Evaluation of Certain Adjuvants as Phagostimulants and UV - Protectants of Nuclear Polyhedrosis Virus of Helicoverpa armigera (Hbn.)

Abstract

Laboratory experiments were conducted to evaluate the efficacy of certain adjuvants possessing phagostimulant and UV-protectant properties in increasing the efficacy of nuclear polyhedrosis virus (NPV) against Helicoverpa (=Heliothis) armigera (Hbn.), An adjuvant - mix consisting of Frenchbean/cotton seed kernel extract 10% + crude sugar 10% + glycerol 1% + egg white 1% + whitening agent (Tinopal)0.1 % was the most effective in increasing mortality due to NPV in larvae of H. armigera. Crude sugar 10% along with either Frenchbean extract 10% or cotton seed kernel extract 10% also significantly increased the NPV mortality but these were not as effective as the treatments with adjuvant - mix with full complements of the different components. Either Frenchbean or cotton seed kernel extract - based adjuvant-mix recorded significantly lower LT₅₀ values than NPV used alone. Frenchbean/cotton seed kernel extract 10% + crude sugar 10% also recorded lower LT₅₀ values than NPV alone but were higher than those recorded by NPV + full complements of adjuvant - mix. Frechbean or cotton seed kernel extract-based adjuvantmixes were able to protect the virus from UV light. The differences in mortalities between UV -exposed and unexposed were not significant in virus treatment with adjuvants.