ALTERNATIVES TO NEONICOTINOIDINSECTICIDE-COATED CORN SEED:AGROECOLOGICAL METHODS ARE BETTER FOR
FARMERS AND THE ENVIRONMENT

MAY 2017

ABOUT CENTER FOR FOOD SAFETYCENTER FOR FOOD SAFEY (CFS) is a non-profit public interest andenvironmental advocacy membership organization established in 1997
for the purpose of challenging harmful food production technologies
andpromotingsustainableagriculture.

CFS

combines

multipletools and strategies in pursuing its goals, including litigation andlegal petitions for rulemaking, legal support for various sustainableagriculture and food safety constituencies, as well as public education,
grassroots organizing, and media outreach.

AUTHOR: DOUG GURIAN-SHERMAN, Ph.D.

ACKNOWLEDGEMENTS
The author thanks Angelika Hillbeck, Professor, Swiss Federal Institute ofTechnology, and John Tooker, Professor of Entomology, Pennsylvania State
University, for their helpful reviews and suggested edits. Their reviews greatly improved the report. At Center for Food Safety, the report was reviewed
and improved by Peter Jenkins and Larissa Walker, and the copyediting of
Courtney Sexton. The author also thanks Patrick Riggs for his design andproduction of the report, and Andrew Kimbrell for his support. The report
also benefited from helpful discussions with Marcia Ishii-Eiteman at Pesticide
Action Network and Michael Gray at the University of Illinois. However, in theend, the author remains solely responsible for any shortcomings in this report.

To access this report as a PDF,
visit Center for Food Safety online at:www.centerforfoodsafety.org/reports

2 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

CONTENTS
EXECUTIVE SUMMARY

4CHAPTER 1 - Introduction

11

CHAPTER 2 - The Value of Neonic Seed Coatings for Insect Pest Control

14

A.

Background – Insect Pests of Corn Targeted by Seed Treatments and theArguments in Favor of Seed Coatings

14

B.

Beyond Seed Coatings: Agroecological and Integrated Pest Management(IPM) Alternatives

16

C.

The Rise of Neonic Seed Coatings – Why Now?

18

1.

Agronomic Reasons do not Explain the High use of Seed Coatings

18

2.

Concentration in the Seed Market and other Economic Factors

21

CHAPTER 3 - Harm Caused by Early-Season Insect Pests of Corn, the Efficacy of Neonic
Seed Coatings, and Safer Alternatives

24

A.

Peer-reviewed Research and Report Methodology

25

B.

General Performance of Corn Neonic Seed Coatings

26

1.

Aginfomatics Report, and General Lessons about the Infrequency ofHarmful Levels of Early-Season Secondary Insect Pests of Corn

29

2.

Summary and Conclusions from Studies on General Protection Against
Early-Season Pests by Neonic Seed Coatings

34

C.

Early-Season Insect Pests Targeted by Neonic Seed Coatings

35

1.

Subterranean Pests

36

2.

Above-Ground Pests

44

3.

Corn Rootworm

47

CHAPTER 4 - If Neonic Seed Coatings of Corn Are Eliminated, Will Other Insecticides
Replace Them?

52

CHAPTER 5 - Potential for Reduction of Crop Yield Due to Neonicotinoid Seed Coatings

54

CHAPTER 6 - Agroecology, and Correcting the Myopic Focus on Specific Pests

56

CHAPTER 7 - Some Social Implications of Seed Coatings

59

CHAPTER 8 - Summary, Conclusions and Recommendations

62

A.

Agroecological, and other Alternatives to Neonic Seed Coatings

64

1.

Other Available Treatments

65

2.

Would Other Insecticides Simply Continue Harm to the Environment if
Neonic Seed Coatings were Discontinued?

65

3.

Why Are Neonic Seed Coatings of Corn So Widely Used?

66

RECOMMENDATIONS68

REFERENCES

71

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 3

EXECUTIVE SUMMARY

N

eonicotinoid (neonic) insecticides are heavily implicated in substantial environmental
harm to pollinators, aquatic organisms, birds and possibly people. Neonic coated corn
seed is the most extensive use of an insecticide on any crop in the United States, affecting
close to 90 million acres of farmland, along with the broader environment.
Yet harm from neonic coated corn seed is unnecessary. As this report shows, agroecological andother alternative farming methods that are not highly dependent on pesticides are available andresult in high productivity. These methods rely instead on knowledge of the ecology of corn pests
and the use of biological diversity to ensure productivity and resilience, while minimizing pollution.
This report is the first detailed analysis of the peer-reviewed research on the efficacy of neonic seedcoatings of corn that includes each of the most important early-season pests found in the U.S. Midwest and elsewhere. It is the first extensive analysis of non-insecticidal alternatives to neonics, which
are not usually considered in efficacy field trials. Understanding these alternatives is critically important if we are to limit or eliminate the use of prophylactic seed coatings of corn—to the benefit of
the environment—while at the same time supporting the vitality of farms. The report also analyzes
the reasons for the dramatic exponential increase in the use of neonic seed coatings since the mid2000s, in order to better understand the reasons for the nearly ubiquitous use of these insecticides
on corn.

4 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

This report shows that:
1. It is uncommon for neonic seed coatings to increase corn yield, even undercurrent farming practices. Some scientists explicitly recommend against theiruse as a “cheap form of crop insurance” for growers;

2. The early-season insect pests targeted by neonic seed coatings of corn occur
sporadically, and the published peer-reviewed evidence reveals that they
infrequently reduce corn productivity in the absence of insecticide use;

3. Industry sponsored analysis that relies heavily on non-peer-reviewed researchcontains several biases that overestimate the value of neonic seed coatings
for improving corn yield. It includes an undisclosed number of field trials
designed to encourage higher levels of pests, which exaggerates the benefit ofneonic seed coatings compared to typical commercial farms. It also includes
an unknown number of trials for the major corn pests, corn rootworms. These
pests can cause substantial yield losses if untreated, but there are more effective
and more reliable alternatives than seed coatings to control them.

4. There is no reliable evidence that problems from these pests have increased

substantially in recent years, contrary to some anecdotal claims. Experiments
conducted over the past 15 years have not indicated that these pests havebecome common problems;

5. This belies the almost ubiquitous prophylactic use of neonic seed coatings.

Research has shown that about 71 to near 100 percent of corn are coated withneonics, exposing a huge area of the country to these insecticides. And there isno evidence that the trend for treating the vast majority of corn seed will abate;

6. The conditions that may occasionally favor early-season corn pests can usually
be avoided by small changes in farming practices that reduce the occurrence ofearly-season pest infestations without resorting to insecticides.

7. Some research suggests that neonic seed coatings may sometimes actually

decrease yields or reduce profit. This may occur because neonics may reduce
the populations of organisms that normally help keep pest insects in check.
Farmers may be unaware of this possibility. This important issue should receive
additional attention.

8. For all of the reasons stated above, only a limited acreage of corn would betreated with alternative insecticides if neonic seed coatings were restricted. For
example, only about 30 percent of corn acres were treated with insecticides

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 5

prior to the commercial introduction and rapid adoption of neonic seedcoatings, and mainly for pests that are not the primary target of neonic seedcoatings. And if ecological means of avoiding or controlling these pests were
widely adopted, only a very small percentage of corn acres would rely on otherinsecticides.

9. Because it has been shown that those alternative insecticides are not moreenvironmentally harmful than neonics, net harm would be greatly reducedwith the elimination of prophylactic neonic corn seed coatings.

10. Any means of controlling pests can occasionally fail. The more beneficial social

response, if deemed necessary, should be crop insurance for farmers rather
than the use of harmful pesticides.

There is not a large amount of peer-reviewed research literature that analyzes the efficacy and yield
benefit of neonic corn seed coatings for controlling early-season corn insect pests in the field; andthere are even fewer data quantifying the prevalence and impact of these pests on corn yields. In
other words, the current justification for the prophylactic use of these insecticides is based primarily
on anecdote, or limited scattered research, not extensive published, peer-reviewed science. One
purpose of this report is to collect and analyze the available peer-reviewed research and make itavailable in one place, to present a more coherent and cogent understanding of these issues. The
result of this process shows that the early-season pests of corn are not often significant problems onfarms. Given the considerable research supporting the high likelihood of extensive environmental
harm caused by insecticidal seed coatings, and the effective alternatives that are available, there is nosocially or environmentally responsible justification for continuing their unrestricted use.

“As summarized in this report,
neonic seed coatings are aprominent example of thereliance on expensive andharmful insecticides for thecontrol of pests as a pale
substitute for free biologicalcontrol provided by advanced
farming systems based on thescience of agroecology.”

As summarized in this report, neonic seed coatings area prominent example of the reliance on expensive andharmful insecticides for the control of pests as a pale
substitute for free biological control provided by advanced
farming systems based on the science of agroecology. They
are a symptom of even more extensive environmental harmand lack of sustainability caused by industrial farming.

The industrial farming system is antiquated, emerging fromearlier industrial and green revolutions, and allows thetransnational companies that have near monopoly control
over pesticide and commodity seed sectors to acquire
excessive profits. The almost ubiquitous coating of corn seedwith neonics and other pesticides prior to purchase by farmers by these companies or seed dealers
greatly limits the ability of farmers to choose non-coated seed if they prefer it. This allows seed andpesticide companies to benefit from the sale of products, such as unneeded insecticides that prop up
the industrial model, at the expense of society broadly and at unnecessary cost to farmers.

6 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

Farmers may also see neonic seed coating as a cheap form of insurance to avoid perceived risks
or uncertainties from insect pests. Such uncertainties may arise from inadequate or inaccurate
information about these pests or viable alternatives to avoid or control them. Supplying that
information from reliable, trusted, and independent sources may alleviate those concerns. The
limited labor required of farmers to use coated seed, due to application of corn seed coatings byseed companies or dealers prior to purchase, may also contribute to farmer acceptance. Farmers
also face institutional challenges that discourage them from adopting farming methods that are
better for the environment and rural communities. For all these reasons they need support to end
their use of neonic coated corn seed.
This report evaluates some of the social constraints that may discourage policies that would restrict
the use of neonic-coated seed, despite their limited benefit to farmers. It also considers policychanges that would help farmers implement ecologically sound alternatives to neonic seed coatings.
Using agroecology approaches to grow our crops rather than industrial methods not only avoids
most of the harm of insecticides like neonic seed coatings, but has also been demonstrated toprovide profound benefits for water and air quality, reduction of climate change emissions, andincreased biodiversity and quality of rural environments and communities.
Some integrated pest management methods that avoid occasional early-season corn pests require
only minor changes from current corn production practices. These include monitoring for pests,
with insecticide use if needed, earlier weed control or cover crop termination, or minor delays inplanting dates. More extensive changes based on the science of agroecology, such as more diverse
crop rotations, would bring more dramatic benefits to both farmers and the environment.
Until we recognize the scientific and social irrationality of industrial farming and the harm it causes,
and understand that we have viable and sustainable alternatives, we will continue to address the

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 7

crises of industrial agriculture in a piecemeal way that encourages pesticide use and does not correct
the fundamental problems that underlie the current system.
The following recommendations would be important steps toward the elimination of prophylactic
neonicotinoid seed coatings and moving toward farming systems that are better for the environment,
farmers and their communities.

RECOMMENDATIONS
1. Restrict the use of neonic seed coatings of corn. The published research showsthat prophylactic use of neonic corn seed coating is unjustified for its mostimportant purpose of protecting yield. If not eliminated, use should be limited
to acres for which heavy infestations of early-season secondary pests occur andare not avoidable or controlled by available non-insecticide methods.

2. Conduct surveys of farmers by USDA/NASS or USDA/ERS or independent
university scientists to better understand why, and what percentage of farmers
believe they need neonic seed coatings of corn. The data from farmer surveys
would help better understand how such farmers can be assisted if prophylactic
neonic seed coatings are eliminated. Utilize farmer survey results to actively
develop outreach tools that help farmers avoid secondary pest insects, oruse alternative treatments to control early-season secondary insect pests.
This should be done through USDA, especially through public, independent
extension services working with farmers to alleviate concerns about restricting
the use of neonic corn seed coatings. It is critical that farmers are integrally

8 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

involved from early stages of this work—including decision making—to ensurethat the results are of practical value to them.

3. USDA/NRCS should include consideration of early-season secondary insect

pests and ecologically sound methods of reducing these pests as part ofits Conservation Stewardship Program and EQIP grants, especially those,
like longer crop rotations, that have multiple benefits. Such grants would beconsistent with the goals of the NRCS.

4. Implement, through USDA/RMA, insurance premium support for the rarecases where secondary pests cause substantial damage to corn yield, andsuch impacts were unavoidable by other viable approaches, as discussed inthis report. Other alternative methods for providing insurance could also
be considered. One reason that farmers seem to desire neonic seed coatings,
despite the infrequency of damage from the targeted insects, is as a form of“cheap insurance”.

5. Conduct additional publicly supported research to fill in holes in our knowledgeof early-season secondary insect pests of corn, and to refine agroecologicalalternative practices to avoid or control them. These should emphasize
system-level farming practices that reduce pest numbers in general, as well as
providing numerous other benefits to the environment, farmers and society.
Research should also be supported that improves scouting and other detection
and infestation prediction methods for early-season insect pests.

6. Seed companies should be required to make uncoated corn seed of desirable

corn varieties readily available. The Department of Commerce and theDepartment of Justice should investigate whether illegal monopoly practices
have made it excessively difficulty for farmers to acquire uncoated corn seed.
The elimination of farmer choice is contrary to principles of a democratic
economy.

7. EPA should release its analysis of the efficacy, benefits, and costs of neoniccorn seed coatings. It should fully weigh both quantifiable and unquantifiablevalues in assessments of proposed systemic insecticide products, including at aminimum these foreseeable cost categories:•

honey bee colony impacts and resulting reduced yields of pollinatedcrops,•

reduced production of honey and other bee products,

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

| 9

•

harm to other pollinators and other beneficial and non-target
organisms•

financial harm to beekeepers and consumers,•

loss of ecosystem services, and•market damage from contamination events.

EPA should also require verification by independent scientists and economists (preferably publishedin peer-reviewed journals) for claims of efficacy, crop yields, and economic benefits associated withall products. It should reject applications to register any prophylactic insecticides that undermine
basic IPM and agroecological principles, may harm organic farm production, or are not costeffective, either for the farmer or the nation as a whole.

