The Scientist 15[21]:11, Oct. 29, 2001

EPA Reauthorizes Bt Corn

Action means a seven-year reprieve for controversial crops

By Barry A. Palevitz

The U.S. Environmental Protection Agency announced on Oct. 16 that it had reauthorized commercial planting of genetically modified corn varieties transformed with genes from the bacterium Bacillus thuringiensis. Bt corn, as it's known, makes toxic Cry proteins lethal to caterpillars of the European corn borer and other damaging insects.1 The proteins are harmless to humans. As a result of EPA's action, seed companies can now market the products for another seven years, depending on compliance with requirements set forth in the re-registration document.2 The agency provisionally approved Bt cotton in late September.

EPA reached its decision after a year-long review of the crops. According to spokesperson David Deegan, the agency relied in part on advice from scientists asked to examine the matter. The scientific advisory panel, or SAP, reviewed risks and benefits of Bt corn, first planted in 1996. Says Stephen L. Johnson, assistant administrator of EPA's Office of Prevention, Pesticides, and Toxic Substances, "Bt corn has been evaluated thoroughly, � and we are confident that it does not pose risks to human health or to the environment. Consumers should be assured that these corn varieties show no signs of any adverse effects to human health."

By its action EPA also extended the reach of genetically modified corn by okaying a new variety called Herculex, developed and marketed by Pioneer HiBred of Des Moines, Iowa, in collaboration with Indianapolis-based Dow AgroSciences. The agency approved the new seed, which contains a gene called Cry1F, last June, but only temporarily until it completed review of existing Bt cultivars. The latest ruling extends Herculex sales for seven years.

Why Approval?

With GM corn in cultivation since 1996, EPA examined what the scientific community knows about the risks and benefits of the crop, including potential harm to Monarch butterfly larvae that may eat milkweed leaves laced with corn pollen. A 1999 laboratory study raised caution flags about the impact of Bt corn pollen on the beautiful nontarget insects. However, EPA concluded that "scientific evidence demonstrates that Bt corn does not [have an] impact [on] monarch butterfly populations." The SAP had already gone on record to that effect in a preliminary report issued in October 2000. According to a 2001 census of Monarch numbers, the insects are thriving, at least for now.

EPA was bolstered in its decision by six papers in the October 9, 2001 issue of Proceedings of the National Academy of Sciences. (The papers were released on the Internet on September 14 and the agency postponed its announcement for two weeks, pending public comment on the new data. The original registrations expired at the end of September.) Still, in re-registering the crops, the agency called for additional long-term monitoring of nontarget species for potential harm.

Some Happy, Some Not

EPA's ruling came in a good week for the biotech industry. According to preliminary results of a survey released on Oct. 18 by the International Service for the Acquisition of Agri-Biotech Applications in Manila, total acreage planted in GM crops worldwide reached 125 million acres--or 50 million hectares--in 2001, a 10 percent increase over the previous year and a 30-fold jump since1996, when the crops were first introduced. EPA's re-registration of Bt corn pleased Doyle Karr, public affairs manager for Pioneer Hi-Bred, who hailed the decision as "good news. It shows that EPA has a lot of confidence in these products and their safety." Eric Sachs, director for scientific affairs at biotech giant Monsanto in St. Louis, congratulated EPA on the reassessment process, saying "The agency was very comprehensive and thoughtful, � ensuring that it evaluated the breadth of relevant issues, engaged the highest order of scientific knowledge, and considered all perspectives and arguments before moving forward."

Jane Rissler, senior staff scientist at the Union of Concerned Scientists, which opposed re-registration, wasn't as complimentary. "EPA did a shoddy reassessment," she says. In fact, "EPA does as little assessment as it can get away with." Why? Rissler thinks "the agency is doing the companies' bidding. It's clearly biased in favor of this technology." She also worries that the decision will have long-term implications for foreign trade: "This will be seen with far more skepticism in Europe and Japan than in this country."

Benefits of Bt--No Brainer or Boondoggle

Not everybody agrees on whether Bt in corn is good for the environment--for example, whether it reduces pesticide use to an environmentally beneficial extent--though the evidence is more definitive for soybean and cotton. According to Rissler, EPA "cannot legitimately claim a benefit for consumers or the environment," yet that's precisely what it's doing. She thinks EPA's Johnson was wrong in stating that Bt "helps to protect the environment by reducing the amount of conventional pesticides used," though the SAP cited potential reductions in its October 2000 preliminary report.

Entomologist Marlin Rice of Iowa State University surveyed 7,000 corn farmers in six states about changes in pesticide use between 1996 and 1998 compared to the previous five years. According to Rice, 26 percent reported applying less pesticide by 1998. Rice thinks "that should be a sociological and environmental advantage."

Rice's data only cover field corn, which typically requires fewer pesticides. In his survey, 50 percent of the farmers hadn't used any pesticides in the previous five years. In contrast, growers of sweet corn for human consumption do much more spraying. While sweet corn accounts for less than 1 percent of corn acreage in this country, it requires 60 percent of the pesticide needed to control pest caterpillars. Entomologist Galen Dively of the University of Maryland in College Park says Bt makes a difference in sweet corn too.

