Bt Plants Less Likely to Affect Non-Target Arthropods

Results of a study conducted by entomologists from Cornell University showed that genetically modified (GM) plants expressing Bt insecticidal proteins are less likely to harm the target pests’ natural enemies. The researchers compared the effect of common insecticides and BT proteins on the diamondback moth larvae and its wasp parasite, Diadegma. In nature, caterpillars parasitized by Diadegma usually die.

Bt-resistant diamond back moths were used to separate out the effect of insecticides and Bt proteins on the caterpillar and parasitic wasp. The scientists observed that parasitized caterpillars fed with insecticide treated plants, to which they were resistant, survived and developed to moths since the wasp larvae were killed by the insecticide the caterpillar ingested. When Bt-resistant caterpillars were fed with Bt plants on the other hand, the wasp larvae developed into adults killing the diamond back moth.

“Our studies make it clear that Bt plants are a win-win situation to control pest insects and to enhance biocontrol and biodiversity," noted Anthony Shelton, who together with Mao Chen, conducted the study.

The complete article is available at http://www.news.cornell.edu/stories/June08/SafetyofBt.mf.html