Weather-Driven Population Trends of Helicoverpa armigera (Hubner) in Chickpea Ecosystems

Abstract

Chickpea (Cicer arietinum L.) is a vital pulse crop widely cultivated in South Asia and the Mediterranean region. However, its production is severely impacted by the gram pod borer, Helicoverpa armigera (Hübner), a major pest causing substantial yield losses. The study investigates the seasonal incidence and population dynamics of H. armigera in chickpea fields during the Rabi seasons of 2022–23 and 2023–24 was conducted at the College of Agriculture, Sumerpur (Pali), India, with a focus on the influence of meteorological factors. The pest was first observed in the 46th Standard Meteorological Week (SMW) in both years, with peak infestations recorded in the 49th & 50th SMW and 8th SMW (February), coinciding with the flowering and podding stages of the crop. Regression analysis indicated that maximum temperature had a significant positive effect on larval population in 2022–23 (p = 0.003), while minimum temperature exerted a significant negative influence (p = 0.01). In 2023–24, relative humidity emerged as a significant factor (p = 0.01), whereas temperature effects were non-significant. Correlation analysis further suggested that fluctuations in temperature and humidity played a crucial role in pest dynamics. To model the population growth of H. armigera, Exponential and Gompertz regression models were evaluated using Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). The Exponential model demonstrated a superior fit across both years, with lower AIC and BIC values compared to the Gompertz model, suggesting its efficacy in predicting larval population trends. These findings underscore the necessity of integrating predictive models into pest management strategies to enable early detection and control.