Effect of Thermal Stability Test on DpNPV (Nuclear Polyhedrosis Virus) and Its Formulation against Mulberry Leaf Webber, Diaphania pulverulentalis (Hampson)

Effect of different temperature on the inactivation of nuclear polyhedrosis virus to Diaphania pulverulentalis (Hampson) larvae were studied under laboratory conditions. The larval mortality was maximum (80%) observed in DpNPV suspension 1x10⁹ polyhedra significantly maximum mortality 92 per cent observed in DpNPV formulation (Starch 5% + Congored 1% + Tween 80 1% + DpNPV 1x10⁹ POB/ml). No larval mortality was observed when DpNPV suspension was exposed to 50°C for 20 minutes, similarly no larval mortality was observed when DpNPV formulation was exposed to 60°C for 5 minutes indicating complete inactivation of virus. The present findings showed that the rate of larval mortality was decreased with the exposure to temperature which indicated the loss in pathogenicity of DpNPV.