Screening of cowpea [Vigna unguiculata (L.) Walp.] accessions against pulse- beetle, Callosobruchus chinensis (L.)

A total of 52 accessions of cowpea including two checks (Pusa Komal and Local variety) were screened for resistance to pulse beetle, Callosobruchus chinensis under no-choice artificial infestation conditions. There were significant differences among the accessions in terms of number of eggs laid, development period, adult emergence, number of emergence holes, weight loss and growth index of C. chinensis on cowpea. Based on growth indices, Pusa Komal (0.04081) and IC328859 (0.04112) were resistant while IC106033 (0.06819) and Local variety (0.06816) were most susceptible to C. chinensis. Of the 52 accessions screeened, 11 accessions were resistant, 15 moderately resistant, 13 moderately susceptible, 8 susceptible and 5 were highly susceptible to C. chinensis. Correlation between growth index and growth parameters of pulse beetle on different cowpea accessions indicated that growth index had significant negative relationship with mean development period (r = -0.68) and significant positive relationship with adult emergence(r = +0.80). Adult emergence had a positive relationship with weight loss (r = +0.22).