Synergistic Effect of Nucleopolyhedrovirus with Synthetic Pyrethroids against Helicoverpa armigera(Hübner)

The joint action between nucleopolyhedrovirus (HearNPV) and synthetic pyrethroids at sub lethal concentration against third instar larvae of Helicoverpa armigera oo nifferent tosts (cotton leaves, cottoo nquares, cottoo nolls, bhendi fruits and redgram pods) were investigated. The joint application of HearNPV + pyrethroids at LC₂₅ + LC₂₅ revealed synergistic interaction as the combined application on different hosts showed 9.27 - 27.68 and 21.68–40.91% more than the expected mortality at LC₅₀ of HearNPV alone and LC₅₀ of pyrethroids alone, respecttvely.