa-
ted sampling areas were personally contacted, and completed
interviews were obtained from 58 eligible farm operators. This
required 2 weeks' work by a team led by Mr. L. E. Bailey.
3. The Illinois Farmer Survey
In the Iowa survey, the interview questions were present-
ed to a number of interviewees with minimum guidance from the
interviewer in order to identify possible misunderstanding of
questions, and to determine how the questions might be handled
were they presented by mail. Indications were that the question
form could very well be handled by mail.
We then conferred with project consultants at the Univer-
sity of Illinois, Urbana, and with members of the Agricultural
Economics Department. At their suggestion, we contacted Dr. C. H.
Sandage of the Farm Research Institute at Urbana, a small organiza-
tion that is administratively independent of the University, but
cooperates in many of its projects. Dr. Sandage, President of the
Farm Research Institute, is a recognized expert in farmer surveys
in the Midwest. Dr. Sandage agreed with our opinion that the ques-
tion form was well suited to use by mail.
Considering the" production patterns of corn and soybeans
in Illinois in relation to geography (Figures 1 and 2) , it was
decided to eliminate the southern third of the state from the sur-
vey. Through the Farm Research Institute, question forms were then
mailed to 253 farmers operating 320 acres or more in central and
northern Illinois. This sample consisted of all farmers eligible
by virtue of farm size and geographical location out of a standing
panel of about 900 farmers. 239 completed interviews were obtained
by the deadline date in October of 1973, a 94.5% response. Every
county in the northern two-thirds of Illinois is represented among
151
-------
the 239 respondents, giving us a complete scatter of responses
from the desired area.
4. Tabulation and Analysis of the Survey Results
The completed question forms from both the Iowa and Illinois
farmer surveys.were then tabulated by RvR personnel. Each question
form includes a total of 149 information items. Thus, a total of
almost 45,000 information items were processed. The raw tabulated
data were then carefully analyzed, summarized and evaluated, and
comparisons were made with previous studies pertinent to the object-
ives of this project. These comparisons are included in the body
of the report.
It is noteworthy that the results of our survey were in
good agreement with the results of several major previous surveys
in cases where the surveys contained comparable questions. This
lends support to the findings in our survey and, in several instances,
permitted extension of trends (examples: Tables 17, 18, 21, 26).
C. Previous Studies
Our search of the literature and of the state of the art
in the early phases of this project revealed a number of previous
farmer and related surveys that were applicable to the objectives
of this project in whole or in part. The results of these previous
studies have been discussed in the body of this report and were
considered in arriving at findings and conclusions. Complete re-
ferences to these studies are included in the literature reference
section, under the respective authors' or originators' names.
Studies in this category include the following:
152
-------
Beal et al. (1966)
Beal et al. (1969)
Beal and Bohlen (1957)
Hestand et al. (1971)
Illinois Cooperative Crop Reporting Service (1973b)
Inter/Agriculture (1970, 1971)
Kerr (1970)
Petty (1974)
Prairie Farmer (1970, 1972)
Smith and Heady (1970)
Thomas and Evans (1963)
U. S. Department of Agriculture(1968a, 1970b, 1972b, 1974)
Wallaces Farmer (1970, 1971)
D. Other Contacts
A fourth important resource used extensively in this
project consisted of numerous personal, correspondence and/or
telephone contacts with the following groups:
Federal/State Cooperative Extension administrators,
specialists, and area and county agents;
State University agronomists; agricultural economists;
agricultural engineers; entomologists; plant pathologists;
rural sociologists; statisticians; survey specialists;
and weed scientists;
Pesticide manufacturers, wholesalers, retailers, and
sales representatives;
State government officials dealing with pesticide problems;
Private agricultural consultants;
Other knowledgeable persons.
A list of the individuals whom we contacted in the course
of this project follows. We gratefully acknowledge all contribu-
tions of information, advice and comments from these persons.
153
-------
Dr. Samuel R. Aldrich
Assistant Director
College of Agriculture
University of Illinois
Urbana, Illinois
Dr. M. A. Anderson, Dean
College of Agriculture
Iowa State University
Ames, Iowa
Howard D. Baker
Asst. Professor, Sampling and Survey Methods
Statistical Laboratory
Iowa State University
Ames, Iowa
Dr. George M. Beal, Chairman
Department of Sociology and Anthropology
Iowa State University
Ames, Iowa
Dr. O. G. Bentley, Dean
College of Agriculture
University of Illinois
Urbana, Illinois
Dr. Joe M. Bohlen
Professor of Sociology
Iowa State University
Ames, Iowa
Keith Boyer
Brayton Chemicals, Inc.
