Abstract
The role of nutrition on the symptom expression of cowpea seedlings to co-infection by Fusarium oxysporum f.sp. tracheiphilum (Fot) or f.sp. phaseoli (Fop) and Sunn-hemp mosaic virus (SHMV) has been studied. Reduction in fresh weight of plants and in leaf area were more pronounced in cowpeas grown in complete nutrient conditions than in those grown under conditions of deficiency of N, P or K. Infection by Fot or Fop reduced growth significantly compared with healthy controls grown in all types of nutrient except when N was omitted. Plants co-infected with either of the fungi and SHMV had lower fresh weights and smaller leaf areas than those infected by any of those pathogens alone. The concentration of SHMV was highest in the leaves of plants given complete nutrient and in those co-infected with Fot or Fop than those singly infected by the virus.
