Detection of Potato virus Y associated with African nightshade leafy vegetable (Solanum scabrum miller) in Kenya

The African nightshades (ANS) have been part of the food systems in sub-Saharan Africa for generations. They are particularly attractive to small scale farmers because the risks of crop losses are much lower compared to the exotic vegetables. Plant viruses are economically important pathogens affecting African nightshade production. More than 200 plant viruses are reported to infest solanaceous family crops. This study was carried out to detect Potato virus Y associated with African nightshade. Symptomatic leaf samples were obtained from four agro-ecological zones in Kenya. The viral pathogens were detected using serology and molecular techniques. Laboratory experiments were carried out at the University of Nairobi and Kenya Plant Health Inspectorate Service (KEPHIS) from February 2017 to August, 2018. Field samples had the highest mean viral percentage frequency of 44.8% compared to greenhouse samples having 29.8% using serology methods. Molecular testing revealed that greenhouse and farm field sample were positive for the three Potato virus Y strains PVYN:O (necrotic recombinant), PVYO (ordinary) and PVYNTN (necrotic). Detection of Potato virus Y in ANS suggests that it is prevalent in the sampled regions and could cause problems to other solanaceous crops.