Burlington, Iowa
Bert O. Brayton
President, Brayton Chemicals, Inc.
West Burlington, Iowa
Alvin F. Bull, Editor
Wallaces Farmer
Wallace-Homestead Company
Des Moines, Iowa
Maclay Burt, Executive Secretary
Association of Applied Insect Ecologists
Santa Clara, California
Dr. Gerald A. Carlson
Department of Economics
North Carolina State University
Raleigh, North Carolona
154
-------
Fred C. Corey
Agricultural Technology Company
McCook, Nebraska
Dr. E. A. Dickason, Professor and Chairman
Department of Entomology
The University of Nebraska
Lincoln, Nebraska
Everett J. Dietrick
Rincon-Vitova Insectaries, Inc.
Riverside, California
Dr. L. A. Falcon
Division of Entomology & Parasitology
University of California
Berkeley, California
Don Fox
Thompson-Hayward Chemical Co.
Kansas City, Kansas
Dr. Roy D. Hickman
Associate Professor
Statistical Laboratory
Iowa State University
Ames, Iowa
J. C. Hogancamp
Division of Plant Industry
Illinois Department of Agriculture
Springfield, Illinois
Dr. C. B. Huffaker
University of California
International Center for Biological Cohtrol
Albany, California
Dr. Howard P. Johnson
Professor, Soil and Water
Department of Agricultural Engineering
Iowa State University
Ames, Iowa
Dr. David L. Keith
Cooperative Extension Service
University of Nebraska
Lincoln, Nebraska
155
-------
Dr. Ellery L. Knake
Extension Weed Scientist
Professor of Agronomy
University 'of Illinois
Urbana, Illinois
Leonard W. Kramp, Superintendent
Division of Feeds, Fertilizers & Standards
Illinois Department of Agriculture
Springfield, Illinois
Dr. Ronald D. Lacewell
Department of Agricultural Economics & Rural Sociology
Texas A & M University
College Station, Texas
Wayman S. Lipsey
General Manager
Agri-Research Associates, Inc.
Burlington, Iowa
Dr. Leon Moore
Extension Entomologist
University of Arizona
Tucson, Arizona
David McMurray
Brayton Chemicals, Inc.
West Burlington, Iowa
Dr. Richard B. Norgaard
Department of Agricultural Economics
University of California
Berkeley, California
Dr. H. B. Petty, Jr.
Extension Entomologist
Professor of Insect Control
University of Illinois
Urbana, Illinois
Dr. Paul M. Ritty
Research and Development, Pesticides
Dow Chemical U.S.A.
Shawnee Mission, Kansas
Gene Schwartz
Agricultural Consulting Service
Holdrege, Nebraska
156
-------
Dr. William D. Shrader
Professor of Soil Management
Department of Agronomy
Iowa State University
Ames/ Iowa
Fay M. Sims
Professor of Farm Management (Extension)
Department of Agricultural Economics
University of Illinois
Urbana, Illinois
Dr. Ray F. Smith, Chairman
Department of Entomological Sciences
University of California
Berkeley, California
Everett G. Stoneberg
Department of Agricultural Economics
Iowa State University
Ames, Iowa
Richard D. Strong
Commodity Specialist
California Farm Bureau Federation
Berkeley, California
Dale M. Studt
Crop Production Specialist
Extension Area Office
Mason City, Iowa
Dr. E. R. Swanson
Professor of Farm Management
Department of Agricultural Economics
University of Illinois
Urbana, Illinois
Dr. Harvey E. Thompson
Extension Crop Specialist
Professor of Crop Production
Department of Agronomy
Iowa State University
Ames, Iowa
Dr. F. Tom Turpin
Department of Entomology
Purdue University
Lafayette, Indiana
157
-------
M. R. Van Cleave, Director
Pesticide Section
State Chemical Laboratory
Iowa Department of Agriculture
Des Moines, Iowa
Dr. Robert van den Bosch
Chairman, Division of Biological Control
Entomological Sciences
University of California
Albany, California
Dr. George W. Ware
Department of Entomology
University of Arizona
Tucson, Arizona
Dr. Theo F. Watson
Professor and Entomologist, Cotton Insects
Department of Entomology
University of Arizona
Tucson, Arizona
158
-------
Page l
Appendix A
RvR Project //53/Farm Survey 1973 Form #
SECTION A: GENERAL
1. How many acres of land (including all crops, pastures, diverted
acres, farmstead, etc.) do you operate this year?
