MIDWEST RESEARCH INSTITUTE
MRI
EPORT
A/STUDY OF THE EFFICIENCY OF THE USE OF
PESTICIDES IN AGRICULTURE
VOLUME
Midwest Research Institute
425 Volker Boulevard
Kansas City, Missouri 641 10
RvR Consultants
6400 Hodges Drive
Shawnee Mission, Kansas 66208
FINAL REPORT
July 1975
Contract No. 68-01-2608
MRI Project No. 3949-C
For
Environmental Protection Agency
Strategic Studies Unit, OPP (HM568)
401 M Street, N.W.
Waterside Mall, Room 507
Washington, D. C. 20460
Attn: Mr. Allan Zipkin
Project Officer
MIDWEST RESEARCH INSTITUTE 425 VOLKER BOULEVARD, KANSAS CITY, MISSOURI 64110 • 816 56V0202
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MRI-NORTH STAR DIVISION 3100 38th Avenue South, Minneapolis, Minnesota 55406* 612 721-6373
MRI WASHINGTON, D.C. 20005- 1522 K STREET, N.W. • 202 293-3800
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A STUDY OF THE EFFICIENCY OF THE USE OF
PESTICIDES IN AGRICULTURE
VOLUME I
By
Rosmarie von Rumker
Gary L. Kelso
with
Freda Horay
Kathryn A. Lawrence
Midwest Research Institute
425 Volker Boulevard
Kansas City, Missouri 64110
RvR Consultants
6400 Hodges Drive
Shawnee Mission, Kansas
66208
FINAL REPORT
July 1975
Contract No. 68-01-2608
MR! Project No. 3949-C
For
Environmental Protection Agency
Strategic Studies Unit, OPP (HM568)
401 M Street, N.W.
Waterside Mall, Room 507
Washington, D.C. 20460
Attn: Mr. Allan Zipkin
Project Officer
'1ST
[MSTITUTE 425 VOLKER BOULEVARD, KANSAS CITY, MISSOURI 64110 ° 816561-0202
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PREFACE TO VOLUME I
This report describes the results of a study conducted jointly by
Midwest Research Institute (MRI) and RvR Consultants during the period
1 August 1974 to 14 February 1975. The study was performed for the Stra-
tegic Studies Unit, Office of Pesticide Programs, U.S. Environmental Pro-
tection Agency (EPA), under Contract No. 68-01-2608, entitled "A Study
of Wasteful Pesticide Use Patterns." The EPA Project Officer was Mr. Allan
Zipkin.
Work on this program (MRI Project No. 3949-C; RvR Project No. 67)
was conducted with Dr. Rosmarie von Rumker as task leader. The program
was under the general supervision of Dr. H. M. Hubbard, Director of MRI's
Physical Sciences Division, and Dr. E. W. Lawless, Head, Technology Assess-
ment Section. The MRI project members consisted of Mr. Gary Kelso, Group
Leader; Miss Kathryn Lawrence; and Mr. Francis Bennett. Dr. Arthur Allen
acted as consultant to the program. The RvR project members were Dr. Rosmarie
von Rumker and Mrs. Freda Horay.
Approved for:
[DWEST RESEARCH) INSI
lubbard, Diifecflor
Physical Sciences Division
2 July 1975
iii
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CONTENTS - VOLUME I
Page
List of Figures viii
List of Tables ix
Abstract 1
Sections
I INTRODUCTION 3
II DEFINITION AND IDENTIFICATION OF PESTICIDE WASTES AND
LOSSES 8
Efficient Use of Pesticides 8
Pesticide Wastes and Losses 8
Avoidable Versus Unavoidable Pesticide Wastes and
Losses 9
Pesticide Wastage 9
Pesticide Losses. . . 9
Types, Causes and Other Characteristics of Avoidable
Pesticide Wastes and Losses 11
Unnecessary Use 11
Overuse 12
Misuse 13
Unwanted, Avoidable Discharge, Deposit or Migration . 13
III SUMMARY 15
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CONTENTS - VOLUME I (continued)
Page
IV CONCLUSIONS AND RECOMMENDATIONS 19
V PESTICIDE USE PATTERNS ON CORN 22
Production of Corn in the United States 22
Quantities of Pesticides Used on Corn 27
Herbicide Use Practices 34
Insecticide Use Practices 37
Summary 49
References to Section V 52
VI PESTICIDE USE PATTERNS ON SORGHUM 54
Production of Sorghum in the United States 54
Quantities of Pesticides Used on Sorghum 57
Herbicide Use Practices 61
Insecticide Use Practices 65
Summary 78
References to Section VI 79
VII PESTICIDE USE PATTERNS ON APPLES. 81
Production of Apples in the United States 81
Quantities of Pesticides Used on Apples ' . 81
Fungicide Use Practices 91
Insecticide Use Practices 92
Herbicide Use Practices 100
Use of Miticides, Fumigants, and Plant Growth
Regulators 100
Miticides 101
Fumigants 101
Plant Growth Regulators 102
Summary 102
References to Section VII 104
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CONTENTS - VOLUME I (concluded)
Page
VIII WASTES AND LOSSES OCCURRING DURING AND AFTER PESTICIDE
APPLICATION 106
Study Approach 106
Study Areas 107
Summary of Discussions and Findings in Volume II. ... 108
Pesticide Wastes and Losses Occurring During
Application 108
Waste Potential During Application. . . 108
Loss Potential During Application 109
Pesticide Losses After Application and by Miscellaneous
Discharge 110
Loss Potential After Application 110
Miscellaneous Pesticide Discharges 114
Appendix - Criterion Scheme for the Selection of Survey Crops. . 115
vii
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FIGURES
No. Page
1 Aerial foliar insecticide application: typical losses
between spray nozzle and site of toxic action 10
2 Farm production regions 24
3 U.S. corn acreage (1971), by state 25
4 U.S. sorghum acreage (1971), by state 56
5 U.S. commercial apple production (1971), by state 82
viii
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TABLES
No. Page
1 Estimated rate of total vs. needless use of pesticides on
corn, sorghum, and apples 16
2 U.S. corn acreage, yield, value and production, 1971 to
3
4
5
6
7
8
Corn acreage in the U.S.
Pesticide usage on U.S. c
Herbicides used on corn,
Insecticides used on corn
Miscellaneous pesticides
Use of pesticides on corn
1971
in 1972, 19
orn crop in
by region,
, by region
used on cor
in the U.S
73, and 1974 by major
1971 by region ....
1971
, 1971
n, by region, 1971. . .
. in 1964, 1966, and
26
28
29
30
31
32
9 Estimated extent of chemical weed control on corn in the
U.S., 1959 to 1968 34
10 Insecticides recommended against corn soil insects in 1974
by extension entomologists in eight midwestern states . . 40
11 Extent and profitability of the use of insecticides on corn
in Illinois, 1972 to 1974 41
12 Estimated use and profitability of soil insecticides for
corn rootworm control in Illinois, 1964 to 1974 43
13 Use of corn soil insecticides in Illinois, 1964 to 1974 . . 45
ix
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TABLES (continued)
No.
14 Corn acres treated with soil insecticides in selected states
compared to acres needing treatment and acres harvested for
grain, 1974 . . . 48
15 U.S. sorghum acreage, yield, value and production, 1971 to
1974. 55
16 Pesticide usage on U.S. sorghum crop in 1971 58
17 Herbicides used on sorghum, by region, 1971 59
18 Use of pesticides on sorghum in the U.S. in 1964, 1966, and
1971 60
19 Estimated extent of chemical weed control on sorghum in the
U.S., 1959 to 1968 62
20 Rates of application of major sorghum herbicides recommended
in Texas, Oklahoma, Kansas and Nebraska 64
21 Use of insecticides for greenbug control in the Texas Sorghum
Pest Management Program in 1973 compared to pre-program
use (1972). . . 68
22 Use of disulfoton against the greenbug on sorghum in the
Hale County, Texas Pest Management Program, 1973 69
23 Effects of disulfoton applications against greenbug on
sorghum on subsequent treatments against spider mites . . 71
24 Use of insecticides on sorghum in Clay County, Nebraska, by
pest management program participants and nonparticipants,
1973 74
25 Rates of application of disulfoton against greenbug and mites
on sorghum recommended by public agencies and in selected
pest management programs 76
26 Pesticide usage on U.S. apple crop in 1971 by region. ... 84
27 Fungicides used on apples by region, 1971 85
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TABLES (concluded)
No. Page
28 Insecticides used on apples by region^ 1971 86
29 Herbicides used on apples by region, 1971 87
30 Miscellaneous pesticides used on apples by region, 1971 . . 88
31 Use of pesticides on apples in the U.S. in 1964, 1966, and
1971 89
32 Apple acreage in Washington 93
33 Use of pesticides on apples in the Lower Yakima Valley under
IPM versus non-IPM programs 94
34 Use of pesticides on apples in Pennsylvania under IPM versus
non-IPM programs 96
35 Rates of application of Guthion® 50% wettable powder on
apples recommended by public agencies and in selected
insect control programs . 97
36 Likelihood of pesticide drift during crop treatment in
agriculture by method of application Ill
37 Estimated losses during and after application of pesticides
to corn, sorghum and apples (1971) 112
A-l Use of pesticides on selected crops by pesticide category,
1971 117
A-2 USDA IPM programs by crops, 1972 and 1973 118
A-3 U.S. acreage and farm value of selected crops, 1972 .... 119
A-4 Ranking summary by crops 120
A-5 U.S. acreage and farm value of commercial vegetable crops,
1972 122
xi
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CONTENTS - VOLUME II
Sections
I Introduction
II Summary
III Pesticide Wastes and Losses Occurring During Application
IV Pesticide Losses After Application and by Miscellaneous Discharges
Appendix A - Field Studies on Pesticide Drift During Application
Appendix B - Field Studies on Pesticide Runoff After Application
Appendix C - Pesticide Usage on the U.S. Corn, Sorghum, and Apple Crops
(1971)
Appendix D - Pesticide Application Rates Recommended by the USDA and
Manufacturers' Product Labels
Appendix E - Extension Service Recommended Pesticide Application Rates
for Apples, Corn, and Sorghum in Selected States
xiii
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ABSTRACT
A study was made of the efficiency of the use of pesticides to
identify and quantify the wastes and losses which occur in the treat-
ment of agricultural crops. The study was reported in two volumes. The
first volume identified the management practices and decisions for three
crops—corn, sorghum, and apples—that may lead to wasteful pesticide
use, and quantified the pesticide wastes occurring on each crop as a re-
sult of these management practices. The second volume identified the
physical factors that cause pesticide waste and losses both during and
after crop treatment for agriculture in general, and estimated the ap-
plication and postapplication pesticide losses and wastes that occurred
in 1971 for each of the three above crops. The physical factors which
were examined extensively in this study were pesticide overapplication
and nonuniform distribution, pesticide drift, and pesticide losses from
crops due to runoff and soil erosion.
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SECTION I
INTRODUCTION
BACKGROUND
The use of pesticides in the agricultural sector of our society is
often required for the effective production of food and fiber. Crops
have to compete with weeds, insects, fungi, nematodes and other pests
which would decrease yield quantity and/or quality if left uncontrolled.
Pesticides are also employed against insects and other pests threatening
human health or comfort, or destroying structures, stored products, etc.
Controlling the pests that attack food crops is a monumental and
ever-increasing problem. Throughout the world there are 18,000 species
of weeds, 1,800 of which cause annual economic losses. Each major crop
is infested with between 10 and 50 different weeds, and most cultivated
crops are subject to infestation from about 200 weed species. There are
over 10,000 species of pest insects, 50,000 species of fungi causing
1,500 different diseases, and more than 1,500 species of nematodes that
can damage and destroy crops. Despite the advanced pest control technology
available today, these pests cause losses amounting to about one-third of
the potential agricultural production each year.
Though pesticides have become necessary to assist man in meeting
vital health and nutritional needs, they can be damaging as well as bene-
ficial to both man and his environment. To minimize the cost and maximize
the benefits of pesticides to society as well as to the individual user,
pesticides must be used in the most efficient and effective way possible.
Unfortunately, not all of the quantities of pesticides used in agriculture
are employed in this manner. Unnecessary or otherwise nonbeneficial uses
of pesticides and unwanted, avoidable discharges of pesticides into the
environment are wasteful economically as well as ecologically.
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The U.S. Environmental Protection Agency has been charged by the
Congress to regulate pesticides in such a manner that the economic,
social, and environmental costs of their use do not exceed benefits.
In carrying out this mandate, the Agency is interested in promoting the
most effective and efficient use of pesticides where they are needed,
and in assisting farmers in protecting their crops from pests at minimum
cost to themselves and to society. The objective of avoiding pesticide
wastage and losses has assumed increased priority and urgency as a result
of the energy crisis. Many pesticides are petroleum-based chemicals. The
production, formulation, distribution and application of all pesticides
consumes additional energy. On the other hand, control of pests by other
conventional methods may require more labor, larger amounts of fuel for
farm equipment, or other costs.
This study deals with the efficiency of the use of pesticides. Here,
efficiency is used in the sense of being inversely related to wastage and
losses of pesticides, and our study excluded energy considerations. The
study focused on the identification and quantification of avoidable pesti-
cide wastes and losses that cause unnecessary costs to users as well as to
society, without offsetting benefits.
OBJECTIVES
The major objectives of this study were:
* To define and identify pesticide wastes and losses.
* To identify and evaluate wasteful pesticide use practices on
selected agricultural crops.
* To identify and evaluate avoidable pesticide losses during and
after application.
* To quantify avoidable pesticide wastes and losses in as much de-
tail as possible.
STUDY APPROACH
To accomplish these objectives, this project was divided into the
following four major tasks which were conducted under a joint effort by
MRI and RvR Consultants.
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Task 1 - Select Suitable Crop/Pest/Pesticide Systems for Detailed Study
Many of the parameters of pesticide use cannot be studied in a
broadly general way, but only as they apply to specific crop/pest/pes-
ticide systems. Several criteria were considered and evaluated in order
to select three study crops; these included volume of pesticides used
on the crop, crop acreage, crop farm value, and existence of integrated
pest management programs on the crop. A numerical rating system was de-
veloped (see Appendix A, Table A-4), and the crops which rated highest
were: (a) corn; (b) cotton; (c) the conglomerate category of vegetables;
and (d) soybeans. Other crops that ranked high, but with some variation
in order depending on the criteria used, were sorghum, apples, and wheat.
Cotton was dropped from further consideration because it is already
the subject of several other studies. Sorghum was selected ahead of soy-
beans because of pesticide use patterns and the greater number of inte-
grated pest management studies on sorghum. Apples were selected ahead of
vegetables since no single vegetable species appeared to be as suitable
as apples. Therefore, the crops selected for study were: (a) corn; (b)
sorghum; and (c) apples.
The detailed data and considerations on which this choice of study
crops were based were developed by RvR Consultants and are included in
this report as Appendix A.
Task 2 - Define and Identify Pesticide Wastes and Losses
Our search of the literature failed to produce any publications in
which pesticide wastage and losses have been defined, analyzed and cate-
gorized systematically. This was therefore an important requirement early
in the project. An initial set of definitions was developed by the proj-
ect team and then further improvements and refinements were made in con-
sultation with the EPA project officer. The results of these efforts are
presented below in the section on "Definitions and Identification of Pes-
ticides Wastes and Losses."
The categorization of pesticide wastes and losses indicated several
different principles by which the subsequent tasks might be organized.
For several reasons, we have structured our studies along two general
themes: (a) pesticide wastage due primarily to management decisions
before application, and (b) pesticide losses due primarily to physical
factors during and after application.
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One of the major reasons for this structure is that wastage of pes-
ticides due to management decisions before application differs greatly
among different crops, pests, types of pesticides, and geographic regions,
so that generalizations or extrapolations to or from other crops, pests,
types of pesticides or regions cannot be made. By contrast, findings in
the area of pesticide losses during or after application due to physical
factors may apply to crops, pesticides or regions other than those stud-
ied if the physical and environmental conditions of the pesticide use are
sufficiently similar. Thus, investigations on drift, runoff and other as-
pects of pesticide losses due primarily to physical factors were useful
in Task 4 regardless of the crop involved, while in Task 3, our investi-
gations had to focus on the three selected crop/pest/pesticide systems,
and our findings apply only to them.
Task 3 - Identify and Evaluate Wasteful Pesticide Use Practices on the
Three Selected Study Crops
This task was carried out primarily by RvR Consultants with MRI
furnishing some of the statistical data for the crop pesticide usage
and crop acreages. For each of the study crops, the use patterns of
herbicides, insecticides, miticides, fungicides and other pesticides
were studied in relation to the need for treatment. Management factors
that might contribute to nonbeneficial uses of pesticides were investi-
gated. Special attention was given to pesticide application rates and
frequency of.application as:
* Specified in the registered label of the product;
* Recommended by the Federal/State Cooperative Extension Service;
* Recommended by other crop protection advisors;
* Commonly used by growers;
* Required for economic pest control; and
* Used in integrated pest management programs (where applicable).
In line with the objective to quantify pesticide wastage and losses
in as much detail as possible, quantitative aspects received prime atten-
tion throughout this phase of the study.
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The data and information needed in this task were obtained from
a variety of sources, including a thorough search of the literature
and interviews with experts such as public and private crop protec-
tion advisors, growers, and other knowledgeable persons. Some of
these interviews were conducted by telephone, others in person in the
field and at several recent scientific meetings.
Furthermore, a limited mail survey was conducted of extension ento-
mologists, weed scientists, and plant pathologists working in the lead-
ing corn, sorghum, and apple producing states. The results of this survey
were also helpful to the project.
Task 4 - Identify and Evaluate Avoidable Pesticide Wastes and Losses
Occurring During and After Application
This task was carried out by MRI. The study examined the problem of
pesticide wastes and losses occurring during and after application. The
approach taken to this aspect of the study is given in Section VIII.
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SECTION II
DEFINITION AND IDENTIFICATION OF PESTICIDE WASTES AND LOSSES
EFFICIENT USE OF PESTICIDES
This study deals with the problem of efficiency in the use of pesti-
cides. According to contemporary dictionaries, "efficient" is broadly de-
fined as "producing the desired effect or result with a minimum of loss
or waste."
When pesticides are used in agriculture, the desired effect usually
is to prevent a yield loss (quantity and/or quality) that pests would
cause if left uncontrolled. Maximizing efficiency in the use of pesti-
cides requires minimizing pesticide wastes and losses; wastes and losses
are inversely related to efficiency.
PESTICIDE WASTES AND LOSSES
Pesticide wastes and losses may be categorized by a number of dif-
ferent criteria which are partly overlapping. These include:
* Avoidability (some wastes and losses are avoidable, some are not);
* Type °f waste or loss (unnecessary use, overuse, misuse, etc.);
* Cause of waste or loss (management decisions, physical factors);
* Relationship to time of application (before, during, after); and
* Quantity of pesticide involved.
These different aspects of pesticide wastes and losses and their in-
terrelationships require some further definition and discussion.
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AVOIDABLE VERSUS UNAVOIDABLE PESTICIDE WASTES AND LOSSES
Pesticide Wastage
For purposes of this study, pesticide wastage, or wasteful use is
defined as unnecessary use, overuse or misuse of pesticides. Every ap-
plication of a pesticide is preceded by someone's decision to make that
application. At that decision point, wasteful pesticide uses could be
avoided by a decision not to make an unnecessary application, or not to
apply the pesticide at an unnecessarily high rate. Therefore, most or
all wasteful pesticide uses are avoidable in principle. (It is recognized,
of course, that things are not that simple in practice because decision-
makers often have no certain way of knowing whether a given pesticide
use is necessary or not, or whether a given rate of application is too
high, too low, or just right.)
Pesticide Losses
For purposes of this study, pesticide losses are defined as unwanted
pesticide deposits, or pesticide quantities that do not reach the intended
target and, therefore, do not contribute to accomplishing the purpose of
the application. In most pesticide uses, very little of the pesticide ap-
plied actually reaches the site of action within the target pest. Thus,
by this very broad definition, a large percentage of all pesticides is
"lost."
A schematic description of the possible fate of a given quantity of
insecticide sprayed topically on a crop for insect control is helpful in
illustrating the situation (Figure 1, taken from a recent report by von
Riimker et al., 1974*). The percentage loss figures (in terms of the quan-
tity applied = 100%) do not represent one specific case, but were compos-
ited from several field studies. Typical losses due to drift were taken
from the studies by Adair et al. (1971), Akesson and Yates (1964)^ and
Brazzel et al. (1968). Losses due to surface runoff from the target area
were composited from the studies by Caro et al. (1973), Ritter et al.
(1974), and White et al. (1967). Information on the propensity of pesti-
cides for volatilization and leaching has been reported by von RUmker
and Moray (1972). Furthermore, it was assumed that the degree of ground
cover of the target crop in the target area is 75%, and that not more
than 10% of the insecticide quantity impacting on the target crop will
impact near target insects. Of the quantity impacting near target insects
(4% of the applied rate), only a small portion will actually be absorbed
by the target insects through contact, inhalation, and/or ingestion. Thus,
ultimately, only a very small fraction of the quantity applied (much less
than 1%) will reach the site of toxic action inside the target insect.
References are given at the end of each section of this report.
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Quantity Applied
100%
307.
In Target Area
70%
107.
J
157.
On Target Crop
457.
1
Near Target Insect
47.
Drift and
Misapplication
Volatilization
Leaching, and
Surface Transport
Off Target Crop
Off Target Insect
> 37.
No Contact
Absorbed by Insect
through Contact,
Inhalation, and Ingestion
< 17.
Not at Site of Action
Site of Toxic Action
Inside Insect
« 17o
Off Target
Area
Ground, other Nontarget
Surfaces in Target Area
•Residue on
Treated Crop
Percentage distribution figures do not represent one specific case, but are composited
from several different field studies and assumptions on the degree of ground cover
and the density of target insects on the target crop.
Source: Report published by von Rttmker, Lawless, and Meiners (1974), p. 108.
Figure 1. Aerial foliar insecticide application: typical losses
between spray nozzle and site of toxic action.
10
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Under field conditions, the rates of pesticide losses at each step
may vary greatly, depending upon all elements in the system and their
interrelationships, including the physical factors discussed in greater
detail in other sections of this report. Regardless of how these factors
interact, however, frequently only a very small fraction of the insecti-
cide applied becomes effective for the intended purpose, i.e., controlling
the target pest. Shaw and Jansen (1972) presented a similar mass balance
for herbicide use. Mass balances for other types of pesticide uses, such
as fungicides or soil insecticides, may be somewhat different, but they
may also be quite inefficient if evaluated in this manner.
Thus, large quantities of chemical pesticides could be saved, and
unwanted residues on treated crops and in the environment could be re-
duced, without sacrificing benefits, if the pesticide's route from the
application equipment to the site of action inside the target pest could
be made more efficient and less wasteful. Unfortunately, however, at the
present state of pest control technology, a large percentage of the pes-
ticide losses depicted in Figure 1 are unavoidable and cannot, therefore,
be considered to be wasteful in a practical, operational or economic sense.
These facts suggest the need for research aimed at improving the efficiency
of pesticide application systems, and at the development of technologies
for more efficient, less wasteful delivery of pesticides to their targets.
Our investigations in this project deal primarily with avoidable pes-
ticide wastes and losses. Among the loss mechanisms depicted in Figure 1,
drift, misapplication, and surface transport (runoff) are at least in part
avoidable. These loss mechanisms were studied and are reported in Volume
II of this report.
TYPES, CAUSES AND OTHER CHARACTERISTICS OF AVOIDABLE PESTICIDE WASTES AND
LOSSES
For purposes of this study, avoidable pesticide wastes and losses
are considered to include four major routes of waste. These categories,
their definitions, underlying causative factors, relationship to time of
application, and the quantities of pesticides likely to be involved are
as follows.
Unnecessary Use
No treatment required, i.e., use of a pesticide in the absence of
an established need to control or suppress the target pest(s).
11
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Examples:
* Use of pesticides in preprogrammed application schedules based on
the calendar instead of actual need.
* "Insurance"-type applications made regardless of need.
Unnecessary pesticide uses result from management decisions. Every
application of a pesticide is preceded by a decision to make that appli-
cation. Unnecessary applications are avoidable by a decision not to ap-
ply. Unnecessary pesticide uses may involve substantial quantities of
pesticides. Therefore, the question if and to what extent pesticides are
used unnecessarily received primary attention in our evaluation of pes-
ticide use patterns on corn, sorghum, and apples (Section V, VI and VII).
This question cannot be studied or answered in general terms, but only
in relation to specific crops, pests, and pesticides, as the findings
detailed below demonstrate.
Overuse
Too high a rate, i.e., use of a pesticide at a rate of application
higher than necessary for the intended pest control or suppression purpose.
Examples:
* In many instances, insecticides provide economic control of target
pests at rates of application much lower than those required for
99 to 100% kill. When applied at high rates, insecticides often
destroy beneficial predators and parasites that would help to sup-
press pest insects and mites. When their natural enemies are de-
stroyed, these secondary pests may then build up to damaging pro-
portions that require additional applications of chemical insecti-
cides or miticides. Thus, application of insecticides at higher
rates than necessary for economic control of target pests is often
biologically as well as economically wasteful, and sometimes even
counterproductive.
* Pesticide overuse may also occur during application as a result
of miscalibration of application equipment, driving properly cali-
brated equipment at a speed slower than that used in calibrating,
double treatment of field or orchard borders, excessive overlapping
of application swaths, etc.
