The Influence of Cowpea Cultivar on the Host Preferences of Cowpea Bruchids [Callosobruchus maculatus (F.)]

Callosobruchus maculatus (F.) is a major storage pest that causes significant quantitative and qualita-tive losses during storage and sale of cowpea (Vigna unguiculata L. Walp.). In this study, the behavioral response of cowpea bruchids (C. maculatus) to five local (‘Gombe’, ‘Drum’, ‘Sokoto’, ‘Big’, and ‘Honey’) and improved (ITI6K-1966-1, ITI5K-2377-1, ITI6K-1984-1, ITI4K-1903-1, and ITI5K-2386-1) cowpea cultivars was investigated using a Y-tube olfactometer. Gas chromatography-mass spectrometry (GC-MS) was used to analyze and identify the compounds of cowpea oils extracted using n-hexane, ethanol, and water solvents. The results showed that cowpea genotype had a significant effect on the decision time for attraction to the cowpea. Although mated female bruchids generally showed shorter decision times than male bruchids, gender significantly affected the attractiveness of only two cultivars. The solvent used for extraction had no significant effect on the time taken to decide on the attractiveness of different cowpea genotypes. Of the 20 bioactive compounds identified in local cultivars and 19 in improved cultivars, 13 were common to both cultivar groups. Bioactive compounds present in the highest percentages may be used as effective baits for monitoring and control of cowpea bruchids.