How to Identify Ringspot Viruses and What to Do About Them

If you purchase an item through links on this page, we may earn a commission. Our editorial content is not influenced by commissions. Read full disclosure.

Wouldn’t it be wonderful if only a few diseases affected the plants in our gardens? Unfortunately, that’s not the case, and sometimes it seems like every time you turn around, there’s a new pathogen to discover.

You hear the word “ringspot” for many plant infections, but it’s not always the same pathogen or it may be different strains. Although they share the same name and often have similar symptoms, there are different types of ringspots.

Let’s discuss the difference between ringspot viruses, the problems they cause, and the plants they infect so you can use effective control strategies.

Contents

What is Ringspot?

Ringspot is a catch-all term for viral diseases that affect plants.

While gardening, you will come across ringspots when dealing with various plants. Depending on the environment, ring spot variety or strain, and plant, the virus will have different characteristics, modes of infection, and symptoms.

Here are some of the more common forms of infection that use the term ringspot.

Tobacco ringspot virus

This virus can also go by other names, including cucumber ringspot. It affects many crops and plants, and sometimes ringspot is named after the particular plant it infects. To keep things simple, tobacco ringspot is the name of the virus that infects subsequent plants with ringspot.

Less commonly, tobacco ringspot virus is known to infect:

Tobacco ringspot virus symptoms normally begin with stunting of young plants, as well as damage to young and established leaves. Often the leaves are smaller than they should be.

Leaves show small brown spots with light yellow edges or halos as the virus progresses. You will likely see yellow lines on the leaves when you inspect them closely. At first the leaves may appear to have yellow stippling in the form of many small yellow spots.

In advanced stages of the virus, the buds will become infected. They sometimes bend down and form a hook shape, before turning brown and falling from the plant.

If the plant survives long enough and produces fruit, symptoms will likely appear on the fruit.

Tobacco ringspot virus is usually transmitted from infected to healthy plants by the dagger nematode (Xiphinema spp.). Other insects that spread the virus between plants are grasshoppers, thrips and flea beetles.

Usually, tobacco ringspot is introduced to the garden through infected seeds and plants. Use only certified seeds and get plants from trusted sources.

Tobacco ringspot is incurable, so prevention is the only method to focus on. The virus can overwinter on surrounding weeds and wild plants, so clean up the garden and surrounding area.

Remove dead and dying leaves as they fall from the plants. Practice good hygiene by cleaning tools thoroughly. Any plants infected with this virus should be removed and destroyed away from your other plants and your compost pile. Burning is best if you can do it in your area.

Tomato ringspot virus (ToRSV)

Tomato ringspot virus is very similar to tobacco ringspot virus, and it has even been called tobacco ringspot virus no. 2. Hey, I said this was getting a little complicated.

Tomato ringspot virus can affect many other plants, and often the name changes to reflect infection of this type of plant.

Tomato ringspot virus can infect:

Flowers and ornamental plants that can be infected include:

Other plants may be infected depending on local conditions and virus strain.

Symptoms of tomato ringspot virus are similar to those of tobacco ringspot, but there are small differences. The plant may be stunted or fail to thrive and, at the same time, show no other physical signs of infection. On top of that, the plant will slowly decline.

The foliage often suffers from chlorosis, which causes the leaves to turn yellow as if not getting enough sunlight. The chlorophyll is then affected.

Cane fruits often become dry and crumbly.

When the members of the prunus genus are infected, the leaves turn pale and wilt early in the growing season before turning purple or red. Fruit size is severely affected and quality is poor. Indeed, the water flow is affected by the virus.

A key sign to look for is that the bark, both above and below the soil line, is becoming mushy. In bad infections, this can actually cause the tree to collapse.

yellow bud mosaic

Yellow bud mosaic is a disease caused by ToRSV. It infects peach, almond and other closely related trees. It is sometimes called peach yellow bud mosaic virus (PYBMV).

First, the lower branches lose all the leaves, and as the virus spreads upwards, the upper branches lose them as well. Leaf veins turn white which, combined with defoliation, has adverse effects on fruit and general tree health.

