Selection for Permethrin Resistance in the Tobacco Budworm (Lepidoptera: Noctuidae)

Abstract
Selection of larvae of Heliothis virescens (F.) with permethrin at the LD90 level produced resistance. After 11 generations of continuous selection pressure, the LD50 in the F12 generation increased 37-fold compared to the LD50 of the F1. Cross-resistance to cypermethrin in this strain was high. In the F12 generation, LD50 and LD95 values were 7.9- and 50-fold greater, respectively, than LD50 and LD95 values of a strain collected in the field in 1981.