|Pilcher, C - IA STATE UNIV|
|Obrychi, J - IA STATE UNIV|
|Rice, M - IA STATE UNIV|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 20, 1996
Publication Date: N/A
Interpretive Summary: The European corn borer is a serious pest in the Corn Belt costing farmers yield losses from $15 to $50 per acre of corn. With increasing restrictions on pesticides, the call for sustainable agriculture, and the mandate for less surface and ground water contamination, the demand has never been greater for innovative methods to control this pest. Transgenic corn hybrids with resistance to feeding by European corn borers offer a novel approach. Toxin-producing genes from a bacterium, Bacillus thuringiensis, that kills European corn borers are inserted into corn plants killing young corn borers as they feed. To be certain that these transgenic plants do not harm beneficial insects (insect predators) that eat pest insects, scientists fed pollen from transgenic corn to generalist predators. Corn pollen does not have acute toxic effects on the prominent insect predators found in corn. The results of this research show that beneficial insects will remain effective when transgenic corn is planted.
Technical Abstract: Laboratory studies determined the effects of feeding corn pollen expressing Cry1Ab protein derived from Bacillus thuringiensis subsp. kurstaki (BT) on three predatory species: Coleomegilla maculata DeGeer (Coleoptera: Coccinellidae), Orius insidiosus Say (Heteroptera: Anthocoridae), and Chrysoperla carnea Stephens (Neuroptera: Chrysopidae). No acute detrimental effects of the transgenic BT pollen (Cry1Ab protein) on preimaginal development and survival were observed among these predators. The following survival percentages (plus/minus)SEM were observed: C. maculata, 89 (plus/minus) 2.2 percent (BT corn pollen), 69 (plus/minus) 5.9 percent (non-BT corn pollen); O. insidiosus, 63 (plus/minus) 12 percent (BT corn pollen), 44 (plus/minus) 10.2 percent (non-BT corn pollen); and C. carnea, 49 (plus/minus) 3.5 percent (BT and non-BT corn pollen). No differences were observed in the abundance of Ostrinia nubilalis (Lepidoptera: Pyralidae) predators (coccinellids, anthocorids, chrysopids) on BT or non-BT corn during two years of field evaluations. Predator numbers observed before, during, and after pollen shed suggest no detrimental effects of BT corn on natural enemy movement in corn. Additional studies are needed to test for chronic and reproductive effects over several generations before concluding that transgenic BT corn pollen has no effect on insect predators.