Tomato necrosis

Tomato necrosis, caused by the virus Orthotospovirus tomatonecroanuli, is a highly destructive plant pathogen belonging to the Tospoviridae family. It poses a significant threat to solanaceous crops worldwide, often resulting in severe yield losses and degraded quality of the fruit in both open-field and protected cultivation systems.

The virus has a broad host range, primarily infecting tomatoes, peppers, and eggplants, while also persisting in various weed species that serve as viral reservoirs. At the cellular level, the virus interferes with the plant's metabolic pathways, causing stunted development, leaf chlorosis, and systemic necrosis that impairs the photosynthetic ability of the plant.

Visual symptoms usually include dark necrotic lesions on leaves and stems, often accompanied by leaf curling and deformation of growing points. Infected tomato fruits frequently develop characteristic ring spots, blotchiness, and surface depressions. These symptoms make the produce commercially unmarketable and demonstrate the severity of the systemic infection.

Transmission occurs primarily through biological vectors, with various thrips species, particularly the Western flower thrips, acting as the main culprits. Once a thrips larvae feeds on an infected plant, it acquires the virus and remains infectious for its entire lifespan. The efficiency of this vector-borne transmission makes the virus extremely difficult to contain once established in a crop.

Integrated pest management (IPM) is essential for controlling this disease. Key strategies include:

• Sourcing certified disease-free transplants.
• Implementation of strict greenhouse sanitation to eliminate weeds and debris.
• Use of yellow or blue sticky traps for early detection of thrips populations.
• Targeted insecticide applications to reduce vector numbers.
• Prompt roguing and destruction of symptomatic plants to prevent secondary viral spread.