10 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

CHAPTER 1

INTRODUCTION

A

ccording to recent data (Douglas and Tooker 2015, US EPA 2017)1,2, neonicotinoid
insecticides, mainly clothianidin and thiamethoxam, are applied to between about 71 andalmost 100 percent of corn seed in the United States. This means that this use exposes close
to 90 million acres of farmland, and also surrounding environments, to these insecticides. This is
the most extensive use of an insecticide on a crop in the United States by a wide margin.
Neonicotinoid use has been linked to widespread environmental harm, and therefore should be
replaced with ecologically-sound alternatives. These insecticides harm pollinators that are necessary
for full productivity of about 75% of crop species, especially nutritiously important fruits, vegetables
and nuts (Klein et al. 2007)3, and most wild plant species (Ashman et al. 2004)4. These pollinators(Godfray et al. 2015)5 include both honeybees (Krupke and Long 2015, Mogren and Lundgren 2016)6,7
and wild bees (Woodcock et al. 2016, Whitehorn et al. 2012)8,9. Neonic seed coatings have similarly
been shown to harm other important beneficial insects, called natural pest enemies (Douglas etal. 2014, Douglas and Tooker 2016, Leslie et al. 2010, Mullin et al. 2005, Seagraves and Lundgren2011)10,11,12,13,14 that usually keep destructive crop pests in check in healthy farm ecosystems (Douglas
et al. 2014, Douglas and Tooker 2016, Letourneau et al. 2011, Losey and Vaughan 2006)15,16,17,18.
Neonics have also been implicated in harm to aquatic invertebrates (Morrissey et al. 2015, Van Dijk
et al. 2013)19,20, that are critically important food sources for fish and for providing other ecosystem
functions, are linked to declines in farm-associated birds (Hallmann et al. 2014, Mineau and Palmer2013)21,22, and may harm people (Cimino et al. 2017)23. They have become the most widely used

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 11

insecticides in the world, and are found almost ubiquitously in our streams (Hladik and Kolpin
2015)24.
In addition to their high toxicity to insects and other organisms, neonicotinoid insecticides haveseveral properties that can make them particularly harmful. First, they persist for a substantial periodof time in the environment, with soil half lives of a year or more, depending on the particular neonicand environmental conditions (Krupke and Long 2015)25. Extended persistence of pesticides has
been recognized to be undesirable since the long persistence of many organochlorine insecticides
was found to contribute to environmental harm in the 1970s. Second, neonics are systemic: they
are taken up by and spread throughout the plant, making virtually all plant parts and exudates
potentially toxic. Most other widely used insecticides are not systemic. Third, they are highly
water soluble, and so they can leach from fields and be transported into streams and groundwater
easily. They are therefore found at harmful concentrations beyond agricultural fields (Krupke etal. 2012, Mogren and Lundgren 2016, Hladik and Kolpin 2015, Morrissey et al. 2015, Van Dijk et
al. 2013)26,27,28,29,30. And fourth, the high toxicity to insects and other invertebrates means that evenwhen spread out and diluted by transport through the plant or in the environment, they will often
remain at concentrations that can be lethal or harmful to beneficial organisms. This combination ofproperties makes neonic seed coatings particularly threatening to the environment.
For all of these reasons, it makes sense to greatly reduce the use of neonic seed coatings in the shortterm, with a long term goal of eliminating them. However, it is important to know how decreasingor eliminating them would affect corn farming. In particular, it is important to understand whether
and how often yield losses may result, and whether there are viable and safer farming practices that
could substitute for neonic seed coatings.
Determining whether prophylactic neonic seed coatings of corn are needed based on whether—and if so, how much—they protect corn, and comparing them to other means of protection is
the primary goal of this report. In particular, we need to consider not just substitution by otherinsecticides or toxins, which may also cause environmental and social harm (Douglas and Tooker,2016)31, but also viable farming methods that may reduce the need for insecticides generally, andneonic seed coatings specifically.
To determine the justification for prophylactic neonic seed coatings, this report analyzes at length
for the first time the peer-reviewed research on each of the most important early-season insect pests
that are targeted by neonic seed coatings of corn. In doing so, the agronomic and biological factorsthat favor or discourage these pests are considered.
Another important consideration of this report is whether neonic seed coatings may be justified
for reasons other than yield protection. One important possible reason for using them could be topreserve other desirable methods of insect control. In particular, the report considers whether theuse of neonic seed coatings might delay or prevent the development of resistance by corn rootworms

12 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICSto other means of controlling these important pests. Other important considerations for the useof neonics explored in this report are how they fit into current industrial farming systems, andwhether alternatives can be practical for most corn farmers.
Our analysis of the science research literature found that there is no good evidence that neonicseed coatings of corn provide needed yield protection on a consistent or even predictable basis.
Other alternatives, especially growing corn by using sound ecologically-based farming practices,can reliably provide consistently high productivity and profits (Davis et al. 2012, Lechenet et al.
2014)a,32,33. There are also simple farming practices that can be used to avoid harmful infestations ofthese pests. Systems-based, agroecologocal methods also have the potential to profoundly improvethe environment, including water quality and biodiversity, and improve soil fertility which benefits
farm productivity and resilience (Liebman and Schulte 2015)34. For these reasons, there is no sociallyacceptable justification for continuing the widespread use of prophylactic neonic seed coatings andthe environmental costs incurred from this use.
Finally, prophylactic neonic seed coatings are analyzed in the context of some of the social forcesthat strongly encourage current industrial corn farming practices that include neonic corn seedcoatings. Given the findings of the report that widespread prophylactic use of neonic seed coatingscannot be justified based on yield protection, other reasons for the extensive use of these insecticides
are considered. It is important to understand why prophylactic neonic seed coatings are so widelyused, if viable and ecologically robust alternatives that can work for farmers are to be implemented.
The most likely explanation is found to be monopolistic control of corn seed whereby companies
dictate seed coatings, rather than proactive choice by farmers. Several reasons why farmers may
accept this situation are also explored, such as risk or uncertainly aversion, and how this may bealternatively addressed.

Research on agroecological methods have not controlled specifically for neonic seed coatings,
based on research for this report. Their results have pertained to several different pesticides andother parameters, and therefore can be extrapolated to pesticide use generally. But studies comparing
agroecological systems to industrial farming that control specifically for neonic seed coatings areneeded.
a

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 13

CHAPTER 2

THE VALUE OF NEONIC SEED COATINGS FORINSECT PEST CONTROL
A. BACKGROUND: INSECT PESTS OF CORNTARGETED BY SEED TREATMENTS AND THE
ARGUMENTS IN FAVOR OF SEED COATINGS

I

nsects targeted by neonicotinoid seed coatings of corn are early-season pests that attack thecorn seed in the soil or the young plant, according to university extension publications (Grayand Steffey 2000)35 and pesticide product labels (Poncho 600 Label, 2010)36 which serve as thelegal basis for the use of pesticides.
The most often mentioned early-season pests include wireworm species (Agriotes, Melanotis,
Limonius and Conoderus among others), which are the immature forms of click beetles, grapecolaspis (Colaspis brunnae), corn seed maggot (Delia platura), white grub (Phyllophaga spp.), black
cutworm (Agrotis ipsilon) and corn flea beetles (Chaetocnema pulicaria). Other secondary pests
such as billbugs and stinkbugs can be controlled by rescue treatments rather than prophylactically,
and there is little literature on their importance (Gray and Steffey 2000)37. For several of the pests
not specifically addressed in this report, there is little or no published literature on prevalence orcontrol (Gray and Steffey 2000)38. The labeled pests are sporadic, usually considered relatively minor
in most locations and most years, and often found only in some parts of corn fields when they occur
in economically significant numbers.

14 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICSBy contrast, corn rootworms (primarily western, Diabrotica virgifera virgifera, and northern, D.
barberi) and European corn borer (Ostrinia nubilalis) have been consistent major pests in the
United States because they are both more prevalent, and cause increased and more widespread
damage more frequently (Gray et al. 2009)39. Rootworm, also labeled for neonic seed coatings, hashistorically been well controlled by using sound ecological practices like crop rotations, althoughrotation resistance now occurs in limited parts of the pest’s range in the US. Both are typicallycontrolled by most non-organic farmers in the U.S. by the use of several types of transgenic Bt
toxins, and historically by soil-applied insecticide in continuous monoculture corn.
Several potential advantages of seed coatings compared“But these potential advantages
to insecticides applied to the soil include lower volume
are offset by high levels of
per area treated, possibly less exposure to farmers andenvironmental
harm
over
farmworkers, and ability to treat soil-inhabiting pests thatmuch larger areas when corn
could not be controlled by insecticide rescue treatments,
seed is routinely coated with
if the insects were discovered after planting (e.g.
neonicotinoids compared tofrom observed seedling damage). But these potential
the acreage treated in previous
advantages are offset by high levels of environmental
years with applied insecticides.”harm over much larger areas when corn seed is routinely
coated with neonicotinoids compared to the acreage
treated in previous years with applied insecticides. For example, while volume of insecticide per unit
area treated is usually lower for seed coatings, the area treated by prophylactic coated seed is muchgreater than was previously treated by applied insecticides (Douglas and Tooker 2015)40, therefore
exposing a wider area of the environmental to harm (Gurian-Sherman 2015)41. Exposure to farmers
or farmworkers can also occur through substantial dust released from seed coating at planting(Krupke et al. 2012)42, or from dust blown from soil due to the persistence of these insecticides.
And though rescue treatments (treatment after insect infestations are detected) are not possible forsome of these pests, they can be used for most above-ground early-season pests (Gray and Steffey2000)43. Scouting can facilitate decision making about treatment before planting for subterraneanpests not amenable to rescue treatments. This would be needed on only a relatively small fractionof the land now exposed to neonicotinoids through seed coatings, if seed coatings were not used.
More importantly, agroecological and integrated pest management (IPM) alternatives can usually
avoid economically relevant levels of these pests in the first place, thereby avoiding the use of any
insecticides in most cases. All these topics are discussed in more detail below.

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 15

B. BEYOND SEED COATINGS: AGROECOLOGICALAND INTEGRATED PEST MANAGEMENT (IPM)
ALTERNATIVES
To address these issues in this report, we analyzed the science literature to determine 1) whether
the pests that are the targets of neonicotinoid seed coatings are important and consistently or
predictably harmful, such as might justify prophylactic seed coatings for yield protection, 2) whether
neonic insecticide coatings are effective in preventing significant yield loss, and 3) whether there
are alternatives to seed coatings that are preferable, especially from the perspective of crop yield andbenefit to the environment or public health.b
Importantly, the report also evaluates whether these pests can be controlled by the use ofagroecological and IPM farming practices that do not rely on the use of harmful insecticides. Unlike
industrial agriculture which relies heavily on pesticides, agroecology is based on understanding
the interdependence of organisms in farming systems with each other and their environment, as
well as the social systems that support or interfere with them. It relies on biodiversity and genetic
diversity to protect crops from pests, and builds on indigenous faming systems that have developedin ecological contexts for millennia (e.g. Altieri 2004)44.

Yield protection is only one measure of value, and is highly problematic and overemphasized in
the context of food security (e.g. see A. Sen, 1981. Poverty and Famines: An Essay on Entitlement
and Deprivation. Clarendon Press, Oxford). But it is one measure that farmers often consider to bevery important.
b

16 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

Various agronomic practices have considerable impact on pests, including those targeted by neonicseed coatings. Where such practices exist, it is important to ask whether they can be effective andprofitable, or whether it makes sense to provide programs to assist farmers in implementing them.
Where effective methods based on the ecology of the insects and farming systems can be usedinstead of either seed coatings or soil-applied insecticide rescue treatments, these would be highly
desirable due to their broad benefits to the environment and public health.
Research on individual early-season pests analyzed below reveals that they usually may be avoided
by simple crop management practices based on understanding the ecology of these pests. A later
section of the report considers how more extensive agroecological farming can not only reduce
early-season pests, but also provide other ecosystem benefits.
The early-season insects that may be the targets of neonic seed coatings include both subterranean
and above-ground species. It impractical to treat subterranean pests with insecticides applied to soil
after the crop has been planted. Therefore, one possible alternative to neonic seed coatings, rescue
treatments using other applied insecticides, are not feasible during the growing season for thosepests. However, detection of some of these pests before planting could allow treatment as needed
prior to planting, and potentially far less often than is currently the case for neonic seed coatings.
The soil dwelling pests considered here typically require more effort to detect, such as by the use oftraps or soil cores, prior to planting. However, such tests are generally available. For above-groundpests, rescue treatments can be used.
Those pests that are already well controlled by othermethods argue against the need for neonic seed coatings“Research on individual earlyseason pests analyzed below
per se for the purpose of reducing or avoiding yield loss.
reveals that they usually
However, other considerations in addition to yield may
may be avoided by simple
also be relevant, including: The relative cost of alternatives;
crop management practices
their relative risks and benefits to farmers, farmworkers, thebased on understanding thegeneral public, and to the environment; and convenience
ecology of these pests.”or labor reduction. For example, if rescue insecticide
treatments are used instead of prophylactic seed coatings,
will those be more or less harmful to the environment and farmer or public health (Douglas andTooker 2016)45? In this example, the less frequent use of rescue treatments must be weighed against
their greater volume per use, and their relative toxicity and risk compared to neonic seed coatings.

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 17

Neonicotinoid Use (million kg)
2

1

0

1995

2000

2005

2010

Maize Source:
Soybean
CottonWheat
Douglas and Tooker 2015
Orchards
Vegetables
Other
C. THE RISE&OF
NEONICSEED
COATINGS– WHY
Grapes& FruitCrops
NOW?
Neonic seed coatings were virtually unknown before about 2003, but since 2004 their use has
increased exponentially so that now between about 71 to almost 100 percent of corn seed in the
U.S. is treated with neonic seed coatings (Douglas and Tooker 2015, US EPA 2017)46,47. This trend
raises several questions about the reasons for the near ubiquity of neonic corn seed coatings that are
relevant to the topics addressed by this report. For example, why has the use of these seed coatings
started in recent years, and why have they been adopted so quickly and are now so widely used? Is
this justified based on yield or crop quality reductions due to the targeted insect pests?
There are probably several explanations for the rapid rise of neonic seed coatings. First, neonics
are a relatively new class of insecticides, the first was introduced in the U.S. in 1994 as a sprayed
insecticide (Douglas and Tooker 2015)48. The systemic nature of neonics also facilitates their use as
seed coatings compared to earlier insecticides (which were also occasionally used to coat seeds, butwere not systemic).
1. Agronomic Reasons do not Explain the High use of Seed Coatings
Some planting practices have changed over the last several decades, such as increased use ofconservation tillage or no-till, and planting corn at higher densities. These practices have been
associated with the increase of some crop pests. However, they largely preceded neonic seed coatings

18 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

by a decade or more. Conservation tillage reached about 30 percent of corn acres by about 1994 andremained flat thereafter through at least 2008, while no-till showed similar trends, remaining under
20 percent (National Research Council 2010)49. This was a decade before neonic seed coatings began
their exponential rise. Another estimate found about 23.5 percent of corn acres were farmed using
no-till practices as of 2005 (Horowitz et al. 2010)50, compared to the ~70 to almost 100 percent useof coated corn seed.
Increasing amounts of monoculture make corn more vulnerable to several pests. However, cornsoybean rotations still dominate production. For example, monoculture corn increased from 15 to
20 percent in Iowa between 2001 and 2007 (Stern et al. 2008)51. While monoculture has increased,that increase represents a small fraction of the acreage treated with coated seed, and neither theincrease nor total percent of monoculture corn acres can account for the high percentage of coatedcorn seed.
Occurring almost simultaneously with the“Occurring almost simultaneously
swift rise in neonic seed coatings was the 2003
with the swift rise in neonic seedregistration of the engineered Bt trait for corncoatings was the 2003 registration
rootworm control from Monsanto (Cry3Bb1,of the engineered Bt trait for cornor RootGard) and its rapidly increasing use,
rootworm control from Monsantofollowed by several other Bt genes directed at(Cry3Bb1, or RootGard) and its
rootworm in subsequent years, with total Bt
rapidly increasing use…”
traits accounting for 76 percent of corn by 2013
(Fernandez-Cornejo 2014)52,c. Conventional
farmers using these traits in monoculture corn, where rootworm is often a problem, would nolonger need to use broad spectrum soil-applied insecticides to control this pest. However, Bt for
rootworm does not control the early-season pests that could have previously been controlled bysoil-applied insecticides prior to Bt (if the pests were present!). This could possibly leave those acres
vulnerable, opening a market for an additional insecticide treatment – in this case, neonic seedcoating. But rootworm is not a problem pest on the majority of acres that rotate corn with soybeansor other crops (except where rotation-resistant rootworms were present beginning in the early ‘90s).
Historically, applied insecticide use for corn covered about 30 percent of acres in the 1990s through2003 (see Douglas and Tooker 2015), primarily for the control of corn rootworms, and to a lesser
extent to control European corn borer, where the latter is not a target of neonic seed coatings.d
So again, the historical acres treated with insecticides alone cannot explain the much larger area
treated with neonic seed coatings. It is possible that some of the acreage treated with soil-applied
USDA does not separately determine the acreage devoted to each Bt trait or gene. However,increasingly, corn varieties contain multiple traits.
cd

The acreage treated for corn rootworm and corn borer may overlap to some extent.

