Mosaic Viruses

How to Identify and Control Mosaic Viruses

Mosaic Virus


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Here are tips on how to identify, control, and prevent mosaic viruses on a variety of plants.

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, squashes, cauliflower, and cucumbers. 

Cucumber mosaic virus is one of the most common types of mosaic viruses, and it is usually spread by aphids. As can be inferred from its name, cucumber mosaic virus often affects cucumbers, but it is also a common problem for tomatoes, melons, squashes, and other plants.

Tobacco mosaic virus spreads through seeds and direct contact, and the best way to avoid it is to grow resistant varieties. 


    How to Identify Mosaic Viruses and Damage

    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. 
    • Cucumber mosaic virus: Infected plants are stunted and often exhibit “shoestring sydrome,” which is a characteristic malformation in which the edges of the leaves fail to develop, with the leaf veins developing as long, narrow strips. Tomatoes are small and misshapen.
    • Tobacco mosaic virus: Infected plants have mottled and yellowed leaves and twisted or deformed young growth.


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

    Control and Prevention

    How to Control Mosaic Viruses

    Once plants are infected, there are no controls. Remove all the infected plants and destroy them. Also, be sure to disinfect your gardening tools.

    Prevent Mosaic Viruses

    • Plant resistant plants when available in your garden. Resistant varieties of tomatoes have yet to be developed for cucumber mosaic virus, but tomatoes that are resistant to tobacco mosaic virus may have some slight resistance to cucumber mosaic virus as well.
    • 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. Look at our other tips for controlling aphids.
    • Control your weeds. Some types may serve as hosts for the disease.
    • To avoid tobacco mosaic virus, soak seeds in a 10 percent bleach solution before planting and avoid handling tobacco near plants.

    Reader Comments

    Leave a Comment

    Squash mosaic disease

    So my zucchini and pumpkin has mosaic disease. I took them out of the garden. My questions are how long can the virus live in the dirt? When would it be safe to plant susceptible plants in that row of dirt again? And also what are some veggies if any that I can plant in there now to get a fall harvest? Or good ones to plant in that dirt next spring?

    planting after mosaic virus

    Sorry to hear the news. The mosaic virus can overwinter in the roots of perennial weeds, flowers, and some crops plants. It grows with the plant in the spring, appearing in the upper leaves. However, it can not live in extremely dry conditions. As for planting now, avoid plants varieties that are susceptible to the cucumber mosaic virus; grow resistant cultivars and use resistant seeds. Consider using row covers to prevent aphids from reaching plants in the first place (aphids bring on CMV). This page from the Tennessee cooperative extension service provides a list of vegetables and varieties and resistance:

    You might get more information from your local cooperative extension service. Search for your state here and find the resources:

    Mosaic virus

    Would parsley and raspberries be susceptible to the mosaic virus? I see some new growth that is spindly with twisted stunted leaves. Would pruning out infected growth on the raspberries help control? Thanks for your reply in advance.

    Mosaic Virus in Raspberries and Celery

    Yes, mosaic viruses can affect both raspberries and celery. Cutting out infected material can slow the virus’ spread to adjacent plants, but it will not cure the infected plant. Unfortunately, once a plant has contracted a mosaic virus, it will always be infected. 


    i have a container garden inside of a screened enclosure and I know my cucumber plant has the CMV. Would the aphids have been able to get to the plant inside the screen, or were they already on the plant when I bought it? The plant still grows and the new growth stays nice for a few days but eventually the leaves get the same pattern and the small yellow flowers wilt and die off. Im guessing this will continue so my only option is to rid of the entire plant?

    Cuke with the virus

    Sad to say, there is no cure, no fix. As for the origin, it could have been aphids already in the plant or the plant could have been infected before you purchased it by the people who handled it or their tools.

    Mosaic Virus

    My infected tomatoes and peppers (mosaic virus) are all grown in pots, and irrigated via drip irrigation.
    1. Am I correct in assuming that, since my tools need disinfection (my hands!), that I will have to toss out my SOIL and disinfect or replace my irrigation lines and drips? Will soap and water suffice for the pots and drips?
    2. My herbs (basil and mint) grew side-by-side with my tomatoes and peppers. Should I be treating them the same? I'm assuming so (but don't know), because I don't think that aphids, etc., are non-migratory...


    Mosaic virus treatment

    The TMV (tobacco mosaic virus) transmits extremely easily, so to your second question, yes, treat all of your plants, especially those that are/were side-by-side with the tomatoes and peppers.

    About your first question…yes, toss out your soil and all tools should be washed. If your drip irrigation equipment cam in contact with the infected plants or soil, it should be washed.

