Tomato chlorosis

Crinivirus tomatichlorosis refers to a group of viral infections caused by members of the Crinivirus genus within the Closteroviridae family. These pathogens are strictly phloem-limited, meaning they disrupt the translocation of nutrients in the host plant, leading to stunted growth and significant physiological distress.

The primary host for this virus is the tomato plant (Solanum lycopersicum), though its host range is known to include other Solanaceous crops and several weed species. The presence of these alternative hosts is a critical factor in the epidemiology of the disease, allowing the virus to persist in the absence of commercial crops.

Symptoms typically manifest as interveinal chlorosis (yellowing) of the leaves, which often starts on the lower canopy and spreads upwards. In severely affected plants, the foliage may become brittle, show upward curling, and develop necrotic patches. The reduction in photosynthetic area significantly impacts fruit set and the overall weight of the harvest.

Transmission occurs exclusively through insect vectors, specifically the whiteflies Bemisia tabaci and Trialeurodes vaporariorum. These insects acquire the virus by feeding on the phloem sap of infected plants. Once acquired, the virus can be transmitted to healthy plants, creating a cycle of rapid dissemination, especially in protected greenhouse environments.

Management of tomato chlorosis is centered on the exclusion of the vector and sanitation. Strategies for control include:

• Rigorous weed management around greenhouse facilities to remove potential virus reservoirs.
• The use of insect-proof screens to prevent whitefly migration.
• Integrated Pest Management (IPM) practices, including the release of beneficial predatory wasps.
• Regular scouting and immediate removal of infected symptomatic plants.
• Sanitation protocols for tools, equipment, and clothing to prevent mechanical spread.