Plant viruses are scary diseases that may appear seemingly out of nowhere, burn through a selected species or two, then disappear again once those species have died off. Tomato ringspot virus is more insidious, affecting a wide range of plants besides tomatoes that includes woody shrubs, herbaceous perennials, fruit trees, grapevines, vegetables, and weeds. Once this virus is active in your landscape, it can be passed between plants of different species, making it difficult to control.
What is Ringspot?
Tomato ringspot virus is caused by a plant virus that’s believed to be transferred from sick plants to healthy ones through pollen and vectored throughout the garden by dagger nematodes. These microscopic roundworms live in the soil, freely moving between plants, albeit slowly. Symptoms of tomato ringspot vary in plants from highly visible, yellow ringspots, mottling, or general yellowing of leaves to less obvious symptoms like gradual overall decline and reduced fruit size.
Some plants remain asymptomatic, making it difficult to pinpoint the origin point when this disease appears. Tragically, even asymptomatic plants can transfer the virus in their seeds or pollen. Ringspot virus in plants can even originate in weeds sprouted from infected seeds. If you observe symptoms of tomato ringspot in your garden, it’s important to look at all plants, including weeds.
What to Do for Tomato Ringspot
Tomato ringspot virus in plants is incurable; you can only hope to slow the spread of the infection in your garden. Most gardeners will destroy both infected plants and those symptom-free plants that surround them, since they may be infected, but not symptomatic. Caneberries are notorious for showing ringspots in early spring, only for them to disappear by midsummer. Don’t assume because these symptoms clear up that you plant is cured –it’s not and will only serve as a distribution point for the virus.
Cleaning tomato ringspot virus from your garden requires you to rogue out all potential hiding places for the virus, including weeds and trees, then leaving the garden fallow for up to two years. Adult nematodes may vector the virus for up to eight months, but larvae carry it too, which is why so much time is needed to guarantee its death. Take great care to ensure that any stumps are completely dead so the virus doesn’t have any plants to host it.
When you replant, choose disease-free stock from reputable nurseries to prevent bringing tomato ringspot virus back into your landscape. Commonly affected landscape plants include:
It may be difficult to completely eradicate ringspot virus in annual plants that are replaced frequently, but by removing any volunteer plants and not saving seeds, you can keep the virus from spreading to more valuable, permanent landscape plants.