International Crops Research Institute for the Semi-Arid Tropics, Patancheru-502324, Andhra Pradesh.
Helicoverpa armigera (Lepidoptera: Noctuidae) is responsible billions of dollars worth crop loss every year. Sole reliance on synthetic chemicals to manage H. armigera led to the development of pest resistance to insecticides, pest resurgence ecological hostility and added economic loss. Biological control methods involving insect-pathogenic microorganisms, especially insect-infecting viruses, has been recognized as the potential alternative to synthetic pesticides for reducing the pest population and reduction in chemical sprays. NPVs are widely distributed and can infect more than 400 arthropod species belonging to six insect orders, Lepidoptera, Hymenoptera, Diptera, Coleoptera, Thysanura, and Trichoptera, as well as from Decapoda (class Crustacea). NPVs are naturally occurring pathogens of H. armigera, and it occurs in Asia, Africa and Australia. NPV belongs to the family Baculoviridae is well studied and utilized for pest control worldwide. The virus is bacilliform-shaped and contains circular double stranded DNA genome. First NPV-based pesticide was realized in 1975. Since then several strains of NPV have been used to develop commercial biopesticides in America, Australia, India, China and Thailand. HaNPV has been shown to be highly effective in controlling H. armigera on a range of crops. At present among various bio-pesticides, major emphasis has been placed on the use of HaNPV to control H. armigera. However, NPV-based pesticides are under exploited due to non-availability of quality products, and variation in pathogenicity and virulence at different geographic locations lowering its efficacy in controlling the pest. NPV strains with desirable attributes need to be identified from nature for the identification of virulent and stable strains suitable for use in diverse agro-eco regions. Major work is focused on development of recombinant NPV insecticides to improve the strain efficacy, but commercial development of recombinant NPV insecticides still remain unsolved due to non availability of cost-effective means of mass production. The present status and future prospects of NPV in plant protection is discussed in this paper.
