SEASONAL DYNAMICS OF INSECT PESTS OF BLACK GRAM (Vigna mungo L.) IN A COASTAL AGROECOSYSTEM

Abstract

In this study, the seasonal population dynamics of insect pests of black gram (Vigna mungo L.) and their relationships with meteorological parameters were studied. The field experiments were done in the summer and kharif seasons of 2024 at Pandit Jawaharlal Nehru College of Agriculture and Research Institute (PAJANCOA & RI), Karaikal, Puducherry, India. The monitored insect pest complex comprised of defoliators (Phyllotreta striolata Fabricius and Omiodes indicata Fabricius) and pod borers (Maruca vitrata Geyer and Lampides boeticus Linnaeus). During summer, peak pest populations were observed during 13th and 14th Standard Meteorological Weeks (SMW). Correlation analysis revealed significant positive associations between maximum and minimum temperature and the populations of M. vitrata and L. boeticus, whereas morning relative humidity (RH) exhibited significant negative associations with their populations. During the kharif season, peak pest populations were generally observed during the 33rd and 34th SMW. During this season, morning and evening RH showed strong positive correlations with M. vitrata and L. boeticus populations and the maximum temperature had a negative correlation with M. vitrata and L. boeticus populations. Multiple linear regression models showed that the meteorological variables explained 60-79% of the variation in pest populations (R² = 0.60-0.79). These findings highlight the seasonality of insect pests and their relationship with weather parameters, providing a better reference for understanding insect pest dynamics and developing weather-based IPM strategies for black gram.