    Cucumber diseases/virus caused by yellow beetles

    If my plant has been infected is the food edible still or not?

    infected fruit

    We suggest that when in doubt, throw it out, especially if the harvested part is a part that is directly affected, such as leaves. If fruit shows no blemishes, it might be OK to eat it, even if the rest of the plant shows symptoms. Some diseases only cause cosmetic damage to the fruit, not internal, and would be fine to eat. Others, though, that attack the interior of the fruit will likely, at the very least, affect quality and flavor. Most plant diseases are not transferable to humans. Some bacteria, etc., are, however, or some fungi, although not harmful directly, can produce compounds that are. If a plant is weakened, secondary infections may also arise.

    Tomato Virus

    It appears my garden has the Tomato/cucumber virus. It started on my cucumber mottled marks on leaves, that eventually dry out. The cucumber started fruiting early and I have 2 nice cucumbers but the new growth flowers and then the new fruit goes nowhere. I have lots of new growth, but the leaves dont last long. My tomatoes have been loaded with fruit. I have been enjoying beautiful cherry tomatoes for about 2 weeks. Last week I noticed a few spots on the leaves and then almost overnight the plants are covered. I am still getting ripening tomatoes but the leaves themselves are almost all brown. My peppers are at the other end of the garden and are starting to show some spots of yellow. The peppers are bountiful and starting to ripen.

    I live in Central Florida and am gardening in Straw Bales. Because I garden in my backyard I have one long row of plants. Tomatoes, cucumbers, Green beans. peppers (with herbs in between), The only thing not showing leaf distress are the green beans. I have used Neem oil to control insects as well as ladybugs. The only insect I have found was the squash vine borer in my zucchini. All the infected plants were removed. I have not seen aphids.

    After days of research, it seems like my garden is done for now. I will remove all the plants, straw bales, and ground cover. My question would be concerning the metal poles, tomato cages, wire trellis, drip lines and garden equipment. Can everything be disinfected with bleach water? I read one suggestion of covering everything with liquid milk. The garden area is between a wooden fence and the house, do I need to bleach these down too? Can I clean the area and work on a new garden in the fall or maybe even some summer crops or are my backyard garden days over?

    virus prevention

    Viruses enter through wounds - such as feeding insects, pruned stems, etc. Some can also travel via infected seeds. If your tomato/cucumber has cucumber mosaic virus (CMV), this is spread by aphids and by contaminated tools, etc. Clean your tools regularly with a 10-percent bleach solution (cleaning your wire cages, poles, trellis, and other equipment might be helpful as well before next growing season, but you don’t need to do the fence or house) and use row covers to discourage insects from transmitting the disease to healthy plants. Wash hands often with soap and water. Destroy all infected plants (do not compost) and also remove weeds–many can harbor viruses, or attract insects that transmit them. Control aphids; silver-reflective mulches can help repel them. Choose cucumber resistant to CMV. Splash up from infected soil should be curbed by your straw bale method.

    For other viruses, the same advice stands: disinfect your tools, or soak rowcovers in the 10 percent bleach solution. Choose resistant varieties, if available. Remove weeds. Remove any diseased plant promptly. Wash hands thoroughly before handling different plants. To avoid tobacco mosaic virus, do not use tobacco products near the garden. Rotate crops each year.

    You should be able to still grow a garden each year if you keep up with these precautions. Most viruses are transmitted actively by a vector, mainly feeding insects, so if you control those, or prevent their damage, then you may be fine.



    Hi Gary,

    Hi Gary,

    You didn’t mention if you had blooms. Bean blossoms will drop from the plant if the weather is too hot and too much nitrogen in the soil will prevent pods from setting. High humidity can also cause bloom drop. Go to our beans page at for more information about growing and caring for bean plants.

    I'm having a real bad start

    I'm having a real bad start to spring! I had bought Merical Grow Organic planting items, several differant things made by them. I then attempted to start everything by Certified organic seed, I planted the seeds in an eggshell to get really healthy strong roots, peppers were planted with 2 match sticks and fetilizer, peas were planted in the potting soil mix. Well ending result to this was alot of little knats on the pepper pods and the peas took off in 2 days, sprouted and then turned yellow then died. I then called a nursery to see if they sold Certified Organic plants, I was told yes and went to get them brought them home found out they were NOT Certified at all! They may have been Organic but they were not Certified anyhow come to find out the strawberry p[lants had aphids and the leaves on the peppers, tomatoes, broccoli and cucumbers all had signs of discolored yellow leaves, drying fron tip of leaf and leaves curling downward, I had planted one of the strawberry plants in a 5 gallon self watering bucket, planted banana pieces into soil 2" down and aphids up and left shop. I had cut most of the bad leaves off the tomatoes, peppers are wilting in seedling pots, broccoli is inside under grow lights with most of the peppers and a few tomato plants, the cucumbers and a few tomatoe plants are outside. The only plant that is planted is the one Fresca strawberry plant, I live in zone 3 in MD and the weather here is crazy nice one day, snow, rain and cold another, I am doing self watering, planting by the moon and loosing my mind with the plants that i bought. HELP!!! ANYONE!

