Tomato Spotted Wilt Virus — Permaculture Database

Overview

A destructive virus with an extremely wide host range (over 1,000 plant species), transmitted by thrips. Causes distinctive ring spots, bronzing, and wilting in tomatoes and many other crops. Tomato Spotted Wilt Virus cannot be cured with sprays. Management means preventing spread through insect vectors, infected seed or sap, and removing sources of inoculum early. Causal agent: Tomato spotted wilt virus (TSWV), Orthotospovirus. In regenerative gardens, prioritize sanitation, airflow, and unbroken soil cover over calendar spraying, and intervene early when symptoms appear.

Symptoms

Bronze or purple discoloration of young leaves. Ring spots on fruit and leaves. Growing tips may die back. Stunted, one-sided growth. Dark streaks on stems. Fruit develops raised rings and bumps. Compare several plants and note whether symptoms spread after rain, insect feeding, or wet foliage. Photograph undersides of leaves and cut stems when wilt is present to refine the diagnosis. Rule out simple drought, fertilizer burn, and herbicide drift before assuming a pathogen - abiotic injury often mimics disease.

Environmental Conditions

Variable

Prevention

Control thrips populations (the only vector). Use reflective mulches to repel thrips. Plant resistant varieties. Remove weeds that harbor thrips and virus. Use insect screening in greenhouses. Mulch to reduce splash, clear season-end debris, and avoid working plants when wet. Design beds for airflow and diverse plantings that support beneficial insects without creating permanent humid pockets around susceptible crops.

Management

No cure. Remove infected plants immediately. Control thrips with spinosad or insecticidal soap. Remove weed hosts. Reflective mulch reduces thrips landing. Monitor with blue sticky traps. Prefer drip irrigation, morning watering, and open spacing so leaves dry quickly. Disinfect pruners between cuts on woody plants. Use copper, sulfur, or biological products only as labeled protectants when pressure is high - they rarely reverse advanced infections alone. Destroy (do not casually compost) highly infectious debris.