As part of an extensive and systematic programme to find genetic sources of resistance to Aphis craccivora, a major pest of cowpea, Vigna unguiculata, a total of 181 accessions from the germpiasm collection at the International Institute of Tropical Agriculture were screened in glasshouse tests using a simple visual damage scale. Twenty-four accessions showed considerably reduced damage. To confirm these results on IS selected accessions, aphid population growth over 10 days was recorded. Zero aphids were found on three accessions (310,408-P2 and 801); another six accessions had populations of less than 30, compared with 200–400 on susceptible varieties. The other accessions showed only partial antibiosis and/or tolerance.
