Studies of the occurrence of gram pod borer, Helicoverpa armigera on chickpea at new alluvial zone of West Bengal

The incidence of 0.06 larvae / five plants of gram pod borer was observed at 8th standard week during rabi, 2017-2018 but in 2018-2019 incidence was observed during 1st standard week with 0.2 larvae / five plants. The gram pod borer population reached peaks with 2.2 and 0.66 during 12th standard week and 9th standard week during rabi, 2017-2018 and 2018-2019 respectively. Later declined trend was observed. The data recorded in the experiment were subjected to correlation for both the years, against weather parameters in order to know the influence of abiotic factors on the incidence of Helicoverpa armigera population in chickpea. The correlation analysis showed that, both maximum and minimum temperature, relative humidity were positively correlated during both years. Pod damage due to pod borer according to weekly recorded data of larval incidence was 48.73% during 14th SMW in first year and 24.01% during 11th SMW in second year.