Broad bean mottle

Broad bean mottle is a viral disease caused by the Broad bean mottle virus (BBMV), a member of the Bromoviridae family. This virus primarily affects members of the Fabaceae family, posing a significant risk to fava beans (Vicia faba) and lentils (Lens culinaris). As a systemic infection, the virus spreads through the vascular system of the host plant, resulting in significant physiological disturbances.

The characteristic symptoms of the infection include leaf mottle, mosaic patterns of light and dark green, and sometimes chlorotic spots. Infected plants typically exhibit stunted growth, reduced leaf size, and occasional distortion of the foliage. In severe cases, the entire plant structure becomes weakened, flower development is inhibited, and seed production is drastically reduced.

The virus is primarily transmitted by insect vectors, specifically beetles such as leaf beetles (Chrysomelidae) and weevils (Curculionidae). Mechanical transmission through infected tools or plant-to-plant contact can also occur. The disease persists in weeds and alternative host plants during off-seasons, providing a reservoir for infection as soon as the next growing season begins.

The economic impact of Broad bean mottle is substantial, often leading to heavy crop yield losses. In addition to reducing the quantity of harvested grain, the virus impairs seed viability, making it a critical threat to the supply chain of high-quality legume seeds. The severity of the damage is largely dependent on the stage of plant development at the time of initial infection.

Management of the disease relies on integrated pest and disease control, as there are no direct chemical treatments to cure infected plants:

• Use of virus-free, certified seeds for planting.
• Implementation of strict weed control to remove virus reservoirs.
• Integrated pest management to control beetle vectors using appropriate insecticides.
• Crop rotation and spatial separation from previously infected legume fields to break the infection cycle.