28
Jun
Seeds Coated with Neonicotinoid Insecticides Again Identified as an Important Factor in Butterfly Decline
(Beyond Pesticides, July 28, 2024) Most people don’t like bugs, but the fact is that insects form the foundation of human flourishing, both for their ecosystems services, like pollination of food crops, and for their aesthetic joys. But insect populations globally are declining two to four percent a year, with total losses over 20 years of 30-50 percent, according to a new study of the interacting effects of pesticides, climate, and land use changes on insects’ status in the Midwest. Teasing out the relative influence of these stressors has been a major obstacle in determining the causes of the declines and ways to mitigate them.
The icon of insect beauty in the U.S. is the monarch butterfly, whose vibrant coloring, elegant form, and spectacular migrations inspire everyone. Beyond Pesticides has covered the distressing decline of these creatures, most recently in the June 24 Daily News. Monarchs prefer milkweed plants, but also visit many other flowers. Milkweed often grows along the margins of fields, so monarchs are widely exposed to pesticides and habitat disturbances associated with agriculture.
The new study was published in PLoS One by a team of scientists from the Washington Department of Fish and Wildlife, Michigan State University, Iowa State University, and Georgetown University. Of the three drivers of insect loss, the study confirmed unequivocally that insecticides lead the pack in causing the loss of richness and abundance in Midwest butterfly species, particularly monarchs. “Overall declines are overwhelmingly supported by the evidence,†they write. Monarchs, bumblebees, dragonflies and lowland butterflies all drop catastrophically in areas where pesticides are used.
In the pesticide category, the study considered weed control (herbicides including glyphosate), reactive insect control (the sprayed insecticides pyrethroids and organophosphates), and prophylactic insect control (neonicotinoid-treated and Bt genetically modified seeds). The researchers considered all of the highest-use pesticides including their main active ingredient, target organisms, application timing, and mode of application (preventive, as on seeds or in soils, or reactive, in response to pest outbreaks), whether the pesticide spills over into nontarget areas, and how persistent it is in the environment. And while the steep crash of monarch butterflies coincides neatly with the introduction of glyphosate, the authors note that while herbicides reduce habitat diversity sharply, they do not directly kill insects like pesticides do. The study’s end result was clear: seeds coated with neonicotinoids are causing the most damage.
Neonicotinoids are the most widely used insecticide type in the world. While generally considered less toxic to mammals than organochlorines and carbamates, but much more toxic to a wider variety of insects—not just pests but also beneficials and charismatic butterflies, their serious adverse impacts on human health are becoming increasingly defined. (See here and here.) Up to 85 percent of applied neonicotinoid insecticides, including on seeds, can leach into the environment. Thus, beyond exposure to neonicotinoids via plant tissue or direct spray, there is deep concern about the residues that remain in soil and water and are incorporated into non-target plants.
The study used advanced and innovative methods to overcome the difficulty of determining the relative influence of pesticides, climate and land use changes. In their target region of the Midwest, agriculture comprises 60 percent of land use in most counties, and corn and soybeans dominate the crop types. The Midwest also has the densest network of butterfly monitoring activities, which the researchers accessed for species and abundance data.
Large-scale climate and land use data are also publicly available, and changes in these factors can be sensed remotely. But acquiring reliable information about pesticides is frustrating because much of it is protected by the obscurantism of chemical companies and the shirking of responsibility by regulators. Granular data about pesticide use does exist, but this data is often proprietary. To get that data, the researchers acquired results of an annual survey called AgroTrak, conducted by Kynetec, Inc., a market research company. The survey draws from databases of growers who receive federal payments, membership lists of farmers’ associations, and subscribers to agricultural publications, correlated with USDA groupings of areas with similar climate, geography and cropping practices. Respondents to the survey provide information from the previous year about which seeds they use and the types and amounts of pesticides they have applied to individual fields.