12
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Pesticide overuse due to selection of too high a rate of application
(first example above) results from management decisions prior to applica-
tion. This type of overuse is avoidable and may involve substantial quan-
tities of pesticides. It was evaluated in detail in the studies of pesti-
cide use patterns on corn, sorghum, and apples (Sections V, VI and VII).
Pesticide overuse during application (second example above) results
most often from improper operation of application equipment. This route
of waste was examined in our studies on pesticide losses during and after
application as reported in Volume II.
Misuse
Use of a pesticide not registered or otherwise not suitable for the
intended purpose, or use of a registered suitable pesticide in an unsuitable
manner.
Example:
* Selection of the wrong pesticide, wrong target pest, wrong formula-
tion, and/or wrong application method.
Pesticide misuse as defined in the Federal Insecticide, Fungicide and Ro-
denticide Act and the 1972 Amendments thereto is illegal and may result in
prosecution.
Pesticide misuses occur most often as the result of inadvertent er-
rors on the part of persons supervising or making pesticide applications.
Such misuses are avoidable or reducible to the extent that human error
can be reduced by education, training, supervision, etc. Compared to the
other categories of pesticide wastes and losses, misuses do not involve
large quantities of pesticides and were not studied in detail in this
project. The misuse category is included among the definitions of pesti-
cide wastes and losses for completeness1 sake.
Unwanted, Avoidable Discharge, Deposit or Migration
Unwanted, avoidable discharges of pesticides into the environment due
to excessive drift or runoff, improper disposal of pesticides or containers,
spills, dumping, etc.
Examples:
* Pesticide spills due to puncturing, breakage, tearing or other fail-
ure of containers, leakage of tanks or hoppers, leakage or breaking
of parts of application equipment, etc.
13
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* Improper disposal of leftover concentrated or diluted pesticides,
or of pesticide containers, especially containers not completely
emptied.*
* Excessive, avoidable drift during application of pesticides due to
too small particles, too great distance between nozzle and target,
unsuitable weather conditions, etc.
* Excessive post-application pesticide loss from target areas in-
herently subject to runoff due to topography of the area, lack of
terracing or contouring, etc.
Pesticide losses of this type occur during or after pesticide applica-
tion. They are avoidable only in part. Pesticide spills occur most often
as a result of operating accidents which are mostly uncontrollable and
usually involve relatively small quantities of pesticides. Disposal of
pesticide containers and of residues in the pesticide application equip-
ment involve substantial quantities of pesticides, but the techniques
used to accomplish these tasks are within the control of pesticide users.
Any waste involved in inefficient disposal techniques can be resolved
through educating pesticide users as to the proper methods of disposal
and as to their importance. Therefore, pesticide spills and disposal did
not receive detailed attention in this study; they are briefly discussed
in Volume II.
Excessive, avoidable drift during application and excessive, avoid-
able runoff after application involve substantial quantities of pesticide
losses throughout agriculture that can be reduced by proper application
techniques and conservation methods. These two mechanisms of pesticide
loss were studied in detail, as reported in Volume II.
14
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SECTION III
SUMMARY
The results of this study are summarized below in two sections. In
the first section, our findings concerning the efficiency of the use of
pesticides on corn, sorghum and apples as influenced by pre-application
management decisions are set forth. Our studies showed that the use pat-
terns of different types of pesticides (herbicides, insecticides, fungi-
cides, etc.) and the degree of efficiency with which they are used on
the three crops varied considerably. The findings reported in this sec-
tion are applicable only to the crop/pest/pesticide systems studied.
In the second section, our findings on pesticide wastes and losses
during and after application are summarized. In this part of the study,
our investigations were not limited to corn, sorghum arid apples, and
many findings may apply to other crops to which pesticides are applied
in a similar manner.
EFFICIENCY OF THE USE OF PESTICIDES ON CORN, SORGHUM, AND APPLES AS
AFFECTED BY PRE-APPLICATION MANAGEMENT DECISIONS
Table 1 presents an overview of our findings concerning the effi-
ciency of the use of pesticides on corn, sorghum, and apples as affected
by management decisions prior to application.
Herbicides are used extensively on corn and sorghum. In the opinion
of weed research and extension scientists working with these crops and
of corn and sorghum growers, these herbicide uses are essential to the
efficient, profitable production of these crops and involve minimal, if
any, pesticide wastage. We found no field research data to show whether
or not economic weed control in corn or sorghum could be obtained by
substantially lower herbicide inputs.
15
-------
Table 1. ESTIMATED RATE OF TOTAL VS. NEEDLESS USE OF PESTICIDES
ON CORN, SORGHUM, AND APPLES
Pesticide
Herbicides
c/
Insecticides"
Fungicides
Other Pesticides^/
_a/ In the case of corn
b/ Estimated % needless
Crop
Corn
Sorghum
Apples
Corn
Sorghum
Apples
Corn
Sorghum
Apples
. Corn
Sorghum
Apples
and sorghum
uses applii
% of
Crop5/
Treated
90
70-80
Small
50
60-70
> 90
% of Quantity
Applied Used
Needlessly
Small
Small
Negl.
90
I/
Negl.
Negl.
Small
Negl.
Negl.
Small
Negl.
Negl.
Negl.
Quantity Used
Needlessly-^
(1.000 Ib AI)
Small
Small
Negl.
12,800
2,900-3,400
1,040-1,560
Negl.
Negl.
Small
Negl.
Negl.
Negl.
mi tic ides in the case of apples) used on the three crops in 1971 according to
the USDA pesticide use survey.
£/ Includes miticides in the case of apples. No substantial quantities of miticides are
used on corn or sorghum.
d/ Needless uses consist primarily of insecticide applications to field not needing the
treatment.
e/ Needless uses consist of insecticide applications in the absence of established need
for treatment, of applying insecticides at higher than minimum effective rates, and
of insecticide or miticide applications necessitated by preceding injudicious
pesticide use.
f_/ Excluding seed treatment.
g/ Includes fumigants, defoliants, desiccants, plant growth regulators, etc.
Source: RvR Consultants, this study.
16
-------
On apples, herbicides are used only in relatively small quantities.
We did not find any indications or evidence of wasteful herbicide use on
apples.
Insecticides/miticides are used on an estimated 50% of the U.S. corn
acreage harvested for grain, on 60 to 70% of the grain sorghum acreage,
and on a very high percentage of all apple orchards. As discussed in the
sections dealing with insecticide use practices on the three study crops,
we estimate that approximately 50% of the quantities of insecticides ap-
plied to corn, at least 50% of the insecticides applied to sorghum, and
20 to 30% of the insecticides applied to apples are used needlessly.
In the case of corn, insecticide treatments are applied to many fields
that do not need the treatment. In the case of both sorghum and apples,
needless uses include insecticide applications in the absence of an estab-
lished need for treatment, applications at higher than minimum effective
rates, and insecticide or miticide applications that become necessary
secondarily as a result of preceding injudicious pesticide applications
which destroyed naturally present beneficial predators and parasites.
On all three crops studied, an important prerequisite to actually
realizing these potential insecticide savings would be the widespread
adoption and implementation of integrated pest management procedures.
Only small quantities of fungicides are used on corn and sorghum.
Fungicide uses on these two crops were therefore not studied in detail.
Much larger quantities of fungicides are used on apples. Most of
the currently available commercial apple fungicides have to be applied
on preventive, preprogrammed application schedules for optimal biological
and economic effectiveness. No practical nonchemical methods for the con-
trol of fungal diseases of apples are currently available to growers, and
no "integrated disease management" programs for apples have yet been de-
veloped. Thus, apple growers needing to protect their crop against fungal
pathogens do not currently have feasible alternatives to the use of chemi-
cal fungicides on preventive treatment schedules. There is no evidence
of significant wasteful uses of fungicides on apples.
"Miscellaneous pesticides" including fumigants, defoliants, desic-
cants, plant growth regulators and others are used only in small quanti-
ties or not at all on corn, sorghum or apples. Uses of these pesticides
were therefore not studied in depth. The limited information obtained
in the course of pursuing the project's major objectives does not include
any evidence that these "miscellaneous pesticides" are used on corn, sor-
ghum, or apples in a wasteful or inefficient manner.
17
-------
Our estimates of the quantities of insecticides applied needlessly
to corn, sorghum, and apples (Table 1) are expressed in terms of percent
of the total quantity applied, and in terms of pounds of active ingredient.
The latter estimate was calculated by applying the estimated percent need-
less uses against the total quantities of insecticides (and miticides in
the case of apples) used on the three study crops in 1971 according to
the USDA pesticide use survey.
The potential savings in insecticides/miticides shown in Table 1 are
not additive to the estimated losses occurring during and after application
of pesticides as summarized in Table 37 (page 112). In both tables, the vol-
ume estimates are based on the actual uses of the pesticides concerned in
1971, according to the USDA pesticide use survey. If, for instance, 30%
of the quantities of insecticides and miticides used on corn, sorghum,
and apples in 1971 would be saved as a result of pre-application manage-
ment decisions to avoid unnecessary use and overuse, then 30% of the esti-
mated losses during and after application shown in Table 37 would not oc-
cur in the first place. Additional savings in pesticide quantities by
reduction of drift, runoff and other application and post-application
wastes and losses would affect only the remaining 70% of the quantities
of these pesticides.
PESTICIDE WASTES AND LOSSES OCCURRING DURING AND AFTER APPLICATION
The results and findings of this part of the study are given in
Volume II of this report since the material presented is both technical
and extensive. The study approach, the study areas, and a summary of the
results and findings of Volume II are presented in Section VIII of this
volume. For a summary of the work done in this aspect of the study, the
reader is referred to Section VIII, page 106.
18
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SECTION IV
CONCLUSIONS AND RECOMMENDATIONS
No evidence was found in this study, given the present state of
pesticide and pest management technology, that herbicides, fungicides,
fumigants, defoliants, desiccants, plant growth regulators and pesti-
cides other than insecticides and miticides are used on corn, sorghum,
or apples in an inefficient or wasteful manner. Our findings regarding
the use patterns of insecticides and miticides lead to the conclusion
that approximately 50% of the quantities of these pesticides currently
used on corn and sorghum, and 20 to 30% of the quantities used on ap-
ples are used needlessly. At least in part, this is due to the fact
that in practice, persons recommending or making pesticide applications
often have no certain way of knowing whether a given pesticide use is
necessary or not, or whether a given rate of application is too high,
too low, or just right.
Reductions in the quantities of insecticides and miticides used
on corn, sorghum, and apples approaching 50% would require widespread
adoption and implementation of integrated pest management practices,
and greatly improved understanding and acceptance of integrated pest
management principles and procedures by persons making pest manage-
ment decisions and pesticide applications*
Thus, a percentage of the quantities of chemical insecticides and
miticides used on the three crops is replaceable by integrated pest
management. To the degree that chemical insecticides and integrated
pest management services are interchangeable, they compete for the
same users and dollars.
19
-------
It does not follow, however, that the pesticide industry and inte-
grated pest management proponents have to be in adversary positions. It
would seem to be in the best interest of all concerned, industry, growers,
as well as society as a whole, to reduce avoidable wastes and losses of
pesticides, and to use these chemicals as efficiently and effectively as
possible.
Growers need the best and most economical crop protection, not neces-
sarily large quantities of inexpensive pesticides. The pesticide industry
needs a larger operating profit per pound of chemical produced if it is to
develop and market more selective pesticides that will be used in smaller
quantities. No one wants avoidable, nonbeneficial pesticide residues in
the food supply, in the environment, or any place else.
Integrated pest management experts and practitioners are an important
element in improving all aspects of crop protection, including efficiency
in the use of chemical pesticides.
RECOMMENDATIONS
* Promote further development and implementation of integrated pest
management methods and practices.
* Remove legal obstacles to the recommendation and use of pesticides
in integrated pest management programs at rates of application lower
than those registered by the manufacturer.
* Promote cooperation among all concerned (including government agen-
cies, universities, the pesticide industry, integrated pest manage-
ment practitioners, and growers) in the development and implementa-
tion of better crop protection and pest management systems, including
more efficient use of chemical pesticides.
Substantial quantities of pesticides are lost during and after ap-
plication to corn, sorghum, and apples, and probably many other crops as
well. Unwanted overapplication, nonuniform distribution, drift, and runoff
are among the most significant loss mechanisms. Wastes and losses of pesti-
cides during and after application due to these factors are avoidable only
in part at the present state of pesticide and equipment technology. In ad-
dition, efforts to reduce pesticide losses from one of these mechanisms
may increase losses from another. For instance, coarse sprays produce less
drift, but may require more pesticide to produce the desired degree of
plant coverage and control of the target pest. Coarse sprays also are more
likely to result in nonuniform distribution of droplets and uneven rates
of pesticide deposits in the target area.
20
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RECOMMENDATIONS
* Promote development of pesticide application methods and equipment
that will reduce pesticide wastes and losses during application,
in particular, overapplication, nonuniform distribution, and drift.
* Promote soil conservation practices that will reduce post-application
pesticide losses due to runoff and erosion.
21
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SECTION V
PESTICIDE USE PATTERNS ON CORN
PRODUCTION OF CORN IN THE UNITED STATES
In terms of total acreage and farm value, corn is the leading agri-
cultural crop in the United States. In 1974, 77.4 million acres were
planted to field corn, that is about 25% of the total U.S. harvested
cropland acreage, and 3.4% of the total land area of the United States
(including Alaska).
Table 2 summarizes the U.S. corn acreage, yield, value, and pro-
duction during the last 4 years, 1971 to 1974. The corn acreage planted
for all purposes ranged from a low of 67 million acres in 1972 to a high
of 77.4 million acres in 1974. In each of the 4 years covered in Table 2,
about 85% of the total corn acreage planted for all purposes was harvested
for grain.
Table 2. U.S. CORN ACREAGE, YIELD, VALUE AND PRODUCTION, 1971 TO 1974
Acreage, yield Year
value, production 1971 1972 1973 1974
Acreage planted for all purposes, 74,055 64,000 71,600 77,400-
1,000 acres
Acreage harvested for grain, 64,047 57,421 61,760 63,746-
1,000 acres
Yield,.!/ bu/acre 88.1 97.1 91.4 72.5^'
Average farm price, $/bu 1.08 1.57 2.55 3>45h/
Farm value, $/acre 95.15 152.45 233.07 250.13^
Total production, million "bushels 5,641 5,573 5,643 4,62Lfe/
a^f Yield per acre harvested for grain.
Ja/ Preliminary.
£/ October 1974.
Sources: U.S. Department of Agriculture (1973, 1974a, c).
22
-------
Corn yields (per acre harvested for grain) during this period ranged
from a record high national average of 97.1 bu in 1972 to a low of 72.5 bu
in 1974. The average price of corn received by farmers increased from $1.08/
bu in 1971 to $1.57 in 1972, and to $2.55 in 1973, an increase of 136% over
this 2-year period. Average farm prices for the 1974 crop are not available
at this writing (January 1975). The October 1974 farm price for corn was
$3.45/bu, compared to $2.17/bu in October of 1973, and $1.19/bu in October
of 1972.
The farm value per acre of corn harvested for grain increased from
$95.15 in 1971 to $152.45 in 1972, and further to $233".07~ln 1973, an in-
crease of 145% from 1971 to 1973. Indications are that in spite of the
disappointing corn yield in 1974 due to unfavorable weather, the farm
value per acre of corn for grain will be even higher in 1974 than it was
in 1973.
Figure 2 presents the U.S. Department of Agriculture's division of
the United States into 10 regions.
The total production of corn in the U.S. was about 5.6 billion bushels
in 1971, 1972, and 1973, dropping to 4.6 billion bushels in 1974.
Figure 3 presents a breakdown of the U.S. corn acreage planted for all
purposes in 1971. Table 3 summarizes the U.S. acreage of corn for grain by
major producing states for the last 3 years, 1972 to 1974, showing state
totals for all states growing more than 1 million acres in decreasing order
of number of acres grown in 1974, and subtotals for the Corn Belt States.
In 1974, the five Corn Belt States (Iowa, Illinois, Indiana, Ohio, and
Missouri) raised 33.9 million acres of corn for grain, that is 53.1% of
the national total. All other states growing more than 2 million acres of
corn for grain were also midwestern states, i.e., Minnesota, Nebraska,
South Dakota, and Wisconsin. The five Corn Belt States and the six other
major midwestern corn-producing states combined raised 52.2 million acres
of corn for grain in 1974, that is 82% of the U.S. total.
These data document that while some corn is grown in practically every
state in the Union, the production of this crop is heavily centered in the
midwestern states.
23
-------
U.t. DEPARTMENT OF AGRICULTURE
NEC. ERS I3WA-62 IB) ECONOMIC RESEARCH SERVICE
Figure 2. Farm production regions.
24
-------
Corn Acreage Planted for All
Purposes in Thousands of Acres
Total Acreage = 74,055,000
Figure 3.; U.S. corn acreage (1971), by state.
-------
Table 3.
CORN ACREAGE^ IN THE U.S. IN 1972, 1973 AND
BY MAJOR PRODUCING STATES^
Year
1972
1973
State
1.000 Acres
Iowa 10,600 11,150
Illinois 9,225 9,670
Indiana 4,884 5,240
Ohio 3,090 3,040
Missouri 2,500 2,600
Subtotal, Corn Belt 30,299 31,700
Minnesota 4,899 5,520
Nebraska 5,135 5,850
South Dakota 2,414 2,630
Wisconsin 2,143 2,090
Georgia 1,490 1,670
Michigan 1,722 1,690
North Carolina 1,280 1,400
Kansas 1,250 1,540
Kentucky 968 1,010
Pennsylvania 900 1.040
Subtotal, major producing
states outside Corn Belt 22,201 24,440
All other states 4,921 5,620
United States 57,421 61,760
11,750
10,150
5,500
3,700
2.750
33,850
5,810
5,000
2,300
2,090
1,800
1,730
1,570
1,400
1,120
1.070
23,890
6,006
63,746
a/ Corn for grain.
bj Preliminary.
£_/ Corn belt states; all other states growing more than 1 million acres, in
decreasing order of number of acres grown in 1974.
Source: U.S. Department of Agriculture (1974c).
26
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QUANTITIES OF PESTICIDES USED ON CORN
The U.S. Department of Agriculture (1974b) conducted a survey on the
agricultural uses of pesticides in 1971 (Tables 4 to 7). The Department
reports that corn led all other crops by a wide margin in the total volume
of herbicides used. American farmers used 101.1 million pounds of herbi-
cides (active ingredient) on corn, that is 45% of the total quantity of
herbicides used on agricultural crops in 1971. Corn was second in volume
of insecticides used (preceded by cotton); farmers used 25.5 million
pounds of insecticide active ingredients on corn in 1971, that is 17% of
the total quantity of insecticides used on crops that year. The quanti-
ties of fungicides used on corn are so small that they were not disag-
gregated in the USDA pesticide use report for 1971 (or for 1966). Some
miticides (57,000 Ib) and fumigants (386,000 Ib) were also used on corn
in 1971, according to the USDA survey.
Table 4 provides a breakdown of the pesticides used on corn in 1971
by type of pesticide and by farm production regions, following the U.S.
Department of Agriculture's division of the United States into 10 regions
as shown in Figure 2. In line with the concentration of the production of
corn in the Corn Belt, Lake, and Northern Plains States, these three re-
gions accounted for the lion's share of all herbicides, insecticides, and
"miscellaneous pesticides" used on corn in 1971. As Table 4 shows in detail,
these three regions used 857o of all herbicides, 94% of all insecticides,
87% of all miscellaneous pesticides, and 87% of all pesticides used on corn
in 1971, according to the USDA report.
The use of herbicides, insecticides, and miscellaneous pesticides on
corn in 1971 by major products and by regions is further detailed in Tables
5, 6, and 7. These use patterns vrill be examined in greater detail below,
in the sections dealing with corn herbicides and insecticides, respectively.
Table 8 presents a comparison of the quantities of pesticides used
on corn in the United States in 1964, 1966, and 1971, according to the
USDA pesticide use surveys for these years (U.S. Department of Agriculture,
1968, 1970, 1974b). The total quantity of all pesticides used on corn in-
creased from 41.8 million pounds in 1964 to 70.1 million pounds in 1966,
and further to 127.0 million pounds in 1971, a more than three-fold in-
crease from 1964 to 1971. The use of corn herbicides increased almost
four-fold from 25.5 million pounds in 1964 to 101.1 million pounds in
1971. The quantity of insecticides used on corn increased from 15.7 mil-
lion pounds in 1964 to 23.6 million pounds in 1966, and to 25.5 million
pounds in 1971, an increase of 63% from 1964 to 1971.
27
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Table 4. PESTICIDE USAGE ON U.S. CORN CROP IN 1971 BY REGION
ISJ
00
Herbicides
Region
Northeast
Lake States
Corn Belt
Northern Plains
Appalachian
Southeast
Delta States
Southern Plains
Mountain
Pacific
Total
1,000 Ib
5,250
21,358
54,069
10,700
6,166
2,105
474
127
566
245
101,060
7.
5.2
21.1
53.5
10.6
6.1
2.1
0.5
0.1
0.6
0.2
100.0
Miscellaneous
Insecticides pesticides
1,000 Ib
155
2,749
15,314
5,852
375
42
37
54
928
25
25,531
7. 1,000 Ib 7.
0.6 1 0.2
10.8
60.0
22.9 386 87.1
1.5 - -
0.2
0.1
0.2
3.6 - -
0.1 56 12.7
100.0 443 100.0
Total pesticides!/
1,000 Ib
5,406
24,107
69,383
16,938
6,541
2,147
511
181
1,494
326
127,034
%
4.3
19.0
54.6
13.3
5.1
1.7
0.4
0.1
1.2
0.3
100.0
a/ Fungicides used on corn are not listed separately in the USDA report. Fungicides are not included in the
pesticide total in this table.
Source: "Farmers' Use of Pesticides in 1971 - Quantities," Agricultural Economic Report No. 252, Economic
Research Service, U.S. Department of Agriculture (1974b).
-------
a/
Table 5. HERBICIDES USED ON CORN, BY REGION, 1971-
(1,000 Ib)
NJ
VO
Herbicide
Atrazine
Propachlor
2,4-D
Alachlor
Butylate
Simazine
Linuron
Propazine
EPIC
Dicamba
MCPA
Others
Total
North-
east
3,600
85
350
850
120
110
10
-
10
3
2
110
5,250
Lake
States
13,000
5,250
1,250
1,000
160
120
30
-
100
50
75
323
21,358
Corn
Belt
23,600
13,900
4,800
5,900
3,800
500
600
190
50
150
4
575
54,069
Northern
Plains
6,300
2,000
1,500
100
150
-
100
170
100
60
75
145
10,700
Appalachian
4,500
5
750
400
195
120
10
21
-
-
-
165
6,166
Regions
South-
east
350
-
200
50
1,250
50
5
185
10
-
-
5
2,105
Delta
States
300
40
60
20
-
-
20
2
-
-
-
32
474
Southern
Plains
50
10
9
20
-
-
5
13
2
1
-
17
127
Mountain
250
-
200
20
43
-
20
-
10
10
-
13
566
Pacific
50
10
25
-
100
20
4
2
10
10
3
11
245
Total
52,000
21,300
9,144
8,360
5,818
920
804
583
292
284
159
1,396
101,060
Source: "Farmers' Use of Pesticides in 1971 - Quantities," Agricultural Economic Report No. 252, Economic
Research Service, U.S. Department of Agriculture (1974b).
a./ Use of each individual insecticide, by region, is an MRI estimate.
-------
CO
o
Total
Table 6. INSECTICIDES USED ON CORN, BY REGION, 1971
(1,000 Ib)
Insecticide
Aldrin
Bux
Carbofuran
Ph orate
Diazinon
Carbaryl
Parathion
Heptachlor
Chlordane
Disulfoton
Others
North-
east
5
50
2
5
20
5
4
35
8
21
Lake
States
90
810
790
200
300
100
50
10
200
30
169
Corn
Belt
7,350
1,370
1,140
1,700
800
400
40
1,090
560
20
844
Northern
Plains
235
1,360
630
400
780
1,000
900
-
-
120
427
Appalachian
40
-
20
50
20
100
25
-
30
30
60
Regions
South-
east
20
-
4
1
1
2
2
-
4
-
8
Delta
States
10
-
12
1
-
1
-
-
-
-
13
Southern
Plains
1
30
-
5
-
5
5
-
3
2
3
Mountain
10
-
30
300
80
20
300
-
8
100
80
Pacific
3
•
5
2
5
1
2
-
2
2
3
Total
7,759
3,575
2,681
2,661
1,991
1,649
1,329
1,104
842
312
1,628
155
2,749
15,314
5,852
375
42
37
54
928
25
25,531
£/ Figures for total use of each insecticide and regional totals were obtained from "Farmers' Use of
Pesticides in 1971 - Quantities," Agricultural Economic Report No. 252, Economic Research Service,
U.S. Department of Agriculture (1974b).
b/ Use of each individual insecticide, by region, is an MRI estimate.
-------
Table 7. MISCELLANEOUS PESTICIDES USED ON CORN, BY REGION, 1971
(1,000 Ib)
a.b/
Regions
North- Lake Corn Northern Appalachian South- Delta
Pesticide east States Belt Plains east States
Dicofol - ... . . _
Other 1 - - - - - -
Miticides
Miscellaneous ... 336 - - -
Fumigants
Southern
Plains Mountain Pacific Total
56 56
1
386
Total
386
443
a/ Figures for total use of each pesticide and regional totals were obtained from "Farmers' Use of
Pesticides in 1971 - Quantities," Agricultural Economic Report No. 252, Economic Research Service,
U.S. Department of Agriculture (1974b).
b/ Use of each individual pesticide, by region, is an MRI estimate.
