Dolichos yellow mosaic virus

Dolichos yellow mosaic virus (DYMV) is a significant plant pathogen belonging to the genus Begomovirus within the Geminiviridae family. It is a single-stranded DNA virus that primarily affects leguminous crops. The pathogen is known for its ability to cause severe mosaic symptoms, significantly impacting the physiology and productivity of the host plants.

The primary hosts of the virus include various bean species such as Dolichos lablab, common bean, and mung bean. The virus is highly dependent on its host range, which also includes several weed species that act as reservoirs, allowing the virus to persist in the environment even when primary host crops are not present.

Symptoms of the disease are characterized by yellow mosaic patterns, interveinal chlorosis, and crinkling of leaves. In advanced stages, the foliage may exhibit severe curling and stunting. Infected plants usually show a significant reduction in the number of flowers and pods, leading to stunted growth and impaired photosynthetic efficiency due to the breakdown of chlorophyll in the tissues.

The transmission of the virus occurs exclusively via the whitefly Bemisia tabaci. The insect acquires the virus while feeding on infected plants and transmits it to healthy plants through its saliva. The disease spread is closely linked to the population dynamics of the whitefly, which thrives in warm and humid conditions, making the virus particularly prevalent in tropical and subtropical regions.

The economic impact of Begomovirus dolichoris is considerable, often resulting in complete yield failure in susceptible varieties. To manage the disease, a systematic approach is necessary:

• Deployment of resistant or tolerant plant cultivars.
• Strict control of whitefly populations using appropriate insecticides.
• Removal and destruction of infected plant debris to reduce inoculum sources.
• Weed management to eliminate alternative viral hosts.
• Implementation of spatial and temporal isolation between new and old crop plantings.