Seed treatments | U.S. Environmental Protection Agency analysis shows neonicotinoids do not protect soybean crops
Planting soybean seeds with a neonicotinoid seed treatment offers zero yield benefits, says the U.S. Environmental Protection Agency.
In a memorandum released Oct. 15, the EPA’s biological and economic analysis division reviewed published data and EPA proprietary data on soybeans and neonicotinoids, a class of insecticides applied as a coating to the seed.
The agency determined that the benefits of neonic seed treatments are the same as doing nothing.
“This analysis provides evidence that U.S. soybean growers derive limited to no benefit from neonicotinoid seed treatments in most instances,” EPA scientists and economists noted in the memo.
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“Published data indicate that most usage of neonicotinoid seed treatments does not protect soybean yield any better than doing no pest control.”
The Ontario Beekeepers Association said the EPA report validates its position, that the Ontario government should limit the use of neonicotinoids.
“The EPA study is more evidence that pesticide manufacturers are operating irresponsibly,” said Tibor Szabo, OBA vice-president.
“By pre-treating seed with pesticides, farmers pay for their product whether they need it or not. The loss of our insect pollinators is the price we pay for their profit.”
The EPA findings contradict a Conference Board of Canada study released in July.
In a report titled Seeds for Success: The Value of Seed Treatments for Ontario Growers, the think-tank said restricting the use of neonics would cut corn and soybean yields, increase farmer’s cost and reduce Ontario producer revenue by $630 million a year.
Pierre Petelle, Crop Life Canada vice-president of chemistry, said there is no way to predict where and when an insect pest will attack a crop, so seed treatments are beneficial.
Petelle said Ontario corn yields have increased 30 percent during the last decade, and seed treatments have contributed to those gains.
Neonics, which are applied as a seed treatment to almost all corn and canola in North America and a portion of soybeans, have been linked to bee colony losses.
Two Ontario beekeepers filed a class action lawsuit against neonic manufacturers Syngenta and Bayer Crop Science in September, claiming $450 million in bee colony, pollination and honey production losses since 2006.
The OBA has said neonic seed treatments are applied to 65 percent of Ontario’s 2.5 million soybean acres.
The EPA said neonic seed treatments are ineffective against the major soybean pests in the United States: soybean aphids and bean leaf beetles.
“This is because the limited period of (neonic) bioactivity in soybeans (three to four weeks) does not usually align with periods of soybean aphid presence/activity,” the EPA said.
“Similarly, neonicotinoid seed treatments are not effective in controlling bean leaf beetles as this pest occurs too late in the season.”
EPA scientists said thiamethoxam and imidacloprid, two widely used neonic seed treatments, cost farmers about $7.50 an acre.
The agency said soybean growers would be wiser to skip the neonic seed treatment and apply an equivalently priced foliar insecticide, when needed.
James Knowles, one of the authors of the Seeds for Success study, said the EPA memo does not contradict the conference board report.
“The key purpose of our research wasn’t to determine whether there was a positive yield benefit from neonicotinoids. Our paper was looking at estimating the cost to Ontario farmers if we were to get rid of the neonicotinoids.”
Knowles said the conference board looked at some of the same American studies as the EPA, but also considered University of Guelph research.
“In some of the field tests there was no yield benefit. In other field tests there was a yield benefit,” said Knowles. “It seems to differ pretty strongly between different years and different testing sites…. Some farmers may not benefit, but others might.”
Knowles said the argument to apply a foliar spray isn’t as simple the EPA assumes. The cost of the foliar spray might be the same as an insecticidal seed treatment, but there are also time and equipment costs.
“The foliar pesticides … you have to send a machine out and spray these things down,” he said.
“Whereas the seeds are already treated, so the farmer doesn’t have to do that or spend (money) on extra labour to do that.”
