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Hyblaea puera nucleopolyhedrovirus (HpNPV) is a potential biocontrol agent against the teak defoliator H. puera (Cramer) (Lepidoptera: Hyblaeidae). As part of optimization of the mass production of this nucleopolyhedrovirus, three methods of inoculation were evaluated against the host larvae with various yield parameters as selection criteria. The inoculation methods compared were controlled dose on diet in rearing tubes using a micropipette, controlled dose on leaf discs (prepared from teak leaves) using a micropipette and spraying onto diet filled rearing tubes using an atomizer. Fifth instar H. puera larvae of the weight classes 75-100, 101-125, 126-150, 151-175 and 176-200mg were used for the bioassay. With reference to percentage of harvested larvae, virus production per larva and virus production per inoculated larva (VPIL), spraying viral suspension into rearing tubes filled with artificial diet using a hand sprayer was found to be the most efficient method of inoculation. It was observed that the method of inoculation and age of the larvae has discrete as well as interactive influence on the virus yield parameters.

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.