Detection and Distribution of Viruses Infecting Sweet Potato (Ipomoea batatas L. Lam.) and Their Associated Vectors in Kebbi and Katsina States, Nigeria
Keywords:Aphid, DAS-ELISA, SPCFV, SPMMV, SPV2, whitefly
Sweet potato is a food security crop because of its ability to withstand adverse climatic conditions and provides sustainable food when other crops fail. This security, however, is being threaten by viral diseases. Surveys were conducted for viruses infecting sweet potato in 2020 rainy and 2021 dry seasons in Kebbi and Katsina States. Samples were collected from sweet potato plants and tested for Sweet potato chlorotic fleck virus (SPCFV), Sweet potato mild mottle virus (SPMMV) and Sweet potato virus 2 (SPV2) using Double Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DAS-ELISA). Whitefly and aphid populations were assessed. Results revealed that, the three viruses infected sweet potato in the study areas. Kebbi had higher incidence of SPCFV (17.78%), SPMMV (11.11%), and SPV2 (25.56%) in the dry season, while Katsina had higher incidence of SPCFV (10.00%) in the rainy season. Mean disease incidence in Kebbi was significantly (P = 0.05) higher than in Katsina. Mean symptom severity was not significant (P = 0.05) in the two states and for the two seasons. Aphid was not observed in the rainy season in both states. In the dry season, the mean aphid population per leaf was not significant (P = 0.05) in both states. The mean whitefly population was significantly (P = 0.05) higher in Kebbi (8.86) than in Katsina (6.34) in the dry season, but in the rainy season it was not significant in both states. There was no significant relationship between aphid population and SPV2 incidence, between whitefly population and SPMMV incidence in both states and seasons. SPCFV, SPMMV, and SPV2 occurred in the study areas. Farmers need to be trained on symptom identification and the importance of using only disease-free vines as planting materials.