Tomato Ringspot

Tomato ringspot is a viral disease that can kill far more than your dreams of summer sweet salsa.


This virus infects an astounding number of other plants and it is fatal.

Tomatoes infected with tomato ringspot virus (sorhocam.com) Public Domain

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In addition to tomatoes, the tomato ringspot virus also infects stone fruits, apples, grapes, cucumbers, cowpeas and other beans, strawberries, currants, soybeans, and caneberries, including those luscious raspberries and blackberries. Adding insult to injury, this disease can also infect begonias, geraniums, iris, hydrangeas, and many other popular garden flowers. Sadly, tomato ringspot is an incurable, highly contagious disease. Infected plants (and their neighbors) must be removed and destroyed to prevent further spread.

Tomato ringspot virus on currants (USDA) Public Domain

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The virus responsible for tomato ringspot can be carried  through the air, on pollen, or by dagger nematodes in the soil. As these nematodes feed on roots, the virus is transferred to healthy plants. Dandelion seeds can also carry this disease.


Symptoms of tomato ringspot

Plants infected with tomato ringspot may simply not thrive, slowly declining over time, or they may exhibit yellow ring spots, general yellowing (chlorosis) or mottling, or they may show no signs at all, acting as a way station for the disease without being impacted directly. Caneberries may turn dry and crumbly, similar to dryberry mite infestations. Stone fruits may develop prunus stem pitting or yellow bud mosaic as a result of infection:

    Yellow bud mosaic causes lower branches to lose leaves, moving upward into the canopy as the virus spreads. Leaf veins on either side of the midrib may turn white, and leaflike growths, called enations, may grow along the midrib on the underside of the leaf. This is usually seen on infected almond, cherry, nectarine, peach, and plum trees.

    Prunus stem pitting causes later then normal leafing out. Leaves look pale and tend to wilt in summer, turning red or purple earlier in the season than is normal. Fruit size, quantity, and quality are significantly reduced. All of this is because the virus interferes with the flow of water and nutrients through the graft union, effectively starving the tree. These symptoms look very much like root damage caused by rats and voles, girdling roots, and fungal diseases of roots. The difference being that the tomato ringspot disease causes the bark, both above and below the soil line, to thicken and become spongy. This weakened area often allows the tree to topple over. Before that happens, you will also see pitting in the sapwood of the trunk. Usually the tree dies before pitting is seen in any branches.


How to control tomato ringspot

In a word - you can’t. The disease is incurable and infected plants put nearby plants at risk. The only thing you can do is remove the infected plants, and those nearby, and burn them or toss them in the trash. Just because symptoms disappear does not mean the infection is gone. Plants that no longer show symptoms are still carrying the disease, which can then spread throughout the garden. Once plants are removed, the affected area should be allowed to go fallow for at least 8 months, to starve out any dagger nematodes that may be lurking underground, and remove any potential disease-carrying weeds.


To prevent tomato ringspot, there are a few steps you can take:

• quarantine new plants
• use only disease-free plants
• plant disease-resistant rootstocks
• disinfect tools regularly
• remove infected plants and those surrounding them as soon as the disease is seen

Yes, removing plants from the garden or landscape is disappointing, but having to remove even more plants because of an initial delay could be both costly and heartbreaking. 


And you thought this post was going to be all about tomatoes…


So did I!