Quantitative estimation of Hyblaea puera NPV production in three larval stages of the teak defoliator, Hyblaea puera (Cramer).

Hyblaea puera nucleoployhedrovirus (HpNPV) is a potential biocontrol agent of the teak defoliator, Hyblaea puera (Cramer) (Lepidoptera: Hyblaeidae). To quantify the growth of the virus in the host larvae, three larval stages of the teak defoliator were subjected to quantitative bioassays using specified dilutions of HpNPV. The HpNPV production was found to be dependent on the dose, incubation period as well as stage specific responses of the host insect used. As larvae matured, production of the virus per mg body weight was not found to be in a constant proportion to the increase in the body weight. The combination which yielded the greatest virus production of 3.55 x 10(9) polyhedral occlusion bodies (POBs) was that in which larva weighing 26-37 mg was fed with 1 x 10(6) POBs, incubated for 6 h and harvested at 72 h post infection (h p.i.). The response of the fourth instar larvae was found to be more productive than the third and fifth instar larvae, which makes it an ideal candidate for mass production of the virus in vivo.