Influence of different hosts on induction of midgut glutathione S-transferase in Helicoverpa armigera (Hubner).

Accepted : September, 2010 Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), is well known as cotton bollworm, gram caterpillar, pod borer or American bollworm. It is highly polyphagous pest with broad spectrum of host families including important agricultural crops such as cotton, maize, chickpea, pigeonpea, sorghum, sunflower, soybean, groundnut etc, (Fitt,1989). Insect feeding exhibits a host-range that is manifested by the different plants on which they usually are found. When the host plant changes, insect changes its metabolism to adopt the same, so as to allow it to metabolize the new primary and secondary compounds of new plants. Host plants induce the biochemical constituents in insect through feeding on them also affect the susceptibility of pest to particular insecticides. These hosts plants induced detoxifying enzymes are responsible for detoxification of xenobiotics and chemical insecticides (Yu, 1982). The detoxifying enzymes of insect include mostly Glutathione S-transferase (GST) responsible for insecticide resistance (Yang et al., 2001). Plant species differ in the degree to which they stimulate the biochemical defense of insects. Therefore, research on insect host plant interactions may yield information of considerable value in the development of insect pest management programmes, where insecticides are an integral part of the programme (Berry et al., 1980).