Spatio-Temporal Variability in Infestation and Damage Dynamics of Fall Armyworm (Spodoptera frugiperda) and Pink Stem Borer (Sesamia inferens) in Rabi maize in Telangana, India

A systematic roving survey was undertaken during the rabi season of 2023–24 across 24 maize-growing villages in six districts of Telangana, spanning the Southern, Central, and Northern agro-climatic zones, to assess the incidence, severity, and spatial distribution of FAW, and PSB. Pest incidence was quantified using a standardized W-shaped transect method, with 50 plants examined per field at two critical growth stages: vegetative (20–25 DAS) and reproductive (50–65 DAS). FAW incidence during the vegetative stage ranged from 22.0% (Ramreddipalli) to 70.0% (Palem), with a mean of 48.46% and a coefficient of variation (CV) of 9.74%. Corresponding proportional losses, based on a severity factor of 0.83, were estimated at 18.26–58.10%. By the reproductive stage, FAW incidence declined substantially (11.0–36.0%; mean: 20.13%; CV: 13.76%), with associated damage of 8.8–21.2% (severity factor: 0.80). Severe FAW pressure (>60%) was recorded in 12.5% of surveyed villages at the vegetative stage, whereas only 8.3% reported infestation above 30% during the reproductive phase. In contrast, PSB incidence during the vegetative stage was more spatially variable, ranging from 10.0% (Chilpur) to 44.0% (Khanapur), with a mean of 22.77% and CV of 15.76%. Damage estimates, derived from severity factors of 0.78–0.86, varied between 8.10% and 36.72%. Spatial stratification revealed that 8.3% of villages experienced high infestation (>40%), 33.3% moderate (25–40%), 41.7% low-moderate (15–25%), and 16.7% low (<15%). The contrasting spatiotemporal dynamics of FAW and PSB indicate that FAW exerts maximum pressure during early crop growth, while PSB maintains heterogeneous but persistent incidence during the vegetative stage. These findings emphasize the need for stage-specific, zone-oriented integrated pest management (IPM) strategies, aligned with pest biology and regional agro-ecological contexts, to minimize yield losses in rabi maize ecosystems of Telangana.