SEASONAL INCIDENCE AND REACTION OF GREENGRAM GENOTYPES AGAINST SPOTTED POD BORER, Maruca vitrata (FABRICIUS)

Abstract

Greengram cultivation is hampered by various insect pests, among which the spotted pod borer, Maruca vitrata (Fabricius) inflicts extensive damage. Insecticides are widely used to suppress this damage but are found to culminate in undesirable effects in the environment and humans. Exploring and exploiting host plant resistance in the gene pool of crop plants is an effective, ecofriendly alternative approach to manage such insect pests. Considering this, 333 greengram genotypes were gathered and screened under field condition to identify resistance sources against spotted pod borer during Rabi 2020 and Kharif 2021 at Sivapuri village, Chidambaram, Tamil Nadu, India. The larval population and their active webbing were accessed from flower bud initiation to end of crop growth period and per cent pod damage was worked out after harvest. The results of this study revealed that, the larval population and active webbing and per cent pod damage were the least on IC-39301-1 followed by IC-311451 and IC-39301-1 followed by IC-103207 during Rabi 2020 and Kharif 2021 respectively. In both seasons, the larval population, active webbing, and percent pod damage were higher in the genotype IC-39317, followed by IC-103981. Based on per cent pod damage 4 and 10 genotypes were found resistant, while 182 and 175 genotypes were moderately resistant, 70 and 78 genotypes were tolerant, 56 and 63 genotypes moderately susceptible and 21 and 7 genotypes were highly susceptible in Rabi 2020 and Kharif 2021 respectively. The genotypes which were grouped under resistant and tolerant category in both the seasons were selected for further evaluation to develop desirable varieties.