Maize streak virus

Maize streak virus (MSV) is a devastating plant pathogen belonging to the genus Mastrevirus within the Geminiviridae family. Characterized by a circular single-stranded DNA genome, this virus causes systemic infections primarily in maize, leading to significant economic losses in sub-Saharan Africa and other tropical regions.

The disease is marked by the development of narrow, broken chlorotic stripes along the leaf veins, which is the hallmark symptom. As the infection progresses, these stripes may coalesce, leading to severe leaf yellowing, stunting of the plant, and a drastic reduction in cob development, which often results in complete crop failure if infection occurs at an early stage.

The virus is transmitted by leafhoppers of the genus Cicadulina, most notably Cicadulina mbila. MSV is not seed-borne or transmitted through mechanical inoculation. Instead, it relies on these insect vectors that acquire the virus while feeding on infected wild grasses and subsequently transmit it during feeding on healthy maize plants.

Environmental conditions play a critical role in the epidemiology of MSV. High temperatures and the availability of host plants for the vector facilitate rapid population growth of leafhoppers. Disease spread is most intense during periods when migratory leafhoppers move from dried-out natural vegetation into irrigated or newly planted maize fields.

Management strategies focus on reducing the incidence of the vector and improving plant resistance. Key practices include the use of genetically resistant maize varieties, adjusting planting dates to avoid the peak populations of Cicadulina, and strict weed control in and around fields to remove the virus reservoirs. Seed treatments and early-season insecticidal applications are often employed to protect susceptible seedling stages.