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 19

insecticides to control rootworm overlapped with corn that was infested with harmful levels of one
or more secondary pests, but there are no data found during research for this report documenting
or quantifying this acreage.
In other words, even though many changes in cropping practices discussed above were wellunderway years before neonic seed coating use began an exponential increase in use, they did notlead to notable increases in soil applied insecticides for early-season pests at the time (e.g. Douglas
and Tooker 2015)53. Therefore, it is doubtful that the dramatic rise in the use of neonic seed coating
could be explained by these changing practices.
Even if it was accepted that most of the former 30 percent of corn acres treated with synthetic
insecticides also was infested with high levels of early-season secondary pests—which is highly
unlikely given the minor status of these pests—that would leave unexplained the additional 40 to 70
percent of corn acres currently treated with neonics, but previously untreated with other insecticides.
Another factor contributing to the sharp rise in neonic seed coatings could be the trend toward
longer-season (later maturing) corn, leading to planting earlier in the season (Gray and Steffey2000)54. This means that on average, soil temperatures would be cooler, slowing germination andearly growth, and thereby prolonging the phenology of the crop stages vulnerable to early-season
pests. This is widely known to increase the likelihood of damage by pathogenic microorganisms
or insects. This effect can be exacerbated by no-till, because this practice does not allow the soil towarm as fast as when its surface area is increased by tillage.
While earlier planting may potentially increase corn vulnerability, early-season insect pests muststill be present for them to reduce corn emergence and yield. As will be seen in subsequent sections
on early-season pests, infrequent occurrence of these insects is supported by the research literature.

20 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

It is also important to note, as will be discussed in greater depth later, that while some historicalstudies have shown increases in yield over the past several decades coinciding with earlier planting
dates due to a longer growing season (Sacks and Kucharick 2011)55, experimental evidence suggeststhat delaying planting by a few weeks in the Northern Corn Belt beyond the earliest planting dates
does not necessarily reduce yields (Van Roekel and Coulter 2011)56. Planting about two to three
weeks later than the earliest planting dates would often allow the avoidance or minimization ofdamage from several early-season insect pests if they are present (see following sections on specificinsects). It is recommended in any case that annual planting dates should be determined by actual
weather conditions to maximize yield and avoid problems caused by early planting (Coulter 2015)57.
2. Concentration in the Seed Market and other Economic Factors
In addition to possible farmer-driven interest in seed coatings, there are also market interests atplay. The vast majority of seed coatings are applied by the large seed companies or dealers that now
control most of the corn seed market (Howard 2015)58. Application of neonics to corn seed typicallyoccurs months prior to planting, and prior to purchase by most farmers (Douglas and Tooker2015)59. So unless farmers proactively search for non-coated seed early on, they are unlikely to find
it. And even when purchasing early, farmers may not find uncoated seed because several major seed
companies apparently do not make uncoated corn readily available (Douglas and Tooker 2015)60.
Given that the research analyzed here strongly suggests that substantial stand loss in uncoated seed
would be unusual, seed companies may extract considerable unjustified profit from farmers throughthis practice. It is yet another reason why these company practices should be thoroughly investigated,and USDA subsidized insurance provided against loss to secondary pests as an alternative to coated
seed.
Additionally, the added price of the seedcoatings is usually simply included as an“Given that the research analyzed
overall part of the seed cost, and so may nothere strongly suggests that substantial
be apparent to farmers. Recent research noted
stand loss in uncoated seed would be
unusual, seed companies may extractthat the cost of neonic seed coatings is not madeconsiderable unjustified profit fromavailable to farmers or researchers (Alford
farmers through this practice.”and Krupke 2017)61. Given dramaticallyincreasing corn seed prices due to geneticallyengineered traits (Shi et al. 2010)62, as well as
fungicide seed coatings, it may be difficult for farmers to determine the contribution of neonic seedcoatings to the cost of corn seed. These aspects of the increased economic concentration of the seedmarket have made it much harder for farmers to buy uncoated seed, but have nothing to do withwhether coated seed is needed to prevent yield or financial loss.

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 21

Finally, starting in 2007, corn commodity prices rose dramatically, more than doubling (Trostle
2011)63. This may have made it more attractive for farmers to use neonic seed coatings, and accept
their cost, to protect more of this higher-value crop. In other words, they may have viewed neonicseed coatings as a kind of “cheap insurance” even if the pests that could be controlled by it were
not present often in high numbers (or at the right time of the year) to cause enough harm to justify
the cost. High corn prices did not begin until 2007 and 2008, several years after corn seed coating
use began its dramatic rise in 2004. So corn cost alone cannot explain the exponential increase inneonic seed coatings. And for the past several years, corn prices have diminished to lower historiclevels without apparent reductions in the percent of neonic coated corn seed. It is an open question
whether farmers would want to continue to accept the extra cost of these seed coatings if they could
more readily acquire uncoated seed.
Consideration should also be given to whether inadequate data on prevalence of the pests oralternatives to seed coatings might induce farmers to accept seed coatings, despite infrequent yieldprotection. Under such a scenario, farmers may characterize their desire for neonic seed coatings
as a situation of “better safe than sorry”. This behavior has been observed for Bt technology inorder to reduce risk and ambiguity for other corn insect pests (Barham et al. 2014)64. These authors
note that substantial uncertainties about insect pest risks in particular lead farmers to adopt Bt
insect pest protection, and this reasoning may apply to similar perceived value from insecticideseed coatings. However, in contrast to the pests Bt is primarily intended to protect against, thereis even less information about the secondary pests targeted by neonic seed coatings, they are more
sporadic (less predictable), and cause considerably less overall damage. This could lead to even more
ambiguity and uncertainly than for pests targeted by Bt.
The relatively limited relevant information about the pests targeted by neonic seed coatings is in fact
supported by the literature search performed for this report. The search revealed that information is
not collected in a form readily useful to farmers, and there is very little information readily available
on prevalence of these pests. When combined with company claims or advertisinge suggesting thebenefit of coated seed, such unquantified risk may encourage farmers to accept coated seed without
adequate data to support the perceived need. Relatedly, the challenges of detecting the presence oftarget pests, and the possible reluctance to scout for these insects on large farms that value reduced
labor costs, may have encouraged farmers to accept a technology that requires no extra labor ortime to apply.

One typical example is this Delta Farm Press article from October 28, 2005 (http://www.
deltafarmpress.com/pioneer-adds-dynasty-seed-treatment-lineup)inwhichcompany
representatives claimed substantial value for poncho (clothianidin) corn seed coating. For example:“Utilizing an insecticide seed treatment is a key management tool in protecting seed investmentsfrom corn rootworm and secondary insects. With limited or no rescue treatments available,
preparation can be vital in protecting corn seedlings.”e

22 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

In sum, the dramatic rise in neonic seed coating use discussed
above, leading to a dramatic increase in corn acres treated with
insecticide, cannot be explained by increased need to control
corn pests compared to the period preceding the introductionof neonic seed coatings. The introduction of farming practices
that may have changed pest populations preceded the dramaticincrease in neonic seed coatings by a decade or more, and did notlead to notable increases in soil applied insecticide at the time. Nordoes analysis of a combination of these factors justify their nearlyubiquitous use. As documented in the sections on early-season
pests below, available peer-reviewed research on yield protection
shows that these pests remain infrequent and sporadic.

“In sum, the dramatic risein neonic seed coating
use discussed above,
leading to a dramaticincrease in corn acres
treated with insecticide,cannot be explained byincreased need to control
corn pests compared tothe period preceding the
introduction of neonicseed coatings.”

The default pre-treatment of nearly all corn seed with neonics—
and the associated limited opportunity for farmers to purchase untreated seed—is the only practicethat can readily account for the treatment of almost all corn acres. Farmers may accept this lack of
choice for several reasons, such as uncertainty about the frequency of the pests, reduced labor, andrisk or ambiguity aversion, rather than predictable protection of yield. But the corporate practiceof pre-treatment of corn seed does not appear to be justified by any pest challenge outlined above.
In particular, and importantly, none of these reasons adequately account for whether these treatments
are justified based on losses to pests and cost of the treatment compared to the possible value of cornyield preserved or, especially compared to other alternatives to control or avoid the targeted pests.
Possible additional hypotheses for this large increase, based on actual pest damage and control,
could be 1) neonic seed coatings could be dramatically less expensive (including application/laborcosts), or 2) dramatically more effective than previous insecticides for treating these pests, making
it more economical to treat more acres, or 3) risk to farmers and farmworkers may be reduced or
perceived to be reduced compared to other insecticides. Data on these factors for all of the more
important early-season pests of corn are limited or not available.
However, peer-reviewed research on efficacy and yield benefits of neonicotinoid seed coatings canact as practical surrogates for determining whether neonic seed coatings make sense in terms ofpotential economic value based on yield protection.
One significant limitation of neonic efficacy research by entomologists and economists is that it
typically does not include alternative methods, other than soil-applied insecticides, that may be
more or less effective or provide other benefits. This is a critically important limitation in theavailable research. Importantly, several of these alternative approaches to controlling or avoiding
the pests targeted by neonic corn seed coatings are evaluated in this report.

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 23

CHAPTER 3

HARM CAUSED BY EARLY-SEASON INSECTPESTS OF CORN, THE EFFICACY OF NEONICSEED COATINGS, AND SAFER ALTERNATIVEST

he performance of neonic seed coatings for preserving productivity against combined earlyseason insect pests present in test plots, as well as data on specific pests that are the targets ofcontrol by neonic seed coating, are reviewed in this chapter, along with alternative methods
to either avoid or limit damage from these pests.
Collectively, the literature on pests analyzed below strongly suggests that these pests, singly or
together, only infrequently cause yield damage in the absence of neonic seed coatings. Tests forearly-season yield protection from neonic seed coatings may be aimed explicitly at all pests present,
as in Cox et al. (2007)65. But even for much of the research intended to determine yield protection
against specific pests, the protection against other early-season pests may also be included inpractice. When experiments test for the presence of a specific pest, other early-season pests may
also be present but not detected. The control of all early-season pests that may be present, even if
not specifically looked for, adds to the data on the collective importance of these secondary pests.
This occurs because most often, early-season pest damage is recorded as reduced crop stand or
yield reduction, which could be the result of several early-season pests. For example, Jordan et al.
(2012)66 were specifically interested in annual white grub protection in Virginia. They also looked
for wireworms and found their numbers to be too low to cause damage. But they also acknowledge

24 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

that they cannot rule out the contribution of other early-season pests that they did not specificallymeasure.
Furthermore, conditions that encourage these pests are generally known, so they can often be avoided
by applying this understanding of pest ecology to farming practices. Even without such changes infarming practices, studies conducted in the 2000s indicate that infestations of these pests remain
uncommon. Finally, where tested, neonic seed coatings have not shown efficacy high enough tojustify their use against some of these pests (and their efficacy against other, even more uncommon,
secondary pests has not been specifically tested or reported in the peer-reviewed literature).

A. PEER-REVIEWED RESEARCH AND REPORTMETHODOLOGY
The research on early-season pest damage analyzed in this report often measured both standestablishment (a specific indicator of early-season harm), and crop yield. Ultimately, crop yield ismore important than stand establishment as a practical matter, and is emphasized in this report.
For example, there can be later compensatory growth by corn plants that can make up for somestand losses early in the year. However, other later-season insects or other pests may also affectyield, and need to be accounted for in order for the data in these experiments to be useful. Usually,
experimental design controls for these later-season factors, but such controls are never perfect, andso may add some additional experimental error and uncertainty to the results.
Peer-reviewed and academic extension literature analyzed in this report were found by searching
Google Scholar using multiple relevant keyword combinations (e.g. names of the pests and corn;

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 25

names of specific early-season insects pests of corn; seed treatments and corn), as well as reviewing
the literature that cited these primary sources, and reviewing the references cited by the primaryand secondary research papers.
Relatively few peer-reviewed studies were found aimed at evaluating the performance of neonicseed coatings against all early-season corn pests present at a field site. The limited number of studies
was affirmed by personal communication with several extension entomologists knowledgeable
about corn and corn pests (Michael Gray, University of Illinois, 2015, Jon Lundgren, USDA/ARS,
2016, and John Tooker, Pennsylvania State University, 2016). Additional papers were found on the
biology and control of various specific early-season pests.
The limited number of papers found is indicative of the relatively low importance accorded to thesepests, especially compared to major pests of corn, such as rootworm or European corn borer, forwhich there is a large research literature. The non-peer-reviewed extension literature more often
includes these secondary pests, but generally confirms that they are sporadic and not commonly of
economic significance. These publications inevitably are non-quantitative, providing neither thefrequency of occurrence of heavy infestations nor the yield loss typically caused by these pests whenheavy infestations occur.

B. GENERAL PERFORMANCE OF CORN NEONIC SEEDCOATINGS
Measurement of the prevalence of several early-season insect
pests that may be the target of neonic seed coatings requires
time, so some studies use corn seedling emergence and standestablishment as proxies for damage by early-season pests.
This sometimes includes observation of signs of damage thatcan be attributed to specific pests. Germination and standestablishment can also be affected by soil-borne pathogenic
fungi, so often treatments and experimental controls containseveral fungicide seed coatings. Peer-reviewed studies are
relatively few, but show that neonic seed coatings are not often
useful in preventing yield loss, and are not recommended foruse as “cheap crop insurance” (e.g. Cox et al. 2007)67 in at least one of the main studies. Some studies
conclude that these seed coatings could be of value if high levels of the target pests are present,
but the studies themselves do not often show improved yield or high infestation levels, or provide
data on how frequently high infestation levels occur. A major pesticide industry-sponsored study(Mitchell 2014)68 shows significant average yield protection, but has several serious limitations
that greatly reduce its value for commercial farms. That study is analyzed at length in an effort tounderstand why it comes to seemingly different conclusions about yield protection from neoniccorn seed coatings than the peer-reviewed research literature. Reconciling or otherwise finding“Peer-reviewed studies are
relatively few, but show that
neonic seed coatings are notoften useful in preventing
yield loss, and are notrecommended for use as‘cheap crop insurance’ (e.g.
Cox et al. 2007)67 in at least
one of the main studies.”

26 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

explanations for these differences could allow a more fulsome understanding of yield protection
from neonic seed coatings.
Cox and colleagues performed field tests of clothianidin-coated corn at 0.25 mg and 1.25 mg perseed rates (labeled rates) to determine efficacy for controlling early-season pests in silage corn for
two years (Cox et al. 2007)69. They found that these seed coatings did not provide reliable yield
increases against early-season insect pests in their tests, where these insect populations were low.
The authors note that early planting dates in the Northeast, where the tests were performed, canexacerbate seedling emergence problems, caused by early-season corn insect pests targeted byneonic seed coatings. Trends toward earlier planting dates have been noted to potentially lead togreater early-season insect damage in other corn production regions, and therefore the researchof Cox et al. could be relevant to other regions as well. On the other hand, these experiments wereconducted in corn following soybeans, which is noted in the paper to result in lower likelihood ofearly-season insect infestations, and has also been noted elsewhere (Reeves 1994)70.
In other words, the economically sound practice of rotating corn and soybeans, which was practiced
on an estimated 75 percent of corn acres as of 2006 (Daberkow et al 2008)71, generally leads to reduced
early-season insect pest levels that are below adverse economic thresholdsf. Crop rotation has also
been noted elsewhere to reduce insect infestation levels (Dicke and Guthrie 1988)72, including earlyseason insect pests of corn (Reeves 1994). Cox and colleagues (2007)73 recommended against theuse of seed coatings as “an insurance” against early-season pests in the Northeast. It is unclear how
Economic thresholds depend on several changeable factors, including price of the crop and cost of
the treatment. For example, a treatment that would be below the economic threshold could be above
it at higher crop prices.
f

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well these data would apply to other corn growing regions, although much of the Midwest Corn Belt
shares a similar spectrum of relevant pests.
Wilde and colleagues (2004 and 2007)74,75 tested several neonic (imidacloprid, clothianidin, andthiamethoxam) seed coatings at two rates, against several early-season corn pests, including
wireworms, white grubs, and black cutworm and found that both concentrations were sometimes
effective at several sites in Kansas.
It was notable that in their 2004 paper these researchers tested seed coatings and soil-applied
insecticides in field plots at sites that had a history of these pests, or they artificially infested cornwith several of these insect pests in greenhouses. The previous crop (or non-crop) history at thefield sites were not reported, despite the importance of previous vegetation and cultivation practices
for the presence of these pests. Wireworm, white grub, and flea beetle tests were conducted in fields
that were chosen because of previous heavy infestation of one of the pests. Cinch bugs and Southern
corn leaf beetles were tested in greenhouses by artificially infesting corn with the insects. In otherwords, special conditions were chosen, or special sites utilized that enhanced the likelihood of heavy
infestations, in order to test efficacy, because adequate presence of these pests could not otherwise
be ensured for fields under commercially common cultivation practices. Tests were conducted forthree years, beginning in 2000.
Despite the use of sites that where initially chosen for high infestation rates, none of the sites were
found to have infestations of these pests in 2001 or 2002, reinforcing observations of the highly
sporadic nature of these pests. Even with high initial infestation rates, only 25 percent (3 of 12)
showed statistically significant yield improvements over the three years of the tests.