-------
Table 8. USE OF PESTICIDES ON CORN IN THE U.S. IN 1964, 1966, AND 1971
Year
Type of pesticide 1964 1966 1971
(1,000 Ib of active ingredient)
Fungicides '543 N.A. • N.A.
a/
Insecticides^' 15,668 23,629 25,531
Herbicides^ 25,476 45,970 101,060
Miscellaneous pesticides 76 546— 443—
All pesticides 41,773 70,145^ 127,034^
ji/ Excluding petroleum.
W Includes 117,000 Ib miticides, 429,000 Ib fumigants.
c/ Includes 57,000 Ib miticides, 386,000 Ib fumigants.
df Excluding fungicides.
N.A. = Not available
Sources: U.S. Department of Agriculture (1968, 1970, 1974b).
32
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During the period 1964 to 1974, the total U.S. acreage of corn
harvested for grain was as follows (U.S. Department of Agriculture
1973, 1974a):
Year 1.000 acres
1964 55,369
1965 55,392
1966 57,002
1967 60,694
1968 55,980
1969 54,574
1970 57,358
1971 64,047
1972 57,421
1973 61,760
1974 (Preliminary) 63,746
These data show that the corn acreage in the United States in-
creased by less than 3% from 1964 to 1966, while the use of insecti-
cides increased by 51% (from 15.7 to 23.6 million pounds of active
ingredient), and the use of herbicides by 80% (from 25.5 to 46 mil-
lion pounds of active ingredient). The further increase in the use
of herbicides on corn from 1966 to 1971 is equally striking. While
the acreage of corn harvested for grain increased by 12% from 1966
to 1971, the use of herbicides increased by 120% (from 46 million
pounds in 1966 to 101.1 million pounds of active ingredient in 1971).
These data document that the increases in the quantities of pesti-
cides, especially of herbicides, used on corn are primarily due to
higher average inputs per acre, and only to a small extent to an
increase in corn acreage.
The USDA pesticide use surveys as well as Cooperative Extension
Service publications and state pesticide use surveys indicate that
the use of pesticides other than herbicides and insecticides on corn
is very small or negligible.
The data presented in this section and those on the geographic
distribution of corn presented in the preceding section indicate
that our study on the efficiency of current pesticide use practices
on corn should be focused on the use of herbicides and insecticides
on corn in the Midwest.
33
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HERBICIDE USE PRACTICES
The rate of use of herbicides on corn in the United States has
increased greatly from 1964 to 1971, as summarized above. In 1964,
25.5 million pounds of herbicide active ingredients were applied to
corn, 46.0 million pounds in 1966, and 101.1 million pounds in 1971
(Table 8). Thus, the quantities of herbicides used on corn almost
quadrupled from 1964 to 1971, while the corn acreage harvested for
grain increased by only 16% during this period.
The U.S. Department of Agriculture (1972) conducted surveys on
the use of herbicides on agricultural crops in 1959, 1962, 1965, and
1968. Table 9 presents the results of these surveys for corn. During
the 10 year time span covered, the corn acreage receiving herbicide
treatments increased from 20 million acres in 1959 to 48.9 million
acres in 1968. The percentage of the total corn acreage treated with
herbicides increased from 25% in 1959 to 39% in 1962, 68% in 1965,
and 76% in 1968. Of the 48.9 million acres of corn treated with her-
bicides in 1968 according to this survey, 20.4 million acres were
treated preemergence only (at an average cost of $4.84/acre); 18.9
million acres were treated postemergence only ($2.46/acre); and 9.6
million acres were treated both pre- and postemergence ($6.15/acre).
Table 9. ESTIMATED EXTENT OF CHEMICAL WEED CONTROL
ON CORN IN THE U.S., 1959 TO 1968
Year 1959 1962 1965 1968
Acreage treated with 20,051 25,302 45,012 48,930
herbicides, 1,000 acres
Percent of total corn 25% 39% 68% 76%
acres harvested for grain
Source: U.S. Department of Agriculture (1972).
34
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More recent data on the extent of use of herbicides on corn in
the Midwest were reported by von Rumker and Horay (1974). Of about
300 corn growers in Iowa and Illinois who responded to detailed
questions regarding their pesticide use practices, all but two re-
ported using corn herbicides in 1973. About 857o of the respondents
from both states believed that all of their corn acres need herbi-
cide treatments each year. Based on these farmer responses, on the
findings of other recent pesticide use surveys, and on information
from midwestern weed research and extension workers, vom Rumker and
Horay (1974) concluded that herbicides are used by close to 100% of
all corn growers in the leading midwestern corn-producing states,
and that close to 90% of the total corn acreage in the region is
treated with herbicides. Since a substantial percentage of the to-
tal corn acreage receives both pre- and postemergence treatments,
the total number of "gross" acres treated (acres treated more than
once counted for each treatment) exceeds the total corn acreage
harvested for grain.
Table 5 presents a breakdown of the herbicides used on corn in
1971 by regions and by major individual herbicides. Of the total quan-
tity of herbicides used on corn in 1971 according to the U.S. Depart-
ment of Agriculture (1974b), about 54% (54.0 million pounds) were used
in the five Corn Belt States, and 85% of the total (86.1 million pounds)
in the Lake, Corn Belt, and Northern Plains States combined. Much smal-
ler quantities of herbicides were used on corn in all other regions.
One single product, atrazine, accounted for more than 50% of the
total quantity of herbicides used on corn, according to the USDA survey.
In decreasing order of use volume, atrazine was followed by propachlor
(21.3 million pounds), 2,4-D (9.1 million pounds), alachlor (8.4 million
pounds), and butylate (5.8 million pounds). All other corn herbicides
were used in 1971 in quantities less than 1 million pounds, according
to this source.
Herbicides are used on corn for the control of a variety of weeds
including pigweeds, crabgrasses, lambsquarters, quackgrass, foxtails,
nutsedges, Canada thistle, johnsongrass, barnyard grass, bindweeds,
cockleburs, morning glories, panicums, kochia, velvetleaf, and witch-
grass. Of the 48 states that participated in the corn phase of the
1968 herbicide use survey by the U.S. Department of Agriculture (1972),
42 states reported an upward trend in herbicide use, six reported a
stationary situation, while nine reported a downward trend.
35
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Extension weed scientists and agronomists contacted in the present
study reported that 90 to 95% of the corn acres in their respective
states were treated at least once with a herbicide, and that at least
that many or more corn acres needed the herbicide treatment.
The costs of chemical weed control in corn per acre have increased
substantially during the last 10 to 15 years. Increased costs per pound
of the herbicides have contributed to this increase only to a minor ex-
tent. The major part of the cost increase per acre is due to the fact
that weed species that are more difficult to control are gradually be-
coming more predominant in corn fields, as those species that are easily
controlled recede. As a result, herbicide application rates per acre
were increased, relatively inexpensive herbicides like 2,4-D were re-
placed by more expensive preemergence herbicides, postemergence treat-
ments were added to preemergence treatments, and single herbicides are
being replaced by combinations of two products. The question how fast
this trend will further progress, and what its economic and ecological
end point might be apparently has not received much, if any study thus
far.
The economic part of the question is not pressing as long as the
farm value of the crop increases more rapidly than the cost of using
herbicides, as has been the case in recent years (Table 2). Neverthe-
less, the cost of chemical weed control in corn ($6.00 to $15.00/acre
and up for preemergence herbicides) represents a significant fraction
of the corn production costs and of the farm value of the crop, pro-
viding an economic incentive for corn growers to use herbicides effi-
ciently and at minimum effective rates.
In addition, many herbicides have a limited safety margin between
the rate that will kill weeds and the rate that may injure the crop.
This is another incentive for growers not to use herbicides at rates
higher than necessary.
Several of the U.S. Department of Agriculture/State Cooperative
Pilot Pest Management Projects on corn initiated in 1973 include weed
phases (Illinois, Indiana, Iowa, Nebraska, and Ohio). Pest management
programs for weeds seem to tend in the direction of total farm weed
control. For instance, Illinois' summary on its corn pest management
project for 1973 states: "More emphasis is needed on weed control in
forage crops, small grains, and noncropland along with control programs
in corn and soybeans if the weed seed population in the soil is going
to be reduced and progress in weed management is to be achieved." This
"total farm weed control" concept recently received support from
Rodgers (1974), then the President of the Weed Science Society of
America, and from other prominent weed scientists.
36
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This approach may require more extensive use of chemical herbi-
cides (and of other weed control measures) at least until the weed
seed reservoir in the soil is depleted. No data appear to be avail-
able on how many years this may take under field conditions, whether
benefits will outweigh costs, and how the desired area-wide simplifi-
cation of agro-ecosystems might affect other components of the system,
such as the soil microflora and fauna, and desirable animal species
such as certain birds, game, beneficial insects, and others.
In summary, practically all corn growers and weed research and
extension workers believe that chemical herbicides are essential to
the efficient and profitable production of corn, that the quantities
of herbicides used on corn are needed, and that corn herbicides are
used efficiently. Herbicide costs and the possibility of crop injury
from overapplication provide practical incentives against unnecessary
or wasteful use of corn herbicides. We found no research data to show
whether economic weed control could be achieved by substantially re-
duced rates of chemical herbicides or by other means.
The "total farm weed control" concept promoted in some pest
management programs for weeds will require heavier, rather than re-
duced herbicide inputs at least in the initial weed eradication
phase.
INSECTICIDE USE PRACTICES
As documented above in the section "Quantities of Pesticides Used
on Corn," the use of insecticides on corn increased by 637o from. 1964
to 1971, namely, from 15.7 million pounds of active ingredients in 1964
to 25.5 million pounds in 1971, according to the pesticide use surveys
by the U.S. Department of Agriculture (1968, 1970, 1974b). During the
same time span, the U.S. acreage of corn harvested for grain increased
by only 15.7%. These data indicate that insecticide inputs per acre of
corn increased considerably during this 8-year period.
According to the 1971 USDA pesticide use survey, a total of 25.5
million pounds of insecticide active ingredients were used on corn that
year (Table 6). Of this total, 9.7 million pounds consisted of chlori-
nated hydrocarbon insecticides (aldrin, heptachlor, and chlordane); the
balance was made up of four organic phosphate and three carbamate in-
secticides; and other insecticides that were not disaggregated.
37
-------
Other recent studies indicate that the U.S. Department of Agri-
culture's estimates on the quantities of insecticides used on corn in
1971 are probably too low. For example, von RUmker and Moray (1974)
estimated that 18.5 million pounds of insecticides were used on corn
in 1971 in Iowa and Illinois alone, that is 3.2 million pounds in ex-
cess of the USDA estimate for the entire Corn Belt (Table 6). In 1971,
Iowa and Illinois raised 64% (21.8 million acres) of all corn acres
in the Corn Belt (33.9 million acres).
Furthermore, the use of aldrin on corn in 1971 was estimated to
be 7.8 million pounds by USDA (U.S. Department of Agriculture, 1974b),
but an estimate of 9.4 million pounds for this use was provided by EPA
in the recent aldrin/dieldrin cancellation proceedings (Train, 1974).
This latter estimate appears to be more authoritative and in better
agreement with other information cited above.
In the midwestern corn-growing states, corn may be attacked by
a number of soil and foliar insects. Overall, the soil insects are of
much greater economic importance than those feeding above ground.
Corn soil insects include three species of corn rootworms, and
a number of other insects often referred to as the "soil insect com-
plex." The corn rootworm species occurring in the Midwest are
Diabrotica longicornis, the northern corn rootworm; I), virgifera,
the western corn rootworm; and J). undecimpuncata howardi, the south-
ern corn rootworm. The northern and western species predominate in
Iowa and Illinois. They often occur together and have similar life
cycles and habits. Western corn rootworms are completely, and north-
ern rootworms almost completely resistant to chlorinated hydrocarbon
insecticides in the principal midwestern corn-producing states. Corn
rootworms are usually a problem only on corn following corn, sorghum,
or sunflowers. Corn following soybeans or small grains rarely suffers
rootworm damage.
The "corn 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.
38
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Foliar insects that may attack corn in the Midwest include corn
borers (order Lepidoptera, family Pyraltdidae); the corn earworm,
Heliothis zea; corn rootworm beetles, the adult forms of the corn
rootworms (Diabrotica spp.) discussed above, the corn leaf aphid,
Rhopalosiphum maidis; the corn flea beetle, Chaetocnema pulicaria;
the armyworm, Fseudaletia unipuncta; the fall armyworm, Spodoptera
frugiperda; and grasshoppers (order Orthoptera, family Locustidae).
Table 10 presents an overview of the insecticides that were
recommended against the major corn soil insects in 1974 by extension
entomologists in eight midwestern states, detailed by states, in-
secticides, rates, and target insects. Seven of the eight midwestern
states did not recommend any chlorinated hydrocarbon insecticides
against corn rootworms, the only exception being Indiana which still
recommended aldrin and heptachlor against these insects. Against wire-
worms and white grubs, aldrin, chlordane and/or heptachlor were rec-
ommended in seven of the eight midwestern states; Illinois did not
recommend any chlorinated hydrocarbon insecticides against these
insects. Against cutworms, aldrin, heptachlor and/or chlordane
were recommended in five of the eight midwestern states. Alterna-
tive cutworm control recommendations in Illinois, Minnesota, and
Nebraska included carbaryl, trichlorfon, diazinon, and/or toxaphene.
Against seed beetles and maggots, aldrin and heptachlor seed treat-
ments were recommended in five of the states, while Iowa, Illinois,
and Ohio recommended only diazinon seed treatments.
Entomologists at the University of Illinois have studied corn
insect infestations, and the effectiveness of insecticides in averting
yield losses due to these insects since 1955 (Petty, 1974; Kuhlman
et al. 1973, Randellet al. 1974; Wedberg et al. 1975). Estimates on
the extent and profitability of the use of insecticides on corn in
Illinois in 1972, 1973, and 1974 according to these authors are sum-
marized in Table 11. These estimates indicate that Illinois corn
growers realized net returns from the use of insecticides on corn of
$22.8 million ($3.55/acre treated) in 1972, $22.2 million ($3.55/acre)
in 1973, and $30.7 million ($4.62/acre) in 1974. In each of the 3
years, more than 90% of the total estimated profits resulted from the
use of insecticides against soil insects, based on yield increases
from use of corn rootworm insecticides. Thus, on the surface, the use
of corn soil insecticides appears to be a profitable practice. How-
ever, the estimated profits per acre in Table 11 are averages which,
39
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Table 10. INSECTICIDES RECOMMENDED AGAINST CORN SOIL INSECTS IN 1974
BY EXTENSION ENTOMOLOGISTS IN EIGHT MIDWESTERN STATES
Target insects
State
Iowa
Illinois
Indiana
Ohio
Missouri
Minnesota
South Dakota
Nebraska
Corn rootworms
Carbofuran
Dasanit®
Dyfonate®
Landrin®
Mocap®
Phorate
Carbofuran
Dasanit®
Dyfonate®
Landrin®
Phorate
Carbofuran
Dyfonate®
Phorate
Dasanit®
Bux®
Mocap®
Aldrin
Heptachlor
Dlazinon
Carbofuran
Dasanit®
Dyfonate®
Phorate
Bux®
Carbofuran
Dasanlr®
Diazlnon
Phorate
Carbofuran
Dasanit®
Diazinon
Dyfonate®
Phorate
Carbofuran
Dasanit®
Dyfonate®
Mocap®
Phorate
Bux®
Carbofuran
Dasanit®
Dyfonate®
Disyston®
Mocap®
Phorate
(Lb of
0.75-1.0
1.0
1.0
1.0
1.0
1.0
0.75-1.0
1.0
1.0
1.0
1.0
0.75
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0.75-1.0
0.75-1.0
1.0
1.0
0.75-1.0
1.0
1.0
0.75-1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Wireworms and
white grubs
active ingredient per
Aldrin 1.0
Chlordane 2.0
Carbofuran 0.75-1.0
Heptachlor 1.0
Phorate 1.0
Carbofuran 2.0
Diazlnon 1.5
Aldrin
Heptachlor
Diazinon
Dyfonate®
Mocap®
Carbofuran
Phorate
Aldrin
Heptachlor
Aldrin
Diazlnon
Dyfonate®
Heptachlor
Aldrin
Chlordane
Diazlnon
Dyfonate®
Heptachlor
Phorate
Aldrin
Chlordane
Heptachlor
Aldrin
Chlordsne
Heptachlor
3.0
3.0
4.0
4.0
2.0
2.0
1.0
2.0
2.0
3.0-4.0
3.0-4.0
4.0
3.0-4.0
2.0
4.0
1.0-2.0
1.0
2.0
1.0
2.0
4.0
. 2.0
2.0
4.0
2.0
Cutworms
acre)
Aldrin 1.0-2.0
Chlordane 2.0-4.0
Heptachlor 1.0-2.0
Carbaryl bait 1.0
Carbaryl spray 2.0
Toxaphene 2.0
Trichlorfon 1.0
Carbaryl bait 1.0
Carbaryl spray 2.0
Trichlorfon 1.0
Adlrln 3.0
Heptachlor 3.0
Diazlnon 4.0
Carbaryl spray
or bait
Trichlorfon
spray or bait
Toxaphene 2.0
Carbaryl bait 1.0
Carbaryl spray 2.0
Chlordane 4.0
Heptachlor 2.0
Toxaphene 2.0
Trichlorfon 1.0
Aldrin 1.5-2.0
Carbaryl 1.0-2.0
Diazinon 3.0-4.0
Heptachlor 1.5-2.0
Toxaphene 2.0-3.0
Trichlorfon 1.0
Carbaryl 2.0
Toxaphene 2.0
Trichlorfon 1.5
Aldrin 2.0
Carbaryl bait 1.0
Carbaryl spray 2.0
Diazinon 2.0
Heptachlor 2.0
Toxaphene 2.0
Trichlorfon 1.0
Carbaryl 1.0
Diazinon 4.0
Seed beetles
and maggots
Diazlnon seed treatment
Diazlnon seed treatment
Aldrin
Diazinon
Heptachlor
Lindane
Seed treatment
Diazinon seed treatment
Aldrin
Diazinon
Dleldrin
Heptachlor
Lindane
Seed treatment
Aldrin
Diazlnon
Dleldrin
Heptachlor
Seed treatment
Aldrin
Heptachlor
Lindane
Diazlnon
Seed treatment
Aldrin
Diazlnon
Dleldrin
Heptachlor
Lindane
Seed treatment
Source: von Ru'mker et al. (1975).
40
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Table 11. EXTENT AND PROFITABILITY OF THE USE OF
INSECTICIDES ON CORN IN ILLINOIS, 1972-1974
-------
as further analysis reveals, consist of much higher net returns from the
use of insecticides on corn acres that actually needed the treatment,
and minimal or no returns from acres treated unnecessarily.
Table 12 presents an estimate on the use and profitability of soil
insecticides for corn rootworm control in Illinois for the 11-year period,
1964 to 1974. The assumptions used by the Illinois authors in calculating
these data as summarized in the lower part of the table are very interesting.
They are based on reports from county extension advisors and on research and
field demonstration studies by Illinois entomologists. According to these
sources, only about 40 to 50% of all corn acres treated with soil insecti-
cides during the last 4 years needed the treatment, that is only about 20%
of all corn acres harvested for grain in Illinois during that period. The
yield loss prevented by the use of insecticides on acres needing the treat-
ment averaged 10.0 bu/acre from 1971 to 1973, and was estimated at 6.2 bu/
acre in 1974. The farm price of corn used in the estimate was $1.00/bu for
1971 to 1973, $2.75/bu for 1974. Thus the estimated value of the yield loss
prevented on the acres needing the treatment was $7.00/acre for 1971 to
1973, $l3.65/acre in 1974. Furthermore, it was estimated that on the acres
treated unnecessarily (60% of all treated acres 1971 to 1973, 50% of all
treated acres in 1974), growers realized a net return above the cost of
the treatment of $1.00/acre in 1971 to 1973, and zero in 1974.
The average net gain for all acres treated, $3.50/acre for the period
1971 to 1973, was calculated as follows: of 6 million acres of corn treated
with soil insecticides, only 2.5 million acres = 41-2/3% needed the treat-
ment, returning $7.00/acre net. On the balance of the treated acreage, 3.5
million acres = 58-1/3% of the total treated acreage, net returns from the
treatment averaged only $1.00/acre above the cost of treatment. The average
net gain for all acres treated, therefore, was:
41.667 x $7.00 $291.67
58.333 x $1.00 58.33 . __ .
$350.00 : 100 $3.50/acre
The corresponding data for 1974 were computed in the same manner.
The higher average net returns from the use of corn soil insecticides
in the earlier years (Table 12) are based on the fact that prior to 1971,
corn rootworm populations were considerably higher and thus more damaging,
so that the return from using a corn rootworm insecticide was greater. The
corn rootworm problem has lessened during the last few years. The re-increase
in the average profit per acre in 1974 is due to the increase in the price
of corn and thus in the value of the yield loss prevented, rather than to a
rebound of corn rootworm damage.
42
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Table 12. ESTIMATED USE AND PROFITABILITY OF SOIL INSECTICIDES
FOR CORN ROOTWORM CONTROL IN ILLINOIS, 1964-1974
Corn acres
treated with
soil
Year insecticides
1964 4,091,125
1965 4,733,784
1966 5,443,197
1967 6,204,293
1968 6,261,869
1969 6,508,067
1970 6,610,287
1971 6,142,039
1972 6,085,328
1973 5,738,053
1974 6,014,342
a/ Assumptions:
Cost of insecticide treatment/acre
Farm price of corn/bu
Acres needing treatment relative to
-all corn acres treated
-all corn acres harvested for grain
On acres needing treatment
-yield loss prevented /acre
-value of yield loss prevented/acre
-less cost of treatment/acre
-net return from treatment /acre
Average
profit*/
($/acre)
4.00
5.00
5.00
5.00
5.00
5.00
3.75
3.50k/
3.50
3.50
4.68°-
1971-1973b-/
$3.00
$1.00
41-2/3%
20%
10.0 bu
$10.00
$3.00
$7.00
Total
profit
($)
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
28,175,647
19740-/
$3.40
$2.75
50%
20%
6.2 bu
$17.05
$3.40
$13.65
On acres not needing treatment
net return above cost of
treatment/acre
Average net gain for all
acres treated, per acre
$1.00
$3.50
None
$4.68
Sources: Randell et al. (1974), Kuhlman (1973, 1975)
43
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The estimates on the economic benefits from the use of insecticides
on corn in Illinois discussed above are presented and quoted as given in
the sources cited, in contemporary dollars. One might question if estimates
of this type should not be given in more rounded, less specific terms, or
if dollar figures should be price-adjusted. However, these Illinois data
are derived from an ongoing study. They are updated annually, and they are
widely accepted and used by entomologists, extension personnel and others
in their present form. Therefore, it seemed preferable to present and dis-
cuss them in their original, unaltered form in this report.
A breakdown of the types of corn soil insecticides used in Illinois
during the same 11-year period, 1964 to 1974, is given in Table 13. In the
early days of the use of soil insecticides on corn, chlorinated hydrocarbon
insecticides (primarily aldrin) controlled both corn rootworms and the com-
plex of other soil insects. Today, as pointed out above, western and north-
ern corn rootworms are highly resistant to chlorinated hydrocarbon insecti-
cides in many areas. In recent years, organic phosphate and carbamate
insecticides have been used primarily against resistant rootworms, and
chlorinated hydrocarbons against the other corn soil insects.
The data summarized in Table 13 show that the total corn acreage
treated with soil insecticides in Illinois has remained almost level from
about 1967 to the present, except for relatively small year-to-year oscil-
lations. The acreage treated with chlorinated hydrocarbon insecticides de-
creased from 4.0 million acres (987<> of all acres treated) in 1964 to 1.9
million acres (317° of all acres treated) in 1974.
Shaw et at. (1975) describe two methods for predicting damage from
corn rootworms, i.e., (a) counting adult rootworms per plant on two dif-
ferent dates in August, and (b) counting corn rootworm eggs in soil sam-
ples taken in the field in the fall. If one or more adult corn rootworms
per plant are found on either count in August, a soil insecticide should
be used if the field is again planted to corn the next year. All corn
fields with 5 million or more corn rootworm eggs per acre should be
treated with a soil insecticide the following year. Careful examinations
of rootworm damage and yield loss in corn fields in 1974 showed that there
was no damage at 1 million eggs per acre, only slight damage at 9 million
eggs per acre, moderate damage at 13 million eggs per acre, and severe
damage at 18 million eggs per acre. Thus, the suggestion to treat when
there are 5 million or more eggs per acre is conservative.
44
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Table 13. USE OF CORN SOIL INSECTICIDES IN ILLINOIS, 1964 TO 1974
Year
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
Acres treated with
Chlorinated
hydrocarbons
4,009,303
4,544,432
5,116,605
5,601,572
5,170,726
4,517,931
3,844,740
2,723,119
1,933,089
1,737,510
1,886,042
Organic phosphates
and carbamates
81,822
189,352
326,592
602,721
1,091,143
1,990,138
2,765,547
3,418,920
3,852,239
3,960,543
4,128,300
Total
acres
treated
4,091,
4,733,
5,443,
6,204,
6,261,
6,508,
6,610,
6,142,
5,785,
5,698,
6,014,
125
784
197
293
869
069
287
039 .
328^
053^
342
aj These figures vary slightly from those reported in Table 11 for
reasons not known, but the variations are not large enough to
be of significance to the objectives of this study.
