Effects of sublethal concentration of Imidacloprid on the enzyme activity of sweet potato weevil, Cylas formicarius (Fabricius) (Coleoptera, Brentidae)

Abstract

Application of sublethal (LC₁₀ and LC₃₀) dose of Imidacloprid on sweet potato weevil (SPW) was found to have inhibitory effect on its enzymes viz., glutathione reductase (GR), glutathione peroxidase (GPx), reduced glutathione (GSH) and glutathione S-transferase (GST), while activity of superoxide dismutase (SOD) and lipid peroxidase (LPx) was up regulated when compared to control. The weevil’s expression of SOD increased by 13.53 and 69.44 and LPx by 67.38 and 73.04 per cent respectively, when the sublethal dose was raised from LC₁₀ to LC₃₀. Although GST and GPX did not alter considerably after exposure to the sublethal doses of imidacloprid, weevil activity of GR (65.5-78.1%) and GSH (42.2 and 61.6%) decreased significantly.