2. How many acres of corn are you growing this year?
3. What is the crop rotation sequence of your 1973 CORN acreage?
a/ ____________ acres corn on corn
b/ acres corn on soybeans
c/ acres corn on sod or pasture
d/ _____________ acres corn following another crop
4. How many acres of soybeans are you growing this year?
5. What is the crop rotation sequence of your 1973 SOYBEAN acreage?
a/ ______________ acres soybeans on soybeans
b/ ________________ acres soybeans on corn
c/ acres soybeans following another crop
6. Do you plan to grow more ( ), fewer ( ), or about the same ( )
number of acres of corn in 1974, or are you undecided ( ) at
this time? (Check one.)
7. Do you plan to grow more ( ), fewer ( ), or about the same ( )
number of acres of soybeans in 1974, or are you undecided ( ) at
this time? (Check one.)
8. Is any of your land:
a/ suitable for terracing? (yes or no)
b/ If yes, about how many acres are suitable for terracing?
c/ How many acres (if any) are actually terraced?
9. In your corn and/or soybean growing operations, do you use:
a/ conventional tillage (plowing, disking)? (yes or no)
b/ minimum tillage (till-planting, mulch tillage, etc.)? (yes or no)
c/ no till (zero tillage, slit, slot, sod planting, etc.)? (yes or no)
-------
Page 2
10. Which of the following sources of information did you use in 1973 and/or
1972 in deciding if, when and how to use herbicides (weed killers),
insecticides (insect killers), or other chemical pesticides, which product
to use, what rate of application, etc.? How useful was the information
from each source that you used? Please be sure you check "Yes" or "No"
for each source* and indicate your degree of satisfaction with each source
for which you answered "yes."
Source
Used source
(Check yes or no)
Yes No
If yes, was the
information you received
Very Satis- Unsatis-
good factory factory
a/Chemical retailer ( ]
b/Representative of chemical mfg. ( j
c/Sales leaflets, etc. ( ]
d/Label on chemical container ( }
e/Farm magazines ( ]
f/Newspapers ( }
gAv ( 3
h/Radio ( j
i/Other publications ( ]
J/County agent/Farm Adviser ( j
k/Area extension agent ( }
I/University extension specialist ( j
in/Neighbors, friends, relatives ( j
Meeting or field demonstration conducted by:
n/State/University ( ]
o/Chemical producer or seller ( j
11. State University and/or Federal insect and weed control specialists in your
state conduct field tests each year to find out which products work best for
the control of weeds and insects in different areas, and when and how much
to apply for best results.
a/Did you personally visit such field tests during the
last 3 years? (yes or no)
b/If yes, how many field tests did you see during the
last 3 years?
c/Were the tests you saw during the last 3 years run by Federal, State,
University or County personnel ( ), or by pesticide companies or
retailers ( )? (Check one or both.)
d/Did you receive the results of such tests in written form?
(yes or no)
e/If you have not received such test reports in the past, would you like
to receive them in the future? (yes or no)
-------
Page
12. Assume a competent crop protection advisory service would give you precise
information (by mail, telephone, radio, etc.), based on insect and weed counts,
soil properties, etc., on which herbicides and insecticides to use (by product
name); the amount to use per acre; and the date the product or products should
be applied for best results.
a/Would you follow the advice? (yes or no)
b/lf the service would advise that some or all of your fields do not need
treatment because insect or weed infestations are too low for treatments
to be worthwhile, would you follow the advice? (yes or no)
c/If a fee would have to be charged for such a service, how much would you
be willing to pay per acre? $
SECTION B: WEED CONTROL ON CORN
13. Did you use one or more chemical herbicides (weed killers) on your corn
in 1973? (yes or no)
If no, answer the following questions for 1972. If you did not use corn
herbicides in 1972 either, skip this section and go to question 25.
