author(s)
Aparajita Das, Supriya Biswas and Arup Sarkar

abstract
The present investigation were carried out of field studies for two consecutive seasons, winter and summer seasons of 2015 to 2016, at the instructional farm of Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal. Five cultivars of cowpea and nine cultivars of mungbean were used and the experiment was laid down in a randomized block design and replicated thrice. Population of insect pests was recorded at weekly interval throughout the crop growing period starting from 1^st appearance of the pests. The activity of major insect pests on cowpea initiated after one month of seed germination. Crop stage of one and half month age found to be most vulnerable to pests. On both the season a peak aphid population was found during flowering stage of the crop. Highest population of predator was found during 50th standard week on cowpea (0.5 plant^-1) and mungbean (0.8 plant^-1). Population of insect visitors was recorded from all the varieties of cowpea during winter and summer seasons. During winter season and summer aphid and podfly population (per leaf or pod) was found highest on EC-101967 of cowpea. Highest population of pod sucking bug was found from the variety IC-549343 and pod borer infestation was recorded from the variety EC-101967 both during winter (5.33%) and summer (7.67%). On winter crop highest population of both predator (1.96 plant-1) and pollinator (2 plant^-1) was recorded from EC-101943. Among the varieties of mungbean, aphid, pod fly (plant^-1), number of mined, number of pollinators and pod borer population was found maximum in Sublobata-02 and predators was in TM-99-50 (6.00).