Mosaic Viruses

What are mosaic viruses? This virus infects more than 150 types of plants, including many fruits, vegetables, and flowers. It is characterized by leaves mottled with yellow, white, and light and dark green spots or streaks. Some of the most commonly infected plants include tomatoes, potatoes, squash, and cucumbers. 

How to Identify Mosaic Viruses

Viral diseases are difficult to identify because symptoms vary from plant to plant and may also vary depending on the age of the plant and its growing conditions. However, the most common ways of identifying mosaic viruses are listed below.

  • The leaves are mottled with yellow, white, and light and dark green spots, which appear to be elevated. This gives the leaves a blister-like appearance.
  • Plants are often stunted, or they grow poorly.
  • Plants may have other deformities and their leaves may be crinkled or wavy. 

How to Control Mosaic Viruses

Once plants are infected, there are no controls. Remove all the infected plants and destroy them.


  • Plant resistant plants when available in your garden.
  • Mosaic viruses are mostly spread by insects, especially aphids and leafhoppers. You can try covering your plants with a floating row cover or aluminum foil mulches to prevent these insects from infecting your plants.
  • Control your weeds. Some types may serve as hosts for the disease.


Dear Staff, I was growing

By Aviel on March 25

Dear Staff,

I was growing beans in pots outside on a roof. They became infected with mosaic virus so I uprooted them and threw them away. What crop or flowering plant that is resistant to the virus can I replant in that same soil?

Mosaic virus is on the of the

By Almanac Staff on March 26

Mosaic virus is on the of the most common afflictions of crops. It is transmitted by insects.

Change the soil. Start fresh.

Mosaic virus spreads most commonly from contaminated hands and tools. Place tools in boiling water for 5 minutes and then with wash with a strong detergent. (A dip in bleach is not an effective decontamination.) Wash your containers, too.

After handling contaminiated materials, always wash hands before handling healthy plants.

For better results, plant resistant varieties. And rotate your crops, even in containers.

My cucumber plants were doing

By Teri Schutte

My cucumber plants were doing great until about 2 weeks ago, the leaves started dying off. Progressively got worse, now just about all of the leaves are white or dead. The vines look ok and the cucumbers that were started are still growing, slowly. First year and I was told to water at night, now I have learned to water in the am and to avoid the leaves. Did I kill the plant by watering at night and soaking the leaves? Or do they have a virus, my beans are next to the cucs but they are growing like crazy. I'm in CT so I think it's too late to try again. I'm wondering if I should not grow in the same area as these plants next year- it's a raised bed.

You may have powdery mildew

By Almanac Staff

You may have powdery mildew disease. Try using an horticultural oil spray or mix milk and water in a spray bottle and use it on your plants. Use 3 parts milk to 7 parts water. Milk has been proven effective against powdery mildew.

Hi, I think my cucumber plant

By AmberH

Hi, I think my cucumber plant may be infected, and it is close to my bean plant (climbing vine variety). Can my beans get this virus?

Unfortunately, the cucumber

By Almanac Staff

Unfortunately, the cucumber mosaic virus can be transmitted to your beans.  It's carried by aphids. You will need to destroy any infected plants and avoid planting these crops in the same space next year.

i have the problem with my

By phearen

i have the problem with my eggplant because of mosaic virus! the eggplants which is covered by plastic mulch and equipped with drum drip irrigation are infected by the Mosaic virus and Aphids. Is there any correlated between plastic mulch and Mosaic virus?

We do not know of a

By Almanac Staff

We do not know of a correlation. Eggplants respond favorably to being grown on plastic mulch with drip irrigation. According to our extension office, "Winged aphids are repelled by silver- or aluminum-colored mulches. If there is a probability of severe virus pressure, place reflective polyethylene mulches on planting beds before seeding or transplanting to significantly reduce rate of colonization by winged aphids and delay the buildup of damaging numbers of aphids by 4 to 6 weeks. While this approach is mainly effective in delaying or reducing the incidence of virus diseases transmitted by winged aphids and whiteflies, reflective mulches can also delay the buildup of wingless aphids that arise as a result of colonization by winged individuals. The mulches lose their effectiveness when more than 60% of the surface is covered by foliage or if the mulch becomes fouled with dust or soil. Therefore, they are effective only for the first few weeks after transplanting."

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