Bromus mastrevirus

Mastrevirus bromi is a plant pathogenic virus belonging to the genus Mastrevirus within the family Geminiviridae. This virus is characterized by a circular single-stranded DNA genome. It infects primarily members of the Poaceae family, often persisting in wild grasses, which act as natural reservoirs for the pathogen before it potentially spreads to cultivated cereal crops.

The virus primarily affects grass species within the genus Bromus. However, its impact extends to other related monocots. In agricultural landscapes, the proximity of wild grass margins or unmanaged pastures serves as a primary source of inoculum, significantly increasing the risk of infection in adjacent cereal fields.

Symptoms are typically manifested as foliar streaking, where chlorotic or pale green longitudinal stripes appear along the leaf veins. As the infection progresses, the plant exhibits symptoms of systemic stunting, reduced tillering, and distorted development of the ear or panicle. These physiological stressors inevitably lead to a substantial decrease in grain yield and reduced kernel quality.

The spread of the virus is highly dependent on insect vectors, specifically leafhoppers. Transmission follows a circulative-persistent mechanism, meaning the insect remains infectious for a significant period after acquiring the virus from an infected plant. Environmental factors such as mild winters and warm, dry springs promote the proliferation of leafhopper populations, thereby facilitating wide-scale viral outbreaks.

Effective management requires a multi-faceted approach focused on reducing infection pressure. Key strategies include the systematic removal of grassy weeds, which serve as overwintering hosts for the virus. Additionally, controlling vector populations through the timely application of insecticides is critical. Monitoring the arrival and density of leafhoppers is essential to preventing the transmission of the virus from reservoir hosts to valuable crops.