Differential Reaction of Cowpea (Vigna unguiculata) Genotypes to Pulse-beetle (Callosobruchus maculatus)

Fifty two cowpea genotypes including two checks Pusa Komal and Local variety were evaluated for their differential reaction to pulse beetle, Callosobruchus maculatus under no-choice artificial infestation conditions. Significant differences were observed among the genotypes in terms of number of eggs laid, development period, adult emergence, number of emergence holes, weight loss and growth index of C. maculatus on cowpea. Based on growth indices of C. maculatus on cowpea, three genotypes (IC107466, IC106815 and Pusa Komal) were found resistant, nine as moderately resistant, 18 as moderately susceptible, 18 as susceptible and 4 were highly susceptible. Correlation between growth index and growth parameters of beetle on cowpea genotypes indicated that growth index had significant negative relationship with mean development period (r = -0.90) and significantly positive relation with adult emergence (r = 0.83). Adult emergence had a positive relationship with weight loss (r = 0.43) and number of eggs laid by C. maculatus had a significant negative relationship with adult emergence (r = -0.36).