Effects of malathion on the growth and reproduction of Drawida willsi (Oligochaeta) under laboratory conditions

We investigated the decline and recovery of the growth and reproduction of an earthworm Drawida willsi, which is dominant in field crops, following the application of two recommended doses of malathion (2.2 mg kg−1 – single dose; 4.4 mg kg−1 – double dose) to soil. A sharp decline in the growth of D. willsi (57% in 2.2 and 80% in 4.4 mg malathion kg−1 soil) was observed after 15 d. Under controlled conditions, the decline in growth in each treatment became insignificant after 75 d. Worms took 105 d after application of malathion to resume normal rates of reproduction.