Effect on superoxide dismuatse activity in earthworm Eisenia fetida on direct exposure to neonicotinoid insecticide imidacloprid

Imidacloprid is a systemic insecticide that acts as an insect neurotoxin and belongs to class of chemicals called the neonicotinoides which act on central nervous system of insects. Three concentration of imidacloprid (0.134 μl, 0.195 μl and 0.285 μl) have been used during the experiment for evaluation of enzymatic activity. The increase in superoxide dismutase (SOD) activity suggests that SOD has the capacity to scavenge reactive oxygen species (ROS) under the stress at lower concentration of imidacloprid and it also indicated that the activity of the superoxide dismutase had shown different responses to toxicity of various concentrations of imidacloprid for different exposure periods in earthworm Eisenia fetida. Imidacloprid at concentrations of 0.195 μl and 0.285μl had shown the SOD activities of 6.773 and 7.263 U/mg protein respectively at 48 hr of exposure, while a concentration of 0.285μl has showed an enzyme activity of 6.835 U/mg protein at 24 hr of exposure. The study revealed that the activity of antioxidant enzyme of earthworms is altered due to stress produced by neonicotinoid insecticide. The statistical data of pesticide is highly significant with respect to treatment and time of exposure.