General Info on Tobacco Mosaic Virus


Doesn’t specifically address TMV on marijuana, but does give info on how it’s transmitted, and the level of difficulty in getting rid of it. I have it on one of my plants, and am looking at what needs to be done. Hope this helps you.

Common questions and answers about tobacco mosaic virus

Tobacco mosaic virus is highly transmittable through greenhouses and raises a lot of questions among growers. MSU Extension answers these questions here.

Posted on April 11, 2014 by Heidi Wollaeger, Michigan State University Extension
Tobacco mosaic virus (TMV) on petunia. Photo credit: Heidi Wollaeger, Michigan State University Extension

  1. Tobacco mosaic virus (TMV) on petunia. Photo credit: Heidi
    Wollaeger, Michigan State University Extension
    Tobacco mosaic virus (TMV) is highly transmittable through routine greenhouse operations. If you have found TMV on plants in
    your greenhouse this season, Michigan State University Extension
    recommends their immediate disposal. We have compiled common
    questions from growers and their answers. What is TMV?
    TMV is a single-stranded RNA virus that commonly infects Solanaceous plants, which is a plant family that includes many
    species such as petunias, tomatoes and tobacco. What are the
    hosts of TMV?
    Pathologists estimate that there could be up to 350 plant species susceptible to TMV. According to Spence et al. in the
    European Journal of Plant Pathology, some of the more susceptible
    species that show symptoms are petunia, bacopa, verbena,
    scaevola, diascia, calibrachoa and lobelia. Some species can be a
    host for the virus, but not show symptoms. How stable is TMV?
    TMV is an incredibly stable virus. In fact, it is so stable that it can remain in tobacco plants after the extensive
    processing necessary to make tobacco products. Why do symptoms
    differ between infected plants?
    Symptoms differ between infected plants depending on the stage of disease severity, the genetic line of the virus and the
    host plant. Can tobacco products carry TMV?
    Yes, tobacco products can carry the virus and using them without washing your hands afterwards can potentially spread TMV.
    For that reason, do not use tobacco in the greenhouse or without
    washing your hands prior to handling plant material. Can TMV stay
    viable in plant debris or dead plant material?
    Yes, TMV can stay active in dead plant material for long periods of time. It can even stay viable without the presence of
    a host on surfaces such as greenhouse benches, floors and
    worker’s clothes. How effective is spraying plants with milk to
    prevent the virus from spreading?
    Spraying plants with 20 percent nonfat dry milk has been shown to be somewhat effective in preventing the spread of the
    virus from TMV-infected tobacco plants to uninfected tobacco
    plants. We recommend spraying plants prior to transplanting to
    reduce the risk of spreading TMV as part of a methodical
    management strategy. How “full-proof” is spraying plugs or liners
    with milk?
    While spraying milk on plugs or liners may have some effectiveness in reducing the spread of TMV, spraying milk should
    not be the primary management tool for TMV in your greenhouse. In
    order for milk to inactivate TMV, it must be liquid. Remember to
    continue scouting, testing, disinfecting and implementing the
    best sanitation possible in your facility. How does the milk work
    to inactivate the virus?
    Milk coats the virus and inactivates it. Is it possible to receive a positive and a negative TMV test result from two
    different samples on the same plant?
    TMV may not be spread equally throughout the plant tissue. Therefore, it is possible to test one leaf on a plant and get a
    positive TMV result, while another leaf may yield a negative TMV
    result. If one plant is infected in a combo pot, will the others
    become infected?
    Yes, it is possible for one plant to spread TMV to a neighboring plant just by growing together as their leaves come
    in contact with one another. Is TMV spread by insects?
    No, TMV is not spread by the most common greenhouse insects that often vector other viruses, like thrips and aphids. In
    addition, beneficial insects have not been linked to spreading
    TMV. However, there are a couple minor exceptions that may only
    be applicable to certain production facilities. First,
    pollinators such as bumble bees used in the pollination of some
    greenhouse crops, like cucumbers and tomatoes, can spread TMV.
    Also, larger chewing insects – not common in greenhouse
