Review of maize streak virus disease and management strategies in sub-Saharan Africa

Abstract

Maize streak disease (MSD) induced by Maize streak virus (MSV) is an economically important viral disease of maize in sub-Saharan Africa. Following its first report in South Africa in 1901, the virus has been confirmed in virtually all African countries. Maize streak virus is a member of the Geminiviruses with characteristic monopartite genome, measuring18 × 30 nm in size. Each virion of the MSV contains a single, covalently bound, circular ssDNA molecule of about 2.7 kb. Replication occurs through double stranded DNA (dsDNA) intermediates, using a rolling circle replication mechanism. The virus induces various forms of foliar symptoms such as white, yellow or red streaks in susceptible varieties. Maize streak virus has a wide host range within the grass family (Poaceae) and is transmitted by several leafhoppers (Cicadulina spp.) in a persistent manner. Eleven strains of MSV have been identified, with various degree of pathogenicity, causing maize losses of about US$480 million annually. Management of MSV could be by application of insecticide, early planting, crop rotation and cultivation of resistant genotypes. Among these control options, adoption of resistant varieties is by far the most effective and sustainable. There is need for multidisciplinary approach and continuous collaboration from maize breeders, entomologists and plant virologists in order to eradicate MSD menace in the region.