Multiple and non-recessive resistance to Bt proteins in a Cry2Ab2-resistant population of Helicoverpa zea

Transgenic corn and cotton expressing Cry and/or Vip3Aa proteins from Bacillus thuringiensis (Bt) have been planted for managing lepidopteran coleopteran insect pests more than two decades in the U.S. Evolution of resistance to these Bt is a major threat continued efficacy technology. Understanding patterns cross-resistance dominance target insects essential management pest control. The bollworm, also called earworm, Helicoverpa zea (Boddie), pyramided crops In this study, we evaluated responses Cry2Ab2-resistant (RR), susceptible (SS), heterozygous (RS) strains H. Cry1Ac, Cry1A.105, Cry2Ab2 Vip3Aa39 using diet-overlay bioassays. possessed high levels Cry1Ac but were very Vip3Aa. Cry1 Cry2 RR varied incompletely recessive completely dominant depending on protein concentration. These data suggest that possess multiple non-recessive Cry1/Cry2 proteins. results significant implications understanding field-evolved fields should contribute developing effective strategies control zea.