By Pam Smith
DTN Progressive Farmer Crops Technology Editor
DECATUR, Ill. (DTN) -- There's further evidence this week that the Environmental Protection Agency (EPA) is drawing a tougher line on pesticides. On Thursday, the agency released an analysis that found there is little or no benefit to routine use of neonicotinoid seed treatments for insect control in soybeans.
Neonicotinoid pesticides are a class of insecticides widely used on U.S. crops as a preventative measure to control early-season pests that can attack vulnerable seeds and seedlings. A news release from EPA announcing the report indicated that the agency has been reviewing the insecticide with a "particular emphasis on their impact on pollinators." The insecticide class has been broadly implicated as a contributing factor to the demise of honey bee health.
However, the EPA report made no mention of pollinators and addressed only the economic value of the insecticide. It concluded that there is little or no increase in soybean yields when using most neonicotinoid seed treatments compared to using no pest control at all. There will be a Federal Register notice inviting the public to comment.
"We have made the review of neonicotinoid pesticides a high priority," said Jim Jones, assistant administrator for EPA's Office of Chemical Safety and Pollution Prevention in the press release. "In our analysis of the economic benefits of this use we concluded, that on a national scale, U.S. soybean farmers see little or no benefit from neonicotinoid seed treatments."
EPA cited many scientific publications supporting the analysis and noted that most neonicotinoid seed treatments as currently applied are only active in the soybean foliage for the period of three to four weeks after planting. They added that time period does not always overlap with when the targeted pests cause damage. The document did allow that some neonictinoid seed treatments could provide an insurance benefit against sporadic and unpredictable pests, particularly in southern states.
University of Minnesota entomologist Bruce Potter told DTN that entomologists in his department are preparing an official response to the EPA on the report. He said it is generally true growers don't always see a yield response from these seed treatments.
"However, in some instances they do pay," said Potter. "Neonics are really effective in targeted situations. For example, they are the best way to control seed corn maggot in soybeans. They also work well for [overwintering] bean leaf beetle when we have problems with them." White grub, grape colapsis, early-season soybean aphid, three-cornered alfalfa hopper and wireworms are some other potential early-season pests targeted by neonicotinoids.
Potter said neonicotinoid seed treatments are most economical in situations where the grower can anticipate a problem. "For example, if you have cover crops worked into the soil or livestock manure applied to that field ahead of crop, that's a high-risk field for seed corn maggot," he noted.
Neonicotinoids were first registered for use on soybeans in 2004. Grower adoption has increased rapidly. The EPA analysis said on average, from 2008-2012, neonicotinoid-treated seeds were applied on 30% of soybean acreage, with some individual years approaching 40%. Most soybeans are treated at downstream seed-treatment facilities. Unlike corn, soybean growers often have an option of choosing to not include insecticide in the seed treatment cocktail.
For example, DTN email exchanges with Monsanto revealed the company offers three Roundup Ready 2 Yield soybean options: fungicide plus insecticide (neonicotinoid), fungicide only or an untreated option. A specific dealer may decide to offer all or only some of these options, but they are all available in the market. This is specific to Monsanto brands as other Roundup Ready 2 Yield providers have their own product offerings.
The EPA analysis was particularly critical of neonicotinoid seed treatments as a use to prevent soybean aphid outbreaks because of limited time of activity in the plant. Potter said seed treatments, at best, might slow aphid populations down enough to delay foliar applications. "Foliar options are still best for economic returns," he said.
Potter added that insects rarely cause as much soybean yield loss as growers think because soybean plants are great compensators. Growers also tend to take more preventative measures when soybean prices are high.
Still, he emphasized the importance of neonicotinoids as a tool to manage insecticide resistance and the need for conscientious, responsible use to protect pollinators. "Overuse can lead to insecticide resistance, but losing the option for neonics would increase reliance on increasingly fewer insecticides. This would increase selection pressure against these products and could limit options if resistance developed in another insecticide class," he added.
"Insecticide applications limited to fields with insect populations that present an economic problem will minimize selection for insecticide resistance. Scouting, using economic threshold based treatments when available, incorporating cultural controls and other integrated pest management (IPM) tactics are still pretty good ROI (return on investment) for soybean producers."
The news release noted that the EPA is required by law to do an economic analysis of the benefits of pesticides as well as the risks. It is rare, however, for the agency to draw specific attention to the economics of a product. The agency's conclusions for soybeans were:
• There is no increase in soybean yield using most neonicotinoid seed treatments when compared to using no pest control at all.
• Alternative insecticides applied as sprays are available and effective.
• All major alternatives are comparable in cost.
• Neonicotinoid seed treatment could provide an insurance benefit against sporadic and unpredictable insect pests, but this potential benefit is not likely to be large or widespread throughout the United States.
Read the entire report here: http://www2.epa.gov/…
This announcement marks the second time in a week EPA has made unusual commentary on a pesticide. On Oct. 15, EPA announced approval of a new herbicide, Enlist Duo, with first-ever label requirements to curb overuse that might lead to weed resistance. The agency called a special closed-session press conference to discuss those requirements with reporters.
Pamela Smith can be reached at firstname.lastname@example.org
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