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Mosaic Virus in Garden Plants: How to Identify, Prevent, and Control

virus disease on eggplant, yellow leaf mosaic

Eggplant feeling under the weather—yellow mosaic virus strikes, leaving patchy yellow leaves instead of lush green!

Photo Credit
Lertwit Sasipreyajun

Spotting and Stopping Mosaic Viruses Before They Take Over Your Garden

Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

Ever looked at your prized tomatoes or cucumbers and thought, “Why do my leaves look like a patchwork quilt?” Those splotches, streaks, and stunted stems may be the handiwork of a mosaic virus. These pesky plant viruses can infect vegetables, fruits, and flowers, leaving your garden looking a little… well, under the weather. But fear not, home gardeners! With the right know-how, you can identify, prevent, and manage mosaic viruses, keeping your garden thriving and colorful.

Key Takeaways for Gardeners

  • Mosaic viruses are common but preventable.
  • Early identification and removal of infected plants can limit spread.
  • Focus on resistant varieties, insect control, and hygiene to protect your garden.

What Are Mosaic Viruses?

Mosaic viruses are a group of plant viruses that create a mottled, patchy appearance on leaves, often in yellow, white, or varying shades of green. They can stunt growth, deform leaves, and reduce yields. Over 150 types of plants are susceptible, including common garden favorites like tomatoes, squashes, cauliflower, and cucumbers, but many more are susceptible.

Types of Mosaic Viruses

While “mosaic virus” is a broad category, some types are more common in home gardens:

  1. Bean Common Mosaic Virus (BCMV) and Bean Yellow Mosaic Virus (BYMV) are the primary mosaic viruses that affect beans of all types. Aphids typically spread them, but BCMV is also seed-borne, so do not save seeds from infected plants.
  2. Cucumber Mosaic Virus (CMV) is one of the most widespread mosaic viruses, typically transmitted by aphids. As can be inferred from its name, cucumber mosaic virus often affects cucumbers, but it is also a common problem for many other garden plants, including other cucurbits (melons, squashes), nightshades (tomatoes, peppers, eggplants, potatoes), and leafy greens (lettuce, spinach). Can cause “shoestring syndrome,” where leaf edges fail to develop, leaving narrow strips.
  3. Tobacco Mosaic Virus (TMV) spreads through seed contact and direct handling of infected plants. The leaves show yellow mottling, and new growth may be twisted or deformed. Planting resistant varieties is the best defense.
  4. Yellow Leaf Mosaic Virus (YLMV) is often found in okra, beans, and tomatoes. Spread by whiteflies, the symptoms include yellow mosaic patterns, curling leaves, and stunted growth.

These are just a few common mosaic viruses, but similar viruses may affect many other vegetables and flowers in your garden

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Identification

How to Identify Mosaic Viruses and Damage

Viral diseases are challenging to identify because their symptoms vary from plant to plant and can also change depending on the age of the plant and its growing conditions. However, common signs include:

Mottled leaves with yellow, white, and green patches, sometimes blistered.

  • Stunted or slow growth.
  • Deformed leaves: crinkled, wavy, or twisted.
  • CMV: misshapen leaves and “shoestring syndrome.”
  • TMV: twisted new growth and yellowed leaves.

Regular inspection is key—early detection can help limit spread.

cucumber mosaic virus on spinach leaves
Cucumber mosaic virus causes severe damage and discoloration to a spinach plant.
Photo Credit: University of California. 

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Control and Prevention

How to Control Mosaic Viruses

Once plants are infected, there is no cure. Prevention is your best strategy. For infected plants:

  • Remove all infected plants and destroy. Do NOT put them in the compost pile, as the virus may persist in infected plant matter. Burn infected plants or throw them out with the garbage.
  • Monitor nearby plants closely, especially those that are located near infected plants.
  • Disinfect gardening tools after every use with a bleach solution or an antiviral spray.

How to Prevent Mosaic Viruses

  • Plant resistant varieties when available (e.g., TMV-resistant tomatoes).
  • Control insects that spread the disease, especially aphids and leafhoppers. Floating row covers or reflective mulch can help. Look at our other tips for controlling aphids.
  • Manage weeds, which can host viruses and their insect carriers.
  • Treat seeds of susceptible plants in a 10% bleach solution before planting to prevent seed-borne viruses.
  • Practice garden hygiene: wash hands after handling plants and disinfect tools regularly.

