Digestive proteolytic and amylolytic activities of the gram pod borer Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in response to feeding on different host plants

The gram pod borer, Helicoverpa armigera (Hübner) is one of the most important polyphgous pests ofvarious crops in many parts of the world including Iran. Digestive proteolytic and amylolytic activities ofthe larvae of H. armigera fed on different host plants including chickpea (cultivars Arman, Hashem, Azadand Binivich), common bean (cultivar Khomein), white kidney bean (cultivar Dehghan), red kidney bean(cultivar Goli), cowpea (cultivar Mashhad), tomato (cultivar Meshkin) and potato (cultivars Agria andSatina) was studied. The substrates Azocasein (pH 7 to 13) and starch (pH 2 to 12) were used for assayingproteolytic and amylolytic activities of midgut extracts from H. armigera. The results of this studyindicated that the highest and lowest values of proteolytic activities were in the larvae fed on cultivarDehghan (8.717 U/mg) and cultivar Meshkin (3.338 U/mg), respectively. Also, the highest and lowestvalues of amylolytic activities were in the larvae fed on cultivar Dehghan (0.340 mU/mg) and cultivarMeshkin (0.088.mU/mg), respectively. Optimum pH of digestive proteolytic and amylolytic activities inthe larvae fed on different host plants were 12 and 9, respectively. The results showed that the cultivarMeshkin was the most unsuitable host to this pest, likely due to the presence of some secondarychemicals or proteinaceous protease inhibitors in this cultivar.

کلیدواژه ها:

Gram pod borer ، Helicoverpa armigera ، digestive enzymes ، host plants