Bean rugose mosaic virus

Systematic position and type of pathogen: Bean rugose mosaic virus (BRMV) belongs to the Secoviridae family and the Comovirus genus. It is an obligate phytopathogen containing a single-stranded positive-sense RNA genome. This virus represents a significant threat to legume crops, causing systemic infections that severely impair plant productivity.

Diseases and susceptible crops: The primary host for this pathogen is common bean (Phaseolus vulgaris). The virus induces characteristic symptoms, including severe rugosity (wrinkling) of leaf blades, mosaic patterns (alternating light and dark green tissues), leaf distortion, and general stunting. In severe cases, infected plants may remain dwarfed throughout their growth cycle.

Biology and life cycle: The virus's life cycle is closely linked to its insect vectors. Under field conditions, BRMV is primarily transmitted by beetles from the Chrysomelidae family. While feeding on healthy plants, these beetles introduce viral particles into the plant tissue, facilitating rapid dissemination of the infection across the field. The virus can also persist in seeds, contributing to its transmission over long distances.

Conditions for development and harmfulness: Warm weather conditions favor the activity and proliferation of beetle vectors, which in turn accelerates the spread of the virus. The harmful impact of this pathogen lies in the significant reduction of bean yield and degradation of market quality. Early infection of crops can lead to catastrophic losses, making high-quality commercial production difficult to achieve.

Protection and control measures: Since there are no curative treatments for infected plants, management strategies focus on prevention. Recommended control practices include:

• Using certified, virus-free planting seeds.
• Implementing spatial isolation of fields from weed reservoirs and known infection sources.
• Applying insecticides to manage beetle vector populations effectively.
• Breeding and planting resistant or tolerant bean cultivars.
• Removing and destroying crop residues post-harvest to interrupt the disease transmission cycle.