W A S H I N G T O N, Aug. 21 -- 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.