Importantly, the data the researchers used included information about neonicotinoid usage only between 1998 and 2014, after which the market research company stopped asking its respondents about whether they used neonicotinoid-treated seeds. This was apparently because farmers are less knowledgeable about the pesticides in treated seeds, so the survey did not draw out accurate data.
This problem was also analyzed by a 2020 report, “Sowing Uncertainty: What We Do and Don’t Know about the Planting of Pesticide-Treated Seed.†To get around this data gap, Sowing Uncertainty collected information from other, publicly available sources, but these often have their own weaknesses. For example, the USDA conducts annual voluntary surveys of farmers growing major crops (corn, soybeans, wheat and cotton), but conclusions from this data are also problematic because the data is aggregated and does not provide field-level information. Europe is a patchwork of reporting requirements, some of which provide fairly detailed data, but again, seed treatments are either not reportable or are lumped in with other pesticide uses. The best source of pesticide use data is the State of California, because it requires commercial applicators to report. But seed treatment is not defined as a pesticide in California. Clearly the status of pesticide-treated seeds must be clarified by regulators and included in reporting requirements. Its omission from the reporting system is an example of policy dictated by economic interests.
This is despite the rising use of treated seeds. For example, according to Sowing Uncertainty, “Over the 2012–2014 period, approximately 90% of corn, 76% of soybean, 62% of cotton, and 56% of winter wheat acres in the United States were planted with treated seed.†Yet, the report stresses, government data gathering concentrates on field-applied pesticides.
Attempts to reduce the threat from neonicotinoids in general and seeds treated with them have had mixed success. In the U.S., the U.S. Environmental Protection Agency (EPA) amended the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) in 1988 to allow manufacturers and sales companies not to register or label pesticide-treated articles including seeds, so they are not included in the pesticide use data the Food Quality Protection Act requires USDA to collect.
The European Union totally banned neonicotinoids for outdoor use in 2018, and in the U.S. the next year, neonicotinoid manufacturers caved to a lawsuit by beekeepers and environmental NGOs and asked EPA to cancel the registrations for a dozen of the 59 neonicotinoid products containing clothianidin and thiamethoxam. EPA has already found that three neonicotinoids—clothianidin, imidacloprid and thiamethoxam—are likely to adversely affect the vast majority of endangered species. Beyond Pesticides covered this issue here. Currently, EPA lists five neonicotinoids under registration review—including those three—which it optimistically plans to complete in 2024.
The PLoS study points directly to neonicotinoids as the leading culprit in monarch losses—but, the authors write, this “does not align with the relationship between neonicotinoids and monarch mortality in lab toxicology studies; indeed these lab studies show that neonicotinoids are among the least toxic agents.†This, Beyond Pesticides believes, highlights a severe problem with the methods used by regulators to assess harms to plants, animals, fungi and ecosystems from industrial chemicals: regulatory toxicology tests.
EPA, the Food and Drug Administration (FDA), and other agencies require chemical manufacturers to run batteries of antiquated tests on thousands of laboratory animals, usually culminating in calculating the LD50, or the dose at which half of the test animals die. The companies either conduct the tests and report the result to regulators themselves or outsource the tests to one of the many bespoke consultancies available to produce the desired results. Rarely do the tests include measures of cumulative health effects over time or at the animals’ most vulnerable life stages; nor do they often assess the combined effects of multiple chemicals.
Nor is there a requirement for chemical testing to be conducted together with other stressors such as those examined in the current study, namely climate and land use changes, especially habitat loss. Laboratory tests, the authors note, estimate “field-relevant exposure levels to be well below those expected to cause monarch mortality,†but this disregards the fact that seed treatments vastly increase the buildup of neonicotinoids in the environment. Nor can lab tests determine sub-lethal effects on monarchs in the environment. Laboratory results simply do not predict real-world consequences.
