Notes

• More than a dozen viruses have been found to infect tomatoes. Viruses might be difficult to distinguish from one another. The human eye is only capable of determining that a virus is likely to be the source of a problem. Only by sending a sample to a lab can a definitive diagnosis be made.
• Tomato mosaic virus (ToMV) is the most prominent virus in Florida.
• Viruses can induce symptoms on leaves and in fruit.
• Only laboratory tests can identify plant viruses.
• Plant viruses cannot be cured, hence management efforts should be directed toward reducing virus spread.
• The virus can be spread from plant to plant or by infected seeds or insects.
• Thrips and aphids are major vectors for some viruses.
• Normal plant care tasks, such as tying, removing suckers, and harvesting, can spread viruses via hands, equipment, and clothing.

General ToMV symptoms

• Early infection may cause plants to look yellow and generally stunted.
• Dark and light green leaves mottling.
• There may be twisted, deformed, or diminished leaves.
• At warm temperatures, certain cultivars may show signs of dead leaf tissue.
• Possible uneven ripening of fruits.
• Decreased total fruit yield and average fruit size.
• Fruit with irregular, off-color spots that can be either elevated or depressed.
• Fruits may exhibit browning just beneath the skin (brownwall).

Photo credit: U-scout program of the University of Florida

Management

• For several tomato viruses, there are cultivars that are resistant.
• Seek out disease-resistant seed varieties marked with catalog codes and abbreviations like ToMV and TMV. The resistant tomato varieties can be found here: https://www.vegetables.cornell.edu/pest-management/disease-factsheets/disease-resistant-vegetable-varieties/disease-resistant-tomato-varieties/
• If you have any plants in your garden that you suspect may be infected, remove them immediately to prevent the spread of the virus. Don’t throw them in the compost. Infected plants should be uprooted entirely and burned.
• Always go through reliable retailers while purchasing transplants.
• Make sure to inspect transplants before buying them. Be sure there are no obvious symptoms before selecting a transplant.
• Infected plants often exhibit no visible signs of illness, therefore it’s important to frequently disinfect tools, ideally between each plant.
• There are currently no effective chemical solutions against any other virus. The control of aphids and thrips during the production of transplants can aid in preventing the spread of plant viruses.

More information: Common Tomato High-Tunnel Production Diseases in Florida

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