Abstract:
Nuclear Polyhedrosis Virus (NPV) was isolated from larvae o f Helicoverpa armigera (Hubner), avoracious polyphagous pest attacking wide variety o f economically important crops in Sri Lanka.Effects o f this entomopathogenic virus on larval instars o f H. armigera were studied under the laboratory conditions. Unformulated Polyhedral Inclusion bodies (PIBs) from ground up virus killed larvae ofH. armigera were used to prepare the inoculums. Constant dose o f NPV containing 8x10s PIBs/ml were fed to different larval instars and the percentage mortality and the approximate time to death was found to be dependent on the age o f the larvae. Dose dependent mortality was observed when the 3rd instars larvae treated with serial dilutions o f NPV from JO7 to 10 PIBs/ml.