Frequently Asked Questions

Q. How can I tell if my plant has mosaic virus?

A. Patchy yellow-green mottling, curled or wrinkled leaves, and stunted or misshapen fruit are telltale signs.

Q. Which plants are most at risk?

A. Cucumbers, squash, melons, tomatoes, peppers, beans, and eggplants—plus some ornamentals.

Q. Can mosaic virus be cured?

A. No. Once a plant is infected, it remains infected. Remove and destroy sick plants.

Q. What should I do if I spot it?

A. Pull up infected plants (don’t compost them), disinfect tools, and control insect pests that spread the virus.

Q. How can I prevent mosaic virus?

A. Plant resistant varieties, rotate crops, wash tools and hands, manage weeds, and keep aphids in check.

Just like people, plants sometimes catch a bug. A little prevention goes a long way—wash up, keep things tidy, and let the healthy plants shine.

Plant Disease
About The Author
Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann is the Executive Digital Editor of Almanac.com, the website companion of The Old Farmer's Almanac. She covers gardening, plants, pest control, soil composition, seasonal and moon c...
Read More from Catherine Boeckmann

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Comments

<span>Mary C</span> Tue, 09/19/2023 - 19:02
Do traces of the virus remain in the soil? I assume when pulling out infected plants, we should get all of the roots so none of the virus remains, but I am curious about any organic matter in the soil retaining the virus and transmitting it to any new plant planted in that spot.
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 09/20/2023 - 14:31

Dear Mary,

Yes, traces can remain in the soil. Indeed, you'll want to remove the roots, as much as possible. Below are more tips  to minimize the damage. 

Good luck!

—The Editors

To combat mosaic viruses:

  • Remove all infected plants and destroy them. 
  • Do NOT put them in the compost pile, as the virus may persist in infected plant matter. 
  • Burn infected plants or throw them out with the garbage. 
  • Monitor the rest of your plants closely, especially those that are located near infected plants. 
  • Disinfect gardening tools after every use. 
  • Keep a bottle of a weak bleach solution or other antiviral disinfectant to wipe your tools down with.
 <span>Leslie Vornholt</span> Wed, 04/12/2023 - 13:06
Has anyone tried planting aromatic plants that are effective against viruses in area that had been infected with the mosaic virus? I am thinking of melissia/bee balm, oregano, thyme. I may try a solution to mix in soil with essential oils effective against viruses, too. Anyone have experience using natural methods to purify the soil? Thanks
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 04/13/2023 - 09:33

There have been some studies. To date, only thyme Essential Oil showed significant antiviral activity, but it has to be applied to the soil before the virus, not after. Perhaps plant some thyme and see if it helps!

 <span>Cephas Nkhoma</span> Sat, 08/13/2022 - 14:10
Great advice and guide.
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 07/03/2023 - 12:09

Thanks, Cephas!

 <span>Jeff Butler</span> Sat, 10/03/2020 - 22:25
I have had a problem with this virus for three year, starts in my potatoes then to beans and then to tomatoes. Complete new bed this year and soil, and still my early potatoes are showing the sign of the virus. Are you saying pull all those plants out but then what can I do to the bed to try and eradicate it regards Jeff
<span>Kathy Garcelon</span> Thu, 07/30/2020 - 11:12
I planted one Jostaberry bush beside my red currants. It's leaves (top surface) are now covered with tan colored lines along the leaf veins. The leaves are green but for the tan areas. There is no other color, spots or mildew. If this is a virus, should l just dig up the Jostaberry bush and burn it? It was planted this spring, saw no flowers/fruit. The bush is about 4' tall. Thanks for your help.
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 08/03/2020 - 08:59

Hi Kathy,
It's hard to tell at that stage if the bush is infected with mosaic virus, so wait and monitor it closely. If the leaves continue to show signs over the next week, the smart move is to be proactive and dispose of the plant before others nearby get infected.

 <span>Jimmy Nguyen</span> Fri, 05/01/2020 - 04:57
Gday mate I was clearing out some soil of a plant which I didnt know had mosaic. At this stage im still not too sure so but nonetheless, I poured the soil indiscriminately into my backyard. Any tips?