Lima bean golden mosaic

Lima bean golden mosaic is a devastating viral disease caused by the Lima bean golden mosaic virus (BGMV), a member of the Geminiviridae family. The virus is characterized by its ability to cause severe stunting and discoloration in host plants, leading to significant economic losses in legume production globally, particularly in tropical and subtropical regions.

The primary host for this pathogen is the Lima bean (Phaseolus lunatus), though it can infect various other bean species. Once inside the plant, the virus spreads systemically through the phloem, interfering with vital growth processes and preventing the plant from reaching its full potential in biomass and yield.

Symptoms are distinct and easily recognizable: the foliage develops a bright yellow or golden mosaic pattern, often accompanied by leaf curling, puckering, and significant reduction in leaf size. Infected plants exhibit shortened internodes, bushy appearance, and severe stunted growth. Flowering is significantly impaired, leading to poor pod set and reduced quality of harvestable beans.

The disease is transmitted in a persistent manner by the sweetpotato whitefly (Bemisia tabaci). Environmental factors, such as high temperatures and low humidity, accelerate the life cycle of the whitefly, thereby increasing the rate of viral transmission throughout the field. The virus persists in host weeds, providing a constant inoculum source for commercial plantings.

Effective management requires an integrated approach to break the disease cycle. This includes using certified virus-free seeds, planting resistant cultivars, and implementing rigorous weed control around the field borders to eliminate reservoir hosts. Chemical control of whitefly populations remains a critical component, especially during the early stages of plant development to prevent primary infection.