Effect of Biorationals against the Thrips, Scirtothrips dorsalis Hood Infesting Chilli

The present investigation was carried out to test the efficacy of biorationals against thrips, Scirtothrips dorsalis Hood on chilli. Field experiments were conducted at farmers holding during September 2009 - Febrauary 2010 and November 2009 - April 2010. Among biorationals tested, spinosad 45 SC @ 0.4ml 1^-1 and emamectin benzoate 5 SG @ 0.4g 1^-1 was found to be superior to the standard check dimethoate 30 EC @ 2ml 1^-1 registering the least population of 0.55 and 0.59 / leaf, followed by Beauveria bassiana @ 1 x 108 spores ml^-1 and neem oil 3 per cent which recorded thrips population of 1.01 and 1.11 / leaf. With regard to leaf curl damage by thrips, spinosad 45 SC @ 0.4 ml 1^-1 and emamectin benzoate 5 SG @ 0.4g 1^-1was very effective. Highest dry chilli yield of 1509 kg ha^-1 was registered in spinosad 45 SC @ 0.4ml 1^-1, which was on par with emamectin benzoate 5 SG @ 0.4g 1^-1 (1525 kg ha^-1) with respective additional income of Rs. 30,300 and Rs. 26,400. The highest cost benefit ratio (1:4.30) was obtained in spinosad 45 SC @ 0.4ml 1^-1 followed by 1:4.30 in emamectin 5 SG @ 0.4g 1^-1.