Cucumber mosaic virus in African yam bean (Sphenostylis stenocarpa): Occurrence and management with baking soda

Abstract

African yam bean (AYB) is an underutilized grain legume rich in protein, carbohydrate and minerals. Management of pests and diseases in this legume involves the use of chemical pesticides which have adverse effects on the consumers and the environment. Therefore, this study investigated the use of baking soda (BS) as an alternative for the management of cucumber mosaic virus (CMV) in AYB. Four genotypes of AYB (NGBO349, AYB61, TSs3 and AYB94) were planted on the experimental field of Institute of Agricultural Research and Training, Ibadan in 2017. Treatments involved spraying with 15 g of baking soda per liter of water, 20 g of baking soda per liter of water and these were compared with spraying with an insecticide (lambda cyalothrin). Data were collected on the incidence and severity of CMV in the field. Virus titers were obtained using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Results revealed that the incidence of CMV in all the genotypes ranged between 11.8% and 39.3% while the severity ranged from 2 to 3 on a scale of 1-5. Spraying with 15 g/L of BS did not control CMV in AYB genotypes except in AYB94 in which the virus was absent. Spraying with 20 g/L controlled CMV in all the genotypes except TSs3 while spraying with insecticide controlled CMV in all but one genotype (NGBO349). The study concludes that baking soda at 20 g/L which has been previously used to control fungal pathogens in plants is a good alternative for the management of viruses in plants because it competed favourably with insecticide. However, further studies using polymerase chain reaction is required to validate the findings obtained using ELISA.