    It's better to wait until the

    It's better to wait until the weather is warmer to put any of the warm weather veggies outside. It's too early to put tomatoes and cucumbers outside in zone 3. You can plant peas, spinach, kale etc. in the garden now. They don't mind a few cold nights and days. For aphid control check out our pests page at Don't fertilize young seedlings too much. Wait until they are transplanted outdoors.

    I have had some of the same

    I have had some of the same issues-my seedlings did great until just recently some of them are srarting to spot and some look chewed on
    I know that fertilizing seedlings when too young can damage or kill the plants, so I mixed organic potting mix with equal parts organic topsoil and some peat moss and perlite. I avoided buying kinds containing fertilizer. since it can be difficult to distinguish between fungi, bacteria, insect infestation (my eyes aren't too good anymore) I chose to treat with Neem oil. you can get it many places (lowes,home depot) and isn't expensive. Dilute 0.5 Tbsp per qt H2O and spray on plants.
    Neem is made from vegetable matter
    I hope this helps

    I had a very similar issue a

    I had a very similar issue a few years ago with Miricle grow. I was repotting all of my house plants, as I do each year with Miricle Grow potting soil. A few days later I thought i had fruit flies. So I put out traps and none were going for it...more research...they were fungal gnats...apparently a known problem with Miricle Grow...more research...removed all soil, washed off roots of what I could save and use black gold more gnats...if you are interested research'll be angry.

    Used to love them, now I will never use any of their product again.

    So im a first time gardener

    So im a first time gardener and I was reading the posts here about all the viruses and thing that affect plants. My question is should I end up with any of these an not know it and consume the veggies or fruit will it harm me ir my family?

    Plant viruses do not

    Plant viruses do not replicate or cause infection in humans or other mammals.

    My tomato plants first turned

    My tomato plants first turned yellow and then wilted and now have purple coloring on them and some leaves have holes. The zinnia and sunflower in the adjacent pot also seems to have been infected. However, the tomatoes are very small but do ripen. My question is: Is it safe to eat the tomatoes from this plant (assuming it is infected based on above responses) if thoroughly washed and cooked in heat?


    After removing infected

    After removing infected plants, what about the soil in raised planter beds? Does mosaic virus overwinter in the soil to infect the following year as well? Is there any preventative that is effective?

    Care of the soil is the most

    Care of the soil is the most important part of gardening and the best way to prevent pests and diseases (although your plants may succumb to something, despite your best efforts).
    With all plant residue removed, apply compost or aged manure in fall, plant a cover crop, and and practice rotatation and companion planting next year. Planting resistant varieties can also help.
    For additional advice, see the response immediately below this one.

    All of our squash and

    All of our squash and zucchini plants have mosaic virus. Is it ok to plant more in the same soil or do we need to start fresh?

    First, you should remove and

    First, you should remove and destroy the infected plants. Though you can plant in the same soil, you may want to consider planting elsewhere as any pests that were feeding on your plants will be carrying the virus and can spread it again. 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.

    I have a Bonnie Golieth

    I have a Bonnie Golieth tomato plant that was doing great until 2-3 weeks ago. The leaves are curling upward and some leaves are turning a little brown. It isn't growing any taller or bushier, but I don't see any bugs. I have no tomatoes or flowers on the bush now. What's happening?

    Curled leaves are indeed a

    Curled leaves are indeed a symptom of some tomato viruses, however, you would probably be seeing yellow-green mosaic patterns on the leaves or more mottled leaves, not just brown tips. What's the weather like? Leaf curl and slowed growth also happens in very hot, dry weather with high heat; the plant curls its leaves to conserve moisture. If it's a virus, there's not much you can do. If it's weather and environmental, give it even moisture, cool it down with mulch and perhaps a shade cloth, avoid over fertilization, and do not prune it.

    I am seeing mottling in a few

    I am seeing mottling in a few (out of roughly 30) of my sunflowers. My question is, would mosaic virus only show up on a few of the leaves or be consistent throughout the entire plant? The plant looks otherwise very healthy and growing well. Have I just caught it early? I do not want to risk the rest of my garden. Thank you!

    Mottling is certainly one of

    Mottling is certainly one of the manifestations of mosaic virus. As noted above, there is no fix, so you would be best to destroy the stricken plants. If possible, you should consider planting virus resistant varieties in future and, of course, maintain good soil and growing environment.

