Crotalaria begomovirus

The most prominent symptoms of infection include severe leaf deformation, characterized by curling, puckering, and twisting of the leaf margins.

A typical mosaic pattern appears on the foliage, consisting of light green, yellow, and dark green chlorotic areas due to disrupted photosynthesis.

Infected plants exhibit a clear reduction in overall vigor and a significant stunting of growth compared to healthy crops.

Early-stage infection often leads to shortened internodes, resulting in a stunted or bushy growth habit that is diagnostic of the disease.

Floral development is frequently compromised, resulting in sterile flowers or premature abscission of buds, which significantly reduces reproductive capacity.

Crotalaria begomovirus (Begomovirus crotalariae) is a significant viral pathogen within the Geminiviridae family. These viruses are characterized by their single-stranded circular DNA genome and distinctive twin icosahedral capsids.

As a member of the Begomovirus genus, this virus relies on specific insect vectors for its transmission in nature. The primary vector involved in its spread is the whitefly, Bemisia tabaci.

The virus primarily affects plant species within the Crotalaria genus, which are commonly grown as green manure, forage, or for their ornamental value.

The viral genome is highly efficient at replicating within host cells, leading to a rapid systemic infection that spreads throughout the plant's vascular tissue.

Geographic distribution of this pathogen is strictly tied to the habitat of its vector, favoring tropical and subtropical regions where the whitefly thrives.

The primary driver for the development and spread of this virus is a high population density of whiteflies within the immediate agricultural environment.

High air temperatures and humidity levels are favorable environmental conditions that promote rapid reproduction and migration of the insect vectors.

Weed species belonging to the legume family can act as reservoirs for the virus, maintaining the infection cycle during off-seasons.

Poor agricultural practices, such as high-density planting, create a conducive microclimate that facilitates the movement of whiteflies between susceptible plants.

Lack of crop rotation contributes to a build-up of viral inoculum, increasing the likelihood of widespread infection in successive seasons.

The economic impact of the virus is driven by drastic yield losses and a reduction in the overall quality of the harvested plant biomass.

For crops grown as green manure, the infection reduces the plant's ability to fix nitrogen and accumulate biomass, limiting its efficacy as a soil improver.

Systemic infection often prevents the formation of viable seeds, creating severe losses for producers reliant on seed harvesting.

Additional costs are incurred through necessary management efforts, including the removal and disposal of infected plant material.

The weakened state of infected plants makes them more susceptible to secondary opportunistic fungal and bacterial pathogens, leading to further crop degradation.

The cornerstone of prevention is the strict control of weed populations that serve as overwintering reservoirs for both the virus and the whitefly vector.

Establishing proper spatial isolation between new plantings and areas known to harbor viral infections is a recommended tactical measure.

Monitoring whitefly populations is crucial; timely application of insecticides is necessary once populations reach the economic injury threshold.

Implementing effective crop rotation and optimizing planting dates can significantly reduce the risk of early-season infection by the whitefly vector.

• Use of certified, virus-free seed stock.
• Deployment of yellow sticky traps for monitoring and reducing adult whitefly populations.
• Rogueing (physical removal and burning) of plants exhibiting primary disease symptoms.