Isolation and characterization of baculoviruses from major lepidopteran insect pests infesting jute, Corchorus olitorius Linn

Abstract

Jute hairy caterpillar, Spilosoma obliqua Walker (Arctiidae: Lepidoptera) and jute semilooper, Anomis sabulifera Guenee (Noctuidae: Lepidoptera) duo are the important lepidopteran insect pests infesting jute and causes damage by defoliation. Epizootic caused by a nucleopolyhedrovirus (NPV) was observed in the jute field infested with S. obliqua and A. sabulifera during a routine survey in farmer’s fields. The NPV was isolated and characterized based on polyhedrin gene of NPV which resulted in an amplicon size of 700bp each for the both SpobNPV and AsNPV. Bioassay studies with second instar larvae of A. sabulifera and S. obliqua revealed the median lethal concentration (LC50) of AsNPV as 5.37 × 104 OBs/ml and 2.44 x 104 OBs/ml at 72 HAT (Hours After Treatment). The SpobNPV at the highest POB count @3.2 x106 OBs/ml caused cent per cent larval mortality, similarly AsNPV with POB (Poly Occlusion Bodies) concentration @2.8 x106 OBs/ml resulted in 83 per cent larval mortality. Thus spray application of both SpobNPV and AsNPV can be used as biocontrol agents in Integrated Pest Mangement of lepidopteran insect pests infesting jute.