Studies on salivary and midgut enzymes of a major sucking pest of Tea, Helopeltis theivora (Heteroptera: Miridae) from darjeeling plains, India

Abstract

Helopeltis theivora is a major pest of young leaves and buds of Camellia sinemis. To understand the feeding biology of this mirid bug, its digestive and oxidative enzymes from salivary glands and midgut were analysed. Three common hydrolytic enzymes, amylase, protease and lipase were detected both in its salivary gland and midgut homogenates. Catalase, peroxidase and polyphenol-oxidase were also detected from these homogenates. Catalase activity was higher in salivary gland than that of midgut, contrastingly, the activity of polyphenol-oxidase was greater in the midgut than in the salivary extract. Peroxidase activity was found to be similar. The presence of both hydrolysing and oxidoreductase enzymes in the salivary and midgut homogenates may be related to extra-oral digestion and defense, leading to tissue necrosis and phytotoxic effect in the tea leaves.