The authors emphasize that, because their dataset stopped in 2014, they were not able to consider the effects of climate change since then. The hottest years on record have occurred recently and surely must be affecting monarch abundance and survival more severely than they observed in their study. Even so, climate is unlikely to have outpaced pesticides as the most grievous harm being inflicted on these iconic butterflies and insects in general. Further, the glacial pace of regulatory action contrasts with the breakneck speed of pesticides’ accumulating consequences to insects and ecosystems. Insect loss means bird loss, estimated at 3 billion in the U.S. over the last 50 years. As the PLoS authors emphasize, there is an urgent risk of ecosystem collapse. Yet EPA and other federal agencies continue to give the worst culprits, neonicotinoid treated seeds, a free pass.
What you can do:
- Tell EPA to eliminate pesticides that threaten butterflies. Tell the U.S. Fish and Wildlife Service and Department of Interior to help bring back butterflies by eliminating the use of pesticides that threaten them. Tell Congress that EPA and other agencies need to do their job and protect our most charismatic insects.
- Join a monarch monitoring program to collect data in your area. Training is available.
- Create a monarch-friendly garden.
- Eliminate or reduce your own pesticide use; this will help not only monarchs, but yourself and all the plants, insects, fungi, and animals we depend on for life and joy.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Sources
Insecticides, more than herbicides, land use, and climate, are associated with declines in butterfly species richness and abundance in the American Midwest
Braeden Van Deynze, Scott M. Swinton, David A. Hennessy, Nick M. Haddad, Leslie RiesÂ
PLoS One June 20, 2024
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0304319
New ‘Detective Work’ on Butterfly Declines Reveals a Prime Suspect
The New York Times June 20, 2024
https://www.nytimes.com/2024/06/20/climate/butterfly-declines-insecticides-monarch.html
“Sowing Uncertainty: What We Do and Don’t Know about the Planting of Pesticide-Treated Seedâ€
Claudia Hitaj, David J. Smith, Aimée Code, Seth Wechsler, Paul D. Esker and Margaret R. Douglas
BioScience May 2020 / Vol. 70 No. 5
https://doi.org/10.1093/BIOSCI/BIAA019
[Blog post] “Sowing Uncertainty: What We Do And Don’t Know About The Planting Of Pesticide-Treated Seedâ€
By Aimée Code on 18. March 2020, Xerces Society
https://xerces.org/blog/sowing-uncertainty-pesticide-treated-seed
“Pollinator Week Ends; Pollinator Decline and Biodiversity Collapse Continue with Inadequate Restrictionsâ€
https://beyondpesticides.org/dailynewsblog/2024/06/pollinator-week-ends-pollinator-decline-and-biodiversity-collapse-continue-with-inadequate-restrictions/
“More Evidence Shows Neonics Harm Butterfliesâ€
https://beyondpesticides.org/dailynewsblog/2016/08/evidence-shows-neonics-harm-butterflies/
“Study Shows 50% Decline in Butterfly Population Across the European Union, 1990-2011â€
https://beyondpesticides.org/dailynewsblog/2023/05/study-shows-almost-50-decline-in-butterfly-population-across-the-eu-1990-2011/
Take Action: With Butterfly Decline Mounting, EPA Allows Continued Pesticide Use that Causes Threat
https://beyondpesticides.org/dailynewsblog/2023/06/take-action-with-butterfly-decline-mounting-epa-allows-continued-pesicide-use-that-causes-threat/
“Vanishing: More Than 1 In 4 Birds Has Disappeared In The Last 50 Years”
By Gustave Axelson, Cornell Lab/All About Birds, September 19, 2019
https://www.allaboutbirds.org/news/vanishing-1-in-4-birds-gone/#
Now we have seeds which are coated with anti bug properties. How stupid can we be? This stuff doesn’t wash off but stays on the seeds and rubs off on those not yet exposed. Science tells us, we need bugs! But, we need the right type of bugs. As of today we don’t have the knowledge or know how to develop seeds which can detect the difference. Without such detection we kill all bugs and that will end our food supply. This is why politicians are not scientists as few have a double degree.These coated seeds kill not only bugs but wildlife as they eat the seeds and products of the seeds. They even drop into ourocean ruining it for life as well. STOP manufacturing these seeds
July 4th, 2024 at 9:43 am