Population Fluctuation of Gram Pod Borer in Rabi Pulses of West Bengal

Abstract

During the rabi season of 2021-22, a field research has been carried out at BCKV [District Seed Farm (AB Block)] Kalyani, Nadia, West Bengal for studying the pattern of incidence of gram pod borer or tomato fruit borer (Helicoverpa armigera Hubn.) in relation with prevailing meteorological parameters and to record the population fluctuation in four rabi pulse crops, viz., chickpea (var. KWR 108 and JAKI 9218), fieldpea (var. Rachna and VL 42), lentil (var. IPL 220 and L 4727) and grasspea (var. Prateek and Ratan). During the vegetative stage of the fieldpea, the Helicoverpa population first emerged, then gradually increased and declined near maturity; in lentil and grasspea it was recorded from flowering stage and persisted until maturity; in chickpea it was noticed from pod formation stage and continued up to maturity. None of the weather variables were significantly correlated with the Helicoverpa larvae population recorded on fieldpea and lentil while, regression studies denote that maximum (Max. T) and minimum (Min. T) temperature exhibited the most impact on the occurrence of Helicoverpa in grasspea and chickpea, respectively. The comparative study revealed that, Helicoverpa first appeared on lentil and field pea during the first week of January; then population appeared on grasspea during the end of second fortnight of January. Occurrence of the pest was noticed on lentil, field pea and grasspea in January and February and after that the population shifted to grasspea, fieldpea and chickpea during February to March. Chickpea was the most preferred crop as the highest population observed on this crop coinciding with pod formation stage.