author(s)
Manjunatha KL, N Srinivasa and NR Prasannakumar

abstract
Conventional and newer insecticides were evaluated against chilli thrips, Scirtothrips dorsalis as separate foliar spray application (two sprays at 14 days interval) during Rabi-summer season at two locations in Chikkaballapur (cropping period Dec. 2016 to May 2017 with Local variety) and Bengaluru districts (cropping period Jan. to June 2017 with var. Arka Meghana). The insecticides were applied on 30-60 days old crop during February-March period at the peak infestation of thrips. In Chikkaballapur district one week after application, most of the insecticides resulted in significant reduction in thrips population and were superior to water sprayed control. Of these, spinosad application resulted in maximum reduction of 91% followed by acephate (72%), dimethoate (69%), imidacloprid (61%), fipronil (61%), diafenthiuron (60%), clothianidin (55%) and thiamethoxam (55%) application. Further, spinosad treatment continued to record significant decline in thrips population up to 10 days, and thus resulted in higher green fruit yield of 9 tonnes/acre. In Bengaluru district, within one week after application spinosad resulted in >87 per cent reduction in thrips population and also its extended effectiveness was apparent up to 10 days, hence the fruit yield (13 tonnes/acre) obtained was also highest. It is opined that the conventional insecticides, like acephate or dimethoate may be used alternatively with spinosad, as the avoidable loss with their use was nearly similar (50-61%) or next (65-68%) to spinosad. This practice would also reduce the cost of plant protection as well as the insecticide selection pressure on this key pest of chilli.