Seasonal incidence of major insect pests of pigeonpea in relation to weather parameters

Abstract

The study investigates the seasonal incidence of major insect pests of pigeonpea (Cajanus cajan) in relation to weather parameters. Conducted at the experimental farm of the Department of Entomology, Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani, Maharashtra, during the kharif seasons of 2021-22 and 2022-23, the research aimed to understand pest dynamics under natural infestation without insecticidal intervention. The pigeonpea variety BDN 13-41 (Godavari) was cultivated across a 100 m² plot, adhering to recommended agronomic practices.Weekly observations were recorded on major pests, including Grapholita critica, Helicoverpa armigera, Maruca vitrata, Exelastis atomosa, and Melanagromyza obtusa. Larval counts were systematically assessed, and pod fly incidence was determined through the collection and analysis of damaged pods. Weather data were correlated with pest populations using WASP 2.0 software to identify patterns. The results revealed that G. critica larvae peaked at 2.72 and 1.98 per plant in October during 2021-22 and 2022-23, respectively. H. armigera infestations reached a maximum of 4.36 larvae per plant in December (2021-22) and 4.10 larvae per plant in December (2022-23). M. vitrata and E. atomosa populations exhibited their highest densities in December, correlating with flowering and pod development stages. The peak maggot density of M. obtusa was recorded at 17.20 individuals per 25 pods in January (2021-22). Statistical analysis indicated significant correlations between pest populations and weather parameters, including temperature, humidity, and rainfall. The study underscores the critical role of weather in influencing pest dynamics and highlights the importance of timely, eco-friendly pest management strategies tailored to local climatic conditions.