Larval Extracts and Other Adjuvants for Increased Efficacy of Nuclear Polyhedrosis Virus Against Heliothis armigera Larvae

Laboratory experiments have revealed that 4% larval extracts of Heliothis armigera, Spodoptera litura and Corcyra cephalonica, 20% whole milk, 10% whole egg homogenate, 10% yellow of egg, 10% egg white, 20% tender coconut water and 20% crude sugar increased the efficacy of nuclear polyhedrosis virus against second instar larvae of H. armigera. Measurement of leaf area consumed showed that these adjuvants had acted as phagostimulants and increased the feeding by larvae leading to acquisition of more virus resulting in increased mortality and shorter LT₅₀ values. Pot culture study showed that even though Robin blue and Tinopal both at 1% were not as effective as the other adjuvants in increasing the mortality, they increased the persistence of the virus as seen by the higher percentages of original activity remaining.