Mortality and growth inhibition of brinjal shoot and fruit borer, Leucinodes orbonalis (Guen.) by buprofezin, a potent chitin synthesis inhibitor

Abstract

In the present laboratory study, different concentrations of award 40 SC (Buprofezin) have been applied (topical, potato-dip and topical + potato-dip method) on the 2nd instars larvae of brinjal shoot and fruit borer (Leucinodes orbonalis Guen.) and then mortality, weight reduction or cuticular change was observed at 3 HAT (hours after treatment), 3 and 7 DAT (days after treatment) application. No mortality or weight reduction was observed at 3 HAT. The significant level of mortality and weight reduction was observed at 3DAT from all applying methods but the maximum mortality and weight reduction was found at 7 DAT. It was also observed that potato-dip method was highly effective than topical method regarding mortality and weight reduction while almost similar efficacy was found from potato-dip and combination (topical + potato-dip) methods. Cuticular abnormalities were found when larvae were treated with higher concentrations of buprofezin in comparison with that in the water-treated control. Moreover, larval mortality and weight reduction were clearly dose-dependent. The lower dose (200 ppm) was ineffective for topical application method but was effective in case of potato-dip and combination methods. Therefore, it is concluded that buprofezin is a potent IGR (insect growth regulator) molecule to reduce L. orbonalis populations through inhibition of chitin biosynthesis.