Yellow Vein Mosaic Disease in Okra (Abelmoschus esculentus L.): An Overview on Causal Agent, Vector and Management

Abstract

Okra (Abelmoschus esculentus L.) belongs to the Malvaceae family and is one of the most essential and popular vegetables globally. It is rich in proteins, carbohydrates, and vitamins. Abiotic and biotic factors threaten okra productivity. Okra yellow vein mosaic disease (OYVMD) is the most destructive disease of okra. The causal agent, [(i.e., Okra yellow vein mosaic virus (OYVMV)] of this disease belongs to the family Geminiviridae and genusBegomovirus. OYVMV is a monopartite with additional ssDNA molecule. This virus has two components DNA-A for protein coding and DNA-B for symptoms induction. Whitefly transmits OYVMV in persistent manner. Characteristic symptoms of OYVMV infected okra plants are chlorosis, dwarfing, and yellowing of veins and fruits. High temperatures with moderate rainfall enhance the development of OYVMV disease and the whitefly population. However, high humidity with low temperature and rainfall has no significant role in developing the OYVMD and whitefly population. Moreover, the virus also affects the secondary metabolites in the infected okra plants. The virus can be managed through various strategies including the application of plant defense activators, the development of resistant varieties and by controlling its vector via pesticides and plant extracts. Various plant defense activators such as monopotassium phosphate (KH₂PO), salicylic acid, benzoic acid, and citric acid enhance resistance in okra against OYMVD. In addition, the resistance to OYMVD can also be achieved by successfully incorporating high yielding but resistant cultivars of acceptable quality. In this review, we have discussed history, economic impact, symptomology, disease development under a natural environment, genetics and management of OYVMV.