Tobacco Mosaic Virus
Tobacco mosaic virus (TMV), Tobamovirus
Overview
Tobacco mosaic virus (TMV) is a highly stable, mechanically transmitted virus that infects tobacco, tomato, pepper, and many other solanaceous and ornamental plants. It survives for long periods on tools, clothing, greenhouse surfaces, and dried plant debris. Infection spreads when sap from an infected plant contacts a wound on a healthy one. In gardens and greenhouses, workers often move the virus while pruning, staking, or handling transplants. TMV rarely kills mature plants outright but can reduce vigor, fruit quality, and marketable yield.
Symptoms
Leaves develop light and dark green mosaic mottling, blistering, or distortion. Young leaves may be narrowed or puckered. On tomato, fruit can show uneven ripening, browning, or internal discoloration. Severely infected seedlings are stunted and may never recover full growth. Symptoms vary with strain, host, and temperature; heat can mask mosaic patterns temporarily. Necrotic local lesions appear on some resistant hosts after inoculation.
Environmental Conditions
Variable
Prevention
Start with certified virus-free seed and transplants from reputable sources. Quarantine new plants briefly and scout for mosaic before mixing them into production beds. Sanitize tools and wash hands routinely during pruning and transplanting. Keep weeds that host solanaceous viruses out of beds and greenhouse edges. Rotate solanaceous crops and remove crop debris after harvest. Choose resistant varieties for high-value greenhouse or seed-saving plantings.
Management
Remove and destroy infected plants promptly; do not compost them in open piles that workers will handle later. Wash hands thoroughly after touching suspect plants, and avoid smoking or handling tobacco products before working in the garden. Disinfect knives, stakes, and clippers between plants with a dilute bleach or milk dip commonly used for TMV sanitation. Replace heavily contaminated greenhouse benches and trays when practical. Grow resistant tomato and pepper cultivars where TMV pressure is high.