Rearing of Helicoverpa armigera Hubner and Characterization of its Gut Proteinases

Background: The genus Helicoverpa includes the Old-World species Helicoverpa armigera, Hubner (Lepidoptera: Noctuidae) generally considered to be the most important species within group. It has been recorded on more than 200 host species in India and is most damaging to cotton, pigeon pea, cow pea, chick pea, ground nut, sorghum, pearl millet, tomato and many other crops of economic importance. H. armigera is being polyphagous pest with high reproductive and damaging potential, its suppression became difficult over past decade due to development of resistance to several chemicals. The current study was aimed to isolate and characterize the gut proteinases of Helicoverpa armigera. Methods: During the period 2016-2018, H. armigera larvae were collected from the field and reared on an artificial diet and maintained under controlled conditions in the laboratory at Dr. Panjabrao Deshmukh Krishi Vidyapith, Akola, India. The laboratory conditions were maintained at temperature 28±2oC, humidity 75±5% and 14:10 hours light: dark period. The gut proteinases were isolated and were estimated by Bradford method. The total Helicoverpa gut proteinase activity, trypsin like activity, chymotrypsin like activity and electrophoretic visualisation of proteinases were done. Result: Total Proteinases activity was found to be 2.10 U/gut. Trypsin like activity was found to be 1.89 U/gut and chymotryptic activity was observed as 1.81 U/gut. The trypsin like activity was slightly more than chymotryptic activity.