Optimization of in vivo production of nucleopolyhedrovirus in homologus host larvae of Helicoverpa armigera

Abstract

Optimization of virus yield is crucial for minimizing the cost of production and to perfect its large scale-production using in vivo production system. Therefore, separate experiments were conducted to optimize the inoculum dose, larval age, incubation period, and physical status of the harvested larvae for in vivo Helicoverpa armigera nucleopolyhedrosis (HaNPV) mass production. Seven to eight day old larvae treated with an inoculum dose of 1×10 4 resulted in maximum POBs yield/insect coupled with the desirable proportion of larval harvest and shall therefore be considered as suitable stage for optimum virus production with an incubation period of 7 days. While comparing the HaNPV productivity on the basis of the physical status of the harvested larvae, the maximum POB yield per larva was obtained by harvesting the dead larvae. However, harvesting dead larvae was very difficult and there was high microbial contamination. Thus harvesting moribund larvae was the best option for optimum production of HaNPV. © 2007 Academic Journals.