14. Name the product or products used (in decreasing order of quantity used):
15. Did you use the same single product or combination of products in 1972?
1971? 1970 ? (Answer yes or no for each year.)
16. If no, a/ why did you switch products?
b/ On whose advice did you switch products?
17. During the last 5 years, has your cost (dollars per acre) for chemical
herbicides on corn:
increased? (yes or no) If yes, about how much? %
decreased? (yes or no) If yes, about how much? 7.
remained about the same? (yes or no)
18. Indicate which of the following statements best describe the results of your
use of corn herbicides this year and last year.
For each year, check a, b or c; and d, e or f.
1973 1972
GUc-4 032*- (^a/Corn nearly weed-free
jb/Weeds suppressed sufficiently to prevent yield loss
control unsatisfactory
"2*/d/Money for corn herbicides was well spent ( ) ( )
\e/Money for corn herbicides was wasted ( ) ( )
^ \f/Should have spent more money for corn herbicides ( ) ( )
19. Do all of your corn acres need chemical herbicides each year? (yes or no)
20. If no, do you treat only the weedy areas ( ), or treat all corn acres
regardless ( )? (Check one.)
21. Compared to the mid-1960's, do the corn herbicides that you use today (this
year or last year) give you better ( ) or poorer ( ) weed control? (Check one.)
-------
Page 4
22. What benefits do you obtain from using herbicides on corn? (Check one or more,
and/or describe benefits not listed.)
a/Save Labor ( )
b/Facilitate planting ( )
c/Control weeds ( )
d/Good-looking fields ( )
e/Save cultivating ( )
f/Save other tilling operations ( )
g/No benefits ( )
h/Other benefits ( ), please describe;
23. Assume the cost of all corn herbicides were twice as high as what you actually
paid this year:
a/would you still use the product or products you used this year in the same
amounts and on the same number of acres of corn? (yes or no)
b/lf no, what would you do instead? ^
24. Assume all corn herbicides would be removed from the market or become ineffective
against corn weeds:
a/would you continue to grow corn?
b/lf yes, how would you control weeds?
(yes or no)
c/If no, what other crop or crops would you grow instead of corn?
SECTION C: INSECT CONTROL ON CORN
25. Did you use one or more chemical insecticides (insect killers) on your
corn in 1973? (yes or no)
If no, answer the following questions for 1972. If you did not use corn
insecticides in 1972 either, skip this section and go to question 35.
26. Name the product or products used (in decreasing order of quantity used):
27. Did you use the same single product or combination of products in 1972?
1971? 1970? (Answer yes or no for each year.)
28. If no, a/why did you switch products?
b/On whose advice did you switch products?
29. During the last 5 years, has your cost (dollars per acre) for chemical
insecticides on corn:
increased?
decreased?
remained about the same?
(yes or no)
(yes or no)
If yes, about how much?_
If yes, about how much?
(yes or no)
-------
Page 5
30. Indicate which of the following statements best describe the results of your use
of corn insecticides this year and last year.
For each year, check a, b <>r c; and d, e or f.
1973 1972
\on*.r a/corn suffered no insect damage whatsoever ( ) ( )
^ | b/Insects suppressed sufficiently to prevent yield loss ( ) ( )
-t-^^y^Vc/Insect control unsatisfactory ( ) ( )
**? ( d/Money for corn insecticides was well spent ( ) ( )
> e/Money for corn insecticides was wasted ( ) ( )
**(f/Should have spent more money for corn insecticides ( ) ( )
31. Do all of your corn acres need chemical insecticides each year? (yes or no)
32. If answer is no, how do you decide which corn acres to treat and which not?
33. Assume the cost of all corn insecticides were twice as high as what you actually
paid this year:
a/would you still use the product or products you used this year in the same
amounts and on the same number of acres of corn? (yes or no)
b/If no, what would you do instead?
34. Assume all corn insecticides would be removed from the market or become ineffective
against corn insects:
a/would you continue to grow corn? (yes or no)
b/If yes, what would you do to minimize insect damage?
c/If no, what other crop or crops would you grow instead of corn?
SECTION D: WEED CONTROL ON SOYBEANS
35. Did you use one or more chemical herbicides (weed killers) on your soybeans
in 1973? (yes or no)
If no, answer the following questions for 1972. If you did not use soybean
herbicides in 1972 either, skip this section. Interview is completed.
