Begomovirus of tobacco whitefly

Begomoviruses are a genus of plant viruses containing single-stranded DNA, which are exclusively transmitted by the tobacco whitefly, Bemisia tabaci. Once the insect vector ingests the virus from an infected plant, the virus circulates within the vector and is subsequently injected into the phloem of healthy host plants. This leads to a systemic infection that severely disrupts the plant's physiological and developmental processes.

These viruses have a broad host range, primarily affecting economically important crops in the Solanaceae, Cucurbitaceae, and Fabaceae families. Crops such as tomatoes, peppers, cucumbers, and legumes are highly susceptible. The prevalence of the tobacco whitefly as a global pest has significantly increased the incidence and geographical spread of these viral diseases in both tropical and temperate agricultural systems.

Symptoms of Begomovirus infection are distinct and often devastating to crop quality. Common manifestations include yellow mosaic patterns on leaves, severe curling or crinkling of leaf margins, and stunted plant growth. In many cases, infected plants exhibit reduced flowering and fruit set. Fruit development may be aborted, or the fruits produced may show symptoms like uneven ripening and internal discoloration.

The severity of an outbreak is closely correlated with the population density of Bemisia tabaci. Environmental conditions that favor the rapid reproduction of whiteflies, such as high temperatures and relative humidity, are critical drivers of viral spread. In greenhouses, these viruses can cause complete crop failure if the whitefly population is not managed proactively from the early stages of plant development.

Management requires an integrated pest management (IPM) strategy. Key tactics include the use of fine-mesh insect-proof screening in greenhouses to exclude whiteflies, the application of systematic insecticides to manage vector populations, and the removal of weed hosts that act as reservoirs. Additionally, breeding for resistance and utilizing clean, virus-indexed planting material remain the most sustainable solutions for long-term control.