6-Regulation: Concerns over refuge size for US EPA-approved Bt corn
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TITLE: Concerns over refuge size for US EPA-approved Bt corn
SOURCE: Nature Biotechnology, Vol 21 (5): 467-468, by Kendall Powell
DATE: May 2003
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Concerns over refuge size for US EPA-approved Bt corn
As a new transgenic corn hits US fields for this year's growing season,
it's no surprise that controversy swirls about its stalks. The dispute
centers not on the plant itself - which even opponents say is likely to
be safe and beneficial to the environment - but on the crop's potential
The Environmental Protection Agency (EPA; Washington, DC), which approved
the corn in February, finds itself at odds with its own scientific
advisory panel over the question of how to manage pest resistance to the
crop. The unheeded scientific advice, and other decision-making glitches,
left critics wondering whether EPA regulation is firmly grounded on the
best scientific advice.
"The EPA is calling for science-based regulation, but here that does not
appear to be the case," says Scientific Advisory Panel (SAP) member David
Andow, a corn entomologist at the University of Minnesota in St. Paul.
Panel members convened by the EPA in August 2002 were mystified and
frustrated when the agency bypassed some of their major recommendations.
Other technical experts say they were asked to give their opinion on the
corn, then blacklisted from the advisory panel later.
US growers will plant an estimated one million acres of Monsanto's (St.
Louis, MO) YieldGard Rootworm corn this year. The crop expresses a
Bacillus thuringiensis (Bt) protein that is toxic to rootworm larvae,
which cause an estimated $1 billion in lost revenues annually. Another Bt
corn targeting the European corn borer was approved in 1996.
Monsanto estimates 12-15 million acres will eventually be planted to
replace heavily infested acres now treated with broad-spectrum
insecticides. Those insecticides include organophosphates and carbamates
rated among the most harmful to the environment and human handlers. The
EPA and SAP members agree on the benefits of reducing chemical use and
the specificity of the built-in pesticide.
The major disagreement, however, is the size of the transgenic crop
'refuge,' or adjacent nontransgenic plants. The refuge provides a pool of
unexposed insects to mate with any resistant insects, diluting resistance
genes. Thwarting resistance is key to sustaining use of the crop. The SAP
majority recommended a 50% refuge be planted, meaning the same amount of
nontransgenic corn must be planted beside or within transgenic crops. The
EPA required a 20% refuge in the 3-year registration, the size Monsanto
and another group of experts recommended.
"The EPA takes resistance management very seriously for all Bt products,"
says spokesperson David Deegan. "We want to be sure we are doing what we
can to safeguard its use." He says the EPA decided to go with a 20%
refuge because they received additional data from Monsanto that showed it
would be acceptable using conservative assumptions. The EPA calculated
that even if 100% of crops were transgenic, resistance wouldn't occur for
7-15 years. Deegan says, "All of our risk assessments are science-based
and that was absolutely the case [here]."
Deegan admits there were secondary reasons for the decision, too,
including the economic and practical reasons for having a 20% refuge.
Monsanto spokesperson Bryan Hurley argues that a 50% refuge would cancel
the benefit of insecticide reduction, discouraging growers. And he says a
consistent refuge size for both Bt crops of 20% will increase grower
But Andow contends he found inconsistencies when he back-calculated the
Monsanto data in support of a 20% refuge. And other panel members say
there wasn't enough data in general to make any decision other than the
most conservative approach. They point to major questions remaining about
a 'low dose' Bt crop that only kills about half of exposed insects.
Another group of experts, NCR-46, made up of extension scientists in the
corn belt who study rootworm pest management, recommended a 20% refuge
only during an interim registration period while testing was ongoing.
But some SAP members criticized a 'register now, test later' approach.
"This is like the FDA approving a drug with flimsy science and saying to
then do the safety testing," says Fred Gould, an insect population
geneticist at North Carolina State University in Raleigh. "I don't think
that's how you do science." The SAP also reiterated a recommendation from
a 2000 panel that asked for better EPA guidelines for safety testing the
crop's effects on nontarget insects (see "EPA guidelines for safety
testing in the works").
The scientific wrangling may be an artifact of a botched process, which
some say resulted from tighter conflict-of-interest rules. In spring of
2002, many SAP and NCR-46 members say they were asked to be on the panel,
only to be told a few months later they were disqualified because they
had received research funds from Monsanto. After clarifying the rule to
include only grants within the last year, some were reinstated. Only one
NCR-46 member, Bruce Hibbard of the USDA's Agricultural Research Service,
remained on the SAP and he was the only member to have worked extensively
with the Bt plants.
Lance Meinke, chair of NCR-46 at the time and rootworm expert at the
University of Nebraska says only those with company ties will have access
to the transgenic corn for greenhouse and field testing before its
approval. "It's good to have people looking from the outside," he says.
"But it would have been beneficial for everybody to get a balanced
panel." The decision left experts frustrated they were not allowed to
participate fully in the process. Others will forego future company funds
so they can stay in the regulatory game.
The EPA's Larry Dorsey, executive secretary of the SAP says the conflict-
of-interest criteria have been in place since 1995, but that a new waiver
form included more specific language on conflicts, alerting potential
members to the ties that disqualified them. "It is in the best interest
of the agency that these are independent science peer reviews," he says.
"That independence is the most important thing we [on the SAP staff] do."
Others, including Andow, think tighter rules preventing bias on panels
are for the best, but worry that as public agriculture research dwindles,
finding conflict-free experts may become difficult. "More and more people
are taking company money," says Doug Gurian-Sherman, director of the
biotechnology project at the Center for Science in the Public Interest
(Washington, DC). "There are qualified people available for SAPs now, but
where will we be in the future if we continue to cut back on public
funding?" The USDA currently funds the largest portion of genetically
modified (GM) crop risk assessment research at about $3 million per year.
The disquiet over the refuge decision and the panel's makeup belies
deeper problems about the regulatory process for transgenic crops - which
by all accounts will get trickier as new technology and stacked versions
of approved products hit the market. In the end, many say EPA did get the
best advice after all, combining data and recommendations from NCR-46,
the SAP, and Monsanto.
But to the outsider, appearances of an unscientific decision could be
deceiving and detrimental to public trust in the process of agbiotech
regulation. "Internationally, it will hurt the case for GM crops," says
Andow. "It undermines the US saying it has the strictest science-based
regulatory process in the world."