Seasonal Incidence and Influence of Weather Parameters on the Population Dynamics of Helicoverpa armigera (Hübner) in Chickpea under Western Uttar Pradesh Conditions

Abstract

Aim: To investigate the seasonal incidence of gram pod borer, Helicoverpa armigera (Hübner), and to determine the influence of prevailing weather parameters on its population dynamics in chickpea under the agro-climatic conditions of Western Uttar Pradesh. Study Design: A field experiment was conducted during the Rabi season of 2025–26 at the Crop Research Centre, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, Uttar Pradesh. The chickpea variety GNG-1958 was grown under natural field conditions, and observations were recorded throughout the crop season. Methodology: The crop was raised following recommended agronomic practices. Weekly observations on the larval population of H. armigera were recorded from the initial appearance of the pest until crop maturity. Simultaneously, meteorological data, including maximum temperature, minimum temperature, morning relative humidity, evening relative humidity and rainfall, were obtained from the university meteorological observatory. Correlation analysis was performed to determine the relationship between weather parameters and pest population. Results: The larval population of Helicoverpa armigera first appeared during the 1st Standard Meteorological Week (SMW), with 0.65 larvae per five plants. It increased progressively and reached a peak of 5.65 larvae per five plants during the 7th SMW, after which it declined gradually to 0.70 larvae per five plants by the 13th SMW. Correlation analysis revealed weak positive associations between larval population and maximum temperature (r = 0.240), minimum temperature (r = 0.026), and rainfall (r = 0.160), whereas morning relative humidity (r = -0.035) and evening relative humidity (r = -0.512) showed negative associations. All correlations were statistically non-significant, and evening relative humidity had the largest absolute correlation coefficient among the variables examined. Conclusion: The present investigation showed that the 7th SMW was the period of highest observed H. armigera infestation in chickpea, coinciding with the reproductive stage of the crop. Maximum and minimum temperatures showed weak positive associations with larval population, whereas morning and evening relative humidity showed negative associations; none of the correlations was statistically significant. These findings indicate the value of intensified pest surveillance during flowering and pod development, while multi-season observations are required before a weather-based forecasting model can be validated.