28 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICSAs reported in their 2007 paper, there was no yield advantage for coated seed compared to uncoatedseed at a total of 36 sites from 2004 to 2006. As noted by the authors, these sites encompassed awide range of environmental conditions, and the plots were managed for conservation tillage tomaintain organic matter. At all but one site, corn followed a different rotation crop. This supports
the common observation in this report that where agroecological practices are used, infestation andyield loss from early-season pests is highly uncommon.
It also must be asked whether the conditions that favor these (or other) insect pests are caused byfarming practices needed for acceptable productivity and profit. To the contrary, available researchsuggests that the conditions that favor these pests can be avoided by a variety of methods, including
the use of agroecologically sound farming methods that increase biodiversity and do not rely on
insecticides and also have other substantial ecosystem and public benefits. Research suggests thatsuch cropping systems produce equal or higher yields and/or greater profits per acre (Davis et al.
2012, Lechenet et al. 2014)76,77. In the infrequent instances where these pests may still cause problems,
their presence can often be detected through scouting and traps (Furlan and Kreutzweiser 2014)78
and treated as needed, rather than prophylactically. Some treatment thresholds have been suggested
for several of these pests.
Wilde and colleagues (2007)79 also conclude that seed treatments may be useful where early-season
secondary pests are a chronic problem. But those areas should be a very small percentage of cornacres (as discussed above).
This proposed targeting of chronically infested fields is in stark contrast to current practice, whereby
the large majority of corn seed is coated with neonics regardless of pest status. The authors also notethat seed coatings could be useful in combinations with Bt varieties that do not control these pests.
However, in the absence of substantial infestations of these insects, the results of this study do notjustify use of neonics as a default, prophylactic practice.
Alford and Krupke (2017)80 analyzed the dissipation of clothianidin in corn plants grown fromcoated seed, and found levels generally too low for effective pest control within about three weeks
of planting. They suggest that this rapid loss of effective concentrations of neonic may help explain
the inconsistent control often found in the field, especially for corn rootworm in their experiments.
They also found no evidence of early-season secondary pests in their field trial in 2014 and 2015,
which further supports the infrequent occurrence of these pests.
1. Aginfomatics Report, and General Lessons about the Infrequency ofHarmful Levels of Early-Season Secondary Insect Pests of Corn
A study commissioned by the pesticide industry, conducted by Aginfomatics (Mitchell 2014)81,
consists of a meta-analysis of field trials analyzing neonicotinoid seed coating efficacy. Meta-analyses
have the value of combining several studies to achieve increased statistical power, but they also

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 29

necessarily obscure some of the important parameters included in individual studies, but which are
not among the limited criteria that are required to be included in all studies. Therefore, importantdata may be excluded or overlooked in meta-analyses. This is the case for the Aginfomatics metaanalysis.
The Aginfomatics analysis relies heavily on non-peer reviewed research conducted for the industry,or that appeared in compilations of field trials. More than half of their data on neonic corn seedcoatings (51.5%) were from industry sources (and it is unclear whether this includes academic trials
funded in whole or in part by the industry, which is a common practice). The evaluation of thesoundness of these studies, or their particular methodology, does not achieve the level of peerreview. And in the case of industry trials, may not be available to the public.
The Aginfomatics report provides a broad assessment of the efficacy of neonicotinoid seed coatings,
but also has several serious limitations that make its results equivocal, and not ultimately dispositivein assessing the value of neonicotinoid seed coatings for the control of early-season secondary pests
that are the main targets of these insecticides.
i) Field Trials Often Do Not Accurately Represent Commercial
Farming Challenges
As has been widely recognized (e.g. De Janvry et al. 2010)82, field trials are often not representative ofwhat a farmer may be expected to encounter for several reasons. For example, academic researchers
often have more control over the pests and abiotic stresses in small field plots than do farmers, andmay use the most effective and advanced methods, that are not always widely used, available oreconomically feasible for farmers.
Field trials may also be designed for several different purposesthat may bias their results. Relevant to the current evaluation,
as recognized in passing by the authors of the Aginfomatics
report, field trials may be designed to boost pest levels in order
to conduct a more challenging test, making them more likely
to show treatment effects such as improved yields compared
to untreated controls. This kind of testing will give results thatare not representative of what farmers typically experience.
And in particular, it can suggest greater yield protection andbenefit then would typically be encountered on farms. In otherwords, artificially heavy infestation may indicate that an insecticide is effective in killing a pest, but
exaggerates the likelihood that harmful levels of the pest would be present on typical commercial
farms.

“In other words, artificiallyheavy
infestation
may
indicate that an insecticide iseffective in killing a pest, but
exaggerates the likelihoodthat harmful levels of thepest would be present on
typical commercial farms.”

The reason for conducting tests in the atypical fields that may be heavily infested is that if pest levels
are low or non-existent, it is unlikely that an insecticide will reveal any yield difference compared to30 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

a non-insecticide control plot. It is desirable to show how effective the treatment would be if there
were actually substantial levels of the pests present, which is presumably when a farmer would needit.g
Efficacy trials, including those used to test seed coating insecticides, are routinely designed toencourage high levels of pest infestations (e.g. Wilde 2004, Hammond and Cooper 1993, Cox et al.
2007, Kaeb and Tolefson 2006, Kullik et al. 2011, Estes et al. 2016. For full citations, see appropriate
pest sections below), while farmers generally will do the opposite when feasible. Sometimes plots
are even artificially infested, if the insects can be reared in a lab or collected (e.g. Wllde et al. 2004)83.
Estes and colleagues (2016)84 note field tests conducted in Illinois from 2004 to 2006 that wereintended to test the efficacy of different insecticide treatments (soil insecticides and seed coatings)
against early-season corn secondary pests. These trials were performed in fields specifically selected
for reported high infestation levels of these pests in previous years, but despite this, the researcher
found: “However, significant differences among treatments or between treatments and the untreatedcheck in terms of efficacy or yield were observed only infrequently”.
These examples provide further confirmation that even when attempting to slant field tests towardhigher infestation levels of these pests, yield benefit from neonic seed coatings was seen only
infrequently. When placed in the context of the frequency of these pests on typical corn farms, it isIn other words, if there were a balance in field trials between those that attempted to reduce
infestation levels and those that attempted to increase them or were neutral in that respect, the net
result might be no bias in the mean level of efficacy or benefit. But that is not likely to be the casewith sporadic pests.
g

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likely that harm from secondary pests, even when insecticides are not used, would be even lower,
and unusual.
Because we don’t know how many of the field trials evaluated by Aginfomatics encouraged high pestlevels, we don’t know how biased the results may be. This differs from the peer-reviewed literaturecited in this report, which include such methodological information. Given this uncertainty, andthe predominance of encouraging high infestation levels seen in the peer-reviewed literature, theAginfomatics results cannot be taken as representative of what a farmer could expect, and are likely
to substantially exaggerate the efficacy and value of neonic seed coatings of corn.
Countering such bias in test results requires avoiding the inclusion of such tests, or revealing and,ideally, quantifying their biases. This can be done for these sporadic corn pests by including dataon the frequency of their occurrence and the damage they cause at various levels of occurrence
and under various growing conditions. While neither were done in the Aginfomatics report, thefrequency of harmful levels of pest occurrence, and corresponding experimental conditions, areanalyzed in the current report.
ii) Including Rootworm Protection Tests Exaggerates Yield
Protection
A second limitation of the Aginfomatics assessment is that it does not control for or segregate fieldtests for protection against rootworm (mostly Western and Northern corn rootworm), the major
pest of corn, and common in continuous corn (i.e., corn grown more than one year continuously).
For several reasons discussed below, and according to research and extension entomologists, neonicseed coatings should not be relied on to treat rootworm, and are not needed for that purpose(see rootworm section below for references). Practical non-pesticidal methods are available forcontrolling these pests in most areas.
It is possible that many of the field trials analyzed by Aginfomatics showed yield benefits due tocontrol of rootworm rather than secondary pests (rootworm is considered to be a primary pest ofcorn in the United States). This is because rootworms are much more common on continuous cornthan are secondary pests (even when encouraged), and rootworms are often capable of causing large
yield losses. The effects of rootworm might have been controlled in some of the analyzed trials byusing corn varieties that contained Bt for rootworm, such as Monsanto’s Cry3Bb1 gene. But thistrait was not discussed in the Aginfomatics report, and in any case, the first such product was not
approved by EPA until 2003, while the field trials that were evaluated by Aginfomatics commenced
in 1996.
Corn seed coated with 1.25 mg/seed may have acceptable, though unreliable, efficacy against
Western corn rootworm occurring at moderate infestation levels, while the lower rate of 0.25 mg/
seed is generally not effective. The report did not distinguish results from different insecticide seed

32 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

concentrations, but rather averaged them. Therefore, research that used 1.25 mg/seed concentrationsof neonicotinoids would not be distinguished from those using lower levels.
Given the high prevalence of corn rootworms in continuous corn, it is possible that most of thepositive yield values for neonic seed coatings reported in the Aginfomatics study were the result ofcontrol provided against corn rootworm rather than the other early-season pests.
The Aginfomatics study reports an average yield benefit from neonic seed coatings for corn of 17.4%
compared to non-insecticide controls. This greatly exceeds the yield value obtained by the available
peer-reviewed studies, especially when considering that the early-season insect pests other thancorn rootworm often were not present in those studies, and therefore in such environments the seedcoatings typically provide no yield benefit.

iii) Insecticide Controls and Other Possible Biases that Exaggerate
the Efficacy of Neonic Seed Coatings
The average yield benefit for neonic seed coatings compared to other insecticides in the Aginfomatics
report was 4.4%, and should also be qualified by the same concerns as above. In addition, this is avalue averaged for all insecticides. But farmers often prefer the most effective insecticides, if they
are acceptable for other reasons, such as cost and perceived safety. So this average value may again
bias the benefit of neonics compared to the best insecticide options. If farmer preferences for more
effective insecticides were taken into account, the relative effectiveness of applied insecticides may behigher. This could reduce or erase the small apparent yield advantage for neonic seed coating. If, tothe contrary, more effective applied insecticides are more expensive than less effective insecticides,
enough to discourage their use, then the actual yield advantage for seed coatings could be higher.

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Probably most importantly, the authors note that many of the non-neonic insecticides used
for comparison with neonic seed coatings in the field trials were foliar applications. This is an
inappropriate comparison, since foliar applications are intended mostly for later season aboveground pests, not most of the early-season subterranean root and seed pests that are the target ofneonic seed coatings. And in fact, subterranean pests, including rootworms, are typically treatedwith in-furrow, soil applied insecticides. Therefore, these data are invalid comparisons for the
purpose of determining the value of neonic seed coatings.
The Aginfomatics study also does not provide any range data for yield benefit, except to say thata few studies that differed from the mean by six or more standard deviations were excluded as
outliers. This is an important omission because of the sporadic nature of the pests. A relatively small
percent of trials with high yield benefit (but below the six standard deviation cutoff) could skew theoverall mean upward substantially. And given the data from other studies that usually showed noyield benefit, this is probably the case for the Aginfomatics study.

“Due to the many substantial
limitations in the Aginfomatics
report, the results and conclusionfrom their meta-analysis should
not be used to inform farmers
or farm policy concerning thebenefits of neonic seed coatingsof corn in the US.”

From a practical perspective, this also suggests that it
would be more sensible to try to treat specifically theminority of heavily infested farmer fields after scouting,and to avoid farming practices that encourage heavy
pest infestations, than to prophylactically coat mostcorn seed with neonics. Reporting average data obscuresthe fact that most fields (according to all publishedresearch) do not contain damaging levels of these pests.

Due to the many substantial limitations in the
Aginfomatics report, the results and conclusion from their meta-analysis should not be used to
inform farmers or farm policy concerning the benefits of neonic seed coatings of corn in the US.
2. Summary and Conclusions from Studies on General Protection
Against Early-Season Pests by Neonic Seed Coatings
Peer reviewed research found only occasional yield benefit from neonic corn seed coatings forcontrolling early-season secondary pests, and then only in experiments that were designed to increase
infestation above what farmers would typically experience. By contrast, the study by Aginfomatics,
relying on non-peer reviewed and mostly industry funded research, found a substantial average yield
benefit for neonic corn seed coatings of 17.7 percent compared to non-insecticide controls, and 4.4
percent compared to other insecticides. Analysis of all of these results suggests some possible reasonsfor these disparities. The probable reason for at least some of the differences may be explained by:1) bias toward considerably higher efficacy (yield) than farmers would usually experience because
an unknown number of field trials were likely designed to encourage unrealistically high levels ofearly-season insect pests; 2) that analysis did not separate yield improvements due to protection

34 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

from the single most important group of U.S. insect pests of corn, corn rootworms, which are more
properly treated by other means, or avoided by crop rotation, and for which academic entomologists
have said seed treatment should not be relied on (see rootworm discussion below); 3) average values
obscure the sporadic nature of these pests, which means that the substantial majority of farmers
would get no yield benefit, but incur the additional cost of the seed coatings, while those threatenedby unusually high infestation levels have other options (see following sections); 4) neonic seedcoatings were often compared to foliar-applied non-neonic insecticides, rather than soil-applied
non-neonic insecticides, which biases against the efficacy of the applied insecticides. Therefore, thesetreatments would not be effective against subterranean pests, while soil-applied insecticides may be,
and therefore these tests were an invalid comparison. Because of these issues, the Aginfomatics
results cannot be accepted as of practical value to farmers. To the contrary, detailed analysis of
specific peer-reviewed studies shows that early-season secondary pests are sporadic and occur at
economically important levels infrequently, and that there are effective alternatives available to treat
them rather than prophylactic seed coatings.

C. EARLY-SEASON INSECT PESTS TARGETED BY
NEONIC SEED COATINGS
As noted above, the main often-mentioned targets of neonic corn seed coatings are wireworms,
corn seed maggot, white grub, and grape colaspis. Several other early-season pests may also be
the target of seed coatings, especially black cutworms and corn flea beetles. Seed coatings at thehigh dose are also labeled for corn rootworms. The impact and control of these pests are reviewed
individually in the following sections.

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All of these pests, other than rootworms, aresporadic, and not often encountered at levels thatcause economic yield reductions. This is especiallytrue when corn farming is managed in ways that takeadvantage of current understanding of the ecologyof these pests. As is shown below, management
methods that are practical and profitable can beused to largely eliminate the threat from these pests
without the use of insecticides, applied to the soilor on the seed. This is a critically important point
to understand about these pests. Where these best
management practices are not followed, it is usuallymost likely because seed coatings are simpler and more convenient, save labor, or simply because
farmers have little opportunity to buy uncoated seed, not because they reliably improve productivity
or profit.

