Seasonal Population Dynamics of Major Insect Pests of Moringa oleifera Lam. in Relation to Weather Variables

Abstract

A single-season field study was conducted from standard meteorological week (SMW) 40 of 2025 to SMW 15 of 2026 in an established PKM-1 moringa plantation at Agricultural College, Aswaraopet, Telangana, India. Five plants were sampled weekly, with one branch selected in each cardinal direction on every plant. The abundance of the leaf-eating caterpillar (Noorda blitealis), bud worm (Noorda moringae), hairy caterpillar (Eupterote mollifera), grasshoppers, and two ash weevils (Myllocerus viridanus and M. discolor) was recorded together with visible shoot damage and five weather variables. The leaf-eating caterpillar was the most abundant pest and reached 4.60 larvae per branch in SMW 10; shoot damage reached 48% in the same week. After Benjamini-Hochberg correction for multiple correlation tests, maximum temperature was positively associated with leaf-eating caterpillar, bud worm, and M. discolor abundance, whereas evening relative humidity was negatively associated with leaf-eating caterpillar, shoot damage, bud worm, hairy caterpillar, M. viridanus, and M. discolor. Multiple linear regression models explained 27.24-71.77% of the observed weekly variation. All overall models except the grasshopper model were statistically significant, although the independently significant predictors differed among taxa. Maximum temperature was independently associated with leaf-eating caterpillar, bud worm, and M. discolor abundance, while evening relative humidity was independently associated with shoot damage and hairy caterpillar abundance. The findings identify locally relevant seasonal windows for field surveillance, but the single-site, single-season design does not establish causality or provide an externally validated forecasting model. Multi-season studies incorporating plant-level repeated measures, crop phenology, natural enemies, and lagged weather effects are required before operational prediction is attempted.