Population Dynamics of Pod Feeders of Green Gram under Red and Lateritic Zone of West Bengal

Pod feeders such as pod bug ( Clavigralla gibbosa Spinola), flea beetle ( Madurasia obscurella Jacoby), pod borer ( Helicoverpa armigera Hubner), and blue butterfly (Lampides boeticus Fabricius) cause substantial damage to green gram crops in eastern India. This study quantified their population dynamics across two consecutive pre-kharif seasons (2023 and 2024) within the red and lateritic soils of West Bengal, alongside evaluation of key abiotic factors. Peak populations were observed between 15 and 16 weeks, with pod bug 3.37 and 3.40 individuals per plant, flea beetle 1.84 and 1.90, pod borer larvae 1.28 and 1.20, and blue butterfly adults 3.43 and 3.20 in 2023 and 2024, respectively. Pearson's correlation analysis revealed a strong positive relationship between minimum temperature and pest populations (r = 0.53 to 0.74), whereas rainfall and relative humidity had weak or non-significant effects. Linear regression analyses underscored minimum temperature as the dominant explanatory factor, especially for pod borer populations (^R2 = 0.72 in 2023). These findings provide vital insights for climate-informed integrated pest management strategies in West Bengal's green gram agroecosystem.