“In
this
respect,
insecticideseed coating technology can besaid to encourage undesirable
management practices in thatconsiderably more environmentally
destructive insecticide is used
for no benefit to consumers, theenvironment, or even farms andfarmers.”

In this respect, insecticide seed coating technology can be said to encourage undesirable management
practices in that considerably more environmentally destructive insecticide is used for no benefit toconsumers, the environment, or even farms and farmers.
The sections below on individual early-season corn pests analyze the available research on prevalence,
efficacy of seed coating compared to other alternatives, and the availability of ecologically informed
management options.
The pests are placed into one of three subsections, based on whether they cause damage to corn
primarily as a subterranean pest, above-ground pest, or rootworm, which is a special case since it isa primary rather than secondary pest.
The main reason to separate above-ground from below-ground pests is that the former can be
successfully controlled by rescue treatments after scouting, if an insecticide is deemed necessary. By
contrast, subterranean pests cannot be controlled by soil-applied rescue treatments after planting,which makes avoidance through management even more critical as a viable alternative to neonicseed coatings (although, as will be seen, scouting of below-ground pests can allow the successful
application of insecticide prior to planting).
1. Subterranean Pestsi) Corn Seed Maggot:
Corn seed maggot (Delia platura) is reportedly sometimes a problem for growers after additionof fresh organic matter shortly before planting, such as after the termination of some cover crops,

36 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

which encourages egg laying (Hammond and Cooper 1993)85. Hammond and Cooper note that “…
maggot infestations occur at levels sufficient to cause losses only when green, living cover crops…
are incorporated into the soil in the spring” [emphasis added]. Therefore, avoiding incorporationof such organic matter largely avoids losses to corn seed maggot. As with other early-season pests,
it can kill seeds or seedlings, reducing plant stands, and potentially yield, when favorable conditions
exist.
But as with other sporadic early-season insect pests that are the target of neonicotinoid seed coatings,
the conditions that encourage the pest can usually be avoided by sound agronomic and agroecologicalcrop management practices. It is also considered to be a greater threat if susceptible crops areplanted in succession (Delahaut 2007)86, including several vegetable crops that are not commonlyrotated with corn. However, soybean, a crop commonly rotated with corn, is also susceptible. This
points to the need for longer rotations that have been shown to improve productivity of both cornand soybeans and increase farmer profit (Davis et al. 2012)87. But it also implicates growing cornin monoculture, an undesirable practice from a number of perspectives, as a factor for increased
infestation and damage that can be avoided. As with other minor early-season insect pests of corn,
there is inadequate data on its prevalence and impact on commercial farms.
Research has shown that by about two to three weeks after the organic matter is added to soil, thedestructive larval stage of the insect has largely passed. Models based on ambient temperature canbe used to predict when the greatest populations of breeding adult seed maggot flies will be present,in order to avoid planting during this time period. Adult flies breed for only about three days, whichfacilitates the ability to avoid mating populations (Hammond and Cooper 1993)88. Therefore harm
can be avoided, as well as the need for neonicotinoid seed coatings in situations where growers
may be concerned about infestations. Harm can also largely be avoided by avoiding application

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of substantial amounts of green manure or livestock manure, as well as applying these valuable
amendments several weeks before planting.
It should also be noted that despite experimental conditions intended to encourage high corn seedmaggot infestation levels, elevated maggot numbers or yield reductions did not occur in soybeans
in important research by Hammond and Cooper (1993)89, regardless of insecticide seed or soil
treatment, absence of insecticide, or delay in planting date, over the two years of the experiment.
The only statistically significant yield reduction was attributed to high weed infestations in one plot
due to failure of the weed control program, not seed maggot. There were some small differences incrop stand, but these were apparently compensated for by growth later in the season that prevented
yield differences. Soybean may have somewhat greater capacity to compensate for early-season
stand loss than corn (Hicks et al. 1990)90. But it is likely that compensatory growth could also have
prevented yield reductions in corn if similarly small stand differences occurred in that crop (e.g.,Tokatlidis and Koutroubas 2004)91. And in any case, later planting dates resulted in the largest crop
stand, even without insecticide applications. As with experiments noted above, these experiments
further support the sporadic, minor nature of the early-season, secondary insect pests that are thetarget of neonic seed coatings. These experiments show that even when experimental conditions aredeliberately designed to encourage high infestation levels, such pest levels often fail to occur.
Planting early has been a trend to maximize the growing season, especially with longer maturing
varieties. However, this also increases vulnerability to early-season pests generally, since cooler earlyseason soil temperatures increase germination time and slow seedling growth, extending the timethat crops are vulnerable to both insect pests as well as pathogens. This can lead to increased relianceon pesticides. The minor occasional advantages of planting progressively earlier should be weighedagainst the costs to the environment, and the potential impact on highly useful practices such as

38 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

cover crops, which are known to have potential to improve farm sustainability and environmental
quality (McSwiney et al. 2010)92, and may also increase yield (Miguez and Bollero 2005)93. As noted
above, the experiments of Hammond and Cooper (1993)94 provided no yield advantage for earlyseason planting using insecticides compared to planting several weeks later without insecticide
treatments. This has also been seen in the work of Coulter (cited above) more generally.
The caution about possible increased seed maggot infestations corresponding to increased organic
matter incorporation in the spring, such as from cover crops, is important because addition oforganic matter is valuable for improving soil fertility and generally should be greatly encouraged.
However, as noted in other research by Hammond (1990)95, terminated cover crops that remain
unincorporated on the soil surface are largely not attractive to seed corn maggots. Cover crops thatremain on the soil surface can have multiple additional benefits, for example in suppressing weeds(Price et al. 2016)96, lowering soil temperatures later in the season, and conserving soil moisture(Wortman et al. 2012)97.
The issue of management decisions tailored to cover crop species and management illustrates theneed for additional research to better determine effects on early-season pests, as well as extension
support to help farmers take advantage of this important practice that is widely advocated andrecognized for its many positive attributes.
In summary, while seed corn maggot is one of the early-season pests that is most often mentioned
as a potential problem, as with other early pests, there are no data on its prevalence that would
legitimize prophylactic corn seed coatings. Furthermore, research and expert opinion has shownthat the risk of corn seed maggot injury can be largely avoided by highly beneficial practices—such as crop rotation (Reeves 1994)98 with non-host crops—that should be encouraged in any case.
Damage can also be avoided by planting two to three weeks after incorporation of fresh organic
matter, or by leaving terminated crop residues on the soil surface. However, as shown in some of the
only peer-reviewed research on this topic, even when crop management conditions were designed
to encourage high infestation levels of the pest, over a two-year period, infestations remained low.
Given the lack of convincing demonstrations that corn seed maggot is a common problem, as well as
the availability of viable and desirable crop management practices to avoid it, there is no reasonable
evidence that prophylactic neonic corn seed coatings are needed to prevent significant damage by
this pest.
ii) Wireworms
Wireworms are the soil inhabiting larval stage of click beetles, and come from several different
genera (Agriotes, Melanotis, Limonius and Conoderus among others). They are widely distributed infavorable environments and can occasionally be pest problems in corn. As with other early-season
corn pests, there are few data on their prevalence in the U.S., but instead considerable anecdote.

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Because many species of wireworms have long larval phases, often from three to nine years in thesoil, they can be a persistent problem where they occur. However, that also means that once detected,
the problem area can be anticipated and targeted, populations monitored using baited traps, and,if needed, treatment prior to crop planting in subsequent years (Furlan and Kreutzweiser 2014)99.
Similar to other early-season pests, research points to particular, usually avoidable, farm management
practices as the predominant reason for occasional infestations. In particular, it is generally foundthat wireworms are most often a problem when grass crops such as pasture are plowed and corn (orsusceptible crops) follow. Soils with high organic content and consecutive and continuous plantingof susceptible crops have also been identified as risk factors (Furlan and Kreutzweiser 2014, Furlan
2005)100,101. Wireworms at agronomically significant levels can therefore usually be avoided. Crop
rotations that avoid continuous susceptible crops, generally a good agronomic practice in any case,can be used to avoid wireworms (Reeves 1994)102.
While no data for prevalence on U.S. farms was available,
work in Europe has shown that wireworms are found“Crop rotations that avoid
at harmful levels in only about five percent of cornfields
continuous susceptible crops,(Furlan and Krutzweiser 2014)103. Extensive data collected
generally a good agronomic
practice in any case, can beover almost 30 years in Northern Italy suggests that onlyused to avoid wireworms
about four percent of corn acreage would contain factors
102(Reeves 1994) .”that would lead to yield loss (Furlan et al. 2016)104. Theseauthors also cite research consisting of hundreds of fieldtests that show no significant wireworm yield damage, due
to low infestation levels, and growth compensation where some early stand loss occurs.
Where the main two predisposing factors—previous or adjacent grass or meadows and highsoil organic content—were not present, this research found less than one percent infestation at
economically significant levels (Saussure et al. 2015, Furlan et al. 2016)105,106. Although this research
was conducted in Europe, there are many similarities in production methods and wireworm species
or genera. While different species exhibit varied biology and pest characteristics, the European
data applies across the range of genera and species present there, suggesting that it would likely be
relevant for the U.S. as well (e.g. Furlan et. al 2016).
Even where easily avoidable risk factors were highest, it is estimated that only 20 percent of suchacreage would justify treatment (Furlan et al. 2016)107. Therefore, there is no justification forprophylactic treatment of the corn crop in order to address apparently very limited economicallysignificant wireworm problems.

40 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICSiii) White Grubs
True white grubs (Phyllophaga spp.) are larvae of June beetles. As with all other notable earlyseason secondary pests of corn in the U.S., they only occasionally cause economically significant
infestations. And as with other early-season pests, there is limited peer-reviewed research on theprevalence and impact of these insects on corn.
Furthermore, on occasions when white grubs do cause significant yield loss, it is usually in corn
adjacent to shelterbelts or woodlots containing willow, poplar or ash tree species, or when corn isplanted in converted pasture or rangeland. Research over two seasons on dispersal of adult beetles
and infestation of corn showed that 90 percent or more of the beetles deposited eggs within 55 metersof tree sources (Glogoza et al. 1998)108, and larvae were found only in fields bordering shelterbelts.
These authors note that: “Larval populations of P. implicita would seldom be expected to exceed
treatment thresholds beyond 90 meters from shelterbelts.” So even when corn infestation occurs, it
is likely to be restricted to the edges of fields, especially the large fields common in the Corn Belt.
Some entomologists have reported that occasional infestations occur that are not near shelterbelts or
grasslands (e.g. Verenhorst et al. 2015)109, for unknown reasons. But these have not been quantified
and do not seem to contradict the generally infrequent occurrence found in previous research.
White grub larvae also inhabit soil for three years, and first season grubs do not cause economic
crop damage. So although, as with other early-season soil pests, rescue treatments cannot be applied,
infestation can be detected by soil sample of first year grubs, allowing treatment if needed before
possible economic levels of damage during the second and third seasons.

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To summarize, white grubs are occasional pests, and their occurrence in significant numbers canlargely be predicted, and monitored when they do occur. Therefore, in situations where they may
occasionally cause problems, especially adjacent to some tree species, those problem fields canbe treated. Extensive prophylactic treatment of seeds is unjustified, especially because even whenproblems occur, they are often restricted to only a portion of a field. As with other early-season
pests, the limited available data suggest that white grub problems are not typical, or can be avoided
by avoiding problem conditions. Where that is not possible, selective treatment may be used.
In some regions outside the Corn Belt, annual white grubs (e.g. Japanese beetle larvae), may be
more common than true white grubs. For example, Jordan and colleagues (2012)110 found this tobe the case in Virginia. In these experiments, yield protection was found in only 33 percent offields over a three-year period, with a six percent average yield increase compared to the untreatedcontrol. These researchers also collected wireworms, and found their numbers to be too low to cause
damage. They also found that scouting for annual white grubs in the fall was generally predictive of
economically significant populations the following spring, which would allow farmers to treat only
when detected in threatening numbers rather than prophylactically.
iv) Grape Colaspis
Historically, grape colaspis (Colaspis brunnae) was associated with sporadic damage to corn, mainly
when following red clover in rotation. Reports in the late 1990s suggested some increase in damage,and there was speculation that this insect had adapted to the widespread planting of soybeans,
another legume, in rotation corn, leading to increased occurrence (Rice 2003)111. Kaeb (2006)112
noted these reports in the extension literature, but there is little if any documentation of prevalenceor level of damage beyond anecdotal reports. These authors also cite historic literature that corn

42 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

planted under conditions that promote vigorous growth, e.g. avoiding cooler early-spring conditions,do not show serious damage. Furthermore, seed treatment with neonics shows inconsistent control,
even where infestations are found. For example, in several years of trials, Kaeb (2006) found no
stand or yield decrease in untreated fields selected for previous heavy infestation, although greater
plant height was found in treated fields. Plants from treated fields were only two to four percent
taller than untreated fields in July. These authors also report results from Shaw in 2001 that found nobenefits, including for stand height. The authors conclude that seed coatings were beneficial, despitelack of yield increase, apparently based on speculation that under drier early-season conditions,
damaged roots of untreated plants would result in lower yields. However, that was not demonstrated
in the field.
Further, in the two years of their field tests (2004 and 2005), few beetles were found in emergencecages, even in control (no seed treatment) fields, despite previous heavy infestation. As with otherearly-season pests, these results show that even where infestations have been previously seen, they
are sporadic and often do not reoccur.
Similarly, several years of trials with soil-applied insecticides in the mid-2000s only infrequently
showed any yield benefit, despite targeting fields in Illinois with a history of high infestation levelsof grape colaspis (or Japanese beetle larvae) (summarized in Estes et al. 2016)113. Although thesetrials used soil applied insecticides rather than seed treatments, generally these applied insecticides
have shown comparable efficacy against soil-borne secondary pests compared to neonicotinoid
seed treatments. The main advantage for seed treatments has been convenience and reduced labor
requirements rather than reliably higher efficacy.
Estes and colleagues (2016)114 also saw no yield benefit from soil applied
insecticides for grape colaspis and Japanese beetle grubs in trials from2009 to 2011 for sites not chosen for high infestation levels. However,
the authors noted that, “Although these trials were not placed in areas
with a history of subterranean secondary pests, the trials were no lesslikely to have measurable larval populations when compared with otherfields in the region.” In other words, these trials are representative ofwhat farmers would actually face on commercial farms.

“The main advantage
for seed treatments
has been convenienceand reduced labor
requirements rather
than reliably higher
efficacy.”This paper also notes a number of previous field trials over a period of
three years, from 2004 to 2006, aimed at determining the efficacy ofvarious insecticide treatments in fields that had reported high previous levels of secondary pests.
The authors found that the various insecticide treatments were only infrequently associated withyield improvements compared with untreated controls.
As with other early-season pests, management of corn production is likely to avoid significant
infestations of this pest. First, damage was reported most often with inbred seed corn production,

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and therefore would not affect most growers’ production crops. Second, grape colaspis seems to bea problem almost exclusively when corn follows certain crops like clover, and perhaps more recently
soybeans, in rotation. But it was also never found when corn followed a small grain in rotation(Bigger 1965, reported in Kaeb 2006). Even as late as 1999, it was reported only occasionally whencorn followed soybeans, alfalfa or sweet clover (Steffey, reported by Kaeb 2006). Including a small
grain in corn-soybeans rotations has been shown to increase yields and profits (Davis et al. 2012)115.
Taken together, the very limited research on grape colaspis suggests that it remains only anoccasional pest, and can usually be avoided by good agronomic practices and generally beneficial
crop rotations. Furthermore, even on occasions where grape colaspis is found at levels that may
cause some damage, neonic seed coatings generally provided no yield increase.
2. Above-Ground Pests
As noted previously, the above-ground pests discussed below can all be effectively avoided by using
appropriate IPM or agroecological practices, or controlled by rescue treatment in the unusual
situations where populations of the pest are high enough to require control measures. Because such
rescue treatments would occur on drastically fewer acres than are currently treated with neonic seedcoatings, and because the environmental toxicity of those rescue insecticides are not higher than for
neonics (see later section: “If Neonic Seed Coatings of Corn are Eliminated, Will Other Insecticides
Replace them?”), it is highly unlikely that the environmental impacts of such rescue treatments
would approach those of widespread prophylactic neonic seed coatings. And importantly, research
has shown that agroecological means of avoiding significant infestations of these pests can greatly
reduce or eliminate the use of synthetic insecticides while maintaining high yields.

