Abstract

Cowpea (Vigna unguiculata L. Walp.) is an important cash, food and nutritional security grain legume crop in the semi-arid regions of sub-Saharan Africa. However, its productivity is hampered by several biotic stress factors including numerous insect pests that infest and damage the crop at all its development stages in the field as well as during storage. This study sought to identify new sources of resistance to cowpea aphids. Ten lines were infested with three strains of aphids and their resistance was evaluated. Results revealed that among the cowpea genotypes, line IT97K-556-6 was found to be the most resistant to all the three strains of aphids. Line N ° 2300 was the most susceptible to all the three strains of aphids. KN-1 considered as a susceptible control was found to be resistant. Prior to lines classification based on their resistance to aphids, the analysis of the Area Under the Infestation Progress Curve (AUIPC) showed that IT97K-556-6 has exhibited the higher level of antibiosis. It was the least favorable to the development of aphids and NS-1 was the most favorable. Promising lines have been identified for further evaluation and utilization for improvement in cowpea.

Key words: Vigna unguiculata, Aphis craccivora, antibiosis, genetic resistance, area under the infestation progress curve (AUIPC), control.