Bean yellow dwarf virus

Begomovirus phaseoligallici is a viral pathogen known to cause severe yellow dwarf or gall mosaic diseases in bean crops. As a member of the Geminiviridae family, this virus possesses a circular single-stranded DNA genome. It relies on specific insect vectors to enter the host plant tissue and initiate a systemic infection that impacts the plant's overall physiology.

The primary host for this virus is the common bean (Phaseolus vulgaris). When a plant becomes infected, the virus disrupts normal hormonal balances, which leads to stunted development and leaf abnormalities. While it primarily affects beans, the virus can persist in various weed species, which act as reservoirs and facilitate the persistence of the pathogen in the environment over several seasons.

Infected plants typically display chlorotic mottling, leaf curling, and the formation of characteristic gall-like growths on the foliage. The reduction in photosynthetic area significantly limits the plant's ability to produce flowers and pods. In severe cases, the entire plant may appear distorted and dwarfed, making it easy to identify in the field during the early stages of the crop's development.

The transmission of this virus is strictly dependent on the whitefly Bemisia tabaci. The insect acquires the virus while feeding on infected phloem sap and transmits it to healthy plants. Transmission efficiency is high, and the virus can be spread rapidly across large fields, especially when whitefly populations are booming during periods of high ambient temperature and moisture.

Management strategies for this disease focus on excluding the insect vector and promoting plant resistance.

• Implement systematic whitefly control programs using integrated pest management (IPM).
• Remove and destroy symptomatic plants as soon as they are identified to reduce viral inoculum.
• Control weed populations in and around the field to eliminate alternative host plants.
• Utilize resistant or tolerant bean varieties developed through breeding programs.