Shift in the level of susceptibility and relative resistance of brinjal shoot and fruit borer Leucinodes orbonalis (Guen) to diamide insecticides.

Abstract

Brinjal shoot and fruit borer Leucinodes orbonalis Guen. is a major pest of brinjal in India. The field collected larvae of L.orbonalis were tested for their susceptibility to three diamide insecticides by fruit dip bioassay technique. Cyantraniliprole and chlorantraniliprole were 5.23 and 2.80 times more toxic to L. orbonalis as compared to flubendiamide. Large variation in the susceptibility of L. orbonalis to cyantraniliprole, chlorantraniliprole, flubendiamide was observed and the LC50 values were 0.084, 0.157 and 0.439 mg a.i. L−1, respectively. In span of two years there was a significant increase in the LC50 values of cyantraniliprole (0.062 to 0.085 mg a.i. L−1), chlorantraniliprole (0.097 to 0.157 mg a.i. L−1), flubendiamide (0.284 to 0.439 mg a.i. L−1) to population of L. orbonalis, which showed 1.35, 1.62 and 1.55 fold resistance, respectively indicating faster development of resistance to diamide insecticides.