Fall armyworm (Spodoptera frugiperda J.E. Smith) has emerged as a major invasive pest of maize in India, causing significant yield losses through rapid population buildup and severe defoliation. The present study investigated the seasonal population dynamics and leaf damage caused by fall armyworm on maize during the Kharif season of 2024 at the Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi. A hybrid maize variety (Pusa Jawahar Hybrid Maize-1) was grown under natural infestation conditions without insecticidal intervention. Weekly observations were recorded from crop establishment to harvest to monitor larval abundance, percent plant infestation and leaf injury.Results indicated that larval incidence began in the 32nd SMW of August and persisted until the 44th SMW in late October. The larval population fluctuated between 0.97 and 4.08 larvae per plant, with the peak density observed during the 38th SMW (early September). Correspondingly, percent plant infestation rose steadily from 11.32% in August to a maximum of 83.60% in the 38th SMW, after which a gradual decline was noted as the crop matured. The most intense infestation occurred during September, coinciding with favorable weather characterized by mean temperatures of 29-30 °C and moderate rainfall. Correlation analysis between weather parameters and larval population revealed that wind speed (r = 0.60) and evaporation (r = 0.49) were strongly associated with pest abundance, while minimum and mean temperatures showed moderate positive effects. Rainfall and relative humidity exhibited weak associations, suggesting limited influence on pest buildup during the study period.
Patel et al. (Wed,) studied this question.