Axonopus streak mastrevirus

Pathogen and disease type. Mastrevirus axonopi is a plant pathogen belonging to the Mastrevirus genus within the Geminiviridae family. It is a viral disease primarily affecting the plant's vascular system. The virions possess the characteristic geminate (twinned) icosahedral structure containing a single-stranded circular DNA genome, which is typical for viruses in this group.

Host range and occurrence. The primary hosts of this pathogen are grasses, specifically species of the genus Axonopus. Under field conditions, the virus can also affect various forage grasses and wild grasses that act as asymptomatic reservoirs. The disease is most prevalent in tropical and subtropical regions where environmental conditions favor the activity and survival of insect vectors.

Symptoms and signs of infection. The primary visual manifestation of this infection is chlorotic streaking on the leaf blades. Leaves develop a characteristic mosaic pattern, with light-colored or whitish intermittent lines appearing along the veins. As the disease progresses, plants may exhibit stunted growth, shortened internodes, and a significant reduction in overall vegetative biomass.

Development and transmission. The virus is transmitted primarily through insect vectors, specifically leafhoppers (family Cicadellidae). The transmission is persistent, meaning that after acquiring the virus from an infected plant during feeding, the vector remains capable of transmitting the pathogen for an extended period. Environmental factors such as high vector density and the presence of weed hosts facilitate rapid spread.

Harmfulness and control measures. The economic impact includes reduced pasture productivity, decreased quality of forage, and weakened plant health. As there are no curative treatments for viral infections in plants, management focuses on prevention:

• utilizing resistant grass cultivars;
• managing leafhopper populations with targeted insecticides;
• eradicating weed reservoirs of the virus;
• maintaining proper spatial isolation for susceptible crops.