    I am growing organic squash

    I am growing organic squash and zucchini on my deck in pots planted in organic potting soil. They have become infected with a mosaic virus. I know I must throw away the plants, but should I also throw away the soil? I do not want any future plants to become infected. How should I dispose of the soil if I need to get rid of it? I don't want to spread a virus to the plants in my garden.

    My tomato plants started out

    My tomato plants started out great, and one started turning yellow at the bottom. Over a period of about two weeks it gradually spread up to the top. Adjacent plants started the same cycle. Got a lot of green tomatoes, but some have blossom end rot. The affected plants look awful. It appears to be affecting my whole crop in different stages. Is it a virus? Can I save them?

    Mickey, You are not alone

    Mickey, You are not alone (though that may not be much consolation). We just answered this question. See right below.

    Our tomato plant leaves are

    Our tomato plant leaves are turning yellow from the bottom up. Why?

    When the tomato plant turns

    When the tomato plant turns yellow and starts dying from the bottom up, the plant usually has a fungal disease: either early blight or leaf spot. Often, these diseases are due to too much water from rain or overhead watering. Only water at the base of the plant. Keep leaves dry. Water in the morning. Also, make sure the plants are not crowded and have good air circulation. Ideally, there should be enough room that you could walk around each tomato plant (not that you would). Mulch your tomato plants to control moisture. Be sure to cage or stake well to keep leaves off the ground. Clean up all debris. It can be helpful to provide a fungicide spray weekly, before rain, or at onset of disease before it's too late.
    Copper-based fungicides are considered organic. Speak to a local nursery for brands approved in your area.

    I have pumpkin plants and I

    I have pumpkin plants and I noticed that my plants have white spots and there looking like the leafs are turning white i and on one of my pumpkin plants I had black and moldy looking stems I pull thises up but what is wrong with my pumpkin??

    Hi, Atonya, It soulnd like

    Hi, Atonya,
    It soulnd like powdery mildew, an air-borne disease. You can purchase organic suphur and make a tea with it, them spritz the plant/s; that should kill the mildew.
    Several sources suggest that if your plant has established fruit (pumpkins)—that they are growing— they have a good chance to mature, even if all of the leaves turn black and wither.
    In future, consider getting mildew-tolerant/resistant varieties. Quite a few, but not all, cultivars are listed here:

    My squash and zucinni and

    My squash and zucinni and eggplants are growing well with many flowers. However, they are not producing fruits. I notice particularly on the egg plant that the leaves have many hole (no indication of worms or insects on the leaves) and a number of stems appear to have been cut off and removed. The plants are about 4 weeks old, and were transplanted into newly tilled soil with a lot of worms in the soil and added garden soil. They were fed just this past week. Also my tomatoes appear to be growing too fast and are spliting. We have had some periods of 2" or greater rains and then several week of no rain. I am watering with a soaker hose about a half hour twice a day when not raining. Any suggestions?


    After reading many comments I

    After reading many comments I need to ask this question to be sure if I am reading right. Can mosaic virus spread to other crops? Another words, if my cucumber plant is affected and I have pepper plants near the cucumbers, it can spread to the peppers? Please respond.

    Hi Alex, Yes, the virus can

    Hi Alex,
    Yes, the virus can spread to your peppers. Insects spread the virus as they move from plant to plant. If your cucumber plants have the virus you should remove and destroy them. Controlling the insect pests in your garden is the best preventive control of mosaic virus.

    tobacco virus

    My landlord lets me help in the garden and share the harvest. I smoke, but never until the evening when I read. He is scared that I will infect his plants. I assured him I bathe before I go out into the world and I never handle tobacco until the evening, in private,. Is this enough?

    I planted my spring garden

    I planted my spring garden approximately four weeks ago (five 4x8 raised beds0. Everything looked great but I noticed some mosaic yellow splotches on my zucchini last week. Now after a week it has spread to everything including tomatoes, cucumbers, and melons. The plants look healthy with only a few leaves around the bottom with the yellow. If I keep removing the mosaic leaves is there a chance to stay on top of it? Or since it is early in the year should I bag it and start all over again? I have placed white fly strips and have used some spinosed with some other aphid controls. Is it too late?

    It's best to remove and

    It's best to remove and destroy the plants. They will not produce well and any fruit will taste bitter.

    My hydrangia bush, camellia

    My hydrangia bush, camellia tree and geranium seem all infected by mozaik virus and I need to cut them first in order to get rid of them. I heard that we need to clean the clipper after cutting the virus infected plants. How should I clean them? Just using water is good enough or any special soap to use?

    Dear Staff, I was growing

    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

    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

    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

    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

    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

    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

    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

    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."

    Mosaicvirus control

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