36. Name the product or products used (in decreasing order of quantity used):
37. Did you use the same single product or combination of products in 1972?
1971? 1970? (Answer yes or no for each year.)
-------
Page 6
38. If no, a/why did you switch products?
b/On whose advice did you switch products?
39. During the last 5 years, has your cost (dollars per acre) for chemical herbicides
on soybeans:
increased? _ (yes or no) If yes, about how much? _ 7.
decreased? _ (yes or no) If yes, about how much? _ %
remained about the same? _____ _ (yes or no)
40. Indicate which of the following statements best describe the results of your use
of soybean herbicides this year and last year.
For each year, check a, b or c; and d, e or f.
K-£ <«v*- r a/Soybeans nearly weed- free
?** < b/Weeds suppressed sufficiently to prevent
"^ «*. *
41.
42.
_ } e/Money
l/K\^f /Should
for
for
soybean
soybean
have spent
Do all of your
If no, do y
ou
soybean
treat on]
herbicides
herbicides
more money
acres need
Ly the weed]
yield loss
was well spent
was wasted
for soybean
herbicides
1973
T7
( )
( )
(
(
(
)
)
)
chemical herbicides each year?
! areas ( ),
or treat all soybean
acr<
iS
1972
T7
( )
( )
(
(
(
(yes
)
)
)
or
no]
regardless ( )? (Check one.)
43. Compared to the mid-19601 s, do the soybean herbicides that you use today (this
year or last year) give you better ( ) or poorer ( ) weed control? (Check one.)
44. What benefits do you obtain from using herbicides on soybeans? (Check one or
more, and/or describe benefits not listed.)
a/Save labor ( ) e/Save cultivating ( )
b/Facilitate planting ( ) f/Save other tilling operations ( )
c/Control weeds ( ) g/No benefits ( )
d/Good- looking fields ( ) h/Other benefits ( ), please describe:
45. Assume the cost of all soybean herbicides were twice as high as what you actually
paid this year:
a/would you still use the product or products you used this year in the same
amounts and on the same number of acres of soybeans? (yes or no)
b/If no, what would you do instead?
46. Assume all soybean herbicides would be removed from the market or become
ineffective against soybean weeds:
a/would you continue to grow soybeans? (yes or no)
b/If yes, how would you control weeds?
c/If no, what other crop or crops would you grow instead of soybeans?
-------
Appendix B
R V R CONSULTANTS
P. O. BOX 953 SHAWNEC MISSION. KANSAS 66201
TELEPHONE 8 1 3/722-8793
ROSMARIE VON RUMKER. Sc. D
RvR Project #53/Farm Survey
Notes for Interviewers.
20 August 1973
The term "pesticides" includes insecticides (insect killers) ,
herbicides (weed killers), fungicides (fungus killers), nematicides,
miticides, rodenticides, and other substances that will destroy or
repel pests, or offer protection from pests. "Pests" are unwanted
animals, plants, or viruses which cause injury, disease or destruct-
ion to desirable plants, animals, structures, goods, or to man
himself. Forms of life which may be pests include insects, weeds,
fungi, bacteria, viruses, nematodes, mites, rodents, snails, slugs,
birds, and other organisms.
In this project, we are primarily interested in the insects and
weeds that attack corn and soybeans.
The background and purpose of this study are outlined in the attached
2- page Project Summary ("Introduction" and "Objectives") .
The following comments will serve to further explain certain individ-
ual questions.
Question 1; "How many acres (all crops combined) do you farm this
year?" Include all acres farmed, including pastures, diverted
acres, etc.
Questions 3 and 5 , concerning crop rotation sequences for the corn
and soybean acreage, this information is important to the project
because weed and insect problems vary somewhat, depending upon the
preceding crop. For instance, in corn on corn, corn rootworms tend
to be a problem; in corn on sod or pasture, other soil insects are
sometimes abundant.
Question 8; Terracing reduces soil erosion and thus possible water
pollution from pesticide residues in the soil. For this reason,
terracing practices are of interest to us in this project.
-------
Page #2
RvR Project #53/Farm Survey
Notes for Interviewers Continued
uestion 9; "In your corn and/or soybean operations, do you use
"a] Conventional tillage; (b) Minimum tillage; or (c) No till?"
