Distribution of Bollworm, Helicoverpa zea (Boddie), Injured Reproductive Structures on Genetically Engineered Bacillus thuringiensis var. kurstaki Berliner Cotton

Abstract Bollworm, Helicoverpa zea (Boddie), larvae are commonly observed feeding in genetically engineered Bollgard cotton. Although no information is currently available characterizing the levels of injury bollworms cause, ≈25% of the Bollgard acreage in the United States receives at least one insecticide application annually targeting bollworm populations. Studies were conducted to determine the levels of fruiting form injury that can occur from bollworm larvae feeding on white flowers of two types of genetically engineered cotton. The two types of genetically engineered cotton included the original Bollgard that produces one protein (Cry1Ac) from Bacillus thuringiensis variety kurstaki Berliner and Bollgard II that produces two proteins (Cry1Ac + Cry2Ab) from B. thuringiensis kurstaki. In one study, individual larvae (24 ± 6 h old) were placed in first position white flowers of Deltapine 5415 (non-Bollgard) and Deltapine NuCOTN 33B (Bollgard). Larval infestations were made on 50 plants for each of 5 d...