44 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

i) Black Cutworm
There have been some reports of increased prevalence of black cutworm (Agrotis ipsilon) in recent
years, possibly in connection to increases in no-till agriculture over the past three decades. As withother secondary pests analyzed in this report, however, the available research strongly suggests that1) even under conditions that are expected to foster high infestation rates, economic damage isuncommon; and 2) harm can largely be avoided using best management practices that are ecologicallyand environmentally sound. Furthermore, academic extension entomologists recommend against
relying on seed neonic coatings for preventing significant damage from black cutworm. Finally,
unlike subterranean early-season pests, black cutworm feeds above ground, and so is amenable torescue treatments in the uncommon event that it is needed.
Research in 2011 (Kullik et al. 2011)116 shows that in only one of six field trials over a two-year
period was yield reduction from black cutworm observed, despite these tests being conducted on
farms selected for substantial infestations in previous years.h This yet again illustrates that even
where conditions are considered to be most favorable for infestation (which can usually be avoided),
infestations of secondary pests like black cutworm are the distinct exception. Additionally, the lowdose of clothianidin (0.25 mg/seed) was ineffective against black cutworm and the high dose (1.25mg/seed) was significantly less effective than Bt in the only trial where yield loss was observed in
the control. Although the authors claim that the low dose may enhance performance of Bt in somecases, it was not the case in their own experiments concerning yield.i
Earlier work identified conditions that may enhance infestation of black cutworm (Showers et al.
1985)117. Several sets of experiments showed that black cutworm levels could be problematic in
no-till fields that were infested with winter weeds. However, when the weeds were killed at least
8 to 14 days before planting corn, black cutworms were rarely a problem. This is because black
cutworms apparently cannot feed on dead and dried plant material, and therefore starve prior tocorn emergence. Using such ecological information to develop environmentally and economicallyappropriate farming practices should be highly prioritized over insecticide use.
Kullik and colleagues found a single field test where significant yield reduction occurred in thecontrol plot that had been treated with herbicide on the days that the corn was planted, a practice
The authors reported only two of six field tests in their Table 3. They mention in the text of thepaper that there were in fact six field trials, but that only two had infestations of black cutworm
when tested (despite a history of infestation). More accurate reporting would have included all six
tests in their Table 3.
hKullik et al. write that they used doses of 25 mg/seed and 125 mg/seed. This is 100 fold higher thanthe legal labeled rate, and we assume here that these designations were a clerical error. If they were
accurate, efficacy data from this paper would be irrelevant from a practical perspective, but data on
the prevalence of black cutworm would remain of value.
i

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expected to exacerbate black cutworm problems. As the authors acknowledge, cutworms that lose
their weed food source simply move to corn seedlings when they are killed shortly before cornseedlings emerge. In other words, it is highly likely that even in the single field trial where cutworm
yield reduction occurred in the untreated control, those losses could have been avoided simply bykilling the weeds (by whatever methods) two weeks earlier.
Finally, since black cutworm is an above-ground pest, it is feasible to use rescue insecticide
treatments to control it. This should be discouraged in favor of ecologically-sound management,
in which case the need for rescue insecticide use should be rare. As noted by academic extension
entomologists, such treatments, especially granular soil-applied insecticide, are effective (Krupke
and Obermeyer 2015)118. State-supported pheromone traps, or scouting, can be used to determine
whether black cutworms may be a problem (Purdue University Extension)119. Entomologists notethat reliance on neonics, even to the extent that they may sometimes be effective, is risky because
infestation can also occur after the insecticide residue levels become too low to be effective (Krupke
and Obermeyer 2015)120. These entomologists recommend against reliance on neonic seed coatings
to control black cutworm.
In summary, multiple practical agronomic alternatives to neonic seed coatings are available toprevent or control infestations of black cutworm, in the unusual instances where it is a problem.
These methods should be highly encouraged. Where they may rarely fail, rescue treatments canbe used, and work better than neonic seed coatings in any case. Although costs (e.g. labor) may besomewhat higher for applied insecticide use on a per use basis, it should be considered whether theinfrequency of such use may result in lower costs over time compared to the continuous cost of seedcoatings applied every year.
ii) Corn Flea Beetles
Corn flea beetles (Chaetocnema pulicaria) may sometimes reachproblem levels after warm winters in the Corn Belt. Extension“The large majority ofentomologists have developed a guide for determining thefield corn acres, planted
possibility of high beetle numbers based on average temperatures
for production rather
from December – February. Flea beetles are mainly a threat tothan seed, should be
productivity due to transmission of a bacterial disease called
resistant to the mostdamaging phase of the
Stewart’s wilt, rather than through direct feeding. Field corndisease.”varieties are widely available that have resistance to the moreoften serious wilting (vascular) phase of the disease, and often
have some resistance to the leaf phase, while inbred corn lines used
for hybrid seed production, and sweet corn, may be susceptible (University of Illinois Extension)121.
Kuhar and colleagues (Kuhar et al. 2002)122 found that control of Stewart’s wilt by neonic seedvaried and was generally moderate, and considerably lower than was provided by genetic resistancein sweet corn. They also reported some phytoxicity due to imidacloprid seed coatings. The large

46 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

majority of field corn acres, planted for production rather than seed, should be resistant to the mostdamaging phase of the disease.
Although corn seed treatments can protect seedling corn (Wilde et al. 2004)123 it is rarely needed
to prevent stand and yield loss due to feeding of the beetles. And because hybrid field corn that is
resistant to Stewart’s wilt is readily available, this disease is not usually a problem for commodity
corn production.
Where avoidance of Stewart’s wilt is needed, delaying planting by about two to three weeks, in early
May in Iowa, largely avoids feeding by beetles carrying the bacterium (Nutter 2007)124. As noted inseveral sections above, delaying planting by a few weeks also can avoid potential black cutworm andseed corn maggot infestations, often without yield penalty, and is generally beneficial for avoiding
early-season insect and fungal pests. Where high levels of corn flea beetles are present, extension
entomologists recommend one of many available rescue treatments (Purdue University Extension2016)125.
Although the frequency of damaging levels of corn flea beetle in field corn has not been well
documented, it is generally predictable, avoidable by sound agronomic practices; and where thoserarely fail, effective rescue treatments are available. For all of these reasons, neonicotinoid seedtreatments are not needed to protect field corn from flea beetles.
3. Corn Rootworms
Several authors report no significant yield protection value in neonic seed treatments at the lower(0.25 mg/seed) rate, and only moderate and unreliable yield improvement at the higher label rate
(1.25 mg/seed) (Cox et al. 2007)126 for Western and Northern corn rootworms, the most widespread
species, and those most prevalent in the Corn Belt. Cox and colleagues note that although neonicseed coatings provided acceptable protection against the moderate infestation levels of theirexperiments, they are not reliable for controlling Western corn rootworm and recommend against
its use as “a cheap insurance policy” in the Northeast for rootworm or secondary pests.
Several field trials in Illinois in 2006 found no significant control of rootworms in heavily infested
corn at the high rate of 1.25 mg/seed, and reported that this was consistent with previous tests (Grayet al. 2006)127. Similarly, Petzold-Maxwell et al. (2013)128 did not find significant yield advantage
when the high rate of clothianidin seed treatment was used in addition to Bt, or in non-Bt corn. Bt
was shown to be more reliably effective.
van Rosen and Ester (2009)129 summarize the research literature as showing inconsistent protection
provided by neonic seed treatment of corn against rootworms. Therefore farmers that rely on thesetreatments may face substantial yield losses in cases where it fails, which may have been avoided by
the use of more effective methods, such as crop rotation where rotation-resistant rootworms are notprevalent.

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The unreliability of neonic seed coatings for protection against rootworm is also well summed
up by several university entomologists (Obermeyer et al. 2006)130. While recognizing that neonicseed coatings are attractive for their convenience and related reasons (that they are “wrapped”
directly into the seed), they raise caution about the marginal efficacy of these products: “Using
seed-applied insecticides for corn rootworm control in high-risk areas may be a gamble becauseof the inconsistencies that have been seen in university trials throughout the Midwest. The labels
literally state 'protect' or 'protection' from rootworm... not control.” They relegate the possible value
for rootworm to low or moderate impact areas. However, they also note; “Before deciding to use
any of these options, be sure that you actually need it in your growing area – many areas of the state[Indiana] have little rootworm pressure and can get by simply by continuing to rotate corn withother crops in alternating years.” This advice to consider the actual situation on the farm is clearly
not possible when corn is pretreated with neonics. The field tests conducted by these researchers also
found both Bt and soil-applied insecticides performed much better than coated seed for rootworm
protection.
Recent research further confirms that neonic seed coatings are not reliable for control of rootworms(Alford and Krupke 2017)131. This research measured and modeled the reduction of neonicconcentration in corn plants over time, and tested efficacy in fields where rootworm infestations
were encouraged by planting late-season corn as a trap crop. They found that even the high doseof clothianidin seed coating provided no yield benefits in two years of trials, and only moderate
efficacy in reducing root damage. They suggest that one reason for inconsistent efficacy for neonicseed treatment of corn is reduction of concentration of the insecticide within about three weeks.
They also suggest that because of the limitations of these seed coatings, they are unlikely to makeeconomic sense when corn prices are relatively low, as in 2014 to 2016.

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They conclude that because of the poor match between the duration of efficacy of neonic seedcoatings of corn and the phenology of early-season insect pests, “…coupled with the sporadic
occurrence of economic infestations of secondary pests indicates that most US maize producers areunlikely to realize benefits from the NST [neonic seed treatment] approach.”
Rootworms are often a problem in continuous corn, and in significant part for that reason, farmers
usually rotate corn with non-susceptible crops—particularly soybeans—in the Corn Belt. As noted
above, about 75 percent of corn is rotated, mostly in a two-year rotation with soybeans. Crop
rotations essentially obviate the need for insecticides to control rootworms–except where rotation
resistant rootworms have evolved. These rootworms were selected and flourished in short cornsoybean rotations which are too short to take advantage of most of the benefits or longer crop
rotations (Davis et al. 2012)132. Although there are uncertainties due to gaps in important data,
longer rotations may be considerably less likely to allow the development of rotation resistance(Onstad et al. 2003)133. And wheat added to corn-soy rotations has resulted in substantially reduced
rootworm damage where rotation resistance is prevalent, to below economic thresholds in someresearch (Schroeder et al 2005)134, although these authors caution that wheat may not always
adequately reduce damage.
Growing corn continuously has long been understood to be inadvisable in its
promotion of pests such as rootworm. Even the short corn-soybeans rotation“Growing corn
continuously
is inadvisable for a number of reasons, from reduced yields, to greater reliance135
has long beenon pesticides, to greater environmental pollution (Davis et al. 2012) , andjunderstood toshould be discouraged for all of these reasons. Enablement of such generally
be inadvisable
destructive practices by the use of seed coatings (which are also unreliable forin its promotion
rootworms) or other insecticides should likewise be discouraged in favor ofof pests such
longer crop rotations. In fact, to the extent that arguments are made in support
as rootworm.”of seed coatings on the basis of higher yield, longer crop rotations are morereliable and more productive, as well as providing multiple environmental andpublic health benefits (Davis et al. 2012)136. As discussed elsewhere in this report, there are several
structural, market and policy reasons why farmers may feel compelled to use industrial farming
methods, including growing corn continuously. Therefore, efforts to encourage farmers to change
their practices must focus on these barriers.
i) Rootworm Resistance Management
As noted above, in addition to yield protection, pest control measures may have other benefits
that are important to consider. One hypothetical benefit of neonic corn seed treatments might be
the reduction of resistance development by rootworms to other treatments. Rootworm has shown
The corn-soybean rotation has several agronomic advantages over continuous corn, including
usually higher corn yields and less need for nitrogen fertilizer use. But compared to longer rotations,
it has multiple disadvantages (Davis et al. 2012).
j

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a high propensity toward developing resistance to control methods, and so good stewardship toprevent resistance should be a high priority. However, recent research suggests that the use of neonicseed coatings may actually facilitate development of resistant rootworms (Petzold-Maxwell et al.
2013)137.
The addition of clothianidin seed coatings to Bt rootworm-protected corn delayed adult emergencefrom the soil by about 12 days compared to non-Bt corn used as required resistance management
refuges. Refuges are intended to supply non-Bt resistant adult rootworms to mate with possible
Bt-resistant adults emerging at low frequency from Bt corn.k However, the delayed emergence due
to seed coating use would likely lead to assortive mating, whereby Bt resistant adults would beless likely to find and mate with non-resistant adults emerging earlier from the refuge. This cansubstantially increase the probability of resistance emerging to Bt, since it defeats the basic purposeof the refuge. Even when the non-Bt refuge corn seed was also coated with clothianidin, adults
emerged much earlier than from seed with both Bt and seed coating. The seed coatings exacerbateddifferences in emergence dates seen for non-coated Bt vs. non-coated non-Bt refuge corn.
Therefore, using neonic seed coatings on Bt corn, the most effective treatment currently available
other than crop rotation, may compromise that control method. Bt is already rapidly succumbing
to resistance (Jakka et al. 2016)138 because it does not provide a high dose and is overused under
the promotion of the unsustainable industrial farming model, which eschews agroecological,
biologically diverse farming methods like long crop rotations. Use of neonic seed coatings may
accelerate this process.
Because Bt toxins active against rootworms do not provide a “high dose” as defined by resistancemanagement models, the refuge strategy is significantly compromised. However, assortive mating
due to neonic seed coatings may exacerbate an already problematic situation.
k

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Furthermore, the widespread prophylactic use of neonic seed coatings is more likely to lead torootworm resistance (as well as other corn insects) to these insecticides than occasional use, forexample in response to actual high pest levels (van Rosen and Ester 2009)139. Prophylactic use
provides continuous high selection pressure, which is known to favor resistance development ingeneral. And rootworms are notable for their propensity to develop resistance to insecticides andeven to rotation. Neonic resistance is already emerging in the closely
related Colorado potato beetle (van Rosen and Ester 2009)140. And
seed coatings do not provide a high dose, which is also generally“Therefore, widespreadassociated with more rapid development of resistance.
prophylactic
useofTherefore, widespread prophylactic use of neonic seed coatings for
rootworm control may be self-defeating from the perspective ofconserving these means of pest control. It should also be noted thateven where neonic seed coatings are not used to target rootworms,
these insects may be exposed inadvertently, and therefore selection
for resistance may occur.

neonic seed coatings
for rootworm control
may be self-defeatingfrom the perspective ofconserving these meansof pest control.”

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CHAPTER 4

IF NEONIC SEED COATINGS OF CORN ARE
ELIMINATED, WILL OTHER INSECTICIDESREPLACE THEM?

