By Emily Unglesbee
DTN Staff Reporter
ST. LOUIS (DTN) -- Growing Bt-corn hybrids could come with a whole new set of rules by 2016, if a new EPA proposal is finalized without changes.
On Jan. 28, the agency released a proposed framework for delaying the development of corn rootworm resistance, as part of the five-year reregistration review of Bt-corn products that target the corn rootworm.
Among its many proposals, the drafted document would require manufacturers of Bt seed to ensure 70% of their customers in "high-risk" rootworm areas are using crop rotation, pyramided Bt-products, or non-Bt hybrids combined with a soil insecticide. The proposal, which was prompted by the continued development of western corn rootworms that can tolerate Bt proteins, is likely to stir industry and farmer concerns, industry experts told DTN.
"EPA's initial proposal here has some good suggestions but other ones that are going to be challenges," said Nathan Fields, director of biotechnology and economic analysis for the National Corn Growers' Association. "We have concerns with how the EPA is going to enforce things like crop rotation, multiple modes of action, or changing modes of actions."
The agency's proposal is posted online at http://1.usa.gov/…, and will remain open for public comment through March 16 at http://1.usa.gov/….
"We are seeking input from all stakeholders, including corn growers, non-governmental organizations, industry, academia, and the general public, on this proposal," the EPA said in its press release.
INSIDE THE PROPOSAL
The drafted proposal has three major goals. The first is to require companies, as a condition of reregistration, to ensure that Integrated Pest Management steps such as crop rotation and pyramided Bt products are used by a set percentage of their customers. The second would aim to change when and how farmers react to "unexpected damage" in Bt-corn fields, in the hopes of speeding up resistance detection. Finally, the proposal attempts to establish and standardize the sampling and testing methods used by scientists to determine Bt-resistance in a rootworm population.
The most stringent requirements would fall on farmers in "red zones," where the risk of resistance is high because of widespread Bt corn use and rootworm infestations. "These areas ... include portions of Iowa, Illinois, Nebraska, western Indiana, southwestern Wisconsin, southern Minnesota, and eastern South Dakota," the agency concluded in a press release.
Here, companies would be required to ensure that 50% of their customers were rotating fields out of Bt corn, most likely into soybeans, at least every two years. Companies would also have to prove that a quarter of their farmer-customers were using "multiple modes of action," such as a pyramided Bt-corn hybrid. Another quarter would be required to use a non-Bt corn hybrid, combined with a soil-applied insecticide.
No more than 10% of a company's customers in the "red zone" could use single-protein Bt products. Adding soil-applied insecticides on top of Bt-products would be banned.
The proposal also lowers the damage threshold that would prompt growers to report unexpected rootworm damage on Bt-hybrids to companies. In single-protein products, a node injury score of 1 would require reporting; in pyramided products, a node injury score of 0.5 would trigger reporting.
Once damage of that level is reported, the proposal would require companies to ensure that growers immediately implement "remedial action," such as beetle bombing (adult beetle spraying), even before resistance is confirmed.
These requirements echo common university and Extension recommendations for delaying the development of rootworm resistance to Bt, but making them mandatory is alarming to the industry, Fields told DTN.
"The theory of this is fine," he said. "Crop rotation, switching modes of action, using non-Bt with soil-applied insecticides -- the execution of these are not difficult, but requiring growers to do it and how that's going to be managed is the challenge."
Limiting the management options available for certain growers is also a troublesome precedent, Fields added: "Some of the things affect freedom to operate, such as not being able to use any soil-applied insecticides on top of Bt products -- things like that could be a challenge from a grower standpoint and are a concern."
The NCGA supports the adoption of pyramided Bt-products over single-protein Bt-hybrids, but forcing growers away from them might not be necessary, Fields noted. "From the surveys done by the tech companies this year, the results suggest that adoption is already very high," he said. "That's one of those issues that the marketplace will drive."
The seed industry is likely to push back against parts of the proposal. A committee composed of companies that develop and market Bt-products, called the Agricultural Biotechnology Stewardship Technical Committee, is representing the seed industry's interests during the reregistration process with the EPA, Monsanto Communication Manager Jeff Neu said.
Jeff Bookout, a Monsanto employee and chairman of the ABSTC, said the committee supported some of the proposal's tenets, such as the increased need for dual modes of action against rootworm, but not all.
"We [ABSTC] also believe in the farmer's ability to freely choose the appropriate management practices that fit their fields and individual situations," Bookout said in an email. "We will continue to work with EPA to gain industry alignment on the most appropriate approaches for insect resistance management to effectively steward Bt traits and preserve their long-term durability."
After the comment period closes in March, the agency will finalize its new registration requirements for Bt manufacturers, most likely in time for the 2016 growing season, Fields said.
You can find the EPA's press release regarding the new proposal at http://1.usa.gov/….
Emily Unglesbee can be reached at Emily.firstname.lastname@example.org
Follow Emily Unglesbee on Twitter @Emily_Unglesbee.
© Copyright 2015 DTN/The Progressive Farmer. All rights reserved.