EVALUATION OF TOXICITY AND COTOXICITY OF BIOPESTICIDES AGAINSTDIAMONDBACK MOTH, PLUTELLA XYLOSTELLA (L.)

Abstract

ABSTRACT In India, the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is an important pest of cruciferous vegetables and causes severe economic losses. This pest has ability to evolveresistance in laboratory and field to almost all groups of synthetic insecticides. Despite of these, management with synthetic insecticides has been considered to be the easy and favorable option byfarmers in India which indeed increase the cost of cultivation and obviously reduction in the actual net profit. The use of microbial and botanicals pesticides are also available in the market and theyare relatively cheap. These pesticides are eco-friendly and the residual toxicity is extremely low. Inthis study, we have evaluated the in vitro toxicity and co-toxicity of different groups of microbial and botanicals pesticides on the field derived population of P. xylostella using leaf dip bioassay. Among microbial pesticides Lipe (Bacillus thuringiensis subsp. kurstaki)) was found to be veryeffective than MVP II (Cry1Ac) and XenTari® (Bacillus thuringiensis subsp. aizawai). Anosom®(1% EC) was found to be most effective against P. xylostella among botanicals as evidenced fromlowest LC50 value of only 0.1ppm. Being a botanical pesticide, Anosom® (1% EC) could be usedas a substitute to synthetic insecticides in integrated management of P. xylostella. Co-toxicity of pesticides against second instars larvae of P. xylostella was assessed using binary mixture of twobotanical pesticides at three different combinations (1:1, 1:2 and 2:1 ratio) and found that all thecombinations show synergistic effect against diamondback moth. Objective of present research is toinvestigate toxicity and co-toxicity of botanical and microbial pesticides against diamondback mothso that it could be used as substitute to chemical pesticide for integrated management of diamondback moth.