Arizona farmers who grow genetically modified cotton can skip some of their usual insecticide spraying. Those crops have the same impact on crawling insects and the same yield as unmodified cotton does, according to a field study.
Yves Carrière of the University of Arizona in Tucson and his colleagues monitored 21 commercial fields of so-called Bt cotton, which carries genes from the Bacillus thuringiensis bacterium. Bt cotton makes a bacterial toxin that tends to kill moths and butterflies. Arizona cotton growers count on this biotech variety to knock out pink bollworms.