Correlating the pheromone-trapped adults of Spodoptera frugiperda (J. E. Smith), with the weather parameters in maize fields of Assam, India

Abstract

Assam, a north-eastern Indian state, has experienced the invasion of fall armyworm (FAW) in recent years. The correlation study of weather factors with the adult population was undertaken with the adults caught in the pheromone traps installed in maize fields, of 3 districts of Assam during 2023-24. There was a positive correlation with the maximum temperature in 4 out of 9 occasions, and with minimum temperature in 7 out of 9 occasions of seasonal correlations across the districts, which led to a positive correlation (r=0.331 and r=0.459, respectively); however, the effects of minimum temperature on the adult population are more pronounced. Rainfall was positive, but insignificant. Three linear models were developed by the multiple linear regression analysis for weekly adults trapped against these weather parameters for two seasons, as well as their pooled data. All models are statistically significant, and the key factor contributing to variation in weekly trap catch was the temperature variable. The Durbin-Watson value of each season was near 2.0, which indicated that no serious autocorrelation in residuals occurred. These models will help in predicting the pests in the future.