Population dynamics of defoliator pests and two spotted spider mite of ash gourd

Abstract

In present study, field experiment on population dynamics of insect pests of ash gourd was conducted in farmer’s holdings in Tamil Nadu during 2015-2016. Result revealed that that the major defoliator pests such as pumpkin caterpillar, red pumpkin beetle, leaf miner and two spotted spider mite. Peak population of Diaphania indica (7.5 larvae / plant) was recorded in third week of February and first week of March. The maximum population of red pumpkin beetle, Raphidopalpa foveicollis was recorded in second week of December (2.20 / plant). The leaf damage by Liriomyza trifolii was recorded to be highest (23.7 per cent) during third week of March. Number of Tetranychus urticae was recorded to be the highest during fourth week of March (18.20 / cm2 leaf area). Correlation analysis between weather parameters and abundance of insect pests of ash gourd revealed that temperature and relative humidity played a major role with significant positive influence on the population build-up of defoliator pests and two spotted mite.