W A S H I N G T O N, Aug. 21, 2000 -- Iowa State Universityresearchers said today they found more evidence that pollenfrom bioengineered corn could be deadly for Monarchbutterflies, prompting environmentalists to renew demands fortighter restrictions on the crop.
The Iowa study published in the journal Oecologia comes ata time when the U.S. Environmental Protection Agency haslaunched its own review of the safety of corn and cotton plantsmodified to contain a pest-fighting gene.
The Clinton administration has faced growing pressure duringthe past year from consumer and environmental groups, as wellas some U.S. trading partners, who say not enough is yet knownabout the long-term safety of biotech crops. The seed industryand agribusiness contend that gene-spliced crops have undergonethousands of tests and pose no more safety risks thanconventional crops.
Iowa State researchers John Obrycki and Laura Hansen saidtheir research showed Monarch butterfly caterpillars were seventimes more likely to die when they ate milkweed plants carryingpollen from Bt corn, compared to conventional corn.
Gene Used as Pesticide
Bt is short for bacillus thuringiensis, a naturally occurringsoil bacterium that acts as a pesticide. The gene has beeninserted into millions of acres of UL.S. corn and cotton plantsto repel the European corn borer, bollworms and other pests.
The researchers placed potted milkweed plants in and aroundBt cornfields to simulate naturally occurring conditions.
Pollen from Bt crops also drifts onto nearby plants,including those eaten by harmless insects like the Monarch. Theorange and black butterflies are at greatest risk within 10meters of Bt fields, Obrycki said in an interview.
“There exists a good possibility that we will see somemortality of Monarchs in the field,” he said. “The level andamount will depend on the timing of when the corn is sheddingits pollen and when the Monarch larvae are in the fields.”
The Iowa study analyzed the impact on larvae from two typesof BB corn developed by Novartis AG and sold under the brandnames NatureGard and Attribute. The research built upon work byCornell scientists who created a stir one year ago when theyreported Monarch larvae died when fed relatively large amountsof Bt corn pollen in the laboratory.
Novartis defended the safety of its Bt corn, saying the newstudy did not duplicate real-world conditions.
“Research conducted outdoors doesn’t indicate what happensin a field environment,” said Novartis spokesman Rich Lotstein.“The weight of evidence of published and preliminary researchindicates that milkweed within one meter of Bt corn fields arehighly unlikely to be dusted with toxic levels of Bt pollen.”
A dozen university researchers stretching from Canada to theMidwestern corn belt are currently studying Bt corn fields andwhether the pollen impacts migrating Monarch butterflies.
University of Illinois scientists said in June they found noill effects for black swallowtail butterfly caterpillars whoate pollen from a variety of Bt corn developed by PioneerHi-Bred International, a unit of DuPont Co.
EPA Conclusions in September
EPA officials said they would review the new Iowa study,along with other scientific research as part of broadassessment of health and environmental risks for humans,animals, insects and other plants.
The agency aims to publish its views by mid-September andwill spend the winter months analysing regulations to see whatchanges, if any, may be needed in buffer zones surrounding Btfields or other rules. An EPA advisory panel of independentscientists will also weigh in with its own recommendations.
“Based on what we’ve seen so far, we’re not seeing anyimpact on any non-target organism, particularly the Monarchbutterfly,” Steve Johnson, an EPA deputy assistantadministrator, said in an interview.
He downplayed environmentalists’ concerns about the latestbutterfly study.
“If we were confronted by information that raisedsignificant public health or environmental issues, thencertainly we could take immediate action,” Johnson said. “Basedon the reviews of all the data that have come in, we don’t seeany reason to take any kind of action at this time.”
Green Groups Want More
Rebecca Goldburg, a scientist with Environmental Defence,said the Iowa research shows farmers should be required toplant 40-foot wide buffer zones around Bt corn fields.
“The EPA already requires that farmers growing Bt corn plant20 percent of their acreage in non-Bt corn, in order to slowthe evolution of pests resistant to Bt toxins,” Goldburg said.“Planting some or all of this 20 percent acreage as bufferzones would be only a small additional step.”
Goldburg co-authored a landmark National Academy of Sciencesreport on biotech crops earlier this year that concluded morelong-term research was needed into the potential risks forhuman and animal health.
In addition to the EPA, the U.S. Agriculture Department andthe Food and Drug Administration (FDA) are also involved inregulating gene-spliced crops and food. The FDA is expected toissue proposed regulations next month that would require foodmakers to have mandatory consultations with agency scientistsbefore a biotech food can be marketed.
About 20 percent of the U.S. corn crop — or 15.6 millionacres — was planted with Bt varieties this year, according toU.S. Agriculture Department estimates.