REACTION OF COWPEA GENOTYPES FOR RESISTANCE AGAINST LEGUME POD BORER, Maruca vitrata (Fabricius)

Among different pulses, cowpea is considered as most important source of nutrition to human and livestock. Several insect pests cause major constraint in cowpea production. Among the pests, the legume pod borer, Maruca vitrata (Fabricius) is a serious threat which ultimately reduces the quality and quantity of the economic produce. Management of M. vitrata using insecticides is commonly followed. But, indiscriminate use of insecticides leads to unwanted repercussions in the environment. It prompted to turn the focus on eco friendly methods to manage this pest. Among various management methods, use of tolerant and/or resistant genotypes is the first line of defence against insect pests. In the light of this consideration, 280 cowpea genotypes were screened against M. vitrata during Rabi, 2020 and Kharif, 2021 seasons at Vallampadugai Village, Cuddalore district, Tamil Nadu state, India. The per cent flower and pod infestation were noted at different days after sowing. The results revealed that, minimum flower infestation was noted on IC-202800(6.60% and 5.00%) in both rabi and kharif. Maximum infestation in rabi and kharif was noted on IC-249141(76.66%) and IC-9883 (66.66%) respectively. Minimum and maximum per cent pod infestation was noted on IC-39870 (15.00% in rabi and 10.00% in kharif) and EC-161916(100% in rabi and 93.33% in kharif) in both seasons. Based on per cent pod damage, 30 genotypes were found highly resistant, with 52 moderately resistant, 81 susceptible genotypes and 38 highly susceptible genotypes in rabi season. In kharif, 18 genotypes were highly resistant and 86 genotypes have recorded moderately resistant in contrast to 13 genotypes secured highly susceptible ratings.