O

ne important question that has been raised as a caution about reducing or eliminating
neonic seed coatings of corn is whether they would be replaced by other insecticides thatare equally, or more harmful. As has been discussed throughout this report, however, there
are several reasons why this concern has no merit.
First, many fewer acres of corn would be treated with insecticides if the nearly ubiquitous use ofprophylactic corn seed coatings ended, and only acres that were actually infested with economically
harmful levels of these pests were treated with insecticides. As described in the first chapters of
this report, corn acreage with harmful levels of early-season secondary pests is much less than iscurrently exposed to neonics via coated corn seeds. Although there are inadequate data on theoccurrence and levels of these pests in the United States, it is widely understood that they occur only
infrequently at high levels. This is also supported by the research analyzed in this report.
A rough approximation of the prevalence of these pests can be derived from consideration ofhistorical acreage treated with insecticides. As noted above, only about 30 percent of corn acres were52 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

treated with applied insecticides from the 1990s through 2003 (Douglas and Tooker 2015)141, andmost of those acres were treated for either rootworm or European corn borer. Some acres treated forthese pests may have also incidentally controlled early-season secondary pests, but this was likely tohave been only a fraction of the total. The fact that there has not been enough research devoted tothose pests to confidently determine how often treatment was needed is in itself evidence that they
are not important enough to attract more than occasional research efforts.
Furthermore, as seen in the sections on the individual pests, there is no evidence that they haveincreased substantially. Even in instances where field tests were intentionally designed to encouragehigh levels of infestation, or where tests were performed in fields that had recent high infestations,the large majority showed no yield advantage when using neonic coated seed compared to untreatedcontrols. This suggests that it is unlikely that more than a few percent of corn acres have infestationsof these pests that could justify using neonic coated seeds. This is a small fraction of the current
estimates of between 71 to close to 100 percent of acres treated through seed coatings (Douglas andTooker 2015, US EPA 2017)142.
In other words, if neonic seed coatings were eliminated, it is likely that only a few percent of cornacres would turn to applied insecticides to treat early-season secondary insect pests (and should not
be used to control rootworms). In order for this small acreage to equal the harm from neonic coated
seed, the alternative insecticides used on these acres would have to be many times more harmful
on a per unit area basis than neonic coated seeds. However, a recent meta-analysis (Douglas andTooker 2016)143 found that even the highly toxic synthetic pyrethroids are not more toxic to nontarget organisms than neonics. Therefore, it is likely that even if other applied insecticides were
substituted for neonics on all of the acres where infestation levels might justify their use, the harmto the environment would be greatly reduced.
But more importantly, we know enough about the ecology of these pests to largely avoid conditions
that would lead to heavy infestations. Agronomically sound methods are available to greatly reduce
the possibility that these pests would occur in high enough numbers to cause significant crop
damage. These methods were discussed in the sections on the individual pests.
Finally, instead of using harmful insecticides as an insurance mechanism, it is more appropriate touse actual insurance for this purpose. First, as suggested by several entomologists, the cost of theseseed coatings does not justify occasional value for controlling unusually heavy infestations of thesepests.l But in addition, this pesticide-based insurance is “low cost” only when we do not consider
the heavy costs to the environment. Therefore, the continued use of neonic seed coatings of corn isunjustified, even if some of their use would be substituted by other applied insecticides.
For example, Cox et al. (2007), explicitly recommend against using neonic seed coatings as a form ofcrop insurance. Wilde et al. (2007) note that they may be useful where there are chronic infestationsof secondary pests (implying that by contrast, they may not be justified otherwise).
l

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CHAPTER 5

POTENTIAL FOR REDUCTION OF CROP YIELDDUE TO NEONICOTINOID SEED COATINGS

S

everal studies have shown or imply that the use of neonicotinoid seed coatings may reduceyield in some circumstances. Most of these studies analyzed soybeans, but similar effects arelikely in corn. Douglas and colleagues (2014) found that slugs, sometimes an important pest of
no-till soybeans, corn and other field or forage crops, were largely immune to neonicotinoids, whichaccumulated in their tissues after feeding on soybean seedlings grown from coated seed. However,ground beetles (carabids), important predators of crop pests in soybeans and corn, were killed when
they consumed the contaminated slugs. This led to outbreaks of slugs and a five percent soybean
yield reduction in the Pennsylvania tests, compared to untreated controls. This result is additionally
important because there are few effective molluscicides available to control slugs, making biologicalcontrol even more important (Douglas and Tooker 2012)144.
Mullin et al. (2005)145 also found high levels of acute toxicity to numerous carabid species compared
to untreated controls in laboratory-based bioassays and in microcosms using treated corn seed.
As noted by these authors, these important beneficial insects are usually among the species moreresistant to most pesticides compared to some other natural pest enemies, so high susceptibility ofcarabids to neonics is particularly troubling. This is especially so because these experiments wereconducted with seed treated at the low coating rate of 0.25 mg/seed, while clothianidin coated corn
seed intended to control rootworms and several other pests is treated at the 1.25 mg/seed level.
These higher levels may be expected to result in correspondingly higher mortality or morbidity ofnatural pest enemies.

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Ohnesorg et al. (2009)146 did not observe natural enemy reductions in their research on corn seedcoatings. However, more comprehensively, recent meta-analysis of numerous studies identified
significant natural enemy reductions associated with neonic seed coatings (Douglas and Tooker
2016)147.
By contrast other research (O’Rourke et al. 2008)148 found considerably higher levels of carabids inlong (four-year) crop rotations compared to two-year corn-soy rotations. Leslie et al. (2010)149 foundlower activity densities of natural enemies in corn grown from coated seed, and this treatment effectwas eliminated in rotated corn. Longer crop rotations (three or more crops) also have consistently
had higher corn productivity than corn-soybean rotations that rely more heavily on herbicides andsynthetic fertilizers (Gomez et al. 2012, Davis et al. 2012)150,151, although since many variables differ
between these treatments, the increased productivity has not been shown to be due to increased
natural pest enemies. Other research (Meehan et al. 2011, Letourneau et al. 2011)152,153 has shownthat higher natural enemy populations are strongly associated with greater productivity or greater
biological control potential (Geiger et al. 2010)154.
In addition to harmful impacts on ground beetles demonstrated above, Seagraves and Lundgren(2011)155 showed reduced numbers of three other widely disseminated and important protective
natural pest enemies in soybeans grown from neonic (thiamethoxam) coated seed.
The use of insecticides such as seed coatings may mask the biological control value provided bynatural enemies of crop pests, at the same time that they compromise the potential for biologicalcontrol by reducing the populations of natural pest enemies.
But natural pest enemies in diverse agroecosystems do not require purchase, unlike insecticides.
Therefore, even to the extent that neonic seed coatings may provide some minimal control of pests,
they may reduce net profits due to their purchase price compared to relying on natural pest enemies
and other processes, discussed in the next section, that control pests without monetary cost to thefarmer.
One study modeled the value of natural enemies in five Midwestern states in the Corn Belt as atleast $84 million/year for a single important pest of soybeans (Zhange and Swinton 2012)156, orabout $4.20 – $32.60 /ha/year. This model was based on broad spectrum insecticide application,rather than neonic coated seed. But neonics are broad spectrum insecticides for both pests andnatural enemies,m and as noted above, several researchers have observed substantial natural enemy.
Coated seed therefore would likely also cause reduction of income when used prophylactically in the
majority of cases where the target pests are not present in numbers that would exceed the economic
insecticide treatment threshold that takes into account the contribution of natural enemies.
Neonics are generally less harmful to non-insect arthropods such as mites and spiders. But becauseof the large number of insect species that are important natural enemies, we consider neonics to beeffectively broad spectrum despite lower toxicity against some natural enemy taxa.
m

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CHAPTER 6

AGROECOLOGY, AND CORRECTING THE
MYOPIC FOCUS ON SPECIFIC PESTS

I

t is understandable that farmers and research scientists would focus on the harm caused by
specific secondary pests. When these pests occasionally reach high levels, they may cause large
losses of yield and profit. But focusing on individual pests alone does not address the aspectsof the farming systems or practices, at the farm or regional scale, which determine the populationlevels of those pests as well as other environmental impacts.
For example, prevalent monoculture corn farming practices are highly destructive for several
reasons, such as high contributions to eutrophication of both fresh and marine water, and substantial
emissions of the greenhouse gas nitrous oxide due to heavy dependence on synthetic nitrogen
fertilizers. It also often involves reduced addition of organic matter to soil, reducing soil fertility
and organic carbon and nutrient recycling on the farm compared to agroecological systems. In thecontext of this report, they often produce lower corn yields than corn grown in rotation with othercrops. It is not fully understood why this is so (Bennett et al. 2011)157, but reducing pest populations
is one of the factors that contributes significantly to higher productivity. Longer crop rotations havebeen noted for decades to reduce corn pest insects generally, including the pests that are the targetof neonic seed coatings (Reeves 1994)158.
And crop rotation is well understood to control corn rootworms, except where rotation resistancehas arisen in recent years (and even in some of those areas, rotation still often works). Unfortunately,

56 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

there is a trend in U.S. industrial agriculture toward increased monoculture corn rather than longer
rotations (Plourde et al. 2013, Stern et al. 2010)159,160.
Longer rotations in the Corn Belt have been shown to have additional advantages over the common
corn-soybean rotation, including substantially reduced pesticide and fertilizer costs, resulting inhigher profit margins and greater yield for corn and other rotation crops (Davis et al. 2012, Gomez
et al. 2012)161,162. In general, increasing the diversity of farming methods is associated with lower
synthetic chemical dependence without sacrificing productivity (Lechenet et al. 2014)163. Suchbeneficial results may be missed when focusing on a specific pest rather than on the overall collective
impact of all pests, soil quality, and resilience to abiotic factors (e.g. extreme weather) over time.
One often overlooked aspect of farming systems is the importance of biodiversity at the landscapescale in providing natural pest enemies and pollinators for crop protection and production. In
this context, the value of natural enemies may be underestimated in the heart of the Corn Beltdue to the very low maintenance of diverse uncultivated habitat beyond the farm itself. Researchhas established greater positive impact of natural pest enemy populations and diversity whenuncultivated landscape is available locally and regionally to provide habitat for such organisms(Tscharntke et al. 2005, Gabriel et al. 2006, Gabriel et al. 2010)164,165,166.
Most experiments testing the efficacy of neonic seed coatings to control early-season pests of corn
do not report the landscape characteristics that surround the test plots. However, many of them
have been conducted in Corn Belt states that have little uncultivated habitat. And the industrial
farms themselves are also diversity-poor ecological matrices (Perfecto and Vandermeer 2010,
Tscharntke et al. 2012, Mendenhall et al. 2014, Zalucki et al. 2015, Kremen 2015)166,167,168,169,170,171, so
the populations of natural enemies in industrial corn fields is likely to be especially low, for example
when compared to organic farms (Crowder et al. 2010)172.
Therefore the majority of tests that have been conducted to determine
the value of neonic seed coatings may underestimate the potential forbiological control in more diverse agroecosystems. Some estimates ofincreased dependence on insecticides due to loss of natural enemies
have been made, and can be substantial (Rusch et al. 2016)173. For
example, one estimate (Meehan et al. 2011)174 suggests that farms
needed to apply additional insecticides to about 1.4 million ha ofcropland, with costs to farmers of about $48/ha, due to inadequate
habitat for natural pest enemies in seven Corn Belt states in 2007.

“Therefore the majorityof tests that havebeen conducted todetermine the value ofneonic seed coatings
may underestimate thepotential for biologicalcontrol in more diverse
agroecosystems.”

We therefore desperately need policies that address the farm landscapebeyond single farms, and that incentivize practices that facilitate the large benefits that this brings tofarmers and the environment. These policies must recognize the reality that farms are not isolatedislands, but part of larger ecological and social communities.

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A narrow focus on particular insect pests also neglects negative impacts of neonic and otherinsecticides on other farm processes and other types of pests. For example, Smith and others(2016)175 found that harm to weed seed herbivores (often called weed seed predators) may leadto increased weed seed on farms, which could in turn lead to higher herbicide use and thereby
higher cost.n In other words, natural enemies are not only important for reducing invertebrate pest
numbers and impacts, but also the impact of weeds. Significantly, many natural enemies of weed
seeds are ground beetles (many carabid beetles are omnivorous, eating insect pests and weed seeds),
which have been shown in several experiments to be harmed by neonicotinoid seed coatings, as
discussed elsewhere in this report.
Finally, the larger impacts of the biologically simplified
farming systems that rely on neonicotinoid seed coatings
are unaccounted for in a narrow focus on pest control.
These include the impact on farming communities andthe environment broadly. Among these are the loss of
viability of rural towns due to loss of population and jobs,
water and air pollution, general loss of biodiversity, lossof soil fertility, and substantial production of greenhousegasses. All of these important multifunctional values ofagriculture (Boody et al, 2005)176 are ignored by a myopic
focus on insect pests alone. By looking beyond the current
narrowly defined and almost exclusive focus on production and cost savings, broader gains can beobtained for the stability of the farm economy and rural society, as well as the environment (Boodyet al. 2005, Cochrane 2003)177,178.

“By looking beyond the current
narrowly defined and almost
exclusive focus on production
and cost savings, broader
gains can be obtained for thestability of the farm economy
and rural society, as well as
the environment (Boody et al.
2005, Cochrane 2003)177,178.”

The results of this paper were not statistically significant. As the authors note, this could be due
to inadequate sample size. So these results should be considered to be preliminary until confirmedor refuted. But when combined with other research noted in this report of the impact by neoniccoated seed on weed seed natural enemies such as ground beetles (e.g. O’Rourke et al. 2006), it is
not unreasonable to assume that these insecticides may cause some increase in weed numbers anddiversity in crop fields.
n

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CHAPTER 7

SOME SOCIAL IMPLICATIONS OF SEEDCOATINGSThe motivations that drive the use of neonicotinoid seed coatings as they pertain to farming
practices and the larger rural landscape need to be understood as part of food andfarming systems nationally (e.g. Cochrane 2003)179 and globally (e.g. McMichael 2005)180.
In particular, an underemphasized aspect of seed coating technology is that it reduces labor, by
avoiding the time involved in applying insecticides in the field, for scouting for insect pests that are
the main target of this seed technology, or for management of more complex farming systems thatavoid these pests.
And of course, seed companies make additional profit on coated seed. It has long been a recognizedpart of the business model of pesticide companies to encourage dependence on insecticides. Called
the “pesticide treadmill” (Van Den Bosch 1978)181, that reliance on insecticides instead of biologicalcontrol supplied in healthy agroecosystems leads to enhancement of pests that were previously
insignificant, further reliance on insecticides, resistance development by pests, and replacementwith new patented, and therefore more expensive, insecticides.
As noted earlier, farmers also may perceive neonic seed coatings as a relatively inexpensive way to
reduce risk, at least as judged by comments of several extension entomologists. Risk reduction isunderstood to be an important motivation for farmer decision making (Moschini and Hennessey1999)182. Evidence has been provided for risk or ambiguity aversion as one driver of the use of

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engineered Bt insect pest protection of corn in the Midwest (Barham et al. 2014)183. Arguments
about yield may therefore obscure these underlying motivations to use seed coatings as a kind of
insurance against uncertain risk.
It is also possible that research on the minimal yield protection afforded by neonic coated seedis not readily available to farmers from trusted sources, or is countered by advertising for seedcoatings. For example, we are not aware of previous broad analyses of the minimal value of neonicseed coatings, especially including multiple individual pests and detailed assessment of possible
alternatives, such as is contained in this report.
The economic pressure for reduced labor or simplified production systems is in turn motivatedin part by pressure to increase farm size—especially in the Corn Belt (MacDonald et al. 2013)184—which is facilitated by the ability to farm more acres in less time. The biological and ecologicalsimplification that accompanies this trend, however, exacerbates pest levels and results in a vicious
cycle of increasing dependence on harmful chemicals and similar technologies. This has been
identified as one consequence of a “technology treadmill” whereby farmers must continuously
purchase newer and often more expensive technologies to increase yield or cut costs, while paying
increasing land costs, in order to make a profit.
But the large number of existing farms necessitates that while first adopters of new technologies
may initially see increased profits, profit margins shrink as most farmers eventually adopt the
new technology. Non-adopters that rent land generally lose money and are driven out of business(Cochrane 1993, Levins and Cochrane 1996)185,186. Often the remaining farmers buy or lease more
farmland and increase their size. The tendency to overproduce, driving down crop commodity
prices and profits, has been widely recognized and documented (Ray et al. 2003)187. Investment in

60 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

technologies that facilitate increased farm size such as labor-saving technologies like seed coatingsand engineered traits may also lock farmers into simplified farming systems. This can occur
through debt, lack of knowledge about sustainable farming systems, and other means, making it
difficult to adopt more socially and environmentally beneficial farming methods (Vanloqueren andBaret 2009)188. The resulting tremendous harm to the environment and rural society (Lobao andStofferahn 2007)189 is in turn the result of this simplified farming system that is, on the other hand,
encouraged by the industries that profit from products, including pesticides, which industrial
farming systems rely on.
This also means that farmers will require substantial help through policies, incentives, andregulations to move away from destructive industrial farming practices like neonic seed coatings
to environmentally and socially sustainable agroecology-based farming systems that are also
profitable. Simply relying on the market system will not be sufficient to change farm practices
given the broader socio-economic dynamics. Additionally, reliance on self-interested seed andpesticide companies as major sources of information for farmers is unlikely to encourage adoptionof environmentally and socially beneficial farming systems that do not rely on company products.
Independent publicly supported and trusted sources of information and research are therefore
critically needed.
In the case of neonic seed coatings, however, relatively small
adjustments to farming practices would be needed to achieve
control or avoidance of secondary pests. And even without
these changes, neonics are infrequently needed to protect
yield. Therefore neonic seed coatings are a particularly goodtarget for changing farming practices toward those based on
ecological principles.

