Allexivirus

Allexivirus is a genus of plant viruses within the family Alphaflexiviridae. These pathogens are known to cause chronic, often latent, infections in various vegetable crops. Unlike many other plant viruses, they are characterized by filamentous virions and depend heavily on specific biotic vectors for dissemination within a field.

The primary hosts of Allexiviruses are members of the Amaryllidaceae family, particularly species of the genus Allium. Garlic and onions are the most economically significant crops affected by these viruses. Infection often goes unnoticed in early stages, leading to a gradual "running out" or degeneration of the crop variety over several growing seasons.

Symptoms of Allexivirus infection are frequently expressed as mosaic patterns, chlorotic streaking, and leaf twisting. The impact on the host can be summarized by the following manifestations:

• Foliar chlorosis and mottling.
• Stunting and reduced plant vigor.
• Deformation of the leaves and stalks.
• Reduced bulb size and weight.
• Decreased post-harvest storage life of the produce.

The development and spread of Allexiviruses are closely linked to the presence of mite vectors, specifically the eriophyid mites. These mites act as the primary biological vectors, transmitting the virus while feeding on plant tissues. The persistence of the virus in infected bulbs ensures that it is carried over from one season to the next, often resulting in widespread field infection.

Control strategies for Allexivirus focus primarily on prevention and the suppression of the vector population. Using virus-tested or virus-free planting material is the most effective management strategy. Additionally, controlling eriophyid mite populations with appropriate acaricides and maintaining strict field hygiene by removing symptomatic plants helps mitigate the spread of the virus within the farm.