Influence of Weather Parameters on Seasonal Incidence of Pod Boring Weevil, Apion clavipes Gerst (Apionidae: Coleoptera) on Pigeonpea [Cajanus cajan (L.) Millsp.] under West Bengal Conditions

Pigeon pea is a high protein legume cultivated by marginal farmers in the Indian sub-continent. It exposes a wide variety of biotic stresses especially insect pests. Pod boring weevil, Apion clavipes Gerst is a major concern in eastern India which causes direct damages to economic parts such as flowers and pods. Pod boring weevil, Apion clavipes Gerst infests pigeonpea during vegetative, flowering, pod formation and pod maturity stages. However, there is not much information on seasonal incidence of pod boring weevil, A. clavipes Gerst on this particular host, which is very much essential for forecasting and forewarning of pest incidence and development of Integrated Pest Management module. The seasonal incidence of pod boring weevil was studied in two consecutive years during 2016-17 and 2017-18. The grub and weevil populations in shoots, flower raceme and pods were recorded and obtained weather data from automatic weather station of BCKV, West Bengal and subjected to correlation and regression analysis. The experimental results revealed that pest population started during 43rd SMW (4th week of October) and pest population attained the maximum population of 45.00 grub/plant during 4th SMW (4th week of January). Pest population was observed till 11th SMW (3rd week of March). Seasonal incidence of pod boring weevil negatively correlated with maximum relative humidity, minimum relative humidity and rainfall, whereas, positively correlated with maximum temperature, minimum temperature and sunshine hours.