Dively notes that in Florida, where growers have to apply pesticides about 15 times each season, Bt cuts the number to just one spraying. In Maryland, farmers reduced spraying from five-eight times to one. In New York, applications hit zero. "I've been working with sweet corn for 30 years," enthuses Dively. "It's phenomenal how well Bt works. It's a no brainer."

Responding to arguments that such research isn't peer reviewed, Dively insists that this kind of work often goes unpublished because it's routine. It's not the kind of thing scientists send to journals. Instead, they monitor crop performance, chemical use, and insect damage yearly and make the information available in technical reports and oral presentations (Dively made his observations available to EPA). "A lot of good research is done that's not peer reviewed," he insists. "That doesn't mean it's not legitimate."

Residue of Past Mistakes

EPA's decision doesn't effect prior federal action against the StarLink variety of Bt corn. In September 2000 an independent testing laboratory, at the behest of environmental activists, detected StarLink DNA in taco chips marketed by Kraft Foods, even though it had been approved only for animal feed amid concerns over possible allergic reactions. The Food and Drug Administration eventually recalled hundreds of foods contaminated with StarLink, and developer Aventis stopped selling seed.

The Centers for Disease Control and Prevention, together with the FDA, recently concluded that a sample of people claiming allergic reactions to StarLink lacked the necessary antibodies to elicit such a response.3 Nevertheless, EPA is still withholding approval, claiming it does not "have adequate information to reach a safety finding," according to Deegan.

While re-registration didn't directly concern StarLink, traces of 'tacogate' made their way into EPA's re-registration document. StarLink entered the human food stream in part because of lax regulation and accountability. A recent report released by Resources for the Future and the Pew Initiative on Food and Biotechnology questioned whether EPA and FDA "have adequate authority to condition approval on more active undertakings by the sponsor to ensure that the product is not put to unapproved uses? Can they condition approval on the existence of effective marketplace mechanisms to preserve the identity of lots and channel commodities to specific uses?"4

In re-approving Bt corn, EPA seems to have moved toward stiffer enforcement, though not in the realm of human health. The agency worries that incorporating Bt toxins directly into corn will lead to increased resistance on the part of target insects--and that's where tighter policing comes into play. EPA will now force industry to "educate growers about the best methods of planting Bt corn in order to minimize any potential development of insect resistance."

Anybody planting Bt corn must sign legally binding contractual agreements that, "coupled with grower guides, set forth the terms and conditions for use." The registration also specifies that "companies are now required to implement a system to secure signature of the grower agreements prior to receipt of any seed, and to make grower agreements available to EPA. Further, "to monitor the enhanced requirements, an independent third-party compliance survey of licensed growers will be conducted annually for the duration of the registrations." The regulations are similar to those EPA specified when it relicensed Bt cotton two weeks earlier. Asked whether EPA could yank a company's registration in case of noncompliance, Deegan said, "that's a safe assumption."

Deegan also confirmed that StarLink indirectly spawned the tougher rules: "I think that's definitely true. We all [government and industry] learned something from StarLink."

Rissler agrees the new rules are stronger, but she insists EPA still "doesn't require companies to move fast enough in case of insect resistance. I can't help but note that it's well past time for stronger compliance," she sighs.

Sachs says Monsanto welcomes more oversight. "In general, all of these elements [to control insect resistance] have been in place and will continue to be there in the future," he insists. In Sachs' view, the new rules "will allow EPA to better track the systems that are in place, evaluate the programs' effectiveness, and influence the continued development of the programs. Overall, we're certainly supportive and willing to further involve EPA in the process."

Not the End

EPA's decision came on the heels of an Oct. 10 agreement between Monsanto and Dow AgroSciences to end a legal dispute over patent rights to Bt technology. Dekalb Genetics Corp., a subsidiary of Monsanto, claimed that in developing Cry1F Herculex corn, Dow violated multiple patents held by Dekalb. According to the agreement, Dekalb is licensing the patents to Dow, thereby allowing it to market Herculex.

Both companies have other Bt products in the pipeline, including varieties resistant to corn root worm, another potent pest. Pioneer spokesman Karr expects his company's products to come online as early as 2003, but the feds will have to approve them first. That means a whole new round of supporting data--and presumably more controversy, debate and competition.

Barry A. Palevitz ([email protected]) is a contributing editor for The Scientist.
References
1. B.A. Palevitz, "Bt or not Bt ... transgenic corn vs. monarch butterflies," The Scientist, 13[12]:1, June 7, 1999.

2. Environmental Protection Agency, "Biopesticides registration action document. Bacillus thuringiensis plant-incorporated protectants," Oct. 16, 2001, www.epa.gov/pesticides/biopesticides/reds/brad_bt_pip2.htm.

3. National Center for Environmental Health, "Investigation of human health effects associated with potential exposure to genetically modified corn," www.cdc.gov/nceh/ehhe/Cry9cReport.

4. M.R. Taylor, J.S. Tick, "The StarLink case: issues for the future," Pew Initiative on Food and Biotechnology, October 2001, www.pewagbiotech.org/research/starlink.
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