Seasonal Incidence of Pulse Aphid (Aphis craccivora Koch.) and its Natural Enemies on Field Pea (Pisum sativum L.) in Relation to Some Abiotic Factors in Alluvial Zone of West Bengal

Abstract

Background: Field pea, Pisum sativum L. is an important winter-season pulse crop. It is subjected to damage by both field and storage insect pests and approximately 10-15 per cent reduction in yield was reported due to the infestation of different insect pests. Among these, pulse aphid (Aphis craccivora Koch.) affects plant physiology directly by removal of nutrients or indirectly by dispersal of various viral diseases. The present investigation has been aimed to study the seasonal fluctuations of aphids and their natural enemies as well as their correlation. Another objective was to know the effect of various weather parameters on pulse aphids and their natural enemies which ultimately would be helpful to develop a forewarning model.Methods: The field experiment was conducted at the A-B Block Farm of Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal using two varieties of field pea (KPMR 935 and IFPD 122) during rabi seasons of two consecutive years of 2017-18 and 2018-19 following a Randomized Block Design with three replications. After recording the total population of both pests (nymphs and adults) and their natural enemies across the season, the mean population was worked out and used for correlation and regression studies along with the weather parameters. Result: Maximum aphid population was noticed during the peak pod formation stage of the crop irrespective of the varieties. The pest population was very strongly correlated with the incidence of coccinellid and ant population in both test varieties. Among the weather parameters, both maximum and minimum temperature and sunshine hour showed a positive correlation with the pest population and their natural enemies but relative humidity and rainfall showed a negative correlation. Regression studies indicated that temperature and relative humidity were the most influencing factors over the incidence of aphid in both the seasons.