The different tillage systems in this question are defined as
follows:
a/Conventional tillage includes primary and secondary tillage
operations normally performed in preparing a seedbed for a given
crop. One of these operations usually is plowing.
b/Minimum tillage is the minimum soil manipulation necessary for
crop production. Minimum tillage includes all systems with fewer
tillage operations than conventional tillage. Often, substitute
techniques such as the use of herbicides are employed for weed
control and/or seedbed preparations. Examples of minimum tillage
systems are:
Till-planting, a strip tillage system in which sweeps cut and
remove residue, growing vegetation and a layer of soil over the
row (generally one-third of the row width) ahead of surface
planters in a once-over operation.
Mulch-tillage, also referred to as stubble mulching, is tillage
or preparation of the soil in such a way that plant residues or
other materials are left to cover the surface both before and
after crop establishment.
c/No-till, also called no tillage, slit plant, slot plant, sod plant,
or zero tillage, is a system whereby a crop is planted directly
into a seedbed untilled since harvest of the previous crop.
We are interested in tillage systems in this project because different
tillage practices affect pesticide requirements. They may also affect
soil erosion. Soil that may be transported away from a field in the
process of erosion may carry pesticide residues. Thus, different
tillage practices have an influence on environmental pollution,
especially water pollution, by pesticides.
Question 12. c; Possible fee for crop protection advisory service.
If interviewee has difficulty answering this question, interviewer may
mention that possible fees might be of the order of $0.80 - 1.50 per
acre of all crops to be placed under such a program (not per acre of
all land in the farm).
-------
Page #3
RvR Project #53/Farm Survey
Notes for Interviewers Continued
Section B: Weed Control on Corn
Section C: Insect Control on Corn
Section D: Weed Control on Soybeans
Questions 14, 15 and 16)
Questions 26. 27 and 2:8)
Questions 36, 37 and 38)- The purpose of these three questions is not
to determine exactly what pesticides were used in what quantities.
Therefore, we need only an approximate order of magnitude in response
to questions 14, 26 and 36. What we really want to know is if the
farmer made a change in the pesticides used during the last four years
and if so, why. Thus, questions 16, 28 and 38 are the most important
ones in this sequence, and the two preceding questions are intended
merely to lead up to them. In obtaining answers to questions 16, 28
and 38, try to determine which of the information sources in question
10, page 2 prompted the farmer to switch products.
Question 34. b; "what would you do to minimize insect damage if all
corn herbicides would be removed from the market or become ineffective
against corn insects?" Interviewer should first attempt to get an
answer from the farmer without making any suggestions. If farmer has
difficulty answering the question, interviewer may suggest steps that
might be taken in this situation, such as avoid growing corn on corn
to avoid corn rootworm damage; avoid growing corn on sod to avoid
damage from other soil insects; select corn variety resistant or
tolerant to insect damage, etc.
-------
RvR Project #53
Funded jointly by the Council on Environmental Quality
and the U. S. Environmental Protection Agency, Contract IEQC-325
Title: "Farmers Pesticide Use Decisions and Attitudes on
Alternate Crop Protection Methods"
I. Introduction.
Crop yield losses due to pests including insects,
weeds, diseases, nematodes, and other organisms reduce farming
profits. Modern agricultural production techniques such as
growing large, continuous stands of one crop in succession
(monoculture), use of high yielding crop varieties, irrigation,
use of fertilizers, etc., tend to increase potential crop losses
due to pests, and thus the incentive to prevent such losses.
Since the advent of the synthetic organic pesticides, farmers
have relied increasingly on the use of these chemicals for the
protection of their crops.
In many instances, chemical pesticides provided
spectacular control of target pests when they were first intro-
duced. However, fairly soon, undesirable results also appeared,
including the development of pest strains resistant to pesticides;
increasingly rapid resurgence of target pest populations following
treatments; outbreaks of secondary pests which did not cause
economic damage previously; adverse effects on wildlife; and un-
desirable residue levels on food crops, in human tissues, and
in many other elements of the environment. There is increasing
concern about possible effects of long-term exposure to low
levels of pesticides, alone or in conjunction with other stresses,
on many forms of life, including man himself.
