Tomato spotted wilt

Tomato spotted wilt is a destructive plant disease caused by the Tomato spotted wilt virus (TSWV), a member of the Tospoviridae family and the Orthotospovirus genus. This virus is known for its wide host range, affecting essential crops such as tomatoes, peppers, and various ornamentals, posing a global threat to agriculture.

Infected plants exhibit diverse symptoms, including necrotic spots, bronze-colored rings, and stem streaks. Terminal leaves often show curling and dwarfing, while fruit development is severely hindered, showing characteristic mottling and necrotic lesions. These visual indicators often lead to total crop failure if the infection occurs early in the growth stage.

The biological cycle is strictly dependent on the thrips vector, particularly the Western flower thrips (Frankliniella occidentalis). The virus is acquired by larvae feeding on infected tissues and is then transmitted to healthy plants by adults. Once infected, the thrips remain vectors for their entire lifespan, efficiently spreading the disease across crops.

Disease outbreaks are typically favored by warm conditions and high population densities of the vector. In greenhouse settings, the virus can persist throughout the year if crop debris or reservoir weeds are not properly managed. The ability of the virus to infect both crop plants and common weeds makes it a persistent challenge for commercial growers.

Effective control measures focus on integrated pest management (IPM) strategies, as no chemical cure exists for infected plants. Growers should prioritize the use of high-quality disease-free transplants, the deployment of sticky traps for thrips monitoring, and rigorous weed control. Furthermore, implementing hygiene protocols during pruning and harvesting helps prevent mechanical transmission.

• Integrated use of yellow and blue sticky traps.
• Biological control agents like predatory mites and bugs.
• Screening greenhouses to exclude thrips.
• Rogueing and destroying symptomatic plants.