Source: Adapted from Kuhlman et al. (1973), Wedberg et al. (1975).
Field observations in 1973 and 1974 by these authors indicate that
over one-half of the corn fields in Illinois have rootworra counts of less
than 5 million eggs per acre.
Shaw et al. (1975) also studied wireworm damage to corn. By using
a bait method as a diagnostic tool, 21 corn fields were examined in 1974.
Wireworm larvae were found in only two of the 21 fields baited. One of
these had only one larvae on the six baits placed in each field, that is
considerably below the suggested treatment threshold of four or more
larvae per six baits. The second field had a total of 41 larvae on the
six baits, and use of a soil insecticide was recommended in this case.
The survey indicates that only a small percentage of all corn fields in
Illinois require the use of insecticides against wireworms.
45
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In May and June of 1974, Shaw et al. (1975) investigated many reports
of black cutworm (Agrotis ypsilon) damage in corn received from farm ad-
visers in west-central and southern Illinois. From these reportsj 15 fields
in 10 different counties were selected for observation. For each field,
information was obtained on the 1973 crop preceding corn in the rotation,
tillage practices, field drainage, percent cutworm damage in the highest
damage area within each field, and cutworm control measures taken. Char-
acteristics that appeared to be common to fields with a black cutworm
problem included the following:
* Cutworm problems in previous years (11 of 15 fields).
* Considerable surface debris and litter from no-till, minimum-till,
or chisel plowing (14 of 15 fields).
* Soybeans preceded corn in the rotation (11 of 15 fields).
* Bottomland or low elevation location (13 of 15 fields).
* Poor drainage (14 of 15 fields).
The authors suggest that fields with all of these characteristics
have a high potential for black cutworm infestation and damage. In green-
house experiments, they tested the theory that a large number of black
cutworm larvae could be killed with systemic insecticide placed in the
seed furrow at planting time. A 10% granular formulation of carbofuran
applied in this manner at the rate of 1 Ib of active ingredient per acre
killed 100% of small first and second instar larvae, and 60% of larger
third, fourth, and fifth instar larvae within 48 hr after the larve were
released on the treated plants. A band application of carbofuran at the
same rate of active ingredient per acre was considerably less effective,
particularly on the smaller larvae.
The data summarized in Table 11 show that an estimated 124,430 acres
of corn were treated for cutworms in Illinois in 1972, 93,781 acres in
1973, and 56,756 acres in 1974. The net return estimates indicate that
cutworm treatments were among the more profitable uses of corn insecticides.
The corn acreage treated for the control of all foliar insects of
corn combined amounted to less than 10% of the acreage treated against
soil insects in Illinois in each of the 3 years covered in Table 11.
Among the foliar insects, control of the corn leaf aphid was considered
to be relatively most profitable (net return $7.00/acre), followed by
control of corn rootworm adults (net return $4.00/acre). Insecticides
used against the remaining foliar insects of corn, i.e., the European
corn borer, the corn flea beetle, grasshoppers, and armyworms yielded
rather low economic benefits and accounted for only small percentages
of the total corn acres treated with insecticides.
46
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Comparable, detailed studies and historic data on the usefulness of
insecticides on corn are, to the best of our knowledge, not currently
available for any other corn-producing state. However, several other, al-
though less detailed, estimates on the use of corn soil insecticides from
other sources tend to support the findings of the Illinois entomologists.
In 1973, von Rumker and Horay (1974) investigated the use patterns of corn
insecticides in Iowa and Illinois in connection with a study on farmers'
pesticide use decisions and attitudes on alternate crop protection methods.
Responses from about 300 corn growers in Iowa and Illinois who were inter-
viewed in this study indicated that 53% of the respondents in Iowa and 70%
of those in Illinois used corn insecticides in 1973. Interestingly, only
about one-half of the corn insecticide users, that is only about one-third
of all corn growers interviewed, believed that all of their corn acres need
insecticide treatments each year. Those growers who felt that not all of
their corn fields needed insecticide treatments were then asked: "How do
you decide which corn acres to treat and which not?" Responses to this
question included the following:
* "Treat only corn on corn."
* "Treat only corn on sod."
* "Treat only corn on soybeans."
* "Treat only the seed."
* "Don't know how to tell if I need control chemicals, so I apply
to all acres."
According to these authors (von Rumker and Horay, 1974), Iowa exten-
sion entomologists estimated that in 1973, about 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%).
The entomologists felt that in 1973, chlorinated hydrocarbon insecticides
(for the control of corn soil insects other than corn rootworms) were
actually needed on about 1 million acres, that is about 40% of the acreage
actually treated with these products.
In the present study, extension entomologists from four midwestern
states provided the information on the number of corn acres treated with
soil insecticides compared to acres needing treatment and to total corn
acres in their respective states (Table 14). The responses from Illinois,
Iowa and Indiana combined indicate that in those three states, about 54%
(17.5 of 32.4 million acres) of the corn acreage harvested for grain re-
ceived soil insecticide treatments. An estimated 45% of the treated acres
needed the treatment, that is about 23% of the total acreage.
47
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Table 14. CORN ACRES TREATED WITH SOIL INSECTICIDES IN SELECTED
STATES COMPARED TO ACRES NEEDING TREATMENT. AND
ACRES HARVESTED FOR GRAIN, 1974
oo
State
Illinois
Iowa
Indiana
Nebraska
Totals
-excl. Nebraska
Acres
harvested
for grain
10,150
11,750
5,500
5,000
32,400
27,400
Acres Acres
treated with needing
soil insecticides treatment
(1,000 Acres)
6,000 2,000
5,250 4,000
2,600 300
3,690 N.a.
17,540
13,850 6,300
Acres
needing treatment
as percent of
Acres Acres
treated harvested
33% 20%
76% 34%
12% 5%
N.a. N.a.
45% 23%
Sources: Wedberg et al. (1975); Kuhlman (1975); Extension Entomologists
in Iowa, Indiana and Nebraska (1975)
N.a. = Not available.
-------
The data presented in this section suggest that substantial quantities
of the insecticides used on corn for the control of corn rootworms and
other soil insects are applied needlessly. Based on the thorough studies
conducted in Illinois and the data from several other states discussed
above, especially those summarized in Table 14, we estimate that about 50%
of the quantities of soil insecticides that were used on corn during the
last few years could be saved. In terms of the total quantity of insecti-
cides that were used on corn in 1971 according to the USDA Pesticide Sur-
vey, 25.5 million pounds of active ingredients (Table 4), such savings
would amount to about 12.8 million pounds.
Important prerequisites to improving the efficiency in the use of
corn soil insecticides by avoiding unnecessary treatments include de-
velopment and implementation of practical methods for diagnosing corn
soil insect problems, and for predicting treatment needs. The progress
reported in this regard by Shaw et al. (1975) is indeed encouraging.
As long as the average cost of applying a soil insecticide to an
acre of corn is not much higher than the farm price per bushel of corn,
there is no great economic incentive for corn growers to avoid unneces-
sary corn insecticide applications. However, this situation may change
in the event that the relatively inexpensive chlorinated hydrocarbon
insecticides would no longer be available. For instance, the grower
cost of aldrin 20% granules at 1.5 Ib of active ingredient per acre is
about $2.20/acre, while carbofuran granules at 1.0 Ib of active ingre-
dient per acre will cost about $7.50/acre in 1975, according to pesti-
cide trade sources. Against wireworms and white grubs, carbofuran may
have to be used at up to 2.0 Ib of active ingredient per acre, which
would cost the grower $15.00/acre. Thus, while there has not been a
strong economic incentive against wasteful use of corn spi^l insecti-
cides in the past, this situation may change in the future.
SUMMARY
Corn, the leading agricultural crop in the United States by acreage
as well as by farm value, is produced primarily in 11 midwestern states
including the five "Corn Belt States," i.e., Iowa, Illinois, Indiana,
Ohio, and Missouri. Fungicides and "miscellaneous pesticides" including
miticides, fumigants, defoliants, desiccants, plant growth regulators
and others are used on corn either in very small quantities or not at
all and were therefore not studied in detail in this project.
49
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The quantities of herbicides used on corn in the U.S. quadrupled from
1964 to 1971. More than 100 million pounds of herbicide active ingredients
were used on corn in 1971, according to a report by the U.S. Department of
Agriculture. It is estimated that close to 90% of the total U.S. corn acre-
age harvested for grain is treated with chemical herbicides at present. A
significant fraction of this acreage receives more than one herbicide treat-
ment. Weed research and extension specialists and corn growers are convinced
that chemical herbicides are essential to the efficient, profitable produc-
tion of corn, and that by and large, corn herbicides are used effectively
and without waste.
The costs of chemical weed control per acre of corn have increased
substantially during the last 10 years and continue to rise. In large
part, this increase is due to a gradual change in corn weed populations.
Weeds that are more difficult to control are becoming more prevalent as
those species that are easily controlled recede. However, the farm value
of corn has also increased substantially. Consequently, there do not ap-
pear to be significant economic constraints on corn growers' herbicide
use practices.
Pest management programs for weeds are included in several of the
corn pilot pest management programs that were initiated in 1973. The
"total farm weed control" concept is being considered in some of these
programs. This approach will require increased use of chemical herbi-
cides (and of other weed control measures) at least during the weed
eradication phase. Minimum and no-tillage practices are also likely to
require increased chemical herbicide inputs. We found no data from any
of these studies demonstrating or suggesting that economic weed control
could be obtained by substantially lower herbicide inputs, or by other
mean s.
Thus, there do not seem to be any near-term prospects for a reduc-
tion in the rate of use of corn herbicides, and there are currently no
strong economic incentives for corn growers to move in this direction.
The use of insecticides on corn also increased substantially during
the last 10 years, although not nearly to the same degree as that of
herbicides. Corn is subject to attack by a considerable number of soil
and foliar insects. Soil insects are much more important economically
than those feeding above ground. More than 90% of the quantities of in-
secticides used on corn are used against soil insects. In the Midwest,
corn rootworms are largely resistant against chlorinated hydrocarbon
insecticides; they are controlled by organic phosphate and carbamate
insecticides. Up to the present, chlorinated hydrocarbon insecticides,
primarily aldrin, were the insecticides of choice against the remain-
ing corn soil insects such as wireworms, cutworms, white grubs, seed
beetles and maggots, and others.
50
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Approximately 50% of all corn acres harvested for grain currently are
treated with insecticides. It is estimated that less than half of this
acreage, or about 20% of the total corn acreage harvested for grain, ac-
tually requires insecticide treatments. Thus, it appears that at least 50%
of the quantities of soil insecticides used on corn could be saved.
One important prerequisite to eliminating unnecessary insecticide
treatments on corn is the development and implementation of practical
methods for diagnosing corn soil insect problems, and for predicting
treatment needs. Progress in this direction is being made in several
corn pilot pest management programs.
The chlorinated hydrocarbon insecticides used on corn are rela-
tively inexpensive. At current prices, the cost of an aldrin applica-
tion at 1.5 Ib of active ingredient per acre of corn, about $2.20, is
equivalent to the farm price for 2/3 bu of corn. Thus, there is no com-
pelling economic reason for corn growers to worry whether or not such
a treatment is needed. However, most of the organic phosphate and car-
bamate insecticides are considerably more expensive, providing a greater
built-in economic incentive to avoid unnecessary use.
51
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REFERENCES TO SECTION V
Kuhlman, D. E., Personal Communications (1973) (1975).
Kuhlman, D. E., R. Randell, and T. A. Cooley, "Insect Situation and
Outlook, 1973," Twenty-Fifth Illinois Custom Spray Operators Train-
ing School, University of Illinois, Urbana, Illinois, Summaries of
Presentations, pp. 109-126 (1973).
Petty, H. B., "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 (1974).
Randell, R., T. A. Cooley, and D. E. Kuhlman, "Insecticide Situation and
Outlook, 1974," Twenty-Sixth Illinois Custom Spray Operators Training
School, University of Illinois, Urbana, Illinois, Summaries of Presen-
tations, pp. 85-102 (1974).
Rodgers, E. G., "Weed Prevention Is the Best Control," Weeds Today,
^5(0:8, p. 22 (1974).
Shaw, J. T., W. H. Brink, D. W. Sherrod, and W. H. Luckmann, "Predicting
Infestations of Wireworms, Corn Rootworms, and Black Cutworms in Illinois
Corn Fields," Twenty-Seventh Illinois Custom Spray Operators Training
School, University of Illinois, Urbana, Illinois, Summaries of Presen-
tations, pp. 74-79 (1975).
Train, R. E., "Shell Chemical Company et al. Consolidated Aldrin/Dieldrin
Hearing," Federal Register, 39(203): 37246-37272 (1974).
U.S. Department of Agriculture, "Quantities of Pesticides Used by Farmers
in 1964," Agricultural Economic Report No. 131, Economic Research
Service, Washington, D.C. (1968).
U.S. Department of Agriculture, "Quantities of Pesticides Used by Farmers
in 1966," Agricultural Economic Report No. 179, Economic Research Service,
Washington, D.C. (1970).
U.S. Department of Agriculture, "Extent and Cost of Weed Control with
Herbicides and an Evaluation of Important Weeds, 1968," ARS-H-1, Eco-
nomic Research Service, Extension Service and Agricultural Research
Service (1972).
52
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U.S. Department of Agriculture, "Agricultural Statistics 1973," U.S.
Government Printing Office, Washington, D.C. (1973).
U.S. Department of Agriculture, "Feed Situation," FdS-255, Economic
Research Service (1974a).
U.S. Department of Agriculture, "Farmers' Use of Pesticides in 1971 . .
Quantities," Agricultural Economic Report No. 252, Economic Research
Service, Washington, D.C. (1974b).
U.S. Department of Agriculture, "Crop Production," CrPr 2-2 (11-74),
Statistical Reporting Service, Crop Reporting Board (1974c).
von RUraker, R., and F. Horay, "Farmers' Pesticide Use Decisions and
Attitudes on Alternate Crop Protection Methods," U.S. Environmental
Protection Agency, Office of Pesticide Programs, and Council on
Environmental Quality, Washington, D.C. (1974).
von RUraker, R., E. S. Raun, and F. Horay, "Substitutes for Aldrin,
Dieldrin, Chlordane and Heptachlor for Insect Control on Corn and
Apples," Report in Preparation for the Office of Pesticide Programs,
U.S. Environmental Protection Agency, Washington, D.C. (1975).
Wedberg, J. L., R. Randell, and T. A. Cooley, "Insect Situation and
Outlook, 1975," Twenty-Seventh Illinois Custom Spray Operators
Training School, University of Illinois, Urbana, Illinois, Sum-
maries of Presentations, pp. 99-117 (1975).
53
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SECTION VI
PESTICIDE USE PATTERNS ON SORGHUM
PRODUCTION OF SORGHUM IN THE UNITED STATES
Sorghum is a major feed crop in the United States. Table 15 sum-
marizes the U.S. sorghum acreage, yield, value, and production during
the last 4 years, 1971 to 1974. The sorghum acreage planted for all
purposes ranged from a low of 17.3 million acres in 1972 to a high of
20.8 million acres in 1971. In each of the 4 years covered in Table
15, about 80% of the total sorghum acreage planted for all purposes
was harvested for grain.
Sorghum yields (per acre harvested for grain) ranged from 44.9
bu in 1974 to 60.5 bu in 1972. The average price of sorghum received
by farmers doubled between 1971 and 1973, increasing from $1.06/bu
in 1971 to $2.13/bu in 1973. The farm value per acre of sorghum har-
vested for grain increased from $56.92 in 1971 to $82.89 in 1972,
and further to $125.24 in 1973.
The total production of grain sorghum during the 4-year period
ranged from a low of 609.3 million bushels in 1974 to a high of 936.6
million bushels in 1973.
Figure 4 presents the geographic distribution of the U.S. sorghum
acreage planted for all purposes in 1971. The leading sorghum producing
states in the U.S., in decreasing order of acreage, are: Texas, Kansas,
Nebraska, and Oklahoma. All other states planted less than 1 million
acres of sorghum for all purposes in 1971.
54
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Table 15. U.S. SORGHUM ACREAGE, YIELD,
VALUE AND PRODUCTION, 1971-1974
Acreage, yield,
value, production
Acreage planted for all purposes, 1,000 acres
Acreage harvested for grain, 1,000 acres
Yield,2/ bu/acre
Average farm price, $/bu
Farm value, $/acre
Total production, million bussels
1971
20,756
16,301
53.7
1.06
56.92
875.8
Year
1972
17,300
13,368
60.5
1.37
82.89
809.3
1973
19,300
15,940
58.8
2.13
125.24
936.6
1974
17, 70^
13.583-7
44.9k/
£/
£/
609.3^
a/ Yield per acre harvested for grain.
b_/ Preliminary.
c/ Not available at this time (January 1975).
Sources: U. S. Department of Agriculture (1973, 1974a,c).
-------
Ul
Sorghum Acreage Planted for All
Purposes in Thousands of Acres
Total Acreage = 20,756,000
Figure 4. U.S. sorghum acreage (1971), by state.
-------
QUANTITIES OF PESTICIDES USED ON SORGHUM
The U.S. Department of Agriculture (1974b) conducted a survey of
the use of pesticides by American farmers in 1971. According to this
source, sorghum ranked fifth among individual crops in total volume
of herbicides used (preceded by corn, soybeans, cotton, and wheat),
and fourth in volume of insecticides used (preceded by cotton, corn
and peanuts). The use of fungicides, miticides, fumigants, desiccants,
plant growth regulators and other pesticides on sorghum is so small
that these uses were not disaggregated in the USDA pesticide use re-
port for 1971 (or for prior years).
Further details on the use of pesticides on sorghum in 1971 are
provided in Tables 16 and 17. These data are based on the 1971 pesti-
cide use survey (U.S. Department of Agriculture, 1974b). The USDA re-
port does not break down individual pesticide uses on sorghum by regions
and therefore had to be supplemented by estimates in Table 17.
Table 16 shows that farmers used 11.5 million pounds of herbicides,
and 5.7 million pounds of insecticides on sorghum in 1971. About 81% of
all herbicides, and about 7470 of all insecticides applied to sorghum
were used in the Northern and Southern Plains States, in line with the
geographic distribution of the sorghum acreage throughout the U.S.
(Figure 4). The Corn Belt States used 10.2% of all herbicides, and 1.6%
of all insecticides used on sorghum. Figure 4 suggests that these uses
occurred primarily in the State of Missouri. Small quantities of sorghum
herbicides and insecticides were used in the remaining sorghum-producing
states.
The use of herbicides on sorghumJLn 1971 by major products and by
geographic regions is detailed in Table 17 and will be further discussed
below in the section on sorghum herbicide use practices.
Table 18 presents a comparison of the quantities of pesticides used
on sorghum in the United States in 1964, 1966, and 1971 according to the
USDA pesticide use surveys for these years (U.S. Department of Agriculture,
1968, 1970, 1974b). The total quantity of herbicides used on sorghum in-
creased by 100%, from 2.0 million pounds in 1964 to 4.0 million pounds in
1966, then to 11.5 million pounds in 1971, an almost three-fold further
increase from 1966 to 1971. The use of insecticides on sorghum increased
from 767,000 Ib in 1966 to 5.7 million pounds in 1971, a more than seven-
fold increase. (Disaggregated data on the use of insecticides on sorghum
in 1964 are not available from the USDA survey.)
57
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Table 16. PESTICIDE USAGE ON U.S. SORGHUM CROP IN 1971
00
By Region!!/
Herbicides
Region
Northeast
Lake States
Corn Belt
Northern Plains
Appalachian
Southeast
Delta States
Southern Plains
Mountain
Pacific
1,000 Ib
14
--
1,176
5,834
310
125
287
3,486
251
55
%
0.1
0.0
10.2
50.6
2.7
1.1
2.5
30.2
2.1
0.5
Insecticides
1,000 Ib
..
'
94
1,301
28
406
339
2,927
398
236
7.
0.0
0.0
1.6
22.7
0.5
7.1
5.9
51.1
7.0
4.1
Total Pesticides-/
1,000 Ib
14
--
1,270
7,135
338
531
626
6,413
649
291
%
0.1
0.0
7.4
41.3
2.0
3.1
3.6
37.1
3.7
1.7
Totals 11,538 100.0 5,729 100.0 17,267 100.0
a/ Source: "Farmers Use of Pesticides in 1971--Quantities," Agricultural Economic Report
No. 252, Economic Research Service, U.S. Department of Agriculture (1974b).
b_/ Fungicides and miscellaneous pesticides are not listed separately in the above report,
and are not included in this table.
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Table 17. HERBICIDES USED ON SORGHUM, BY REGION, 197l
(1,000 Ib)
Ui
VO
Region
Herbicide
Atrazine
Propazine
2,4-D
Propachlor
Norea
Arsenicals
MCPA
Others
Total
North-
east
5
-
4
3
-
-
-
2
14
Lake Corn
States Belt
400
350
200
100
50
10
10
56
0 1,176
Northern
Plains
2,600
500
1,000
1,250
200
-
70
214
5,834
Appa-
lachian
160
20
60
.
50
10
-
10
310
South"
east
75
5
20
-
5
10
-'
10
125
Delta
States
115
30
45
50
10
20
-
17
287
Southern
Plains
700
1,680
600
20
100
100
20
266
3,486
Moun-
tains
110
-
100
-
-
20
14
7
251
Pacific
10
-
10
10
3
15
5
2
55
Total
4,175
2,585
2,039
1,433
418
185
119
584
11,538
a/ Figures for total use of each herbicide and regional totals were obtained from "Farmers' Use of Pesticides
in 1971—Quantities," Agricultural Economic Report No. 252, Economic Research Service, U.S. Department
of Agriculture (1974b).
b/ Use of each individual herbicide, by region, is an MRI estimate.
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Table 18. USE OF PESTICIDES ON SORGHUM IN THE U.S. IN 1964, 1966, AND 1971
Type of pesticide
Fungicides .
Insecticides"
Herbicides^/
Miscellaneous pesticides
All pesticides
Year
1964
1966
1971
1,000 Ib of active ingredients
N.A.
N.A.
1,966
N.A.
1,966^
N.A.
767
4,031
40
4,838^
N.A.
5,729
11,538
N.A.
17,267l/
ji/ Excluding petroleum.
b/ Herbicides only.
£/ Excluding fungicides.
£/ Insecticides and herbicides only.
N.A. = Not available
Sources: U.S. Department of Agriculture (1968, 1970, 1974b)
During the period 1964 to 1974, the total U.S. acreage of sorghum
harvested for grain was as follows (U.S. Department of Agriculture, 1973,
1974a):
Year
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1,000
Acres
11,742
13,029
12,813
14,988
13,890
13,437
13,568
16,301
13,368
15,940
1974 (Preliminary) 13,583
These data indicate that the sorghum acreage increased by only 9%
from 1964 to 1966, while the use of herbicides more than doubled (Table
18). From 1966 to 1971, the sorghum acreage increased by 27%, while the
use of insecticides increased more than seven-fold, and the use of herbi-
cides nearly tripled.
60
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During the last 3 years, the sorghum acreage harvested for grain
has decreased somewhat from the record high acreage in 1971.
Thus, while the sorghum acreage appears to be on a slightly up-
ward trend, with considerable year-to-year variations, the use of in-
secticides and herbicides on sorghum has increased dramatically.
The USDA pesticide use surveys, supported by Cooperative Exten-
sion Service publications from the principal sorghum-growing states,
indicate that the use of pesticides other than insecticides and herbi-
cides on sorghum is very small or negligible. Therefore, our study
of the efficiency of current pesticide use practices on sorghum was
focused on insecticides and herbicides.
HERBICIDE USE PRACTICES
The quantities of herbicides used on sorghum in the U.S. have
increased greatly from 1964 to 1971, as documented in the preceding
section. In 1964, almost 2.0 million pounds of herbicide active in-
gredients went on sorghum, 4.0 million pounds in 1966, and 11.5 mil-
lion pounds in 1971 (Table 18).
The U.S. Department of Agriculture (1972) conducted surveys of
the extent of weed control with herbicides in 1959, 1962, 1965, and
1968. Table 19 summarizes the results for sorghum. During the 10-year
period covered, the sorghum acreage receiving herbicide treatments
increased continually, from 2.1 million acres in 1959 to 7.4 million
acres in 1968. The percentage of the total sorghum acreage treated
with herbicides increased from 14% in 1959 to 42% in 1968. Of the
7.4 million acres of sorghum treated with herbicides in 1968 according
to this survey, 2.9 million acres received only preemergence treat-
ments (at an average cost of $6.30/acre); 4.0 million acres received
only postemergence treatments ($3.00/acre); and 500,000 acres received
both pre- and postemergence treatments ($7.80/acre).
More recent data on the extent of use of herbicides on sorghum
in the U.S. from published sources are not available at this time,
to the best of our knowledge. It is estimated that currently, about
70 to 80% of the total U.S. sorghum acreage receives herbicide treat-
ments. This percentage is believed to be even higher for irrigated
sorghum.
61
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Table 19. ESTIMATED EXTENT OF CHEMICAL WEED CONTROL
ON SORGHUM IN THE U.S., 1959 TO 1968
Year 1959 1962 1965 1968
Acreage treated with 2,093 2,665 5,391 7,363
herbicides, 1,000 acres
Percent of total sorghum 14% 23% 32% 42%
acres harvested for grain
Source: U.S. Department of Agriculture (1972).
Table 17 presents a breakdown of the herbicides used on sorghum
in 1971 by regions and by major individual herbicides. Of the total
quantity of herbicides used on sorghum in 1971 according to the U.S.