Farmers use pesticides for economic reasons, i.e., to
prevent profit losses resulting from crop yield losses. This
proposal deals with the factors that enter into farmers' pesti-
cide use decisions, and with farmers' attitudes in regard to
alternate crop protection strategies. It is suggested that this
investigation be focused on the two most important U.S. field
crops (in terms of acreage and cash value), corn and soybeans. A
large and continually increasing acreage of these crops currently
receives applications of chemical pesticides at increasing fre-
quencies and dosage rates. It is estimated that in 1972, at
least 85 million acres of corn and soybeans combined received one
or more treatment(s) with one or more pesticide(s).
There is growing concern among entomologists, weed
specialists, agromonists, economists, an:! ecologists about the
biological and economic wisdom of indefinite continuation of
the present pesticide use patterns on these (and other) crops.
Alternate loss prevention strategies to be studied in this project
-------
that would contribute to a reduction in the use of chemical
pesticides, or at least in breaking the present trend of
rapidly increasing use of pesticides, would have large potential
benefits in view of the large acreages and large quantities of
pesticides involved.
II. Objectives.
The basic objective of this project is to study the
factors that farmers consider in making pesticide use decisions,
and farmers' knowledge of, and opinions on possible alternatives
to the use of chemical pesticides. Such information is needed
for the development of crop protection strategies alternative to
sole reliance on chemical pesticides. To accomplish this object-
ive, questions to be studied include the following:
How do farmers arrive at pesticide use decisions?
What information sources do farmers rely on in making these
decisions? How reliable are these sources? Are they biased?
To what extent do farmers apply pesticides on preventive,
pre-programmed application schedules, and to what extent only
after an actual need has been established?
What is the normal degree and extent of infestation of
the pest(s) against which the chemical pesticide(s) are used
(economically damaging level of infestation; percentage of total
crop acreage likely to be affected)?
Which pesticide use patterns are most wasteful (high
rate of preventive use against pest(s) occurring infrequently or
affecting only a small percentage of the total acreage)?
Would farmers make different pesticide use decisions if
they had
more information on alternatives?
reliable forecasts on the level of pest infestations
and damage likely to occur in a given season?
more complete data on the present and future costs of
their present pesticide use patterns, compared to the
present and future costs of alternatives?
What other information or incentives (positive or nega-
tive) might cause farmers to reduce or eliminate wasteful pesticide
use practices, and to use minimum needed, rather than maximum
tolerated amounts of chemical pesticides?
-------
Appendix C
AGRICULTURAL EXPERIMENT STATION 109 MUMTORO HAIL, URBANA, ILLINOIS 6180!, hllPHONF (217) j 3'I 0240
OFFICE OF DIRECTOR
October 22, 1973
Dr. Rosmarie von Rumker
RVR Consultants
P. O. Box 553
Shawnee Mission, Kansas 66201
II
Dear Dr. von Rvimker:
Dean Bentley asked me to respond to your request for information on multi-
disciplinary studies on insecticides and herbicides. I requested assistance from
several staff members, hence the delay in responding.
I feel there is close liaison among research and_extension wprkers_to the
end that appropriate interdisciplinary considerations are recognized and frequently,
though certainly not always, researched. The following paragraphs illustrate how
multidisciplinary research evolves in the area of corn production.
The nature of agricultural field research is that one first attempts to
thoroughly understand the principles involved. This is best accomplished by^sjtudy-
ing one factor at _a time for example herbicides^on corn. Later the researcher usu-
ally hypothesizes that there are interactions among certain practices which must be
field tested because they are not fully predictable on theoretical grounds alone.
Such studies often begin within the expertise of one researcher or a single depart-
ment, for example the combined effect of date of pJLarvting, plant population and
cultivation on weed problems and utility^of various herbicides. At some point the
researcher, if he has proper liaison with other researchers, will want to know the
effect of alternative seedbed preparation approaches (conventional plowing, chisel-
ing, zero tillage, etc.) on the various weed control strategies and he will, there-
fore, consult with the appropraite agronomy and/or agricultural engineering
specialists. Cultivation is impossible in zero tillage. Leaving residues on the
soil surface impairs the effectiveness of certain herbicides, hence may rule out
non-plow systems on farms where certain weed species are prevalent. The plant path-
ologist enters the picture because certain plant diseases problems are accentuated
by leaving residues of the preceeding crop of the same species on the surface, where-
as others are not. For example, it is my understanding that yellow leaf blight of
corn is dramatically worse almost to the row where corn residues are left on the
surface. Northern leaf blight (Helminthosporium turcicum) is much less affected.
