Tomato spotted wilt virus

Tomato spotted wilt virus (Orthotospovirus tomatanuli) is a destructive plant virus belonging to the Tospoviridae family. It is known for its ability to infect a vast range of plant species, causing systemic infections that can lead to total crop failure if left unmanaged in both greenhouse and field conditions.

The virus has a very broad host range, infecting over 800 plant species including economically important crops like tomatoes, peppers, potatoes, lettuce, and various ornamentals. Because it can survive in weed hosts and various perennial plants throughout the year, the infection pressure in many agricultural regions remains consistently high.

Symptoms of the disease are highly variable depending on the host plant and environmental conditions. Common indicators include chlorotic or necrotic ringspots on leaves, stunted growth, stem necrosis, and distinct bronzing of the foliage. Infected fruits often exhibit mottled appearance, irregular ripening, and surface deformations, significantly reducing marketability.

The primary vector for Orthotospovirus tomatanuli is the thrips, particularly the western flower thrips (Frankliniella occidentalis). The virus is acquired by thrips larvae during feeding and transmitted by the adults. The efficiency of transmission is very high, allowing the disease to spread rapidly through a field once the vector population reaches the economic threshold.

Management strategies must be integrated and focused on prevention. Key measures include the use of virus-indexed, resistant transplants, rigorous weed control to eliminate reservoirs, and effective chemical or biological control of thrips populations. In greenhouse settings, it is crucial to use insect-proof screens and yellow or blue sticky traps for early detection of vectors.