Hyposidra talaca NPV (HytaNPV): a potential baculovirus for efficient control of the black inch worm, Hyposidra talaca Walker (Lepidoptera: Geometridae), a major pest of tea Camellia sinensis (Ericales: Theaceae (L.) O. Kuntze)

Abstract

Abstract Background The black inch worm (BIW), Hyposidra talaca Walker (Lepidoptera: Geometridae), is a pest that defoliates tea leaves in India, posing a significant threat to the tea industry. Nucleopolyhedrovirus (NPV) is capable of infecting larvae of this species, which has raised the possibility of its use as a biocontrol agent. Results Rearing larvae in a semi-synthetic artificial diet produced healthy adults, which is sufficient for mass culture of H. talaca to support one of the IPM components using baculovirus. In artificial diets, the NPV was evaluated for its insecticidal activity against H. talaca. The bioassay findings of inoculated H. talaca nucleopolyhedrovirus virus (HytaNPV) at various concentrations showed that it was effective in killing the BIW. Purified polyhedral inclusion bodies (PIBs) were estimated to a concentration of 1 × 1010 PIBs per ml by mixing with water, and various concentrations of 0.25, 0.5, 1, 2, 5, 7.5, 10 ml/l were evaluated against BIW. Both laboratory and field studies revealed that HytaNPV is an eco-friendly and ecologically safe agent for controlling BIW. Besides no residue was estimated in made tea after the seventh day of exposure, and it is nontoxic to non-target species. Conclusion It was found that NPV is environmentally beneficial for the control of pests on tea plants and in production of pesticide-free tea. Tea ecosystems can reduce their reliance on conventional insecticides by using HytaNPV as an alternative bio-insecticide.