Cowpea Reaction to Single and Mixed Viral Infection with Blackeye Cowpea Mosaic Virus and Cowpea Yellow Mosaic Virus

Abstract

Potted experiment was carried out in the screenhouse of the Crop Protection Department, Faculty of Agriculture, University of Ilorin, Nigeria to determine the yield reaction of cowpea to single and mixed viral infection with Blackeye Cowpea Mosaic Virus (BICMV) and Cowpea Yellow Mosaic Virus (CYMV) at different inoculation regimes. The experiment was laid out in a complete randomized block design (CRD). The two viral inoculums (BICMV and CYMV), were mechanically inoculated to cowpea plants, singly and in mixtures at 2 and 4 weeks after planting (WAP). Plants which served as the control were only buffer inoculated. The results of the experiment showed that mixed inoculation with the two viruses, induced greater susceptibility to the viral pathogens in the plants, compared to single virus inoculations. The study also indicated that, early viral infection at 2 WAP, was more pathogenic and resulted in higher yield losses compared with infections at 4 WAP. The findings confirmed that early viral infection in cowpea was more pathogenic than late infection. It also concluded that the synergistic effect of the two viruses when in mixed infection, resulted in higher susceptibility in contrast to single viral infection.

Keywords: Cowpea, Viral Inoculum, Blackeye cowpea Mosaic Virus, Cowpea Yellow Mosaic Virus, Single and Mixed Infections, Synergism