Department of Agriculture (1974b), 817o were used in the northern and
southern plains states, paralleling the geographic distribution of
the U.S. sorghum acreage (Figure 4). An additional 1.2 million pounds of
herbicides (10% of the total) were used in the Corn Belt States. The
remaining quantities of sorghum herbicides went into six of the re-
maining seven regions; no sorghum herbicides were used in the Lake
States.
Atrazine and propazine, two chemically related triazine herbi-
cides, were used on sorghum in larger quantities than all other herbi-
cides combined (6.8 million pounds = 59% of the total). 2,4-D (2.0
million pounds) and propachlor (1.4 million pounds) were next, while
less than 1 million pounds of active ingredient were used of all re-
maining sorghum herbicides.
Herbicides are used on sorghum for the control of a considerable
variety of weeds including pigweeds, crabgrasses, lamb's-quarters, fox-
tails, johnsongrass, barnyard grass, field bindweed, cockleburs, and
morning glories. Of 27 states that responded regarding sorghum in the
1968 herbicide use survey by the U.S. Department of Agriculture (1972),
19 reported an upward trend in herbicide usage, while eight said their
use trend was stationary.
62
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Several extension agronomists whom we contacted in the present
study indicated unanimously, and independently of one another, that
in their states (including Missouri, Oklahoma, and Colorado), there
are many more sorghum acres needing herbicide treatment than are ac-
tually being treated.
The Kansas sorghum pest management project in 1973 included a
weed element (Mock, 1974a). Objectives for this part of the program
included identification of weed species, collection of detailed
information on soil type, cropping history, and previous weed con-
trol practices, and comparative studies on the effectiveness, costs,
and environmental effects of alternative weed control practices in-
cluding herbicides only, combinations of herbicides and tillage, and
tillage only. Sorghum fields were surveyed for species and density
of weeds once early in the growing season, and a second time about
3 weeks later. A total of 9,230 acres of sorghum in 86 fields of 51
participating producers were surveyed in 1973. Rough pigweed, also
known as redroot pigweed (Amaranthus retroflexus), and barnyard grass
(Echinochloa crus-galli) were found to be the two most abundant weed
species. Sixteen additional broadleaf weeds, and 10 additional grass
weeds were identified and recorded.
The Kansas Pest Management Project Annual Report for 1973 (Mock,
1974a) states that the benefits to sorghum producers from the weed
program are less instantaneous than those from the insect management
phase. Program leaders anticipate that identification of existing
weed problems will result in better tailored control recommendations
for future seasons. In the 1974 sorghum weed management program, all
participating farmers were encouraged to leave one area in each field
receiving weed control measures untreated in order to obtain informa-
tion on the effectiveness of different weed control practices. The
results of the 1974 program are not available at this time.
Our search of the literature and contacts with extension agrono-
mists in leading sorghum-producing states in this project have not
revealed any indications that herbicide treatments are applied on
more sorghum acres than needed. One way in which the use of herbicides
on sorghum might be improved is the determination of minimum effective
rates for individual users. Table 20 summarizes the rates of application
of the four leading sorghum herbicides recommended by the Extension
Services in the four leading sorghum-producing states. Some of the re-
commendations span a two to three-fold range. This degree of latitude
is probably required to cover all extremes of soil, weather and other
use conditions. However, it is often difficult for individual sorghum
63
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Table 20. RATES OF APPLICATION OF MAJOR SORGHUM HERBICIDES
RECOMMENDED IN TEXAS, OKLAHOMA, KANSAS
AND NEBRASKA!/
State
Texa&i'
Oklahoma—'
Kansas^'
Nebraska!!'
PropazineP./
1.2-3.2
1.2-3.2
1.25-2.4
NR
Herbicide
AtrazineW 2,4-D£/ Propachlor^/
(lb active ingredient/acre)
1.2-3.0
1.0-3.0
2.0-2.4
2.0-2.4
0.5-1.0
0.5-0.75
0.3-0.5
0.5
2.25-2.92.
NR
4.0-5.0
4.0
d/
a/ Rates recommended for broadcast treatment. Band application will reduce
amount of herbicide needed.
b/ Preplant or preemergence.
£/ 2,4-D amine postemergence.
d/ Recommended only in combination with propazine in Texas.
el Texas A6M University (1973b).
f^l Oklahoma State University (1974).
£/ Nilson et al. (1974).
h/ Furrer et al. (1972).
NR = Not recommended.
64
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growers to determine application rates optimal for their specific situations.
Thus, there seems to be a definite need for the type of information to be
obtained in the 1974 Kansas sorghum weed management program, as discussed
above.
Depending on the product and rate of application, preemergence treat-
ments of atrazine or propazine, the two most widely used sorghum herbicides,
range in cost from about $4.50 to $13.00 and more per acre. These costs are
substantial in relation to the farm value of sorghum (Table 15) and repre-
sent a powerful deterrent to unnecessary and inefficient use of herbicides.
In summary, there is no evidence that chemical herbicides are used on
sorghum on more acres than needed. The wide ranges in the rates of applica-
tion per acre recommended for leading sorghum herbicides suggest the possi-
bility that some users apply higher rates per acre than required for optimal
economic returns, and that more specific weed control recommendations, tai-
lored to individual farmers' needs, may result in herbicide savings. However,
we found no field research data to prove or disprove this supposition.
The rather high costs of herbicides in relation to the farm value of
sorghum, plus the risk of crop injury from overtreatment are practical de-
terrents to the inefficient and wasteful use of sorghum herbicides.
INSECTICIDE USE PRACTICES
As documented in the section "Quantities of Pesticides Used on Sor-
ghum," the use of insecticides on sorghum increased more than seven-fold
from 1966 to 1971, while the sorghum acreage harvested for grain increased
by only 27% during the same time.
Disaggregated data on the use of individual insecticides on sorghum
are not provided by the U.S. Department of Agriculture (1974b) from its
1971 pesticide use survey. We therefore asked extension entomologists in
the leading sorghum-producing states for information on the most important
sorghum insecticides in their respective areas. Replies received indicate .
that in 1973 and 1974, the total quantity of insecticides used on sorghum
consisted of the following individual products:
disulfoton about 50% of total
parathion about 25% of total
phorate about 10% of total
other insecticides about 15% of total
65
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Until recently, sorghum was a crop that required little, if any use
of insecticides. After the introduction of hybrid grain sorghum varieties
in the late 1950's, the sorghum midge, Contarinia sorghicola, became a
problem in some sorghum growing areas, especially the Texas High Plains.
Texas Agricultural Experiment Station and Extension Service entomologists
soon determined that early, uniform planting of grain sorghum on an area-
wide basis would cause sorghum blooming to occur early in the season, be-
fore midge populations reached damaging levels. Other insect pests of
grain sorghum such as the corn earworm (Heliothis zea), the corn leaf
aphid (Rhopalosiphum tnaidis), the fall armyworm (Spodoptera frugiperda),
the false chinch bug (Nysius ericae) and others require insecticidal con-
trol only occasionally (Latham, 1974; Teetes et al. 1974).
Beginning in 1968, a rapidly increasing percentage of the grain sor-
ghum acreage in the major producing states required insecticidal treatment
against a new, more virulent strain of the greenbug, Schizaphis graminum.
The rapid spreading of this new strain, known as biotype "C," throughout
the Plains States soon caused insecticide applications on sorghum to be-
come a standard practice. Initially, many sorghum growers made preventive,
early season insecticide applications against the greenbug. The Texas
Grain Sorghum Producers Association has estimated that the expenditures
for insecticides used on grain sorghum in the Texas High Plains increased
from an average of $100,000/year prior to 1968 to over $14 million in 1969.
It is estimated that in 1971, Texas High Plains grain sorghum producers
spent about $10 million for insecticides, applying approximately 3 million
pounds of active ingredients to 2.5 million acres of the crop (Teetes et
al. 1974).
It soon became apparent that indiscriminate, preventive early season
insecticide applications for greenbug may contribute to subsequent in-
creases in mite populations due to destruction of predators which would
normally hold these mites in check. Moreover, there are indications that
the Banks grass mite, Oligonychus pratensis, is becoming increasingly re-
sistant to the pesticides used on sorghum in northern Texas, Oklahoma,
and Kansas. This mite is virtually impossible to control with chemicals
in southern Texas where production of corn and grain sorghum has decreased
greatly for this reason (Teetes et al. 1974).
Furthermore, it was feared that the intensive use of insecticides
on grain sorghum may upset the natural balance of predators and parasites
on cotton in areas where cotton and sorghum are grown in close proximity,
as in northern Texas. At present, there are no serious insect pest prob-
lems on cotton in the Texas High Plains and consequently, insecticides
66
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have not been widely applied to cotton, and cotton pests are kept in
check by their natural enemies. Grain sorghum in this area is believed
to serve as a major source of the natural enemies which later are ac-
tive in cotton. Thus, indiscriminate use of insecticides on sorghum may
well have repercussions also on cotton, both directly through insecti-
cide drift, and indirectly by destroying parasites and predators before
they migrate from sorghum to cotton.
These factors demonstrated the need for a pest management approach. A
sorghum pest management program was established as a joint effort of the
Texas Agricultural Experiment Station, the Texas Agricultural Extension Ser-
vice and the Texas Grain Sorghum Producers Board, the State sorghum commodity
organization. The program was initiated in 1973 in the community of Edmonson
in Hale, Castro and Swisher counties in the Texas High Plains. Sorghum pro-
ducers in the program area are progressive farmers who employ production
methods representative of the Texas High Plains area. The entire grain sor-
ghum acreage in the program area was under irrigation, some double-row and
narrow-row sorghum was grown, and fertilizer and herbicide uses were exten-
sive. The program objectives included maintenance of natural control of
greenbugs by beneficial insects to the greatest possible extent, and appli-
cation of reduced, selective rates of insecticide when pest populations reach
economic threshold levels, to reduce control costs and preserve as many bene-
ficial insects as possible (Latham, 1974).
In 1973, the 1st year in which the pest management program was in
operation, a total of 18,346 acres of sorghum grown by 68 producers were
in the program. Research and extension entomologists who have been closely
associated with the greenbug situation throughout the Texas High Plains
indicate that the greenbug populations on sorghum in the area in 1973 were
the highest since 1969, due to an abnormally dry period during May and June
of 1973. It is remarkable that in spite of the unusually heavy greenbug in-
festation pressure in 1973, pest management program participants used fewer
insecticide applications and smaller quantities of insecticides than in
1972, a relatively light infestation year. The data summarized in Table 21
show that the number of insecticide applications per acre was reduced by
237°, the average rate of insecticide applied per acre by 7270, and the cost
.per acre by 50%, considering only the cost of insecticide and application,
by 39% if growers' contributions to scouting costs of $0.50/acre are added
to the cost of insecticide and application. Savings in insect control costs
of this order are significant in relation to the farm value of sorghum
(Table 15).
All participants in the Edmonson (Hale County) pest management program
in 1973 used disulfoton in either the granular or liquid formulation for
greenbug control. Table 22 presents a complete breakdown of the treatments
applied (in terms of formulation and of active ingredient per acre), acres
treated, total quantity of insecticide used, and insecticide costs per acre.
67
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Table 21. USE OF INSECTICIDES FOR CREENBUG CONTROL IN THE TEXAS
SORGHUM PEST MANAGEMENT PROGRAM IN 1973 COMPARED TO
PRE-PROGRAM USE (1972)
1972 1973 Reduction
Average number of applications per acre 1.20 0.93 23%
Pounds active insecticide applied 1.04 0.29 72%
per acre
Cost per acre^ $4.35^ $2.16- $2.19 = 50%
$2.66s- $1.69 = 39%
aj Average of quoted price of four aerial applicators.
b/ Cost of insecticide and application.
cj Cost of insecticide, application, and 50
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Table 22. USE OF DISULFOTON AGAINST THE GREENBUG ON SORGHUM IN THE HALE COUNTY,
TEXAS PEST MANAGEMENT PROGRAM, 1973i/
Rate of application/acre
Formulation
7 Ib 15G£/
5 Ib 15G
1/2 pt 6-L&/
1/4 pt 6LC
1/6 pt 6LC
1/8 pt 6LC
1/10 pt 6LC
No Treatment
AI (oz)
16.8
12.0
6.0
3.0
2.0
1.5
1.2
Acres
treated
2,713
882
649
420
2,338
9,057
887
1,400
Percent of
program acreage
14.8
4.8
3.5
2.3
12.7
49.4
4.8
7.6
Total
insecticide
(Ib AI)
2,849
662
243
79
292
883
66
0
7, Total
insecticide
56.1
13.0
4.8
1.6
5.8
17.4
1.3
0
Insecticide
cost/acre^'
$2.94
2.10
0.90
0.45
0.38
0.28
0.18
0
Totals
18,346
100.0
5,074
100.0
£/ All treatments gave better than 957=, control of the greenbug for the remainder of the season.
W Average of prices quoted by four aerial applicators.
£/ 15G = 157, granular.
d/ 6LC = 6 Ib/gal liquid concentrate.
AI = Active ingredient.
Sources: Latham (1974), Teetes et al. (1974).
-------
Only 157o of the total program acreage were treated at the highest
rate of disulfoton, 7 Ib 15% granular (16.8 oz active ingredient) per
acre, but this accounted for 56% of the total quantity of insecticide
used in the program area. By contrast, a total of 9,944 acres (54% of
the program acreage) were treated at the two lowest rates, 1/8 and 1/10
pt 6 Ib/gal concentrate (1.5 and 1.2 oz active ingredient) per acre;
these treatments accounted for only 18.7% of the total quantity of di-
sulfoton used in the program area. Growers who applied disulfoton at
these low rates realized a reduction of 90 to 94% in the cost of in-
secticide per acre compared to the growers who used the insecticide
at the highest rate.
All treatments detailed in Table 22 gave better than 95% control
of the greenbug for the remainder of the season. A questionnaire survey
of program participants and comparisons of their average yields with
county averages showed that the participants did not have any sorghum
yield losses from the greenbug in 1973, indicating that the pest manage-
ment program recommendations adequately protected sorghum yields.
Another important consideration is the effect of insecticides ap-
plied for greenbug control on subsequent buildup of spider mites, es-
pecially the Banks grass mite. Table 23 summarizes the observations
made in the Hale County, Texas, sorghum pest management program in
this regard in 1973. Spider mites including the Banks grass mite are
considered secondary pests on sorghum in this area. However, once these
mites are released from natural control by destruction of their para-
sites and predators, they may cause more damage to the crop than the
greenbug. The data in Table 23 indicate that the use of disulfoton
at high rates necessitated subsequent treatment for control of spider
mites on 9.2% of the acreage, while only 2.6% of the acres treated at
the low greenbug control rates required subsequent chemical control of
spider mites. Thus, there appears to be a direct correlation between
the use of high rates of disulfoton for greenbug control and the need
for subsequent spider mite control.
The Texas High Plains Sorghum Pest Management Program was continued
in 1974, but results from the 1974 season are not available at this time.
Entomologists connected with the program report that 1974 was an even
worse year than 1973 in regard to greenbug infestations. Normal rainfall
during the early part of the growing season did not occur, and greenbug
infestations reached economic damage thresholds about 2 weeks earlier
than usual, with no help whatsoever from spring rain storms that some-
times knock down greenbug populations. Field as well as laboratory ob-
servations indicate that the greenbug may be developing resistance to
70
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Table 23. EFFECTS OF DISULFOTON APPLICATIONS AGAINST GREENBUG ON SORGHUM ON
SUBSEQUENT TREATMENTS AGAINST SPIDER MITESl/
Rate of application/acre
Formulation
7 Ib 15(£/
5 Ib 15G
1/2 pt 6LC£/
1/4 pt 6LC
1/6 pt 6LC
1/8 pt 6LC
1/10 pt 6LC
No treatment
AI (oz)
16.8
12.0
6.0
3.0
2.0
1.5
1.2
Acres treated
for
greenbugs
2,713
882
649
420
2,338
9,057
887
1,400
Subsequently treated for spider mites
Acres
370
0
60
0
115
200
0
30
"la—
13.6
0
9.2
0
4.9
2.2
0
2.1
Total at high
rates 4,664 430 9.2
Total at low
rates 12,282 315 2.6
Total program
acres 18,346 775 4.2
£/ Observations from the Hale Company, TX sorghum pest management program, 1973.
b/ 15G = 15% granular.
£/ 6 LC = 6 Ib/gal liquid concentrate.
d./ 7o of acres treated for greenbugs.
AI = Active ingredient.
Source: Latham (1974).
-------
the organophosphate insecticides currently used against it. In one loca-
tion, 95% control of greenbugs was previously obtained at 1 to 2 oz active
ingredient of disulfoton per acre while recently, a rate of 2.0 Ib active
ingredient per acre was required to kill a residual greenbug population.
In laboratory tests, a 37-fold increase in tolerance to organophosphate
insecticides was found (Mclntyre, 1974).
These recent developments have caused considerable concern among the
pest management program organizers and participants; their extent and pos-
sible effect on the future of sorghum pest management in this area remain
to be determined at this time.
Kansas, the second largest sorghum-producing state in the U.S. (Figure
4), also had a sorghum pest management program in 1973, involving 98 pro-
ducers and 22,406 acres of sorghum in the three southwestern Kansas counties
of Haskell, Meade, and Stevens.
In the Kansas program, the use of insecticides was recommended only
as labeled because legal considerations did not permit a different course,
in the opinion of state and program officials. Secondly, the question
whether high or low rates of insecticide favor the development of resis-
tance in'target insects is still unresolved among experts. For these
reasons, the main emphasis in the Kansas sorghum pest management program
was placed on using insecticide at labeled rates, but only when needed
(Mock, 1974a, 1974b).
Greenbug infestations developed early in the season in 1973 in the
program area and were more severe than in average years. Populations of
natural enemies of the greenbug, including lady beetles and lacewings,
were high in many fields and in some cases delayed for 10 to 14 days the
buildup of greenbugs to economic injury levels. Between mid-July and 5
August, chemical insecticides were applied to about 70% of the program
acreage. Other sorghum pests became economically important only occa-
sionally. Corn leaf aphids, armyworms and thrips were problematic only
in a few fields.
Mock (1974a) reports that based on a preliminary analysis of scout-
ing data, program participants made an average of 0.77 insecticide appli-
cations per field, whereas only 0.5 applications were needed. Comparing
insecticide use practices, costs, or yields of sorghum within the program
area to those of nonparticipating growers in the same area is of doubtful
value, according to Mock (1974a). All Kansas extension personnel involved
in the pest management program serve all growers in the area, whether or
72
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not they participate in the special program. Therefore, a concerted effort
was made to educate the entire community and to encourage others to adopt
the same practices employed by the pest management program participants.
Thus, it is difficult to identify genuine nonparticipants for purposes of
making comparisons with participants.
In one of the three counties involved in the pest management program
in 1973 (Meade), a buildup of a parasitic wasp, Lysiphlebus testaceipes,
was recognized by the field scouts in late July. Greenbug numbers were
peaking at this time, but parasitism increased rapidly, and within 10 days
of their first appearance, the parasites had decimated greenbug popula-
tions, and many fields did not require insecticide treatment. If the pest
management program had not been in action, many farmers would undoubtedly
have failed to recognize the parasitism and the degree of natural control
it afforded, and would have treated needlessly. Instead, only about 50%
of the total program acreage in Meade County was treated with insecticides
once, and none of the acreage required a second treatment. By contrast,
more than 90% of the program acreage in Haskell and Stevens Counties was
treated, and a small percentage of the acreage in these counties required
a second insecticide application. We calculated from these data as reported
by Mock (1974a) that over the entire program area, about 27% fewer acres
were treated with insecticides than would have been the case if the program
participants in Meade County had not had the benefits of the program.
These data indicate that under the sorghum growing conditions of
southwestern Kansas, implementation of pest management procedures could
reduce the number of sorghum acres receiving insecticide treatments. No
effort was made in this program to determine minimum effective rates of
insecticides and consequently, there are no Kansas data on possible re-
ductions in the rate of sorghum insecticides currently recommended and
used.
Nebraska, third in U.S. sorghum acreage behind Texas and Kansas
(Figure 4), also initiated a sorghum pest management program in 1973.
The program was located in Clay County and included 71 cooperators
growing 6,865 acres of sorghum. Insecticide use practices of program
participants were compared with a sampling of Clay County farmers not
in the program in 1973. Preliminary results of this comparison are
summarized in Table 24 (U.S. Department of Agriculture, 1974d).
73
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Table 24. USE OF INSECTICIDES ON SORGHUM IN CLAY COUNTY, NEBRASKA,
BY PEST MANAGEMENT PROGRAM PARTICIPANTS AND NONPARTICIPANTS, 1973
Acres treated with insecticides
Relationship Acres At Post-
to program No. grown3.' planting emergence Total
Participants 71 6,865 1,131 772 1,903
(16.5%) (11.2%) (27.7%)
Nonparticipants 47 5,940 585 1,677 2,262
(9.8%) (28.2%) (38.0%)
al Acres in the program for participants; all acres grown for
nonparticipants.
Source: U.S. Department of Agriculture (1974d).
The pest management project was not underway until 1 April 1973 and
could therefore not exert any influence on grower decisions on insecticide
use at planting time. Program participants actually treated a higher per-
centage of their sorghum acreage with insecticides at planting than non-
participants. However, the impact of the pest management program is demon-
strated, in the opinion of Nebraska entomologists, in the postemergence
insecticide uses. Program participants made postemergence insecticide
treatments on 11.2% of their acreage, while nonparticipants treated 28.2%.
Combining both planting time and postemergence treatments, program parti-
cipants treated 27.7% of their sorghum acres with insecticides, while non-
participants treated 38.0%. Thus, program participants treated 37% fewer
sorghum acres than nonparticipants.
The Nebraska Cooperative Extension Service recommended planting
time applications of disulfoton and phorate against greenbugs and corn
leaf aphids on sorghum at the rate of 1.0 Ib active ingredient per acre
in 1974'(Roselle et al. 1974a). These recommendations have been dropped
from the 1975 "Insect Control Guide for Corn and Sorghum in Nebraska,"
(Roselle et al. 1974b), with the explanation: "There is evidence that
planting time applications may cause development of resistant greenbugs,
complicating chemical control later in the season." Post-plant applica-
tions of disulfoton and phorate at 4 to 8 oz active ingredient per acre
were recommended in Nebraska in 1974 and will continue to be so recom-
mended in 1975.
74
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As in the Kansas program, no efforts were made in Nebraska in 1973
to determine minimum effective rates of insecticides on sorghum and con-
sequently, no data on this topic are available from the program.
Oklahoma, the fourth-largest sorghum-producing state by acreage,
also had a sorghum pest management program in 1973. However, we were
unable to obtain data on insecticide use patterns and insecticide use
efficiency from that program from published or unpublished sources.
Oklahoma's 1974 sorghum greenbug control recommendations generally fol-
low the product label, except that disulfoton is recommended at only
4 to 6 oz active ingredient per acre as a foliar spray (label == 4 to
8 oz active ingredient per acre).
Table 25 summarizes the rates of application of disulfoton, the
leading sorghum insecticide, for the control of greenbugs and mites on
sorghum recommended by different sources, including the EPA Compendium
of Registered Pesticides, the product label, and the Extension Services
in the states of Texas, Kansas, Nebraska, and Oklahoma. These rates are
compared to minimum effective rates and rates used in pest management
programs.
The disulfoton use patterns recommended in the product label are
practically identical to those summarized in the EPA Compendium. Com-
paring these recommendations to those of the four states studied, it
is interesting to note that only Kansas and Oklahoma still recommend
disulfoton applications at planting time, while Texas and Nebraska do
not recommend this practice because it may cause development of re-
sistant greenbugs, prevent buildup of beneficial predators and para-
sites, and/or result in buildup of mites.
The rates of disulfoton recommended for post-plant foliar applica-
tion against the greenbug in Kansas and Nebraska are identical to the
product label. Oklahoma's recommendations reduce the upper limit of
the range for this use pattern to 6 oz active ingredient per acre, a
reduction of 25% compared to the label limit, 8 oz active ingredient
per acre. The disulfoton rates suggested in Texas for foliar applica-
tion against the greenbug are considerably lower (about 63%) than the
labeled rate. An even lower rate, 1.2 oz of active ingredient per acre
(reduction of 70 to 85% compared to the label) provided better than
95% control of greenbugs in field tests in Texas in 1973.
75
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Table 25. RATES OF APPLICATION OF DISULFOTON AGAINST GREENBUG AND MITES ON SORGHUM
RECOMMENDED BY PUBLIC AGENCIES AND IN SELECTED PEST MANAGEMENT PROGRAMS
Target peBt
Greenbug
Type of treatment
Rate recommended
- in EPA Compend iun£
- in Product Labeli/
Texas
Rate suggested by Ext.
Service-/
Min. effective rate!/
Avg. field use rate
- 1972 (pre-PM)I/
- 1973 (Pest Mgmt)!/
Kansas
Rate recommended by
Ext . Service^/
b/
Insecticide' use in
Pest Mgmt. Program^-'
Nebraska
Rate recommended by
Ext. Service!/
Insecticide-/ use in
Pest Mgmt. Program J-/
Oklahoma
Rate suggested by Ext.
Service)!/
At planting, side
dress or over row
Foliar
application
Foliar
application
Ounces active ingredient/acre
12-16
12-16
.
16
4-8
4-8
1.5-3
1-2
n_
8
8-16
8
"^
16 at planting
8-16 post pltg.
