UTTAR PRADESH JOURNAL OF ZOOLOGY

A field investigation was conducted during the 2022 and 2023 kharif seasons at the Agricultural Research Farm of Banaras Hindu University, Varanasi, to examine the seasonal incidence of rice leaf folder, Cnaphalocrocis medinalis, and its association with selected weather variables. Rice leaf damage was assessed weekly on ten randomly selected hills in an unprotected 100 m² plot planted with the variety Swarna Sub1. The percentage of damaged leaves was recorded from the onset of infestation until crop maturity. Weekly observations were analysed in relation to rainfall, maximum and minimum temperatures, and morning and evening relative humidity, and correlation and regression analyses were performed. During 2022, post-onset leaf damage ranged from 2.5% to 17.5%, with the highest incidence observed during the 37^th Standard Meteorological Week. During 2023, leaf damage ranged from 3.0% to 17.5%, reaching its maximum during the 41^st Standard Meteorological Week. Morning relative humidity showed a positive correlation of 0.50 in both seasons, while evening relative humidity showed positive correlations of 0.55 in kharif 2022 and 0.60 in kharif 2023. Maximum temperature, minimum temperature and rainfall showed weak negative correlations with leaf-folder damage. The observed seasonal pattern indicated that infestation increased during the middle part of the crop season and declined as the crop approached maturity. Under the conditions of this study, relative humidity showed the strongest positive association with rice leaf-folder damage, although further replicated, multi-location studies are required to evaluate its predictive value.