Resistance Development to Bt Crops in Caterpillars:Implications for Pest Management and Cotton/Corn Production in Louisiana

摘要

Bt cotton and Bt corn have been widely planted in Louisiana for more than two decades to manage major caterpillar pests of the two crops. Bt derives its name from the naturally occurring soil bacterium Bacillus thuringiensis that has been introduced into the genes of Bt crops. The bacterium produces crystalline (Cry) and vegetative (Vip) insecticidal proteins that, once ingested by target insects, are activated in the midgut and become toxic. In Louisiana, the primary target caterpillars of Bt cottonare the tobacco budworm and boll-worm. Several other species, including the beet armyworm, fall armyworm and soybean loopers, are secondary pests of cotton. For Bt corn, a complex of stalk borers — including the sugarcane borer, southwestern corn borer and European corn borer — are its primary targets, while the corn earworm (same species as bollworm) and fall armyworm are considered secondary pests.