-
16
4-8
4-8
-
8-16
Reduction
0-507. versus Label
637. versus Label
75% versus Label
727. versus pre-pest mgmt.
Participants treated abt.
277. fewer acres than nonpartlclpanta
-
Participants treated abt.
377. fewer acres than nonpartlclpants
-'
1 1
a/ Primarily Banks grass mite.
b/ All insecticides.
Sources (continued)
fj Latham (1974), Teetes et al. (1974).
£/ Brooks and Gates (1974).
Sources: h/ Mock (1974a).
I/ Roselle et al. (1974b).
£/ U.S. Environmental Protection Agency (1972). J/ U.S. Dept. of Agriculture (1974d).
Al Chemagro Div., Mobay Chera. Corp. (1974). k/ Oklahoma State University (1974).
e/ Texas ASM university (1973a).
76
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Foliar applications of disulfoton against mites (including the
Banks grass mite) are recommended only in Texas and Oklahoma.
In the 1973 sorghum pest management program in the Texas High
Plains, program participants used an average of 4.6 oz of active
disulfoton per acre, compared to 16.6 oz active ingredient per acre
in 1972. This reduction (72%) is especially remarkable because there
was greater insect infestation pressure in 1973 than in 1972, as dis-
cussed above.
For the Kansas and Nebraska sorghum pest management programs,
pesticide use data are not available by individual products, but only
for all sorghum insecticides combined. In the Kansas program, partici-
pants treated about 27% fewer acres of sorghum with insecticides than
nonparticipants. In Nebraska, 37% fewer acres were treated in the pro-
gram area as compared to nonparticipants.
The purpose of the EPA Compendium cited in Table 25 and in the
text above is to ensure that the total amount applied will not exceed
the tolerance established for a particular pesticide. The Compendium
is not designed to recommend application rates.
These data indicate that substantial quantities of the insecticides
used on sorghum against the greenbug could be saved if the preventive,
planting time use of insecticides at high rates of application would be
replaced by postemergence, foliar application of insecticides only as
needed, and at the minimum rates required for yield protection. Based
on the foregoing discussion and the data summarized in Table 25, we
estimate that such savings could amount to 50 to 60% of the quantities
of insecticides currently used on sorghum. In terms of the total quan-
tity of insecticides used on sorghum in the U.S. in 1971 according to
the USDA pesticide use survey, 5,729,000 Ib of active ingredients
(Table 16), savings of 50 to 60% would represent 2.9 to 3.4 million
pounds of insecticides.
One element of uncertainty is the potential development of resis-
tance of the greenbug to chemical insecticides. Experiences obtained
on other crops (examples include cotton, deciduous and citrus fruits,
certain vegetables, and others) indicate, however, that insect resis-
tance problems cannot be overcome, at least not for long, by increasing
the rates and frequency of pesticide applications. Thus, the threat of
greenbug resistance to insecticides would seem to reinforce, rather
than to weaken the need for pest management programs on sorghum.
77
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SUMMARY
Sorghum, a major U.S. feed crop, is produced primarily in the
states of Texas, Kansas, Nebraska, and Oklahoma. The use of herbi-
cides and insecticides on sorghum has increased substantially during
the last 10 years. Fungicides and "miscellaneous pesticides" such as
fumigants, defoliants, desiccants, plant growth regulators and others
are used on sorghum either in very small quantities or not at all and
were therefore not studied in detail in this project.
Herbicides are used on an ever increasing percentage of the total
grain sorghum acreage (currently about 70 to 80%). Extension agrono-
mists and weed scientists believe that many additional sorghum acres
should be treated with chemical herbicides. There are no indications
that herbicides are currently used on more sorghum acres than needed.
Some sorghum growers may be applying herbicides at higher rates per
acre than required for optimal economic returns because of lack of
individualized information on optimal choice of product(s) and appli-
cation rate for their specific situations.
The costs of chemical weed control in sorghum are significant in
relation to the farm value of the crop, an effective economic deter-
rent to the inefficient or wasteful use of sorghum herbicides.
The use of insecticides on sorghum has increased rapidly since •
1968 when a new, more virulent strain of the greenbug, Schizaphis
graminum, spread throughout the major grain sorghum-producing areas.
Preventive, high rate, early season insecticide applications against
greenbugs may accelerate•the development of resistant strains. In
addition, such treatments have been shown to destroy natural parasites
and predators, thus contributing to subsequent increases in mites, es-
pecially the Banks grass mite, Olygonychus pratensis. In areas where
both cotton and sorghum are grown, sorghum is believed to be a major
source of predators and parasites which later in the season migrate
from sorghum to cotton. Decimation of these beneficial insects may
thus affect not only sorghum, but also cotton.
Based on careful analysis of pertinent literature, of current
sorghum insecticide use patterns, of the results to date of three
sorghum pest management programs, and on consultations with ento-
mologists in the leading sorghum-producing states, we estimate that
50 to 60% of the quantities of insecticides currently used on sorghum
could be saved if pest management principles and methods would be
universally adopted and practiced by grain sorghum producers. Such
savings would amount to about 2.9 to 3.4 million pounds of insecti-
cides, based on the 1971 pesticide use survey by the USDA.
78
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REFERENCES TO SECTION VI
Brooks, L., and D. E. Gates, "1974 Kansas Field Crop Insect Control
Recommendations," Cooperative Extension Service, Kansas State
University, Manhattan (1974).
Chemagro Division of Mobay Chemical Corporation, "1975 Product Guide,"
Fall 1974 Edition (1974).
Furrer, J. D., C. Fenster, A. R. Martin, R. Moomaw, and G. Wicks, "A
1973 Guide for Herbicide Use in Nebraska," E.G.73-130, Extension
Service, University of Nebraska (1972).
Latham, E. E., "1973 Annual Report of the Texas Grain Sorghum Pest
Management Program/Hale County, Texas," Texas Agricultural Exten-
sion Service (1974).
Mclntyre, R. C., Personal Communication (1974).
Mock, D. E., "Kansas Pest Management Project 1973 Annual Report,"
Kansas State University Cooperative Extension Service, Southwest
Area Extension Office, Garden City (1974a).
Mock, D. E., Personal Communication (1974b).
Nilson, E. B., 0. G. Russ, W. M. Phillips, and J. L. Condray, "Chemi-
cal Weed Control in Field Crops, 1974," Report of Progress 205,
Agricultural Experiment Station, Kansas State University,
Manhattan (1974).
Oklahoma State University, "Extension Agents Handbook of Insect and
Weed Control-1974," Cooperative Extension Service (1974).
Roselle, R. E., D. L. Keith, and L. L. Peters, "Insect Control Guide
for Corn and Sorghum/Nebraska," EC74-1509, Revised January 1974,
Extension Service, University of Nebraska-Lincoln (1974a).
Roselle, R. E., D. L. Keith, and L. L. Peters, "Insect Control Guide
for Corn and Sorghum/Nebraska," EC75-1509, Revised December 1974,
Extension Service, University of Nebraska-Lincoln (1974b).
Teetes, G. L., R. C. Mclntyre, D. G. Bottrell, and R. L. Haney, "Cut
Grain Sorghum Insecticide Costs with Integrated Control," Texas
Agricultural Experiment Station/Texas Agricultural Extension Service,
Mimeographed Article (1974).
79
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Texas A & M University, "Suggestions for Controlling Insects and Mites
on Corn, Sorghums, and Small Grains," Bulletin MP-339, Texas Agri-
cultural Extension Service (1973a).
Texas A & M University, "Suggestions for Weed Control with Chemicals,"
Bulletin MP-1059, Part I, Texas Agricultural Extension Service (1973b),
U.S. Department of Agriculture, "Quantities of Pesticides Used by
Farmers in 1964," Agricultural Economic Report No. 131, Economic
Research Service, Washington, D.C. (1968).
U.S. Department of Agriculture, "Quantities of Pesticides Used by
Farmers in 1966," Agricultural Economic Report No. 179, Economic
Research Service, Washington, D.C. (1970).
U.S. Department of Agriculture, "Extent and Cost of Weed Control with
Herbicides and an Evaluation of Important Weeds, 1968," ARS-H-1,
Economic Research Service, Extension Service and Agricultural Re-
search Service (1972).
U.S. Department of Agriculture, "Agricultural Statistics 1973," U.S.
Government Printing Office, Washington, D.C. (1973).
U.S. Department of Agriculture, "Feed Situation," FdS-255, Economic
Research Service (1974a).
U.S. Department of Agriculture, "Farmers' Use of Pesticides in 1971 . .
Quantities," Agricultural Economic Report No. 252, Economic Research
Service, Washington, D.C. (1974b).
U.S. Department of Agriculture, "Crop Production," CrPr 2-2 (11-74),
Statistical Reporting Service, Crop Reporting Board (1974c).
U.S. Department of Agriculture, "1973 Summaries, U.S. Department of
Agriculture and Cooperative Extension Service Pilot Pest Management
Projects" (Compilecf from materials supplied by cooperating states),
ANR-5-49 (6-74) (1974d).
U.S. Environmental Protection Agency, "EPA Compendium of Registered
Pesticides, Volume III: Insecticides, Acaricides, Molluscicides
and Antifouling Compounds," Pesticides Regulation Division, Office
of Pesticide Programs, U.S. Government Printing Office (1972 and
Supplements issued subsequently).
80
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SECTION VII
PESTICIDE USE PATTERNS ON APPLES
PRODUCTION OF APPLES IN THE UNITED STATES
Apples are one of the major fruit crops grown in the United States.
Apples were produced commercially on about 526,000 acres in the United
States in 1969, the latest year for which acreage statistics for apples
have been published (U.S. Bureau of the Census, 1973). In 1973, the
total utilized U.S. production of apples was 6.2 billion pounds. The
farm value of the 1973 apple crop was about $512 million. The average
grower price for all sales of apples in 1973 was estimated at $0.088/lb
(U.S. Department of Agriculture, 1974a). Thus, the average value of pro-
duction of apples was about $l,000/acre at 1973 grower prices.
Figure 5 presents a breakdown of the commercial apple production in
the U.S. by states for 1971. The total utilized commercial production
of apples in 1971, 6.1 billion pounds, is very close to the 1973 produc-
tion, 6.2 billion pounds. Thus, the data presented in Figure 5 may be
considered to be representative of the geographic distribution of the
production of apples in the U.S. for the years 1971 through 1973.
As Figure 5 indicates, the leading apple producing states in the
U.S., in decreasing order of volume of production are: Washington, New
York, Michigan, and Pennsylvania. All other states produced less than
500 million pounds of apples in 1971.
QUANTITIES OF PESTICIDES USED ON APPLES
The U.S. Department of Agriculture (1974b) conducted a survey on
the use of pesticides by American farmers in 1971. According to this
source, apples ranked sixth among individual crops in total volume of
insecticides used (preceded by cotton, corn, peanuts, sorghum, and soy-
beans) , and second in volume of fungicides used (preceded only by citrus
81
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00
S3
Commercial Apple Production in
Millions of Pounds
Total Production
Total Not Utilized ( )
Total Production for
Use or Sale
= 6,371.1
290.5
45.2
(4.8)
(1.0)
= 6,080.6 million
pounds
Figure 5. U.S. commercial apple production (1971), by state.
-------
fruits). The use of herbicides on apples was very small; only 0.09%
of all herbicides used in agriculture in the U.S. were used on apples
in 1971.
Table 26 presents a breakdown of the pesticides used on apples in
the U.S. in 1971 by type of pesticides and by regions. Farmers used
7.2 million pounds of fungicides, 4.8 million pounds of insecticides,
548,000 Ib of miscellaneous pesticides, and 197,000 Ib of herbicides
(all quantities in terms of active ingredients) on apples in 1971.
The Northeastern Region accounted for 40.8% of all fungicides,
65.0% of all herbicides, and 49.8% of all insecticides used on apples.
The Pacific Region used the largest share (56.6%) of all "miscellaneous
pesticides," used on apples in 1971. About two-thirds of this pesti-
cide category consisted of miticides in 1971. The heavy use of "mis-
cellaneous pesticides" in the Pacific Region is indicative of the serious
mite problem on apples in this area.
Of all pesticides used on apples, 43.7% were used in the North-
eastern Region, 24.6% in the Midwestern states (Lake States, Corn Belt,
and Northern Plains), 16.5% in the Pacific Region, the balance in the
remaining apple-producing regions of the U.S. The use of fungicides,
insecticides, herbicides, and miscellaneous pesticides on apples in 1971,
according to the USDA (1974b) survey, is further detailed in Tables 27
through 30. For each of the four pesticide categories, use data are pre-
sented by major products and by geographic regions.
Table 31 presents a comparison of the quantities of pesticides used
on apples in the United States in 1964, 1966, and 1971 according to the
U.S. Department of Agriculture's pesticide use surveys for these years
(U.S. Department of Agriculture, 1968, 1970, 1974b). The total quantity
of all pesticides used on apples decreased from 19.6 million pounds
(active ingredients) in 1964 to 18.5 million pounds in 1966, and further
to 12.8 million pounds in 1971. The quantities of fungicides used on
apples changed relatively little, while the quantities of insecticides
declined substantially during this 8-year period, i.e., from 10.8
million pounds (active ingredients) in 1964 to 8.5 million pounds in
1966, and further to 4.8 million pounds in 1971.
83
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Table 26. PESTICIDE USAGE ON U.S. APPLE CROP IN 1971 BY REGION
Region
Northeast
Lake States
Corn Belt
Northern Plains
Appalachian
00
** Southeast
Delta States
Southern Plains
Mountain
Pacific
Totals
Fungicides
1.000 Ib %
2,943 40.8
1,026 14.3 .
853 11.8
12 0.2
1,353 18.8
67 0.9
-
-
16 0.2
937 13.0
7,207 100.0
Herbicides Insecticides Misc. Pesticides
1.000 Ib % 1.000 Ib % 1.000 Ib %
128 65.0 2,403 49.8 116 21.1
349 7.2 29 5.3
11 5.6 831 17.2 36 6.6
5 0.1 -
1 0.5 359 7.4 27 4.9
6 3.0 32 0.7 7 1.3
_ _
.
44 0.9 23 4.2
51 25.9 808 16.7 310 56.6
197 100.0 4,831 100.0 548 100.0
Total Pesticides
1,000 Ib %
5,590 43.7
1,404 11.0
1,731 13.5
17 0.1
1,740 13.6
112 0.9
0
0
83 0.7
2,106 16.5
12,783 100.0
Source: "Farmers' Use of Pesticides in 1971 Quantities," Agricultural Economic Report No. 252, Economic Research
Service, U.S. Department of Agriculture (1974b).
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co
Oi
Table 27. FUNGICIDES USED ON APPLES BY REGION, 1971-
(1,000 Ib)
a.b/
North- Lake Corn Northern
Fungicide east States Belt Plains
Cap tan 1,250 800 400
Other
Dithiocarbamates 800 20 200 10
Dinocap, Dodine,
Quinones 600 160 50 1
Other Inorganics 65 1 -
Zineb 50 1 100
Other Organics 80 30 5 1
Maneb 25 - 50
Ferbam 70 15
Other Copper
Compounds 1 - 45
Copper Sulfate 2 2
Total 2,943 1,026 853 12
Regions
Appa- South- Delta Southern Moun-
lachian east States Plains tain Pacific
900 - 2 40
200 - 2 65
3 10 - 2 95
15 - 460
180 5 - - 4 170
9 10 - - 1 40
40 - - - 5 5
20 5 - - - 8
15 - - - 50
1 7 4
1,353 67 0 0 16 937
Total
3,392
1,297
921
541
510
176
125
118
111
16
7,207
a/ Figures for total use of each fungicide and regional totals were obtained from "Farmers' Use of Pesticides in
1971-Quantities," Agricultural Economic Report No. 252, Economic Research Service, U.S. Department of
Agriculture (1974b).
b/ Use of each individual fungicide, by region, is an MRI estimate.
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Table 28. INSECTICIDES USED ON APPLES BY REGION, 1971
(1,000 Ib)
a.b/
North-
Insecticide east
Inorganics 900
Azinphosmethyl 500
Other
Organophosphorus 300
Carbaryl 300
Chlordane 200
Parathion 60
Endosulfan 100
Ethion 35
Oo
O\ Malathion
Diazinon 6
Bidrin
Methoxychlor 1
Dieldrin 1
Other
Organochlorine
Endrin
IDE (DDD)
H*»pf-nrhlnr
Total 2,403
Lake Corn
States Belt
10 500
100 60
80 35
100 100
50 100
5 10
2 10
-
5
2 4
4
2
-
-
-
-
_L
349 831
Northern Appa- South-
Plains lachian east
140 3
100 7
1 40 2
30 1
10 2
3 15 5
10 2
1 5
10 2
1 - -
2
1
-
- -
2
1
5 359 32
Delta Southern Moun-
States Plains tain Pacific
300
2 200
160
3 180
2 50
4 7
15 25
10 2
3 25
4
5
3 3
1 2
1 3
- 2
.
.
• — — —
0 0 44 808
Total
1,853
969
641
583
373
138
136
69
21
18
12
7
5
2
2
1
1
4,831
.1 /•
-£/ Figures for total use of each insecticide and regional totals were obtained from
"Farmers' Use of Pesticides in 1971 - Quantities," Agricultural Economic Report
No. 252, Economic Research Service, U.S. Department of Agriculture (1974b).
b/ Use of each individual insecticide, by region, is an MRI estimate.
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co
Table 29. HERBICIDES USED ON APPLES BY REGION, 1971
(1,000 Ib)
a.b/
Herbicide
Other Organic
Simazine
Dalapon
2,4-D
Dinitro Group
Diuron
Trifluralin
Total
North-
east
65
20
25
15
2
1
.
128
Regions
Lake Corn Northern Appa- South- Delta Southern Moun-
States Belt Plains lachian east States Plains tain Pacific
1 - 1 . . _ - - 28
5 - - 1 - 10
1 - - 3 - - - 5
3 . i - - 4 :
1 - - 3
1
1 . . . . . -
0 11 0 16 0 0 0 51
Total
95
36
34
23
6
2
1
197
a/ Figures for total use of each herbicide and regional total were obtained from "Farmers' Use of Pesticides in 1971-
Quantities," Agricultural Economic Report No. 252, Economic Research Service, U.S. Department of Agriculture (1974b),
b/ Use of each individual herbicide, by region, is an MRI estimate.
-------
oo
oo
Table 30. MISCELLANEOUS PESTICIDES USED ON APPLES BY REGION, 1971
(1,000 Ib)
a.b/
North- Lake Corn Northern Appa- South- Delta Southern Moun-
Pesticide east States Belt Plains lachian east States Plains tain
Miticides
Dicofol 1 _-- - - - - 2
Omite 69 10 28 - 9 - - - 2
Others 32 - . - - 10 2 - - 9
Fumigants - - ~ ~ ~"
Defoliants and
Desiccants - __- - - -
Rodenticides 5 - - - -
Plant Growth
Regulators 9 19 8 8 5 - 10
Repellents i - _i ~ _z. _l_ _l_ —I— — 1
Total 116 29 36 0 27 70 0 23
Pacific Total
3 6
160 278
30 83
0
0
2 7
115 174
- 0
310 548
a/ Figures for total use of each pesticide and regional totals were obtained from "Farmers' Use of Pesticides in 1971-
~ Quantities," Agricultural Economic Report No. 252, Economic Research Service, U.S. Department of Agriculture (1974b)
b/ Use of each individual insecticide, by region, is an MRI estimate.
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Table 31. USE OF PESTICIDES ON APPLES IN THE U.S. IN 1964, 1966, AND 1971
Type of pesticide
Fungicides^/
Insecticides^'
Herbicides-
Miscellaneous
pesticides^-'
All pesticides
1..000 Ib
1964
7,700
10,828
N.A.
1,037
19,565-^
of active
1966
8.496
8,494
389
1,119
18,498
ingredients
1971
7,207
4,831
197
548
12,783
a/ Excluding sulfur.
b_/ Excluding petroleum.
£/ Includes miticides (100% of total in 1964; about 2/3 of total in
1966 and 1971); fumigants (about 1/3 of total in 1966, none in
1964 or 1971); plant growth regulators (none in 1964 or 1966,
about 1/3 in 1971).
d/ Excluding herbicides.
N.A. - not applicable
Sources: USDA 1968, 1970, 1974b.
89
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The volume of commercial apple production in the United States dur-
ing the last 10 years was as follows (USDA 1973, 1974a):
1964 3,120,000 tons
1965 3,001,000 tons
1966 2,825,000 tons
1967 2,793,000 tons
1968 2,723,000 tons
1969 3,355,000 tons
1970 3,129,000 tons
1971 3,040,000 tons
1972 2,935,000 tons
1973 3,102,000 tons
These production data indicate year-to-year changes in the quanti-
ties of apples produced in the U.S., probably due largely to different
weather conditions, but no definite trends. By contrast, as pointed out
above, the USDA pesticide use data indicate a definite downward trend in
the quantities of insecticides and "miscellaneous pesticides" used on
apples. This reduction in the use of pesticides, especially insecticides,
was thus not correlated with changes in the volume of production of apples,
but appears to be due to changes in pesticide use practice.
This assumption is borne out by information from the field. For in-
stance, Eves and Chandler (1973) report that the average costs for pesti-
cides in the State of Washington were $86/acre in 1967, and $48/acre in
1973. This decline in costs probably represents an even greater decline
in the quantities of pesticides used because the unit costs of pesticides
have increased during this period. Likewise, Brann (1974), advised that
apple growers in New York are using substantially smaller quantities of
pesticides, especially insecticides, on apples in the 1970's than they
were using in the 1960's.
As with other crops, wasteful use of pesticides on apples, such as
misuse, overuse, and/or unnecessary use may occur through poor management
decisions. The data just quoted suggest that substantial progress has
already been made during the last 10 years in correcting wasteful pesti-
cide use practices on apples, and in using pesticides more efficiently.
In the following subsections, current pesticide use practices on apples
will be examined, focusing on opportunities to further improve pesticide
use efficiency, and to further reduce wasteful pesticide uses.
90
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FUNGICIDE USE PRACTICES
Table 31 indicates that the quantities of fungicides used on apples
in the U.S. changed relatively little from 1964 (7.7 million pounds) to
1971 (7.2 million pounds). In 1971, close to 50% of the total quantity
of fungicides used on apples (3.4 million pounds) consisted of captan
(Table 27). Dithiocarbamate fungicides (maneb, zineb, ferbam, and others)
accounted for an additional 2 million pounds, or 28% of the total
quantity of fungicides used on apples. The balance is made up of a
number of additional organic and inorganic fungicides.
The fungicides used most frequently on apples according to Table 27
are used primarily for the control of apple scab (Venturia inaequalis).
Other diseases of apples caused by fungal pathogens requiring control
include powdery mildew (Podosphaera leucotricha), several species of
rusts, rots, and several others.
Apple scab is the single most important fungus disease of apples.
The key to successful prevention of economic damage from apple scab is
to control primary infections. To be effective, fungicides must be
present on susceptible apple tissues before fungus infection takes place,
or within a very short period (generally less than 24 hr) after infec-
tion. Therefore, most fungicides are used on apples preventively or
protectively, that is before lesions caused by the fungal pathogen(s)
becomes visible. Preventive or preprogrammed pesticide applications,
prior to established need, are potentially wasteful. However, in the
case of the fungus diseases of apples, the infection mechanisms of the
fungal pathogens, combined with the capabilities of the most widely
used fungicides, make it necessary to apply these fungicides on preven-
tive application schedules in areas where climatic conditions and pre-
vious experience indicate that fungal infections are likely. Fungicide
applications against apple scab are usually started at the "delayed
dormant" or "green tip71 stages of development of the host, and continued
on regular spray schedules into the summer. In the opinion and ex-
perience of plant pathologists and apple growers alike, this applica-
tion pattern is necessary if fungicides are to be used successfully in
protecting apples from scab and other fungus diseases. There is little,
if any, indication that the fungicides most often used on apples at pres-
ent could be used with equal success in a basically different manner,
in curative (in contrast to preventive) spray programs, or in greatly
reduced quantities.
Furthermore, there are no practical, nonchemical alternatives
available for control of the apple diseases controlled by these fungi-
cides. No predators, parasites, or other biological agents are known
91 .
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that could be employed in "integrated apple disease management" pro-
grams. Thus, at the present state of the art, no practical, proven
alternatives to the use of chemical fungicides on preventive, prepro-
grammed application schedules are available to growers for the control
or management of apple diseases.
For these reasons, these use patterns of fungicides on apples can-
not be considered to be wasteful, but appear to be necessary as dictated
by the biology of the fungal pathogens involved, and the capabilities
of the presently used fungicides.
INSECTICIDE USE PRACTICES
Of the 4.8 million pounds of insecticides used on apples in the
United States in 1971 (Table 28), 1.9 million pounds, or 38% of the
total, consisted of inorganic chemicals, primarily lead arsenate. Among
the synthetic organic insecticides, azinphosmethyl (tradename: Guthion®)
was used in larger quantities than any other single product; its volume,
969,000 Ib, accounted for more than one-half of the quantity of all
organophosphate insecticides, or about one-third of all synthetic organic
insecticides used on apples. Carbaryl (tradename: Sevin®) was the next
largest apple insecticide used in 1971; its volume, 583,000 Ib, amounted
to about 20% of all organic insecticides. Several smaller volume organic
insecticides accounted for the balance of all insecticides used on
apples in 1971.
