Bean golden mosaic

Bean golden mosaic, caused by the virus Begomovirus phaseolicaliconis, is a devastating viral disease affecting common bean crops in tropical and subtropical regions. As a member of the Geminiviridae family, this pathogen is highly efficient at compromising plant development, often leading to severe yield losses that can reach 100% in susceptible varieties.

The transmission of this virus is exclusively dependent on the whitefly Bemisia tabaci. This insect vector acquires the virus by feeding on infected plant phloem tissues and transmits it in a circulative-persistent manner. Once the insect has acquired the virus, it remains a carrier for the remainder of its lifespan, continuously posing a threat to surrounding healthy plants.

Typical symptoms include a striking yellow or golden mosaic pattern on the leaves, which gives the disease its common name. Infected plants often show stunted growth, crinkled and deformed leaves, and reduced leaf size. The reproductive stage is heavily impacted, resulting in flower abortion, poor pod set, and seeds that are shriveled or malformed.

Environmental conditions play a crucial role in disease epidemiology. Warm, dry weather patterns facilitate the rapid population growth of whiteflies, accelerating the spread of the virus across fields. Furthermore, the presence of alternative host plants, particularly weeds and wild legumes, ensures the survival of the virus throughout the year.

Effective management requires an integrated approach. The most successful strategy involves the deployment of resistant cultivars, which are specifically bred to withstand viral pressure. Growers are also advised to implement cultural practices such as avoiding overlapping crop cycles, maintaining weed-free fields, and utilizing appropriate insecticides to reduce the whitefly population density.

• Selection of resistant bean germplasm.
• Implementation of host-free periods to break the viral cycle.
• Systemic insecticide application during the seedling stage.
• Use of physical barriers like mesh netting in small-scale farming.