Seasonal incidence of major insect pests and their natural enemies on Cauliflower (Brassica oleracea var. botrytis) in relation to weather parameters

Abstract

ABSTRACT: A field experiment was conducted to study the population dynamics of major insect pests and their natural enemies in cauli flower eco system in two consecutive cropping seasons i.e., winter 2021-22 and 22-23 at experimental farm of Dr Rajendra Prasad Central Agricultural University, Pusa, Bihar. In cropping season 2021-22, the incidence was at its peak of the pests: Aphids (123.72), Diamondback Moth (12.83), Tobacco caterpillar (1.02), Leaf webber (2.83), and Flea beetle (2.56) per plant were recorded on 12 SMW, 11 SMW, 12 SMW, 9hSMW, and 12 SMW, respectively. Similarly, on 11 SMW, 12 SMW, 12 SMW, 10 SMW, and 12 SMW of cropping season 2022-23 maximum incidence of aphids (147.2), DBM (17.47), tobacco caterpillar (1.65), leaf webber (1.43) and flea beetle (2.53) per plant were recorded, respectively. Maximuın population of Cotesia plutellae were 3.86 and 5.43. Oomyzus sp. were 1.01 and 1.21. Aphidius colimani 13.48 and 15.83, Coccinellids were 5.13 and 9.56, and Syrphids were 2.12 and 2.16 recorded during the cropping season 2021-22 and 2022-23, respectively. The correlation between population of insect pests and natural enemies in relation to weather parameters shown significant positive correlation with temperature (maximum and minimum), rainfall and sunshine while negative and significant correlation to relative humidity (morning-evening) during both the cropping season. The coefficient of determination (adjusted R³) value and regression equations obtained after subjecting insect population data in multiple linear regression analysis in relation to weather parameters indicates significant influence of weather parameter on population build-up of insect pests and related natural enemies.