About one-half of all insecticides used on apples in 1971, 2.4
million pounds (active ingredients), were used in the Northeastern Re-
gion. An additional 1.2 million pounds, or 25% of the total, were used
in the Midwest (Lake States, Corn Belt, and Northern Plains). The
Pacific Region used 808,000 Ib of insecticides on apples in 1971 (17%
of the total), the balance was used in the other apple growing areas,
primarily the Appalachian Region.
Comparing these figures to the geographical distribution of apple
production in the U.S. (Figure 5), it is evident that the production of
apples in the Northeastern Region requires relatively heavier inputs of
insecticides than the Pacific Region.
In the past, insecticides were usually applied to apples on preven-
tive, preprogrammed spray schedules. After some time, it became apparent
that this practice was very detrimental to beneficial parasites and
predators. In the absence of the latter, plant-feeding mites became a
severe problem in many apple-producing areas, especially in the Pacific
92
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Northwest. At first, the use of miticides was stepped up, but several
species of mites soon became highly resistant to practically all avail-
able miticides. This chain of events prompted the development of more
selective apple pest control or management procedures, with emphasis
on the selection of insecticides, miticides, and application rates and
schedules designed to preserve beneficial predators and parasites to
the greatest possible extent. As pointed out above, this de-
velopment has already resulted in a substantial reduction of the total
quantities of insecticides used on apples from 1964 to 1971 (Table 3l)7
In recent years, Integrated Pest Management (IPM) programs were
established in several apple-growing states. The objectives of these
programs include identification, quantification, and documentation of
the pest problems on apples in the area, and development of solutions
to these problems by integrating biological, chemical, and other con-
trol methods to the greatest degree possible. The ultimate practical
objective is, of course, to increase apple growers' profits.
One of the IPM programs on apples was initiated in 1972 in the
Yakima Valley in the State of Washington. Apples are grown on about
36,000 acres in the Yakima Valley,_tha_t is about 40% of the total acre-
age of apples in the state (Table 32). In 1973, 665 acres of apples
were included in this program. In the program area as well as in
neighboring apple orchards, populations of codling moths, mites, and
other apple pests were monitored regularly by mite counts, sex phero-
mone traps, and intensive field observation. Participating growers re-
ceived specific spray recommendations from IPM program personnel.
Table 32. APPLE ACREAGE IN WASHINGTON
Total acres of apples in state, 1969^-' 92,244
Total acres of apples in Yakima Valley^ 36,236
Acres in IPM program in Yakima Valley, 1974k/ 661
£/ 1969 Washington tree_fruit census.
b/ Eves (1974).
93
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Table 33 summarizes the results of this program in 1973 and 1974 as
compared to the pesticide use experience on 2,193 comparable acres of
apples not under IPM in 1973. In the non-IPM area, a total of 9.31 Ib
of pesticide active ingredient was applied per acre, at a cost of
$59.80/acre. In the IPM area, total pesticide inputs were 3.93 Ib/acre
($28.00) in 1973, and 4.5 Ib/acre ($29.00) in 1974. Thus, total pesti-
cide inputs in the IPM program in the 2 years averaged 4.2 Ib of active
ingredient per acre, a reduction of about 55% from the 9.31 Ib active
ingredient per acre in the non-IPM area. Cost savings per Table 13,
all computed on the basis of 1972 prices, were comparable to the sav-
ings in quantities. In reality, IPM program participants savings in
pesticide costs were even greater than indicated by the data in Table
33 because pesticide costs increased from 1972 to 1974.
Table 33. USE OF PESTICIDES ON APPLES IN THE LOWER YAKIMA VALLEY
UNDER IPM VERSUS NON-IPM PROGRAMS
Acres sprayed
Acres against All pesticides used
in Aphids Mites Pound active in- Cost
Program program (%) (%) gradient per acre ($/acre)-/
Non-IPM, 1973 2,193, . 100 , 100 9.31 59.80
IPM, 1973 225 0 0 3.93 28.00
IPM, 1974 661 25 28 4.5 29.00
a/ Basis 1972 prices.
Source: Eves (1974), and Eves and Chandler (1973).
In 1973, no insecticide sprays against aphids or mites were needed
in the IPM area, and in 1974, only about one-fourth of the IPM program
acreage required such treatments, while in the non-IPM area in 1973,
100% of the acreage was treated against aphids and mites. Project per-
sonnel report that when Guthion® is applied against the codling moth at
"standard" rates, buildup of mites to damaging proportions often follows,
necessitating one or more applications of miticides. Conversely, when
used at the minimum rate required for codling moth control, Guthion®
permits survival of mite predators, mites are kept at low levels, and
chemical miticides are required only occasionally.
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Integrated pest management programs on apples in Pennsylvania
have been described by Asquith (1972). The Pennsylvania program is
also centered on the integration of the biological control of mites
with the chemical control of other apple pests. Three different spray
schedules are outlined by Asquith. Table 34 summarizes the results
of these schedules in terms of total cost per acre, and in terms of
the rates of Guthion® (azinphosmethyl) recommended in each schedule.
Data on Guthion® were included in Table 34 because it is the organic
insecticide most widely used on apples, as documented above (Table
28). Table 34 indicates that the cost of all pesticides combined in
the full schedule was $85.15/acre, compared to $60.23 (29% reduction)
in the "alternate middles schedule," and $46.12 (46% reduction) in the
integrated pest management schedule. The "full schedule" recommends
Guthion® applications totaling 6.0 Ib 50% wettable powder (WP) per
acre per season. In the "alternate middles schedule," this quantity
is reduced to 4.0 Ib 50 WP (33% reduction), while in the IPM schedule,
only 2.0 Ib of Guthion® 50 WP are recommended per acre per season, a
reduction of 67% from the full schedule.
Table 35 summarizes the rates of application of Guthion® 50% wet-
table powder for use on apples recommended by different sources, in-
cluding the EPA Compendium of Registered Pesticides, the product label,
and the Cooperative Extension Services in the states of Washington,
New York, Pennsylvania, and Michigan. These rates are compared to
rates recommended in IPM programs, and minimum effective rates, that
is, rates giving economic control in IPM programs.
According to the EPA Compendium (U.S. Environmental Protection
Agency, 1972; page III-D-43.1, issued 30 June 1972), Guthion® may be
used on apples at the rate of 6.0 Ib active ingredient (12.0 Ib 50%
wettable powder) per acre per application, up to eight times per season,
equal to a maximum permissible rate of application of 48 Ib active in-
gredient (96 Ib 50 WP) per acre per season. As pointed out previously
in the section on sorghum, the EPA Compendium is intended to ensure
that the total amount of pesticide applied will not exceed the toler-
ance; it is not designed to recommend application rates.
The product label (Chemagro Corporation, 1970) recommends 2.0 to
2.5 Ib 50 WP/acre/application. The Extension Services' standard recom-
mendations are similar to those on the product label, with a few ex-
ceptions. Washington State (1974) recommends up .to 3.0 Ib 50 WP/acre/
application. Pennsylvania (1974) recommends Guthion® only in combina-
tion with other insecticides such as lead arsenate, dimethoate, deme-
ton, Imidan, or Zolone. Guthion® as one component of such combinations
is recommended at the rate of 0.8 Ib. 50 WP/acre/application. In New
York (Arneson et al., 1974) and Michigan (Jones et al., 1974), the
"standard" rate of Guthion recommended is 2.0 Ib 50 WP/acre/application,
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Table 34. USE OF PESTICIDES ON APPLES IN PENNSYLVANIA UNDER
IPM VERSUS NON-IPM PROGRAMS
Program
Full schedule
Alternate middles
spray schedule
Integrated pest
management
Cost of all pesticides
Reduction
versus full
$/acre schedule
85.15
60 . 23 29%
46.12 46%
Rate of Guthion® recommended
Lb 50 WP/acre
/season
6.0
4.0
2.0
Reduction
versus full
schedule
—
33%
67%
Source: Asquith (1972).
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Table 35. RATES OF APPLICATION OF GUTHION®50% WETTABLE POWDER ON APPLES
RECOMMENDED BY PUBLIC AGENCIES AND IN SELECTED INSECT CONTROL PROGRAMS
Type of
recommendation
or use
Guthion® 50% WP rate Reduction
per application compared to
Per 100 gal.S/per acre "standard"
Rate recommended
- in EPA Compendium—
- in Product Label—'
e/
0.5-0.625^7
max. 12.0
2.0-2.5
Washington
Rate recommended
by Ext. Service*
0.25-0.5S/
1.5-3.0
"standard"
Rate recommended
in IPM Program-
1.25
17-58%
Rate giving economic
control in IPM Program—
0.5-1.0
33-83%
New York
Rate recommended
by Ext. Servicei'
i/
0.5s
2.0
"standard"
Rate used in 1973
IPM Program-l-'
1.43
29%
Pennsylvania
Rate recommended
k/
by Ext. Service—'
- "Standard Program"
- "Pest Management Program" 0.08-0.172-'
0.25^
d/
0.8
0.25-0.5
"standard"
38-69%
Michigan
Rate recommended
by Ext. Service—
I/
2.0
"standard"
Rate used in 1972 IPM
ProgramS/
0.43-0.87
57-79%
a/ 100 gal. dilute spray. Sources:
b/ Basis 400 gal. dilute spray/acre, e/ U.S. Environmental Protection
£/ Basis 600 gal. dilute spray/acre. Agency (1972).
d_/ Basis 50 gal. 6 x cone, spray =
300 gal. dilute spray/acre.
f/ Chemagro Corporation (1970).
g/ Washington State University (1974).
h/ Eves (1974).
i/ Arneson et al. (1974),
j/ Brann (1974).
k/ Pennsylvania State University (1974).
I/ Jones et al. (1974).
m/ Thompson et al. (1972).
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In Washington State, IPM program participants are using Guthion®
successfully at the rate of 1.25 Ib 50 WP/acre, a reduction of 17 to 58%
compared to the standard. IPM program personnel report that economic
control has been obtained at Guthion^ rates of 0.5 to 1.0 Ib 50 WP/acre,
a reduction of 33 to 83% from the standard (Eves, 1974).
In New York, participants in the IPM program in 1973 used Guthion®
at an average rate of 1.43 Ib 50 WP/acre/application, a reduction of
29% compared to the "standard" (Brann, 1974).
In Pennsylvania, the "pest management program" recommended by
Pennsylvania State University (1974) in its 1974 tree fruit production
recommendations calls for the use of Guthion® (in combination with at
least one other insecticide) at the rate of 0.25 to 0.5 Ib 50 WP/acre,
a reduction of 38 to 69% against the rates recommended in the "standard
program." The rates of other insecticides with which Guthion® is to
be combined are similarly reduced in the "pest management program."
In Michigan, Guthion® was used at the rate of 0.43 to 0.87 Ib 50
WP/acre in the 1972 and 1973 IPM programs, a reduction of 57 to 79%
compared to the standard recommended rate (Thompson et al., 1972;
Thompson et al., 1973).
In Table 35, the rates of Guthion® recommended in IPM programs,
or found to be economically effective are, on the average, about 50%
lower than the "standard" recommended, rates. However, it would be
unrealistic to anticipate that the rates of Guthion® currently used
on apples in the field could be reduced by 50% across the board. In
field practice, Guthion® as well as other apple insecticides are al-
ready widely used at rates lower than the "standard." Thus, the po-
tential savings in insecticides suggested by Table 35 have in part
already been realized during the past few years, as demonstrated by
the decline in the total quantities of insecticides used on apples
since 1964. On the other hand, the Guthion® rate data in Table 35
pertain only to single applications. Additional savings in total in-
secticide inputs would be possible if the number of insecticide ap-
plications per season could be reduced. Another possibility of reducing
insecticide inputs consists of treating only so-called "hot spots"
within orchards, rather than entire blocks. Improved pest monitoring
procedures make this approach possible. Further savings in total pes-
ticide input are realized when mite predators are allowed to survive
in sufficient numbers to keep detrimental mites under control, thus
reducing or eliminating the need for chemical miticides.
In discussing the potential for futher insecticide use reductions
with experts in the field, entomologists working on apple insects in
New York State pointed out that apple growers in their state have already
' 98
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been using pesticides only "as needed" during the last few years. They
see only limited room for saving additional pesticide quantities and
costs, of the order of about 10%,, Looking for savings greater than 15%
would be unrealistic, in their opinion,, Somewhat greater reductions in
pesticide inputs and costs appear to be possible in Pennsylvania.
Michigan State University's reports on their apple pest management
programs for 1972 and 1973 (Thompson et al., 1972; Thompson et al.,
1973) do not specify actual or potential savings in pesticide inputs
to be expected from the program, and Michigan's 1974 fruit spraying
calendar (Jones et al., 1974) does not include separate "standard" and
"pest management" spraying schedules.
Entomologists in Washington State believe that substantial reduc-
tions in pesticide inputs could be achieved with increased adoption of
IPM practices (Eves and Chandler, 1973; Eves, 1974) „ However, since
the Pacific Region uses smaller quantities of pesticides per unit of
apple production, savings in that region will have a smaller effect on
the total quantities of pesticides used on apples than pesticide use
reductions in the Northeastern Region with its heavier use of apple
pesticides.
The data in Table 31 show that the quantities of insecticides
used on apples in the U.S. have declined substantially between 1964
and 1971. From the information presented above, we estimate that an
additional 20 to 30% of the quantities of insecticides that were used
on apples in 1971 could be saved, and that this fraction of the total
current volume of use of these chemicals might, therefore, be con-
sidered inefficient or wasteful. Specifically, this estimate is based
on!
* The data summarized in Table 35, showing that the minimum ef-
fective rates of Guthion®, a major apple insecticide, are about
50% lower on the average than the "standard" recommended rates.
* The fact that further insecticide inputs could be saved by
avoiding insecticide application in the absence of established
need for treatment, and by avoiding insecticide or miticide
applications necessitated by preceding injudicious pesticide
use.
* The opinions of research and extension entomologists working on
apple insects in the states of Washington, New York, Pennsylvania
and Michigan as discussed above.
* The historical use patterns of insecticides on apples in the U<.S.
as summarized in Table 31.
Further reductions in the quantities of insecticides used on apples
of the order of 20 to 30% would require widespread implementation of
integrated pest management practices, vastly improved understanding of
IPM principles and procedures by persons making pest management decisions
and pesticide applications, and several other prerequisites.
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If the USDA estimate on the quantities of insecticides used on
apples in 1971, 4.8 million pounds (active ingredient), is representa-
tive of the current level of use, a 25% reduction would correspond to
1.2 million pounds. If the USDA estimate is low, then the quantity of
insecticides that would be saved by a 25% reduction would, of course,
be even greater.
HERBICIDE USE PRACTICES
In 1966, 389,000 Ib of herbicides (active ingredient) were used on
apples, and 197,000 Ib in 1971 (Table 31). In both years, these totals
included simazine, dalapon, 2,4-D, and several other organic herbicides
not disaggregated in the USDA pesticide use reports (U.S. Department of
Agriculture, 1970, 1974b).
Herbicides are used in apple orchards to reduce or remove unwanted
vegetation under and around the trees. Heavy growth in these areas may
harbor mice, snakes, borers, and other vermin. Weeds compete with trees
for water, nutrients, and especially in young plants, light. They may
reduce yield and quality of the apple crop and interfere with operations
such as fertilization, spraying, harvesting, etc.
Chemical herbicides are used in apple orchards because they are often
less expensive and more effective than hand labor or mechanical means of
weed removal. The danger of damaging trees by using the wrong products,
or by over-application represents a built-in safeguard against misuse and
overuse. The herbicides are nearly always applied by ground equipment.
Spray drift is rarely, if ever, a problem.
Thus, the use of chemical herbicides in apple orchards does not ap-
pear to be wasteful. The quantities of herbicides used for this purpose
in 1971 according to the USDA (1974b), 197,000 Ib, are relatively small,
representing only about 0.0970 of the total quantities of herbicides used
on agricultural crops in the United States in 1971.
USE OF MITICIDES, FUMIGANTS, AND PLANT GROWTH REGULATORS
Miticides, fumigants, and plant growth regulators are included in
a category called "miscellaneous pesticides" in the USDA pesticide use
surveys. The use of these products on apples totaled 1,037,000 Ib of
active ingredient in 1964, 1,119,000 Ib in 1966, and 548,000 Ib in 1971
(Table 31). As indicated in footnote 3 of Table 31, the 1964 total
consisted almost entirely of miticides, including dicofol (Kelthane®),
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tetradifon (Tedion®), Aramite, and others, unspecified organic miticides.
In 1966 and 1971, about two-thirds of all "miscellaneous pesticides"
used on apples consisted of miticides. Principal miticides used in 1966
were dicofol, tetradifon, and chlorobenzilate. In 1971, Oraite® was the
leading miticide,,
Miticides
The use of all miticides on apples declined from 1,031,000 Ib of
active ingredient in 1964 to 673,000 Ib in 1966, and further to 367,000
Ib in 1971, according to the USDA farm pesticide use surveys. This
decline is due primarily to the fact that mites developed resistance
to one chemical miticide after another, as indicated by the rapid turn-
over of products in this group. Integrated pest management programs
recently established on apples in several states emphasize biological
control of mites. It is anticipated that increased adoption of such
programs will result in further reductions in the use of miticides on
apples. For instance, in the IPM program in the Lower Yakima Valley in
the State of Washington, IPM program participants applied no miticides
in 1973, while nonparticipants sprayed 100% of their apple acreage
against mites. In 1974, only 28% of the IPM program acreage required
miticide treatments (Table 33).
In retrospect, it appears that the extensive use of miticides on
apples in the 1960*s was economically as well as ecologically inef-
ficient and wasteful. The failure of chemical miticides in major apple-
producing areas, especially the Pacific Northwest, prompted the develop-
ment and implementation of integrated pest management programs. As
the miticide use data indicate, these measures have resulted in very
substantial reductions in the total quantities of miticides used on
apples. Further decreases in the use of miticides on apples are likely
to occur with increased adoption of integrated pest management programs.
Fumigants
According to the USDA farm pesticide use surveys, fumigants were
used on apples to a significant extent only in 1966. In that year,
395,000 Ib of fumigants were included in the total quantity of "mis-
cellaneous pesticides" used on apples. The fumigant total consisted
of 269,000 Ib of sulfur dioxide and 126,000 Ib of other, unspecified
fumigants.
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Soil fumigation is often recommended in situations where a new
orchard is being planted in an old orchard site, for the control of
nematodes and other soil-borne pathogens. In such instances, fumi-
gants are applied directly to the soil in the area to be protected.
The use of fumigants is a relatively expensive practice, a built-in
deterrent to wasteful use. There are no indications that the rela-
tively small quantities of fumigants used on apples are wasteful or
inefficient. There are no effective nonchemical methods available to
growers for the destruction of soil-borne orchard pathogens that would
injure the roots of newly planted apple trees, reduce growth and, in
some cases, even kill young trees.
Plant Growth Regulators
Plant growth regulators have been developed and registered for
use on apples during the last few years, and as the USDA pesticide use
surveys indicate, the use of appreciable quantities of these sub-
stances on apples was registered for the first time in the 1971 use
statistics. Plant growth regulators are used on apples for several
different purposes, including chemical thinning, increase of branch
angles, bloom promotion, delay of water core, promotion of color, and
prevention of preharvest drop. Misuse or overuse of these substances
can produce substantial damage to the quality and/or quantity of the
apple crop, or even to the trees themselves. Thus, there is little
room for error in the use of plant growth regulators, and it is not
likely that they will be used wastefully by apple growers.
SUMMARY
There are no indications that significant quantities of fungicides,
herbicides, fumigants or plant growth regulators are used on apples in a
wasteful manner.
Most of the commercial fungicides currently available for use on
apples have to be applied on preventive, preprogrammed application sche-
dules for optimal biological and economic efficiency and effectiveness.
No effective nonchemical methods for the control of fungal diseases of
apples are currently available to growers, and no "integrated disease
management programs" for apples have been developed at the grower level.
Herbicides, fumigants, and plant growth regulators are used on
apples only in relatively small quantities, and in an efficient and
effective manner.
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The quantities of insecticides and miticides used on apples de-
clined substantially (about 55%) during the last 10 years. In many
apple-growing areas, unilateral reliance on chemicals for the control
of apple insects and mites resulted in failure, primarily in the form
of unmanageable mite problems. This spawned the development and neces-
sitated the adoption of integrated apple pest management methods.
There are indications that substantial further reductions (25 to 50%)
in the quantities of insecticides and miticides currently used on apples
are possible. Further improvement and large-scale implementation of
integrated pest management methods are among the prerequisites needed
to make such potential reductions in insecticide inputs a reality.
In relation to the quantities of insecticides (4,831,000 Ib) and
miticides (367,000 Ib) used on apples in 1971 according to the USDA
pesticide survey (Tables 28 and 30), savings of the order of 20 to 30%
would amount to 1.0 to 1.6 million pounds of insecticide and miticide
active ingredients.
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Soil fumigation is often recommended in situations where a new
orchard is being planted in an old orchard site, for the control of
nematodes and other soil-borne pathogens. In such instances, fumi-
gants are applied directly to the soil in the area to be protected.
The use of fumigants is a relatively expensive practice, a built-in
deterrent to wasteful use. There are no indications that the rela-
tively small quantities of fumigants used on apples are wasteful or
inefficient. There are no effective nonchemical methods available to
growers for the destruction of soil-borne orchard pathogens that would
injure the roots of newly planted apple trees, reduce growth and, in
some cases, even kill young trees.
Plant Growth Regulators
Plant growth regulators have been developed and registered for
use on apples during the last few years, and as the USDA pesticide use
surveys indicate, the use of appreciable quantities of these sub-
stances on apples was registered for the first time in the 1971 use
statistics. Plant growth regulators are used on apples for several
different purposes, including chemical thinning, increase of branch
angles, bloom promotion, delay of water core, promotion of color, and
prevention of preharvest drop. Misuse or overuse of these substances
can produce substantial damage to the quality and/or quantity of the
apple crop, or even to the trees themselves. Thus, there is little
room for error in the use of plant growth regulators, and it is not
likely that they will be used wastefully by apple growers.
SUMMARY
\
There are no indications that significant quantities of fungicides,
herbicides, fumigants or plant growth regulators are used on apples in a
wasteful manner.
Most of the commercial fungicides currently available for use on
apples have to be applied on preventive, preprogrammed application sche-
dules for optimal biological and economic efficiency and effectiveness.
No effective nonchemical methods for the control of fungal diseases of
apples are currently available to growers, and no "integrated disease
management programs" for apples have been developed at the grower level.
Herbicides, fumigants, and plant growth regulators are used on
apples only in relatively small quantities, and in an efficient and
effective manner.
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The quantities of insecticides and miticides used on apples de-
clined substantially (about 55%) during the last 10 years. In many
apple-growing areas, unilateral reliance on chemicals for the control
of apple insects and mites resulted in failure, primarily in the form
of unmanageable mite problems. This spawned the development and neces-
sitated the adoption of integrated apple pest management methods.
There are indications that substantial further reductions (25 to 50%)
in the quantities of insecticides and miticides currently used on apples
are possible. Further improvement and large-scale implementation of
integrated pest management methods are among the prerequisites needed
to make such potential reductions in insecticide inputs a reality.
In relation to the quantities of insecticides (4,831,000 Ib) and
miticides (367,000 Ib) used on apples in 1971 according to the USDA
pesticide survey (Tables 28 and 30), savings of the order of 20 to 30%
would amount to 1.0 to 1.6 million pounds of insecticide and miticide
active ingredients.
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REFERENCES TO SECTION VII
Arneson, P. A», G. H. Oberly, and J. L. Brann, Jr., "1974 Tree-Fruit
Production Recommendations," New York State College of Agriculture
and Life Sciences, 47 pp. (1974).
Asquith, D., "The Economics of Integrated Pest Management," Pennsylvania
Fruit News. 5U5): 27-31 (1972).
Brann, J. L., Jr., Personal Communication (1974)„
Chemagro Corporation, "1971 Product Guide" (1970).
Eves, J. D., Personal Communication (1974).
Eves, J. D., and J. D. Chandler, "The Management of a $28 Apple Pest
Control Program in the Yakima Valley," Washington State Horticul-
tural Association Proc., 69:100-103 (1973).
Jones, A. L., D. Ramsdell, W. W. Thompson, A. J. Howitt, and J. Hull,
"1974 Fruit Spraying Calendar," Extension Bulletin 154, Farm Science
Series, Cooperative Extension Service, Michigan State University
(1974).
Pennsylvania State University, "1974 Tree Fruit Production Recommenda-
tions for Pennsylvania," Cooperative Extension Service, University
Park, Pennsylvania, 96 pp. (1974).
Thompson, W« W. , C. F. Stephens, L. Olsen, and J. F. Cole, "Michigan
Apple Pest Management Annual Report: 1972," Cooperative Extension
Service, Michigan State University, 48 pp. (1972).
Thompson, W» W0, C= F. Stephens, L. Go Olsen, J. E. Nugent, and T. B.
Sutton, "Michigan Apple Pest Management Annual Report: 1973,"
Cooperative Extension Service, Michigan State University, 57 pp.
(1973).
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U.S. Bureau of the Census, "Census of Agriculture, 1969," Vol. V,
Special Reports, Part 15, Graphic Summary, U.S. Government Printing
Office, Washington, D.C. (1973).
U.S. Department of Agriculture, "Quantities of Pesticides Used by
Farmers in 1964," Agricultural Economic Report No. 131, Economic
Research Service, Washington, D.C. (1968).
U.S. Department of Agriculture, "Quantities of Pesticides Used by
Farmers in 1966," Agricultural Economic Report No. 179, Economic
Research Service, Washington, D.C. (1970).
U.S. Department of Agriculture, "Agricultural Statistics 1973," U.S.
