Acute toxicity of endosulfan and malathion on Chironomus ramosus (Insecta: Diptera: Chironomidae) from north Cachar hills, Assam, India.

Acute toxicity tests for the pesticides endosulfan and malathion on the larvae of Chironomus ramosus were conducted. Median Lethal Concentration (LC50) values of endosulfan were 0.55 x 10(-2), 0.16 x 10(-2), 0.089 x 10(-2) and 0.036 x 10(-2) ppb respectively, while those for malathion were 0.139 x 10(-2), 0.054 x 10(-2), 0.019 x 10(-2) and 0.0032 x 10(-2) ppb respectively, at 24, 48, 72 and 96 hr. Thus Chironomus ramosus larvae were more sensitive to malathion at all hours of toxicity tests than endosulfan.