“In the case of neonic seedcoatings, however, relatively
small adjustments to farming
practices would be needed toachieve control or avoidanceof secondary pests.”

The understanding of neonicotinoid seed coatings as part of biological impoverished farming
and food systems is important to better understand how to address these problems in the interestof farmers, rural communities, the environment, and society more broadly. For example, while
it makes sense from the perspective of farm productivity, profit per unit of land, environmental
benefit and so forth to implement agroecological methods to avoid high infestations of early-season
corn pests, the increased complexity and slightly increased labor involved goes against the sociallyand environmentally destructive trends toward increasing simplification and labor reduction peracre that accompany increasing farm size. Only when this larger context is better understood canpolicies be developed that support farmers, the environment, and rural communities.

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 61

CHAPTER 8

SUMMARY, CONCLUSIONS AND
RECOMMENDATIONS

T

he available peer-reviewed literature demonstrates that prophylactic neonicotinoid seedcoatings are not needed to protect corn from yield loss due to early-season insect pests. The
available literature on protection of corn from these pests consistently demonstrates thatthey are not often present at harmful levels. There is not a large research literature on any of thesepests, which is to be expected for pests that are not often of economic concern. In fact, the limited
amount of research itself is highly suggestive of the minor importance of these pests.
The available research also shows that ecologically based practices can further reduce the possibilityof heavy infestations, and in rare cases where this does not work, applied insecticides can be
successfully used.
Research has demonstrated that these pests are uncommon despite the frequent use of experimental
designs that were intended to increase the severity of these pests. In almost all of the research,scientists grew corn test plots under conditions that have been reported to encourage high earlyseason pest levels, used plots where high infestation levels had been observed in previous years, or
artificially infested crops with the target pests. These are common and accepted practices, because
only under moderate to high infestation levels is it likely that enough harm would occur to the crop
to adequately test the efficacy of the treatment. However, this does not represent the conditions
typically found on commercial farms. Therefore such tests are biased in favor of higher damage

62 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

from these pests compared to what would typically be found on farms, and overestimate the valueof neonic seed coatings for actual farms.
Despite tests that were biased toward higher infestation levels than would commonly be observedon commercial farms, only a relatively small percentage of these tests resulted in improved yields
compared to controls where no insecticide was used. Often no yield improvement was observed
unless trials were designed to encourage heavy secondary pest infestations, in which yield
improvement still occurred in only about zero to 25 percent of this research, depending on the pest
and experiment.
There are no data that we are aware of that examines the prevalence of harmful levels of early-season
insect pests on farms. While these pests have been mentioned in academic extension entomology
documents, and there has been some speculation or anecdote that some of these pests may haveincreased in frequency in recent years, there is inadequate research or other documentation to
support this. We could find no substantive evidence that the levels or frequency of these pests haveincreased significantly. And in fact, the available peer-reviewed research suggests that these pests
have not increased significantly, and remain minor and infrequent pests that do not justify almost
ubiquitous prophylactic neonic seed coatings.
A single exception to the peer-reviewed literature is a metaanalysis study of mostly non-peer-reviewed field tests, most ofthem sponsored by the pesticide industry. This study is unsuitablefor determining the realistic yield protection of neonic seedcoatings on corn farms. First, the study does not quantify orcompensate for the bias in experimental design which is intended
to increase pest frequency and levels above those on typical farms,
as discussed above. Although mentioned in passing, the study did
not adjust for the impact of these biases on its reported results.

“A single exception to thepeer-reviewed literature
is a meta-analysis studyofmostlynon-peerreviewed field tests, mostof them sponsored by thepesticide industry.”

Secondly, the study apparently includes tests for rootworm control. Although pesticide labels allow
for control of this primary major pest of field corn, research and research entomologists consistently
recommend against relying on neonic seed coatings for this purpose. Importantly, there are otherbetter, more effective, and more environmentally sound methods of controlling rootworms, especiallycrop rotations in most of the range of these pests. And corn-soybean rotations are already widelyused and practical, although longer rotations should be encouraged. Secondly, there is evidence
that use of prophylactic seed coatings for rootworm control could have negative consequences forresistance management designed to preserve current control measures.
It is likely, based on comparison between the results of the industry meta-analysis and the highly
contrary findings of the peer-reviewed literature, that the yield protection seen in the industrysupported study is largely an artifact of biased study design and, especially, residual rootworm

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 63

control, although this is impossible to say with certainty because these concerns were not addressedin the publication. In any case, the peer-reviewed research should take precedent over this study,
which relies extensively on non-peer reviewed tests.
Finally, in published studies, moderate control of rootworms was achieved, although unreliably,
only when a high dose of 1.25 mg/seed was used. This is five times the dose used to control mostsecondary early-season pests. If widely used to control rootworm, this could substantially increase
the amount of neonics used over a wide area, greatly increasing harm to the environment, including
pollinators, natural pest enemies, aquatic invertebrates, birds and other organisms.

A. AGROECOLOGICAL, AND OTHER ALTERNATIVESTO NEONIC SEED COATINGS
For every early-season insect pest targeted by neonic seed coatings, practical alternative, nonchemical methods have been studied based on the biology and ecology of the pests and crops. For
farmers concerned about secondary pests, use of these methods should substantially reduce thepossibility of harmful infestations, even lower than the already low occurrence of these pests foundin the research literature. Implementation of these practices should make significant infestations ofthese pests highly uncommon.
More broadly, rather than focusing mainly on specific uncommon pests, the use of agroecologicalprinciples, informed and optimized by research, has been shown generally to produce yields as highor higher than those of industrial agriculture, with minimal reliance on pesticides.

64 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

In fact, there is evidence that using neonicotinoid seed coatings may actually reduce yields insome cases, because of demonstrated harm to important natural enemies that help control mostcrop insect pests. Although there are not enough data to verify such impacts in corn, the available
research is suggestive. More research on this important topic should be conducted to better informfarming practices.
Although agroecological research has not
specifically measured the frequency of the“Although agroecological research
has not specifically measured theminor pests that neonicotinoid seed coatings
frequency of the minor pests thattarget, it has shown that regardless of specificneonicotinoid seed coatings target, itpests, high yields and profits are typicallyhas shown that regardless of specificachievable. Agroecological systems achieve
pests, high yields and profits arethese results by fostering biological diversity,
typically achievable.”which breaks pest cycles through crop rotations
and cover crops, and provides high levels ofnatural pest enemies that usually keep pests in check. And when applied on a regional level, thesebenefits are enhanced.
1. Other Available Treatments
For subterranean pests, rescue treatments cannot be used after planting for the rare cases where
heavy infestations occur. But scouting can be done for all of these pests. This can be accomplishedin cases where farm practices would be most likely to encourage high infestation levels—in otherwords, they would not need to be done routinely. For some pests, such as corn flea beetle in several
states, data are available that can predict years in which heavy infestations may be more common.
Several of the more important pests have multi-year life cycles of the harmful larval stage, andtherefore scouting can inform treatment for subsequent years.
For above-ground pests, scouting can also be effective, and in the unusual cases where high infestationlevels are encountered, rescue treatments are available. In most cases, these are considered to be as
or more effective than seed coatings with neonicotinoids.
2. Would Other Insecticides Simply Continue Harm to the Environment
if Neonic Seed Coatings were Discontinued?
Pertinent questions have been raised as to whether the substitution of other insecticides for neoniccoated seeds would result in as much or more harm as using neonic seed coatings themselves. To
the contrary, recent research that demonstrates that seed coatings are as toxic as applied insecticides
like synthetic pyrethroids strongly refutes this argument. The analysis in this report shows that
insecticides are rarely needed to control early-season corn pests, and that crop loss from thesepests can be largely eliminated by using non-chemical methods. While 71 to almost 100 percent of

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 65

corn acres are exposed to neonicotinoids, only a small fraction of this area would likely undergo
exposure to applied insecticides if neonic seed coatings were eliminated. Because neonics are as
toxic as applied insecticides, the greatly reduced exposed acreage exposed to insecticides would
likely greatly reduce harm.
3. Why Are Neonic Seed Coatings of Corn So Widely Used?
Given that significant harm from the early-season secondary pests is uncommon, why are thelarge majority of corn seeds coated with these insecticides? Several possible explanations based onchanges in pest levels were considered in this report, but none of them was supportable based on
available research.
Part of the explanation is likely to be that farmers see these seed coatings as “cheap insurance” even
if the pests they are aimed at are uncommon. Inadequate farmer information about the infrequencyof early-season crop pests and inadequate information about reliable alternatives may lead to risk
and ambiguity (uncertainty) aversion behavior that may favor purchasing coated seed.
Another reason that coated seed may be accepted is that the process of coating is almost always
performed by the seed companies or suppliers before the seed is purchased by farmers, so they do not
require extra labor on the farm. There may also be increased incentive to be additionally protectiveof corn seed due to greatly increased seed price since the advent of expensive engineered traits.
And when corn prices are high, as they were for several years beginning in 2007, there is additional
incentive to “protect the investment in seed” and production. These points were mentioned inseveral publications on corn seed coatings by entomologists. But those scientists also point out thatprophylactic use as “insurance” is not likely to make economic sense.

“Therefore, the monopoly
nature of the seed industry
has virtually eliminated farmer
choice for non-coated seed.”A related issue is that the highly concentrated corn seedmarket allows virtually no choice about seed coatings by
farmers (Douglas and Tooker 2015)190. Several of the major
seed companies are reported to coat all of their corn seed
before sale, not offering uncoated seed. The other major
companies coat almost all of their corn seed. Therefore,
the monopoly nature of the seed industry has virtuallyeliminated farmer choice for non-coated seed.

Finally, it is not clear how often farmers are aware of neonic seed coatings, since this is usually partof a package of traits and coatings. More research on all of these possibilities is needed.
Given the increasingly documented harm to biodiversity and possibly to human health fromneonicotinoid coated seeds, and the clear tremendous overuse of seed coatings compared to pestpressures and non-chemical alternatives, the continued prophylactic use of neonic coated corn seedis unsupportable in terms of social and environmental impact.

66 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

It is also understandable that current large industrial farms are in some ways trapped, or “lockedinto” current practices. This is due to the desire or pressure for simplified, labor-saving methods
that facilitate increasing farm size, which is in turn driven in large part by national and internationalfarm policies and markets, and labor saving technologies like seed coatings and engineered traits.
In particular, the trends toward overproduction and small net profit margins per acre (or even costof production that exceeds corn prices) must be addressed if corn farmers are to be helped to forego
neonicotinoid seed coating and other harmful industrial farming practices.
However, compared to the challenge of changing farming toward agroecological systems that arehighly beneficial to the environment, farms, and rural society, the changes needed to avoid earlyseason secondary insect pests of corn are relatively simple. Therefore ending the use of neonicseed coatings would be relatively easy to accomplish, and is an opportunity to make farming moresustainable.

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 67

B. RECOMMENDATIONS
1. Restrict the use of neonic seed coatings of corn. The published research showsthat prophylactic use of neonic corn seed coating is unjustified for its mostimportant purpose of protecting yield. If not eliminated, use should be limited
to acres for which heavy infestations of early-season secondary pests occur
and are not avoidable or controlled by available non-insecticide methods.
2. Conduct surveys of farmers by USDA/NASS or
USDA/ERS or independent university scientists to better“The published researchunderstand why, and what percentage of farmers believe
shows that prophylactic
they need neonic seed coatings of corn. The data fromuse of neonic corn seedcoating is unjustified for its
farmer surveys would help better understand how such
most important purpose of
farmers can be assisted if prophylactic neonic seed coatingsprotecting yield.”
are eliminated. Utilize farmer survey results to actively
develop outreach tools that help farmers avoid secondary
pest insects, or use alternative treatments to control earlyseason secondary insect pests. This should be done through USDA, especiallythrough public, independent extension services working with farmers to alleviate
concerns about restricting the use of neonic corn seed coatings. It is criticalthat farmers are integrally involved from early stages of this work—including
decision making—to ensure that the results are of practical value to them.
3. USDA/NRCS should include consideration of early-season secondary

68 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

insect pests and ecologically sound methods of reducing thesepests as part of its Conservation Stewardship Program and EQIP
grants, especially those, like longer crop rotations, that have multiple
benefits. Such grants would be consistent with the goals of the NRCS.
4. Implement, through USDA/RMA, insurance premium support for the rarecases where secondary pests cause substantial damage to corn yield, and suchimpacts were unavoidable by other viable approaches, as discussed in this report.
Other alternative methods for providing insurance could also be considered.
One reason that farmers seem to desire neonic seed coatings, despite theinfrequency of damage from the targeted insects, is as a form of “cheap insurance”.
5. Conduct additional publicly supported research to fill in holes in our
knowledge of early-season secondary insect pests of corn, and to refine
agroecological alternative practices to avoid or control them. These shouldemphasize system-level farming practices that reduce pest numbers in general,
as well as providing numerous other benefits to the environment, farmers andsociety. Research should also be supported that improves scouting and otherdetection and infestation prediction methods for early-season insect pests.
6. Seed companies should be required
to make non-coated corn seed of“The Department of Commerce
and the Department of Justicedesirable corn varieties readily
should investigate whether illegal
available.
The
Departmentofmonopoly practices have made it
Commerce and the Department ofexcessively difficult for farmers
Justice should investigate whether
to acquire uncoated corn seed.”illegal monopoly practices have madeit excessively difficult for farmers
to acquire uncoated corn seed. The
elimination of farmer choice is contrary to principles of a democratic economy.
7. EPA should release its analysis of the efficacy, benefits, and costs ofneonic corn seed coatings. It should fully weigh both quantifiable andunquantifiable values in assessments of proposed systemic insecticide
products, including at a minimum these foreseeable cost categories:••

honey bee colony impacts and resulting reduced yields ofpollinated crops, reduced production of honey and other bee
products,
harm to other pollinators and other beneficial and non-target
organisms

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

| 69

•
•
•

financial harm to beekeepers and consumers,
loss of ecosystem services, andmarket damage from contamination events.

EPA should also require verification by independent scientists
and economists (preferably published in peer-reviewed
journals) for claims of efficacy, crop yields, and economic
benefits associated with all products. It should rejectapplications to register any prophylactic insecticides that
undermine basic IPM and agroecological principles, may harmorganic farm production, or are not cost-effective, either for the
farmer or the nation as a whole.

70 |CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS

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Photo Credits:“Wireworm” - Katja Schulz - flickr CC BY 2.0“Western Corn Rootworm” - Sarah Zukoff - flickr CC BY 2.0“Diabrotica virgifera” - Whitney Cranshaw - Wikimedia Commons CC BY 3.0

CENTER FOR FOOD SAFETY ALTERNATIVES TO NEONICS| 75

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