POTENTIAL ILL EFFECTS OF IGR PESTICIDES ON LIFE-HISTORY PARAMETERS IN ECOLOGICALLY IMPORTANT SOIL COLLEMBOLA CYPHODERUS JAVANUS BORNER

The possible ill effects of insect growth regulator (IGR) pesticides on ecologically important soil microarthropod fauna was evaluated using life history parameters in Cyphoderus javanus Borner (Collembola: Insecta) under microcosm conditions. Laboratory reared fresh adults were kept for 16 days on sandy loam lateritic soil treated with agricultural doses of Applaud 25SC (Buprofezin), Takumi 20WG (Flubendiamide), and Rimon 10EC (Novaluron), and a pyrethroid Colt 25EC (Cypermethrin) was used as reference. There was negligible mortality of adults in control (3.1%), but the dose-related lethal effect of IGRs caused highest mortality (33.3%) and lowest survival success (P<0.01) in Applaud 2000 ppm treated soil. Growth rate of C. Javanus decreased in IGRs treated soil; rate of moulting decreased from 0.42 day -1 in control to 0.05 day -1 in Takumi 500 ppm treated soil (P<0.05). Similarly, fecundity declined to 1.8 day -1 in Applaud 2000, as against 4.2 day -1 in control (P<0.01). Survival rate of juveniles declined from 91.1% in control, to 67.6% in 500 ppm Applaud (P<0.05). Other pesticides affected juvenile success at higher doses, to 64.5% in Takumi 2000 ppm (P<0.01), and to 39.2% in Rimon 4000 ppm (P<0.01) treated soils. The above trends were comparable with the ill effects of Colt at 1000 ppm dose. Among the IGR chemicals, Rimon produced minimum ill effects, and Applaud and Takumi probably affected chitin synthesis. These life history parameters in C. javanus are suitable for ecotoxicological