Effect of Vegetable Oils on the Yield of Nucleopolyhedrovirus of Helicoverpa armigera (HearNPV)

Effect of dietary incorporation of three vegetable oils, viz., sunflower, soybean and coconut, on the yield productivity of seven geographic isolates of nucleopolyhedrovirus of Helicoverpa armigera at 1965.78 OB/mm² was evaluated to select the most efficient vegetable oil and the highly promising virus isolate(s). Among the seven isolates, Coimbatore isolate recorded the highest yield of 6.895 x 10⁹ OB/larva, followed by Negamum, Ooty, Parbhani, Mumbai, Hyderabad and Rahuri, when the larvae were fed with virus inoculated standard diet without vegetable oils. Among the different oils tested, sunflower oil enhanced the larval mortality (92.03-94.07% for different isolates tested). However, the yield of virus per larva was significantly increased when both sunflower oil and soybean oil were used as additives along with standard diet. The productivity ratio was also highest when both sunflower oil and soybean oil were used as additives in all the isolates tested. So it can be concluded that sunflower oil can be used as a dietary adjuvant in HearNPV production systems.