The chemical pesticides cause pollution of water bodies as well as ground water, besides getting stored in the plants. These chemicals are toxic and thus extremely harmful to human beings and other animals.
(a) Bacillus thuringiensis: B. thuringiensis toxin genes are introduced into plants to make them resistant to ** by insects and pests. They are available in sachets as dried spores, which are mixed with water and sprayed onto vulnerable plants. When they are eaten by the insect larvae, the toxin is released in the gut and becomes active and ***** the larvae. Specific Bt toxin genes obtained from Bacillus thuringiensis are used in several crop plants which make them resistant to the insect pest.
(b) Nucleopolyhedrovirus: These viruses are excellent candidates for species-specific, narrow spectrum insecticidal applications. This is especially desirable when beneficial insects are being conserved to aid in an overall integrated pest management (IPM) programme.
