Tomato mosaic virus

Tomato mosaic virus (ToMV) is a plant pathogenic virus, which is closely related to the tobacco mosaic virus (TMV).

Symptoms
Symptoms can be found during any growth stage and all plant parts are affected. Generally, infected plants have a light or dark green mottling or mosaic with distortion of younger leaves, and stunting to varying degrees. Severely affected leaves may have a "fernlike" appearance and may show raised dark green areas. Fruit set may be severely reduced in affected plants. There may be internal browning of the fruit wall, yellow blotches and necrotic spots may occur on green or ripe fruit. Some strains can cause yellow mottling of leaves, others cause dark necrotic streaks in stems, petioles, leaves or fruit, or other symptoms to occur.

Symptoms are influenced by environmental conditions such as daylength, temperature, and light intensity as well as by variety, plant age at infection, and virulence of tomato mosaic virus (ToMV) strain. On susceptible cultivars, symptoms may range from severe to none.

Culutural Control
Use a minimum 2-year rotation. Avoid following tomato crops with susceptible crops such as tobacco, sweet pepper, aubergine, or cucurbits. Keep production areas and seedbeds free of weeds and other plants that can serve as hosts for the virus.

If growing transplants in a greenhouse, then use steam-pasteurized soil. Avoid touching or handling plants prior to setting them in the field. Remove diseased seedlings that show leaf twisting, mosaic or unusual growth. Do not touch other seedlings while discarding them. Dip hands in milk while handling plants every 5 minutes (more often if different lots of plants are handled). Rubber gloves will protect hands. Do not clip young seedlings since this increases the possibility of mechanical transmission of the virus from contaminated tools or hands.