Tomato Mosaic Virus

Stunting and yellowing leaves may mean your tomato plants are infected with tomato mosaic virus.

Tomato plant infected with tomato mosaic virus (Mary Ann Hansen, VA Polytechnic, Bugwood.org)

Tomato mosaic virus (ToMV) looks and behaves like tobacco mosaic virus (TMV). While both viruses can infect tomatoes and tobacco, the tobacco mosaic virus can also be found on beets, cucumbers, and lettuce. The tomato mosaic virus infects peppers and potatoes. It can also infect  apple, cherry, and pear trees. 

Tomato mosaic symptoms

Tomato mosaic symptoms can vary greatly, making it difficult to distinguish from other tomato viruses, such as tomato spotted wilt and cucumber mosaic. Along with stunting and chlorosis, other symptoms of tomato mosaic virus include the following:

• Brownwall (internal browning just under the skin) 
• Curled, stunted, or distorted leaves
• Dead areas on leaves can be seen as temperatures rise
• Mottled leaves
• Reduced crop size
• Yellowish rings may appear in the fruit
• Uneven fruit ripening

This disease is very responsive to temperature. If plants are infected while young, they may not exhibit any symptoms until temperatures are warmer.

Tomato mosaic virus leaf symptoms (UGA Plant Pathology, Bugwood.org) CC BY 3.0 US

Tomato mosaic virus lifecycle

These pathogens can survive in dry soil, leaf litter, and infected root debris for up to two years. Add water, and that time is reduced to just one month. While ToMV can be transmitted through infected seeds, it is most often spread by us. The virus gets on our hands, clothes, shoes, and garden tools, and we spread it everywhere we go, to every plant we touch or brush against. Like tobacco mosaic, the tomato mosaic virus can even survive tobacco curing. It is then spread by smokers who haven’t washed their hands before working in the garden.

Tomato mosaic virus management

There are no chemical treatments for tomato mosaic virus. Good cultural practices, such as hand washing, sanitizing your tools, and avoiding infected areas can slow the spread of this disease. 

Tomato mosaic can also infect lamb’s quarters and pigweed, so keep those weeds away from susceptible plants. Installing certified disease-free, resistant varieties is another way to reduce the impact of this disease.

If you suspect tomato mosaic virus in your garden, pull up the affected plant, roots, and all, and put it in a plastic bag. Then, contact your local County Extension Office to see if they offer free testing since that’s the only way to know what you have. If you identify the disease early and notify the Extension Office, healthy plants are more likely to stay that way.