Cross-Resistance Variation among Different Populations of Diamondback Moth,Plutella xylostella(Linn.) to New Insecticides

Abstract

Field populations of DBM sampled from Andhra Pradesh, Karnataka and Delhi were used in bioassays with insecticides acephate, cypermethrin, spinosad, cartap hydrochloride and Cry2Ab toxin over a period of three generations (F1-F3) to obtain respective insecticide resistant strains. The individual insecticide resistant strains were used to estimate the cross resistance against emamectin benzoate, chlorantraniliprole and flubendiamide. The cross-resistance ratios (CRR) obtained based on median lethal concentrations for resistant and unselected strains revealed that CRR of all the three DBM populations in acephate resistant strain (AR) ranged from 0.52–0.82, 0.31–0.64 and 0.37–0.75; cypermethrin resistant strain (CyR) ranged from 0.41–0.76, 0.29–0.80 and 0.37–1.12; spinosad resistant strain (SR) ranged from 0.35–0.64, 0.29–0.65 and 0.37–0.62 cartap hydrochloride resistant strain (ChR) ranged from 0.58–0.88, 0.45–0.50 and 0.50–0.87. Cry2Ab resistant strain (CryR) ranged from 0.29–0.82, 0.33–0.69 and 0.62–0.75 respectively. Except for cypermethrin resistant strain of DBM from Delhi that showed cross resistance to flubendiamide no other DBM insecticide resistant strains exhibited cross resistance to emmamectin benzoate, chlorantraniliprole and flubendiamide.