Although symptoms vary depending on the infected plant, some common signs exist:

  • Slowed growth
  • Obvious yellow spots
  • Soft yellow spots on the fruit
  • Decline of plants
  • Berries
  • Defoliation
  • yellowing of leaves

Once tomato ringspot infects your garden, you can only go into defensive mode. It cannot be healed.

Remove infected plants and destroy them. This also applies to nearby plants, in case they become infected. If you don’t want to remove trees you suspect are infected, get a second opinion from an expert.

Do not replant there for at least 12 months. Try to starve disease-spreading nematodes.

If you suspect a plant has tomato ringspot and the symptoms go away, that plant can still infect others. Sugarcane berries often show signs of infection in the spring and are clear in the summer. This plant is still infected and will carry the disease.

Try these tips to keep tomato ringspot away from your garden or orchard:

  • Quarantine new plants until you are sure they are disease free
  • Ask your local garden center if they have disease resistant varieties.
  • Disinfect your tools often with bleach and water
  • Immediately remove and destroy infected plants and those around them

Papaya ringspot virus (PRSV)

Papaya ringspot virus affects papaya and cucurbits. It is sometimes called watermelon mosaic virus type 1 or papaya mosaic virus.

In addition to infecting papaya in hot regions, it will also infect:

  • Pumpkin
  • Watermelon
  • Cucumber
  • Squash
  • Gourds

In papaya infections, the leaves develop spots and a mosaic pattern, causing yellowing. This can cause the plant to thrash and it can become stunted.

Petioles develop marks that look like water spots or oily streaks. The leaves can become so thin and distorted that they look as thin as a shoelace.

If a papaya tree is infected early in its life, it is unlikely to grow to its full potential and produce decent fruit.

In severe cases, the foliage becomes necrotic and the fruit is covered with large bumps and yellow spots.

In cucurbits, the disease can be confusing for many gardeners. You could be forgiven for thinking someone carved intricate designs into the skin of the fruit, leaving the inner layer intact.

Like other types of ringspot virus, there are differences in the ringspot that affects papaya and cucurbits.

PRSV-P affects both papaya and cucurbits, while PRSV-W only affects cucurbits. So if you’re wondering how papaya ringspot virus got to your pumpkin patch when there were no papaya trees, thank PRSV-W and the insect that spreads it.

Aphids are the primary vector for spreading this virus, and once an infected insect reaches your cucurbits, it can be infected within three weeks.

Papaya ringspot virus is easier to control, and it’s not necessarily as serious a problem as the other ringspot viruses we’ve covered.

Control aphids and you can eliminate the risk of disease. It is important to note that aphids sometimes spread the disease, and sometimes they do not. This is called a non-persistent vector.

Use homemade bug sprays, insecticides specifically for aphids, or regular neem oil sprays.

Remove weeds that may harbor the virus, including clovers, pigweed, lamb’s-quarters and mallows.

Introduce or attract beneficial insects to the garden that like to eat aphids such as ladybugs or lacewings.

Unlike other ringspot viruses, all is not lost when you get it in your cucurbit patch because the virus lives in the aphid, not the plant, so it usually does not spread from one plant to plant unless aphids carry it.

One season you can have it, and the next it doesn’t appear.

You can still save the seeds from your infected cucurbits, eat the harvest, and allow the plant to grow and produce throughout the season. If you control the aphids, the spread will be minimal.

When the season is over, remove the vines and destroy them. I prefer not to put infected plants in my compost pile, regardless of how the infection spreads.

Other Ringspots

Much less common in home gardens are:

  • Pepper ringspot virus
  • Coffee ringspot virus
  • Clover chlorotic ringspot virus
  • Tomato wilt virus
  • Peanut ringspot virus

Was this article helpful?

Yes No ×

We appreciate your helpful feedback!

Your response will be used to improve our content. The more feedback you give us, the better our pages will be.

Follow us on social networks:

Facebook pinterest

Leave a Comment