Bioefficacy against Major Sucking Pest Complex and Residue Dynamics of Fipronil in Green Chilli (Capsicum annum Linn.)

Sucking pest complex (yellow mite, thrips and aphids) in chilli cause considerable economic damage to chilli cultivation. A field experiment was conducted to assess the bioefficacy, phytotoxicity and residue dynamics of fipronil 5% SC in chilli crop. Three doses of fipronil (20, 40, 80 g ai ha^-1) along with a conventional insecticide (dimethoate 30% EC @ 300 g ai ha^-1) and untreated control were tested. Applications of fipronil at 40 and 80 g ai ha^-1 were equally effective against chilli thrips, mites and aphids and had significantly higher green chilli fruit yield. After three rounds of foliar application of 40 g ai ha^-1 at an interval of 15 days, population of thrips, mites and aphids were reduced by 79.2, 32.7 and 78.5%, respectively, as compared to untreated control. Applications of fipronil 5% SC did not cause any phytotoxic symptoms. Natural enemies (predatory pentatomid bug, lady bird beetle and spider) were not affected by fipronil application. A laboratory validated method using gas chromatography equipped with micro-electron capture detector was employed. The half-lives of fipronil in green chilli were estimated to be 2.3, 3.1 and 2.7 days for 20, 40 and 80 g ai ha^-1 treatments, respectively. The dietary exposures of the residues on each sampling day based on the average daily consumption of 0.0055 kg chilli per day were less than the maximum permissible intake (MPI) of 0.0032 mg person^-1 day^-1 for 20 and 40 g ai ha^-1 and dietary exposures was less than MPI value 1 days after application in 80 g ai ha^-1 treatment. The results are useful for schedule spraying of fipronil for the management of insect pest in chilli.