The entomologist becomes involved because corn borer is partially controlled
by chopping corn stalks in the fall or plowing them under. Corn rootworm is greatly
reduced by growing alternative crops in sequence rather than continuous corn.
-------
von Rumker, Rosmarie -2- October 22, 1973
In answer to your question as to whether all of the pertinent variables are
regularly incorporated into single experiments,the answer is no, because that would
be impracticable if not impossible. A cogent reason for not combining all aspects
into single experiments is that the problems to be studied do not all occur at the
same place. The ever-present challenge to researchers is to combine into single
experiments the minimum number of variables jthat must be tested in combination and
then to test other combinations in other experiments so that that overall research
input is most efficiently utilized. One cannot hope to duplicate all of the individ-
ual farm situations involving soil type, cropping sequence, particular weed, insect
and disease problems, seedbed preparation preferences, date of planting, plant popu-
lation, etc. When you combine a large number of variables into a single experiment
you lose some capability to identify the contrj_but.ion_pf each, hence while gaining
insighTTTnto the interaction of multiple factors in the specific location, you lose
capability to develop general principles from which to extrapolate the results to
other locations. Furthermore, the experiment becomes unmanageably large. This in-
troduces additional soil variability which is undesirable because it usually in-
creases unexplainable variability which in turn requires greater differences for
statistical significance.
In the final analysis, the individual farmer must assume considerable
responsibility for fitting pieces together because pre-tailored packages of
practices will always have to be too general to fit his particular system. Each
farmer has certain likes and dislikes. Credit situations are often unique and are
dynamic from year to year. As we have experienced recently the economic picture
sometimes changes suddenly and without time to reprogram a preconceived package be-
fore a critical decision must be made. Supplies of seeds, fertilizers, and specific
pesticides vary among localities and are sometimes subject to sudden changes.
To help farmers in developing well coordinated crop production systems the
University of Illinois has developed a cadre of specialized crop production advisers
consisting of County Extension Advisers who annually receive special training in all
aspects of crop production by experts in soils, fertility, plant breeding, plant
pathology, entomology, agricultural engineering, marketing etc. This program has been
operational in total for at least five years and in part for about ten years.
Coordinated crop production - crop protection schools have been widely held
at county and muticounty levels for fifteen years. The program is jointly planned
and presented, usually on a two-day basis, by four to seven subject matter
specialists from agronomy, plant pathology, entomology, engineering and economics.
This type of educational meeting results in a substantial amount of intertwining of
production practices both for and with farmers.
I am sending the Illinois Agronomy Handbook for 1973 which was jointly pre-
pared by agronomists, entomologists, plant pathologists and horticulturists and the
Proceedings of the Custom Spray Operators School which documents the multidiscipli-
nary approach to practical problems.
I feel that there is close liaison among disciplines here at the University
of Illinois and at Cornell where I was located for fifteen years. I believe a sub-
stantial shift has already taken place over the past twenty years and that it is
accelerating especially in the area of environmental concerns. I have recently
moved into a newly created position as Assistant Director of the Experiment Station
with responsibility as Director of the Environmental Quality Council for the purpose
-------
von Rumer, Rosmarie -3- October 22, 1973
of promoting coordinated activities within the College of Agriculture. Each of the
Task Forces within the Council includes representatives from several departments,
other colleges and outside agencies.
At the University level, the Institute for Environmental Studies was re-
cently established to promote interdisciplinary research and teaching.
The Corn and Soybeans Study Team of the National Academy of Sciences
Pesticide Study Committee will be making an in-dpeth analysis of pest control strat-
egies in the cornbelt during the next six to eight months. It is a multidisciplinary
team as is the parent Executive Committee on which I serve. The products of both
the Study Team and Executive Committee are directed at some of the concerns involved
in your study.
/
Sincerely,
Samuel R. Aldrich
Assistant Director
SRA:ph
enc.
cc: O. G. Bentley
U S GOVERNMENT PRINTING OFFICt 1975- 582-420/243
------- |