Solanaceous begomovirus

The first sign of infection is typically a characteristic chlorotic mosaic on young leaves. Gradually, the leaf surface becomes wrinkled and distorted.

A significant reduction in leaf size occurs, along with leaf curling either upward or downward. Shoot tips often cease growing, leading to a stunted or bushy appearance of the plant.

Coloration of the tissue changes: light patches, yellow spots, or a specific net-like pattern along the veins appear. In severe cases, anthocyanin pigmentation may develop.

Fruits on infected plants develop poorly, become deformed, and lose their marketability. Their quantity decreases drastically, and the ripening process becomes uneven.

When infection occurs at early developmental stages, the plant may stop growing entirely, often leading to death before the onset of fruit production.

The disease is caused by a virus belonging to the genus Begomovirus within the family Geminiviridae. These are single-stranded DNA pathogens characterized by twinned icosahedral capsids.

The virus infects a wide range of crop plants, primarily within the Solanaceae family. Key hosts include tomatoes, peppers, potatoes, and eggplants.

The primary vector in nature is the tobacco whitefly (Bemisia tabaci). The insect acquires the virus while feeding on plant sap and remains capable of transmitting the pathogen for an extended period.

Viral particles localize within the plant phloem, which often delays early detection. Upon entering the plant cell, the virus initiates an active replication cycle, disrupting essential physiological processes.

Genetic variability among begomoviruses presents a significant hurdle for breeding resistant crop varieties. Mutations enable the pathogen to adapt to diverse agro-climatic conditions and new host species.

The primary driver for virus outbreaks is a high population density of the whitefly in greenhouses or open fields. The optimal temperature for the vector's reproduction ranges from 25 to 30 degrees Celsius.

Dry and hot weather promotes intensive migratory behavior of insect vectors. Under these conditions, the risk of disease transmission between plants increases exponentially.

The presence of weeds around fields and inside greenhouses creates reservoirs for the virus to persist between seasons. Weeds can act as asymptomatic carriers of the pathogen.

Failure to follow good agricultural practices, such as planting seedlings near already infected plots, accelerates disease spread. Uncontrolled use of insecticides can also influence the development of epiphytotics.

Long periods without proper insecticide applications allow whitefly populations to colonize new areas rapidly, making the virus difficult to contain in intensive farming systems.

Solanaceous begomovirus causes severe economic losses for growers, reducing crop yields by 50 to 90 percent. In some cases, the infection leads to total crop failure.

The disease disrupts photosynthesis, depleting the plant's energy balance. This physiological stress renders the crops highly susceptible to secondary fungal and bacterial infections.

Produce harvested from infected plants is unsuitable for long-term storage or transport. The fruits lose flavor and nutritional quality, rendering them unfit for sale.

The virus spreads very rapidly within a farm, especially under greenhouse conditions where the environment is optimal for the vector. This requires immediate removal and destruction of infected plants.

Managing the consequences of the infection involves high costs for replacing planting material and implementing rigorous disinfection, which significantly increases the production cost.

The main protection strategy is the strict control of the vector population, the tobacco whitefly. This involves using systemic insecticides and biological control agents.

• Utilizing yellow sticky traps for monitoring and trapping adult whiteflies.
• Thorough weeding and sanitation of surrounding areas that may act as virus reservoirs.
• Implementing fine-mesh screening in greenhouses to physically prevent insect vectors from entering.
• Observing crop rotation and maintaining spatial isolation between plantings of different maturation cycles.
• Using only certified, virus-free planting material produced under strict quarantine and control standards.