Government Printing Office, Washington, D.C. (1973).
U.S. Department of Agriculture, "Fruit Situation," TFS-192, Economic
Research Service (1974a).
U.S. Department of Agriculture, "Farmers' Use of Pesticides in 1971 . .
Quantities," Agricultural Economic Report No. 252, Economic Research
Service, Washington, D.C. (1974b).
U.S. Environmental Protection Agency, "EPA Compendium of Registered
Pesticides. Vol. Ill: Insecticides, Acaricides, Molluscicides, and
Antifouling Compounds," Pesticides Regulation Division, Office of
Pesticide Programs, U.S. Government Printing Office (1972 and supple-
ments issued subsequently).
Washington State University, "1974 Spray Guide for Tree Fruits in
Eastern Washington," Extension Bulletin 419, Cooperative Extension
Service, Pullman, Washington (1974).
105
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SECTION VIII
WASTES AND LOSSES OCCURRING DURING AND AFTER PESTICIDE APPLICATION
This section presents a summary of the topics discussed in Volume II
of this report. Volume II is a detailed discussion of the wastes and losses
of pesticides that occur both during and after pesticide application which
were examined in this study. The summary given here is divided into the fol-
lowing sections:
* Study Approach;
* Study Areas; and
* Summary of Discussions in Volume II.
Each of these sections are presented below.
STUDY APPROACH
The approach taken in this aspect of the study differed from that used
in the studies reported in Sections V, VI, and VII of this volume. Identifi-
cation of factors that cause pesticide waste and loss both during and after
crop treatment was not limited to the three study crops but was made for
agriculture in general since many of the techniques used to treat corn,
sorghum, and apples are used throughout the agricultural community. Each
subject was discussed with reference to agriculture in general when exami-
ning the problem areas that cause inefficient pesticide use.
In line with the objective to quantify pesticide waste and losses in
as much detail as possible, quantitative aspects of each subject examined
were given prime attention throughout this phase of the study. When deter-
mining the quantities of pesticides lost or wasted, only the three study
crops were considered and all quantities were determined for each crop for
the year 1971, the latest year meaningful pesticide use statistics are
available.
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The information needed for this phase of the study was obtained from
a thorough search of the literature, questionnaires, personal, and tele-
phone interviews with persons knowledgeable on the subject matter, and cor-
respondence with agricultural engineers and pesticide equipment manufacturers.
STUDY AREAS
A survey of pesticide wastes and losses caused primarily by physical
factors, indicated that substantial losses could occur both during appli-
cation and postapplication. At the time pesticides are applied, three mech-
anisms cause the greatest loss and waste of pesticides; they are: (a)
nonuniform pesticide distribution on the crop; (b) overapplication of pes-
ticides; and (c) pesticide drift away from the crop area. After application
takes place one of the major pesticide loss mechanisms is transport of the
pesticides from the crop by surface runoff and soil erosion. These areas were
examined in detail in this study and the discussion of each area is given in
Volume II of this report. For the sake of completeness, the wastes and losses
of pesticides caused by the miscellaneous discharges of spills and disposal
are also described briefly.
The major study areas of this aspect of the study, then, were:
1. Pesticide Wastes and Losses Occurring During Application.
* Nonuniform Distribution;
* Overapplication; and
* Drift.
2. Pesticide Losses After Application and by Miscellaneous Discharge.
* Runoff and Soil Erosionj
* Spills; and
* Disposal.
A summary of the discussions of each of these areas are presented in the
next section.
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SUMMARY OF DISCUSSIONS AND FINDINGS IN VOLUME II
The topics of discussion and findings on pesticide wastes and Losses
during and after application are summarized below. The material covered
in Volume II of the study deals with agriculture in general and is not
limited to corn, sorghum, and apples (except when quantities of pesticides
lost or wasted are determined). Many of the findings may apply to other
crops to which pesticides are applied in a similar manner.
Each topic discussed in Sections III and IV of Volume II is summarized
below and the major findings are given.
Pesticide Wastes and Losses Occurring During Application
The waste of pesticides at the time of application is a result of two
major mechanisms: overapplication and nonuniform distribution. Loss of
pesticides at the time of application are primarily a result of pesticide
drift away from the target area. Both the waste and loss potential of pes-
ticides during application through these mechanisms were examined in this
study.
Waste Potential During Application - Waste during application may result
from overapplication or nonuniform distribution of pesticides during crop
treatment. Overapplication ,is defined as physically applying pesticides
at a rate higher than that intended. Nonuniform distribution means dis-
tributing the pesticide unevenly so that some areas of the field receive
heavy dosages of pesticide while other areas receive light dosages.
Both overapplication and nonuniform distribution are caused by
faulty equipment characteristics and/or erroneous equipment operation.
Some of the physical elements of pesticide application equipment that
affect the application rate and the uniformity of chemical disbursement
are the metering devices, nozzles, and spray tank agitation systems.
Some of the more common errors made in operating the application equip-
ment are improper calibration, uneven driving speeds, improper sprayboom
height, and choice of unsuitable pesticide formulations. The unique prob-
lems of nonuniform aircraft spray disbursement patterns involve both
technical and operational aspects.
Overapplication results from:
*• Faulty metering devices.
* Nozzle wear with wettable power sprays.
* Improper equipment calibration.
108
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* Driving too slow when turning around, encountering obstacles,
or driving up a slope.
* Pesticide formulations mixed in a higher concentration than
intended.
Nonuniform distribution results from:
* Faulty metering devices.
* Clogged nozzles.
* Improper spray atomization.
* Inadequate tank agitation systems when spraying emulsions or
wettable powders.
* Uneven driving speeds.
* Improper spray boom height, either too low or too high.
* Poor aircraft spray patterns.
The variables which cause these two problems defy quantification
in the strict sense. However, these problems are important enough to
warrant concern. Overapplication and nonuniform distribution are both
current and future problems that must be dealt with if the efficiency
of pesticide applications in agriculture is to be enhanced.
Loss Potential During Application - Pesticides are lost into the en-
vironment at the time of application when they drift away from the
crop being treated and impact away from the target area. Under certain
circumstances, these losses are substantial and may pose both an im-
mediate and long-term hazard to the surrounding environment. Drift is
neither accidental nor entirely uncontrollable, and its occurrence
reduces the efficiency of agricultural pesticide applications.
Drift is a rather complex physical event which is influenced by
a variety of interrelated factors. The potential for the occurrence
of spray or solid particle drift depends primarily upon meteorological
conditions, properties of the particle itself, and operational appli-
cation techniques. Important factors affecting drift are wind speed
and turbulence; particle size and density; evaporation rate of the
liquid; spray nozzles and discharge pressures; distance between appli-
cation equipment and target; and volumes of pesticide formulations
applied.
109
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This study took all of these factors into account and estimated
the likelihood of drift for various types of equipment and application
techniques commonly used in agriculture, paying particular attention
to field crops and orchards. The estimations developed in this study
are given in Table 36. The biggest drift hazards occur as a result of
using dusts and aerial spraying.
In addition to examining drift losses in agricultural chemical
crop-treating operations in general, the estimates developed in the
study were applied to the three study crops. Between some hard facts
and some assumptions in cases where information was unavailable, the
losses due to pesticide drift during application were estimated for
the applications made to the U.S. corn, sorghum, and apple crops in
1971, the most recent year for which pesticide use statistics on these
crops are available. The estimates for pesticide drift loss are in-
cluded in Table 37, both as percentages and as quantities of active
ingredient used that year.
Herbicide losses were low on a percentage basis, but the quanti-
ties lost were the largest for the four groups of pesticides. Insecti-
cide losses were the highest in the apple orchards primarily due to the
use of dusts and orchard airblasters. Sorghum losses were greater than
those of corn since most insecticides used on sorghum are applied by
air, whereas corn insecticides are applied to the soil, mostly preemer-
gence. Fungicides and other pesticides are not used on corn and sorghum
to any significant extent, while fungicides are used extensively on ap-
ples. Again, drift losses were high in the apple orchards for fungicides
since some are applied as dusts, and about half as sprays from airblasters.
Pesticide Losses After Application and by Miscellaneous Discharge
Pesticide losses that occur after application that were examined in
this study are the result of pesticide transport away from the crop by
the natural forces of runoff and soil erosion. Losses which occur through
miscellaneous discharges are the result of spills and disposal techniques.
Each of these pesticide loss routes are discussed below.
Loss Potential After Application - Pesticide quantities deposited in the
target area may impact on the target crop, on the ground, or on other
nontarget surfaces in the target area. A portion of the deposit on the
crop may be washed off and impact on the ground secondarily at various
times after application.
110
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Table 36. LIKELIHOOD OF PESTICIDE DRIFT DURING CROP TREATMENT IN AGRICULTURE
BY METHOD OF APPLICATION
Formulation Equipment type
Oust Aircraft, venturi
Airblaster
Spray Tractor, boom
sprayer
Tractor, boomless
sprayer
Spray gun
Orchard airblaster
Aircraft, boom
sprayer
Granular Aircraft, venturi
Spreader, centri-
fugal
Spreader, boom
Planter
Pesticide
application method3.'
Air, foliar
Ground, foliar
Ground, foliar
Ground, foliar
Ground, broadcast
Ground, broadcast
Ground, band
Ground , band
Ground, broadcast
Ground, broadcast
Ground, foliar
Ground, foliar
Ground, foliar
Air, foliar
Air, foliar
Air, foliar
Air, foliar
Air, broadcast
Air, broadcast
Ground, broadcast
Ground, broadcast
Ground, band
Ground, band
Target
Trees
Trees
Plants
Plants
Soil
Soil
Soil
Soil
Soil
Soil
Trees
Trees
Trees
Trees
Trees
Plants
Plants
Soil
Soil
Soil
Soil
Soil
Soil
Spray
application volumeJi/
—
-
ULV
LV
LV
HV
ULV
LV
LV
HV
HV
ULV
LV
ULV
LV
ULV
LV
LV
_
-
-
-
"
Estimated percent
drift over 1,000 ft
from targetS.'
70-90
60-80
5-10
1
Negligible
Negligible
Negligible
Negligible
Negligible
Negligible
3-5
40-70
10-40
40-60
10-40
40-60
10-40
10-40
1-2
1
1
Negligible
Negligible
&l Air refers to pesticide application by aircraft, ground refers to pesticide application by ground rigs.
bl HV = High Volume; LV = Low Volume; ULV = Ultra-Low Volume.
£/ Assumes a 3 to 5 mph wind; neutral atmospheric stability (S.R. = 0), air temperatures above 60°F; and
a relative humidity of 50% or less.
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Table 37. ESTIMATED LOSSES DURING AND AFTER APPLICATION OF
PESTICIDES TO CORN, SORGHUM AND APPLES (1971)
Pesticide and
loss route
Herbicides
Drift
Runoff
Total
Insecticides
Drift
Runoff
Total
Fungicides
Drift
Runoff
Total
Other pesticides
Drift
Runoff
Total
Corn
% loss^7 Lb lost (000)
0.8-3.0 800-3,000
0.5-3.2 500-3,200
1.3-6.2 1,300-6,200
0.2-0.7 50- 180
0.3-1.3 80- 330
0.5-2.0 130- 510
Negligible
Negligible
Negligible
Negligible
Negligible
Negligible
Sorghum
% loss8-7 Lb lost (000)
1.0-3.9 120-450
0.6-3.4 70-390
1.6-7.3 190-840
6-25 360-1,400
Negligible
6-25 360-1,400
Negligible
Negligible
Negligible
Negligible
Negligible
Negligible
Apples
7. loss-' Lb lost (000)
Negligible
Negligible
Negligible
21-42 1,000-2,000
Negligible
21-42 1,000-2,000
21-42 1,500-3,000
Negligible
21-42 1,500-3,000
Negligible
Negligible
Negligible
a/ Percent loss refers to the percentage of the amount applied.
-------
The principal mechanisms of pesticide transport away from treated
fields after application are: (a) surface runoff including both sedi-
ment and water; (b) volatilization; and (c) leaching to groundwater.
The magnitude of the losses varies with each pesticide and environmental
conditions. Generally, surface runoff and volatilization are the domi-
nant mechanisms for pesticide loss from cropland. Degradation by chemi-
cal, physical, or biological processes is not a transport or "avoidable
loss" mechanism within the definitions established for this study and
was therefore not included in its scope. Volatilization is a process
which is beyond the control of the farmer once the pesticide has been
properly applied (and soil incorporated, if required). Since this study
deals with avoidable losses of pesticides, only surface runoff was
studied in detail.
The primary objective in examining the incidence of runoff was to
quantify the pesticide losses involved. After defining the variables
that affect the amount of runoff that occurs with rainfall and soil
management practices in agriculture, two methods were used to try to
estimate the quantities of pesticides lost in runoff from the study
crops. The first method involved estimating the amount of runoff oc-
curring on the crops and the concentrations of pesticides involved.
The second method consisted of estimating the total pesticide loss
as a percentage of the amount applied and relating this to the amounts
applied to the study crops in 1971.
The first method proved unsatisfactory. Statistics were developed
for runoff losses only since soil losses cannot be reasonably estimated
for a large crop due to the complexity of the many variables involved.
Both annual runoff maps and rainfall maps were used to estimate the run-
off from the corn and sorghum crops (apples were not included since soil-
applied pesticides are used in small quantities in orchards). Concentra-
tions of herbicides and insecticides in runoff water were determined from
field studies reported in the literature. However, quantification of the
pesticide losses on the two crops was not undertaken by this method since
the variables involved required too many assumptions. There is no current
method of accurately determining the amount of runoff from crops, and the
work done in this study helps to show why.
The second method was used to quantify the herbicide losses from the
corn and sorghum crops in 1971 and the quantities determined are shown in
Table 37. The percentages of pesticides lost as a percent of the amount
applied were determined from field studies reported in the literature.
These percentages were then used with the amount of herbicides actually
applied to corn and sorghum in 1971 to determine the loss.
113
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Table 37 shows that herbicide losses from corn and sorghum crops
amounted to 3% or less of the amount actually applied to the soil. However,
this amounts to as much as 3 million pounds of active ingredient, a sub-
stantial quantity.
Miscellaneous Pesticide Discharges - Pesticide losses due to spills and im-
proper disposal were not evaluated in detail in this study. Losses from
these two mechanisms reduce the overall efficiency of agricultural pesticide
use. However, spills are primarily accidents and disposal techniques are
within the control of man. Pesticide accidents as well as losses due to
improper disposal of pesticides or containers can be reduced or avoided by
improved operator training, performance and supervision.
114
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APPENDIX
CRITERION SCHEME FOR THE SELECTION OF SURVEY CROPS
115
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Many of the parameters to be studied in this project cannot be studied
theoretically or in a vacuum, but as they apply to specific crop/pest/pesticide
systems. Thus, it is important to select crops suitable as "study systems."
A criterion scheme was developed, in accordance with the provisions of
the project work statement (Article I), for this selection. Criteria con-
sidered important and evaluated below include the following:
.* Volume of use of pesticides on the crop;
* Existence of integrated pest management programs on the crop;
* Crop acreage; and
* Crop farm value.
The question of whether or not integrated pest management programs are
in progress on candidate crops is important because these programs will pro-
vide information on minimum levels of pesticide use (dosage rate per applica-
tion, frequency of applications) needed for economic pest control, as opposed
to labeled or recommended rates. This type of information is essential to
Task 5, The Study of Pesticide Wastes Caused by Management Factors, and is
generally not available for crop/pest/pesticide systems that have not yet
been studied from the standpoint of integrated pest management.
The volume of use of pesticides by crops and by pesticide category in
1971 has been summarized in Table A-l. This three-part table covers uses of
herbicides, insecticides and fungicides, respectively, on those individual
crops that account for about 80% of the total use. In each category, crops
were ranked in decreasing order of volume of pesticide used, highest volume
equals one.
In Table A-2, the number of USDA integrated pest management programs in
1972 and 1973 have been summarized for all crops included in Table A-l. The
crops were then ranked in decreasing order of number of IPM programs, largest
number of programs equals one.
In Table A-3, the U.S. acreage and farm value of these crops in 1972
(the latest year for which USDA statistics are available) are listed and
ranked, largest acreage and largest farm value equals one.
In Table A-4, all rankings from Tables A-l through A-3 are summarized,
totaled, and averaged.
116
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Table A-l. USE OF PESTICIDES ON SELECTED CROPS BY PESTICIDE CATEGORY, 1971
Herbicides
Crop
Corn
Soybeans
Cotton
Wheat
Sorghum
Vegetables
Peanuts
Subtotals
All other
crops
All crops
MM Ib
AI
101
37
20
12
12
6
4
192
34
226
% of
total
45
16
9
5
5
2
2
84
16
100
Insecticides
MM Ib
Rank Crop AI
1 Cotton 73
2 Corn 26
3 Vegetables 11
4 Soybeans 6
5 Apples 5
6 Tobacco 4
7 Citrus 3
128
26
154
% of
total Rank
47 1
17 2
7 3
4 4
3 5
3 6
2 7
83
17
100
Fungicides
MM Ib % of
Crop AI total Rank
Vegetables 10 24 1
Citrus 9 24 2
Apples 7 18 3
Peanuts 4 11 4
30 77
10 23
40 100
Source: Andrilenas, P., "Farmers' Use of Pesticides in 1971--Quantities," Agricultural Economic Report
No. 252, Economic Research Service, U.S. Dept.,of Agriculture (1974).
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Table A-2. USDA IPM PROGRAMS BY CROPS, 1972 AND 1973
Crop
Cotton
Corn
Vegetables
Apples
Sorghum
Peanuts
Citrus
Tobacco
Wheat
Soybeans
Number of programs
1972 1973
14 14
6
4 4
2 4
4
2
1
1 1
-
-
Rank
1
2
3
4
5
6
8
7
10
10
Sources: Good, J. M., "1972 Benefit Summaries of Pest Management
Projects," Extension Service, U.S. Department of Agri-
culture, unpublished report (1974).
Good, J. M., "1973 Summaries," U.S. Department of Agriculture
and Cooperative Extension Service Pilot Pest Management
Projects, Extension Service, U.S. Dept. of Agriculture,
unpublished report (1974).
118
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Table A-3. U.S. ACREAGE AND FARM VALUE OF SELECTED CROPS, 1972
Crop
Cotton
Corn*/
Soybeans-
Wheat
Sorghum-
Peanuts
Vegetables
Apples
Citrus
Tobacco
Acreage—
1,000
acres Rank
13,517
57,289
47,755
47,301
13,546
1,486
3,210
N.A. N.
N.A. N.
843
5
1
2
3
4
7
6
A.
A.
8
Farm value
1,000
dollars
2,014,230s!/
7,017,381
4,451,797
2,575,089
1,041,326
477,524
2,023,498
371,455
828,021
1,442,801
Rank
5
1
2
3
7
9
4
10
8
6
a/ Acreage harvested.
b/ For grain.
£/ For beans.
d_/ Including lint and seed.
Source: U.S. Department of Agriculture, "Agricultural Statistics 1973,"
U.S. Government Printing Office, Washington, D.C. (1973).
119
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Table A-4. RANKING SUMMARY BY CROPS
Overall rank
Table
Crop
Cotton
Corn
Soybeans
Wheat
Sorghum
Peanuts
Vegetables
Apples
Citrus
Tobacco
A
3
1
2
4
5
7
6
10
10
10
B
1
2
4
10
10
10
3
5
7
6
C
5
5
5
5
5
4
1
3
2
5
D
1
2
10
10
5
6
3
4
8
7
E
5
1
2
3
4
7
6
N.A.
N.A.
8
F
5
i
2
3
7
9
4
10
8
6
Total,
averaged
3.3
2.0
4.2
5.8
6.0
7.2
3.8
7.0
7.0
7.0
A-F
2
1
4
5
6
10
3
8
8
8
A, B, and
D only
1.5
1.5
4
9
6
7.5
3
5
10
7.5
Source: Tables A1-A3.
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The averaged totals were then again rated by "overall rank." In the
last column in Table A-4, the results of ranking only three criteria, i.e.,
volume of herbicide use, volume of insecticide use, and number of IPM pro-
grams, are given. The rationale for this column is as follows:
* Fungicides represent only a small share of the total volume of
pesticides used on U.S. crops. Therefore, their importance would
be overrated if they would be weighted in this ranking system
equally with herbicides and insecticides which are used in much
larger volume.
* Total acreage and farm value of a given crop are of lesser im-
portance to the objectives of this study than the other parameters.
Regardless of whether one considers the overall ranks from Tables A-l
to A-3 or from Table A-l, Columns 1 and 2, and Table A-2, the system sug-
gests that the following crops should be considered as candidate study
systems: corn, cotton, vegetable, soybeans, sorghum, and apples.
These tentative choices were discussed with the EPA project officer,
Mr. Allan Zipkin, at a project meeting at Kansas City on 13 August 1974.
Mr. Zipkin advised that EPA realizes the importance of cotton as a pesticide-
consuming crop. However, a considerable number of studies have already been
performed on cotton, and EPA would be more interested in gathering data on
other crops. For these reasons, confirmed in a subsequent telephone conver-
sation between Mr. Zipkin and Dr. von Rumker, cotton was eliminated from
further consideration.
Soybeans rated somewhat higher than sorghum in the criterion scheme.
Nevertheless, it was decided to give preference to sorghum as a study crop
because a preliminary survey of available data indicates that some interesting
studies on recommended versus needed rates of insecticides have recently been
performed on this crop.
The criterion scheme further indicates that vegetables should receive
consideration. However, the high ranking of vegetables in comparison to the
other crops is somewhat misleading because, in contrast to all other crops
in the ranking system, vegetables are not a single crop, but a group con-
sisting of some 20 major and additional minor crops. To determine if a single
vegetable crop might be a suitable study crop, the 1972 acreage and farm
value of the 25 vegetable crops considered to be "commercial vegetables"
by the U.S. Department of Agriculture were analyzed (Table A-5). In each
part of the table, the first 10 crops were ranked in decreasing order of
acreage and farm value, respectively, highest acreage and highest farm
value equals one.
121
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Table A-5. U.S. ACREAGE AND FARM VALUE OF COMMERCIAL VEGETABLE CROPS, 1972
Acreage
Artichokes
Asparagus
Beans, lima
Beans, snap
Beets
Broccoli
Brussels sprouts
Cabbage
Cantaloupes
Carrots
Cauliflower
Celery
Corn, sweet
Cucumbers
Eggplant
Escarole
Garlic"
Honeydew melons
Lettuce
Onions
Peas, green
Peppers, green
Spinach
Tomatoes
Watermelons
Totals
1,000
acres
11.1
119.1
74.6
341.9
12.7
46.8
6.6
105.6
97.6
73.4
28.2
32.6
604.9
178.0
3.1
9.9
5.1
12.
219.
93,
377.
47.
37.8
403.6
267.5
3,210.3
.4
.1
.3
.7
.7
Rank
8
4
9
10
1
7
6
3
2
5
Farm value
1,000
dollars
8,222
67,921
18,837
107,484
3,741
39,099
7,916
79,978
94,772
95,649
30,346
104,891
134,815
90,769
4,568
9,167
7,206
13,082
277,320
139,919
57,500
58,096
16,532
492,440
63,228
Rank
5
10
8
7
6
4
9
2
3
1
2,023,498
Source: U.S. Department of Agriculture, "Agricultural Statistics 1973,"
U.S. Government Printing Office, Washington, D.C."(1973).
122
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Considering acreage (probably more important regarding pesticide use
volume than farm value of the crop), candidate vegetable crops and their
usefulness for purposes of this study are as follows:
Sweet corn leads all other vegetable crops in acreage. However, since
field corn in already included in the study, we question the desirability
of studying sweet corn in addition.
Tomatoes are next. However, EPA has recently funded another study on
tomatoes which will probably cover at least some of the parameters to be
investigated in this project. We therefore recommend against tomatoes.
Peas, beans, next in line, as well as watermelons, cucumbers, asparagus
and cantaloupes are relatively healthy crops which do not generally require
high pesticide inputs. Recommend against their selection for this study.
Lettuce and cabbage appear to us to be the relatively most suitable
candidate study crops. These crops would then have to be compared against
apples, the next candidate crop in line from Table A-4. Among apples, let-
tuce, or cabbage, we feel compelled to give preference to apples, for the
following reasons:
* Apples are an economically more important crop than either lettuce
or cabbage in terms of farm value.
* More pesticides are used on apples than on either lettuce or cabbage.
The lettuce acreage is 6.8%, the cabbage acreage 3.3% of the total
acreage of all commercial vegetables. Assuming an average rate of
use of pesticides on all vegetables, about 1 million pounds of in-
secticides would be used on lettuce and cabbage combined. Even if
a relatively higher rate of insecticide use on these two crops is
assumed, their combined insecticide use volume would still not ap-
proach that of apples, 5 million pounds (Table A-l, Column 2).
* Lettuce and cabbage, like corn and sorghum, are annual row crops.
By contrast, apples are a perennial tree crop. Thus, including
apples would add an additional dimension to the study, which would
not be provided by lettuce or cabbage. Pesticide application methods
and equipment for tree crops are different from those for field and
row crops.
123
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In summary, based on the criterion scheme and related considerations
discussed above, and on our several communications on this matter with the
EPA project officer, we propose to select the following three crops as
"study systems" for this project:
* Corn;
* Sorghum; and
* Apples.
This selection is, of course, not meant to be absolutely exclusive.
As project time and resources permit, we may well study and report on
relevant problems pertaining to other crops, especially vegetable crops,
in line with EPA's expressed interest in more information on food crops.
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