Fluctuation patterns of different developmental stages of Helicoverpa armigera (Lepidoptera: Noctuidae) on chickpea (Cicer arietinum) and their relationship with the environment

The relative frequency of occurrence of different developmental stages of gram pod borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and the dependence of its developmental stages on environmental factors, are crucial in the population management. The densities of eggs and larvae were low from December to mid-February due to prevailing cold. Owing to optimum environmental conditions, increasing densities were observed throughout March and they droppped again during the first week of April. The densities of eggs and different larval instars of H. armigera were significantly positively correlated with temperature, and significantly negatively correlated with the average morning relative humidity (RH;%) but not with the average evening RH (%)