Toxicity of imidacloprid [nicotinoid] against earthworm, pheretima posthuma with reference to its effects on protein

ABSTRACT

Imidaclorprid was studied for its effects on earthworm [P. posthumd]. The organism was reared in laboratory at 25 °C with relative humidity 80%, in whole moist soil with compost / manure as food medium contained in wide mouth jars covered with muslin cloth. Imidacloprid [Nicotinoid] was used as test material. Earthworms were exposed to the under test compound through contact method cum feeding method. Average mortalities of imidacloprid were found to be 20, 40, 60, 70 and 80%, against 0.04, 0.08, 0.16, 0.32, and 0.64 ppm respectively and LD50 was determined statistically and found to be 0.11 ppm. Effect of this pesticide on total protein content was determined in head, clitellum and abdominal regions of treated earthworm P. posthuma. Protein was found to be 21.6 mg/ml in head region, in clitellum region it was found to be 36.6, and 30.9 mg/ml in abdominal region respectively, whereas in the control batches it was 27.7, 26.1 and 30.3 mg/ml in head, clitellum and abdominal region respectively. This pattern indicates an increase in protein contents in the clitellum region, a decrease in head region and almost unaffected protein contents was found in the abdominal regions under the effects of imidacloprid on earthworms