FIELD ASSESSMENT OF RELATIVE SUSCEPTIBILITY OF FORTY COWPEA (Vigna unguiculata L. WALP.) ACCESSIONS TO THE POD-SUCKING BUGS

Abstract

This study, which was carried out at the Teaching and Research Farm, Federal University of Agriculture, Abeokuta, Nigeria, to assess the variations in the population densities of Clavigralla tomentosicollis, Anoplocnemis curvipes, Aspervia armigera, Nezara viridula and Riptortus dentipes on forty field-grown cowpea accessions collected from the International Institute for Tropical Agriculture (IITA), Ibadan. The experiment was laid in a Randomized Complete Block Design with three replicates, and the forty accessions which represented the treatments, were grown without fertilizer or pesticides. Data were collected on insect population densities, insect-induced pod and seed damage, and some agronomic characteristics on ten randomly selected cowpea plants at the podding stage. Results showed significant varietal differences in the population densities of pod-sucking bugs (PSB), pod and seed damage across the forty accessions tested. Accessions IT07K-303-1 and IT04K-321-1 were the least susceptible recording significantly lower insect infestation (3.66 and 3.83 respectively in the late season while 7.83 and 7.65 respectively in the early season as well as lower pod and seed damage. IT98K-205-1 as well recorded significantly lower insect infestation and damage however, with high PSB population. IT06K-147-2, IT99K-494-6, IT06K-135, IT97K-390-2, IT04K-227-4 and IT99K-216-48-1 were the most susceptible accessions. Seed damage was found to have significant relationships with moisture, carbohydrate, protein, fat and steroids contents.