Maize rough dwarf virus

Maize rough dwarf virus (MRDV) is a serious plant pathogen belonging to the genus Fijivirus within the Reoviridae family. It primarily infects maize crops, leading to significant yield losses and severe morphological abnormalities in affected plants.

The disease is characterized by extreme stunting, shortened internodes, and the development of distinctive swellings or enations on the abaxial side of the leaf blades and leaf sheaths. These symptoms give the plant a rough, dark green, and deformed appearance, often resulting in complete sterility of the inflorescences.

The virus is transmitted in a persistent, circulative manner by planthoppers, primarily Laodelphax striatellus. Once the insect acquires the virus through feeding, it remains infectious for its entire lifespan. Furthermore, the virus can be passed down to the offspring of the vector, which facilitates its persistence in the environment regardless of the host crop availability.

The prevalence of MRDV is closely linked to the migratory patterns of its insect vectors and the availability of perennial grassy weeds that serve as natural reservoirs. Warm, dry springs that encourage the early movement of planthoppers into corn fields significantly increase the incidence of the disease.

Control strategies for MRDV are mainly preventive, as there are no direct chemical treatments for viral infections in crops. Management focuses on reducing vector populations through timely insecticide applications, strict weed control in and around fields to eliminate reservoirs, and the deployment of resistant maize hybrids that show lower susceptibility to viral colonization.