Host plant resistance in vegetable cowpea genotypes against legume pod borer Maruca vitrata Fabricius

Abstract

Maruca vitrata Fabricius commonly known as the legume pod borer, is a major insect pest newlineof cowpea (Vigna unguiculata (L.) Walp). Studies have shown that this pest can lead to yield newlinereductions ranging from 20 per cent to as high as 88 per cent. To reduce this loss, Legume growers newlineuse chemical insecticides indiscriminately, leading to the development of pesticide resistance. newlineTherefore, effective management of M. vitrata requires use of resistant cultivars. However, very newlinelittle research has been done to identify the sources of resistance in cowpea so far. Hence, newlineidentifying resistant sources and determining the basis of resistance will aid in the development of newlineresistant cowpea cultivars. With the above facts in view, the present study on host plant resistance newlinein vegetable cowpea genotypes against legume pod borer Maruca vitrata Fabricius was conducted newlineat Central Research Station, Department of Entomology, Odisha University of Agriculture and newlineTechnology, Bhubaneswar with two seasons of field experiments during summer, 2021 and kharif, newline2021 along with pot culture experiment during rabi, 2021 with the objectives of screening of the newlinevegetable cowpea genotypes against legume pod borer and to determine biophysical and newlinebiochemical basis of resistance.Sixty vegetable cowpea genotypes including Arka Suman as newlineresistant and Bhagyalakshmi as susceptible check were screened in the field against Maruca vitrata newline(Fabricius) and based on per cent pod damage scale the vegetable cowpea genotypes were newlinecategorized into highly resistant, moderately resistant, intermediate, susceptible, and highly newlinesusceptible groups. From the field screening, three genotypes viz., IC 202796, IC 206240, and IC newline214751 were grouped into resistant category; seven genotypes viz., EC 738122, IC 259063, EC newline367692, EC 390225, EC 367694, EC 724471 and IC 257449 were grouped into moderate resistant newlinecategory. These two categories of genotypes were taken for further studies i.e., dual choice arena newlinetest (DCAT) and no choice test (IPT) to validate their resistance exp