Pest succession and population dynamics of major pests and natural enemies in bitter gourd

A field experiment was carried out to investigate pest succession and population dynamics of major pests and natural enemies in bitter gourd. Bitter gourd variety, “Pusa Vishesh” was investigated during spring summer in 2012 and 2013 in two planting systems: with trailing on support and without trailing. The crop was observed weekly from seedling stage till harvesting for the incidence of various pests and natural enemies. Whitefly (Bemisia tabaci Gennadius) and melon fruit fly (Bactrocera cucurbitae Coquillett) were found as the major insect pests and aphid (Aphis craccivora), red pumpkin beetle (Aulocophora foveicollis) were the minor pests. The population of whiteflies was high when bitter gourd was young and later declined. Fruit fly population was noticed from fourth week of March and reached peak during fourth week of April. Activity of coccinellids started from third week of March and continued till fourth week of May. Correlation with weather factors revealed that maximum, minimum and average temperature had significant negative correlation on the population build up of pumpkin beetle, whitefly, aphid and coccinellid and had positive correlation on population of fruit fly.