In vivo Production of a Nuclear Polyhedrosis Virus Utilizing Tobacco Budworm and a Multicellular Larval Rearing Container²

The effects of viral inoculum and incubation period on virus yield in a method of in vivo production of the multicapsid nuclear polyhedrosis virus of Heliothis armigera (Hübner) were examined utilizing Heliothis virescens larvae reared in multicellular containers. Trays of diet were surface contaminated with virus levels ranging from 54 to 2708 polyhedral inclusion bodies (PIB) per mm² of diet at 7 days after egg infestation. The virus was harvested either at 6 or 7 days after treatment. Within the ranges of this study, the greatest quantity virus was obtained when the diet was inoculated with the 54 PIB level, and the virus was harvested at 7 days. This combination resulted in an average production of 2919 × 10⁹ PIB per tray, with 5.7 × 10⁹ PIB per larvae and 523 collectable larvae per tray. It also represented an increase in polyhedra of 2.43 × 10⁵× compared to the inoculum. The costs of the production were estimated based on prevailing wages and current costs of materials.