    production – such as grasshoppers can spread TMV. Can simply
    brushing an infected plant and then a non-infected plant spread
    Yes, the slightest brush of clothing infected with TMV was sufficient to spread the virus to uninfected plants, according to
    a study by Losenge et al. How can I wash my clothing between work
    days to ensure that the cloth is not harboring TMV?
    Washing clothes with standard amounts of laundry detergent or in milk was effective to inactivate TMV on clothing to prevent
    spread, according to Losenge et al. Is there a preferred hand
    sanitizer on transplant lines?
    To our knowledge, there has not been widely published evidence that there is a preferred type of hand sanitizer for
    TMV. According to the Centers of Disease Control and Prevention,
    alcohol-based hand sanitizers are effective against human viruses
    with a membrane, such as Rhinovirus, also known as the common
    cold. Since TMV does not have a membrane, there is minimal
    evidence that alcohol-based hand sanitizers will inactive it. We
    recommend washing your hands with soap and water as frequently as
    On a transplanting line, we recommend that the plants be sprayed with a milk solution before going through the machine or
    transferred by hand. The milk solution on the plants should still
    be wet as they are transplanted. Employees on a transplanting
    line should wear gloves and periodically dip their hands in milk
    solutions for the most effective control. If a grower needs to
    trim a basket, how do you recommend sterilizing the scissors?
    We recommend dipping your scissors in a container of liquid (20 percent dry powdered milk, 80 percent water) milk to
    inactivate TMV and prevent spread of the virus. Milk has been
    established to be a good disinfectant on cutting tools. Consider
    plug and liner dips into plant growth regulators for aggressive
    species in combination pots for next season. How often should you
    remix a 1:10 bleach solution for disinfecting the greenhouse
    floors and benches?
    We recommend that a grower remix a bleach solution every four hours. How important are the at-home TMV tests in the overall
    management strategy for TMV?
    We recommend using the at-home TMV strips as a tool in a methodical approach to test and rogue all plants that test
    positive, whether they have symptoms or not. We also recommend
    sending in samples of plants to a diagnostic lab, such as MSU
    Diagnostic Services, to have documentation of your results should
    you need it in the future. What should I do with my weed mats if
    I have had the virus in my greenhouse?
    We recommend you dispose and replace the weed mat if you have had TMV in your greenhouse this season. What if I have
    potentially-infected petunias in baskets above tomato
    Tomato plants can also be a host of TMV, so we recommend moving the tomatoes into a less risky area or switching the
    location of your baskets, if possible. A grower performed a TMV
    test and it did not come back positive in 30 minutes, but came
    back positive only after 24 hours. Which result is accurate?
    Always follow the manufacturer’s instructions for virus testing kits. The positive result after 24 hours is likely a
    false positive.
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1 Like

Good Info ! I never realized that it was a problem for MJ.

Yes very great info,im surprised I haven’t infected my plants, I smoke in the house and have messed with my plants with a cig in my mouth.won’t be doing that anymore

1 Like

In all my years of mentoring; I never heard of anyone having TMV on MMJ. I have seen a couple members here attribute their issue to TMV. However; I am not convinced this is happening or even could happen to your Cannabis.

I am not discrediting the Data from the great Ag Universities referenced here. I know this is a serious issue for Tobacco farmers. In fact I live right down the road from a Tobacco farm.

Take my comment for what it is worth. Do not start seeing Goblins, in your grow.

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Hi Latewood,

I’m not going to lie to you. I hope you’re right. I’ve separated the plants in question, and I’m keeping an eye on them. I keep thinking of the many errors I made on my earlier grow, and how they still came out awesome, so this has got me truly perplexed. If nothing else, I hope the info I’ve posted will give people reason to be a little more careful. Let’s face it, most of us live under the 99 out of 100 rule: We all do well, until…we don’t.
Will keep posting to let you know how it goes. Appreciate your honesty!:smile:

Hi @tlibaomx1 any updates?