Incidence pattern of pod borer complex on different red gram cultivars in relation to various weather factors in the Terai agro-ecological zone of West Bengal

A study, conducted in the Instructional Farm of Uttar Banga Krishi Viswavidyalaya (UBKV) during 2023-24 and 2024-25, unveils valuable insights about the seasonal occurrence pattern of pod borer complex on different red gram cultivars and identifies the most promising cultivar under the Terai agro-climatic situation of West Bengal. The study reported 5 species of pod borers, namely Maruca vitrata (Fabricius) , Exelastis atomosa (Walsingham), Lampides boeticus (Linnaeus), Melanagromyza obtusa (Malloch) and Apion clavipes Gerstäcker, infesting the red gram plants in this region. Of them, the population was lowest for M. vitrata (6.31 larvae/plant) and highest for L. boeticus (10.93 larvae/plant). Among the red gram cultivars screened, Pusa Arhar-16 had faced the highest pod borer incidence with 24.43 larvae/plant, whereas the cultivar Upas-120 faced the least incidence with 16.93 larvae/plant. In both seasons, the sampled pod borer complexes were characterized by less dominance and greater evenness. The seasonal incidence pattern suggested the 48th–49th standard meteorological week (SMW), the 50th–51st SMW and the 4th–6th SMW as the most critical periods of pod borer incidence in early-, mid- and late-maturity cultivars respectively. The incidence was initiated by M. vitrata for all the cultivars, followed by E. atomosa and L. boeticus, while M. obtusa and A. clavipes arrived later in the season. Different weather factors were noted to have significant influences on the seasonal occurrence of these pests. Among the 7 cultivars, Upas-120 was recorded with significantly (p < 0.001) greater yield (85.04 g/m2), whereas yield was lowest for Pusa Arhar-16 (58.22 g/m2), suggesting Upas-120 as the most promising cultivar for this region.