Survey of the Symptoms and Viruses Associated with Cowpea (<em>Vigna Unguiculata</em> (L).) in the Agroecological Zones of Kwara State, Nigeria

Abstract

A comprehensive field survey was carried out in 2011 spanning thirty locations within the forest and savannah agroecologies of Kwara State, Nigeria. This was with the objective of having an overview of the prevalence of virus disease symptoms and to specifically identify the viruses infecting cowpea (Vigna unguiculata .L.) in Kwara State. Data were collected on the prevalence of some peculiar virus symptoms on cowpea plants on growing on farms in each location. Symptomatic cowpea leaves were also collected from each location for virus identification in the laboratory. The serological protocol employed for virus detection in the leaf samples was the antigen-coated plate Enzyme linked immunosorbent assay (ACP-ELISA) method. The results of the field survey indicated that the symptoms observed on the cowpea plants were peculiar to those associated with virus disease infection. The symptoms observed were leaf mottling (36.8%), mosaic (24.9%), leaf curl (15.6%), necrotic spots (8.2%) and other symptoms (14.5%). The result of the laboratory assay to detect the viruses present in the leaf samples revealed the presence of four (4) different viruses. The viruses identified were, Cowpea Aphid Borne Mosaic Virus (CABMV), Cowpea Yellow Mosaic Virus (CYMV), Blackeye Cowpea Mosaic Virus (BICMV) and Cowpea Mottle Virus (CPM o V). These viruses were detected infecting the cowpea plants in mixtures of two or three. These results are indicative of the presence of viruses in all the ecological zones of Kwara State where cowpea is cultivated.

Phenotypic and serological evaluation of cowpea (Vigna unguiculata L.Walp) genotypes for resistance to viral infection under field conditions

“…Symptoms observed in the field (mosaic, leaf mottling, vein clearing and necrotic lesion) were similar to symptoms reported elsewhere on legumes affected by viral diseases (Akinjogunla, 2005;Aliyu et al, 2012). The varying symptoms observed in the study are suggestive of different viruses which infect cowpeas in the study area (Aliyu et al, 2012).…”

“…Symptoms observed in the field (mosaic, leaf mottling, vein clearing and necrotic lesion) were similar to symptoms reported elsewhere on legumes affected by viral diseases (Akinjogunla, 2005;Aliyu et al, 2012). The varying symptoms observed in the study are suggestive of different viruses which infect cowpeas in the study area (Aliyu et al, 2012). The variation in symptoms observed in the study could be attributed to the type of viral strains infecting the cowpea, cowpea cultivar, the time of infection, light intensity, environmental temperature, and mixed infections (Jones et al, 1991;Aliyu et al, 2012).…”

“…The varying symptoms observed in the study are suggestive of different viruses which infect cowpeas in the study area (Aliyu et al, 2012). The variation in symptoms observed in the study could be attributed to the type of viral strains infecting the cowpea, cowpea cultivar, the time of infection, light intensity, environmental temperature, and mixed infections (Jones et al, 1991;Aliyu et al, 2012).…”

Evaluation of Cowpea Genotypes for Virus Resistance Under Natural Conditions in Uganda

“…It has been reported that symptom expression depends on the virus type or strain, genotype, species and plant age, time of the year and environmental conditions and some viruses cause similar or related symptoms (Shoyinka et al, 1997). Some symptoms such as mosaic, necrosis, chlorosis, vein banding, stunted growth, leaf deformation, and mottling are associated with viruses such as Cowpea aphid borne mosaic virus (CABMV), Blackeye cowpea mosaic virus (BICMV), Cowpea yellow mosaic virus (CYMV) (Aliyu et al, 2012;Orawu, 2007).…”

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

“…Surveys conducted in Kwara State, Nigeria by Aliyu et al (2012), indicated the presence of viruses in mixed infections on cowpea in the agroecological zones of the State.…”