Tobacco mosaic virus (TMV) is a persistent threat to balsam plants that can lead to stunted growth, poor flowering, and overall decline. Once a balsam plant is infected with TMV, there is no cure. Therefore, effective management of this virus centers on prevention, early detection, and controlling spread. With a multi-pronged strategy of cultural practices, sanitation, and prompt removal of diseased plants, you can successfully manage TMV and maintain healthy, productive balsam plants.
Understanding Tobacco Mosaic Virus
TMV is one of the most widespread and damaging viruses affecting flowering plants. It can infect over 200 plant species, including many vegetables, herbs, and ornamentals like balsam. The virus is extremely stable and can survive up to 50 years in plant debris and soil. It is transmitted through infected sap, plant-to-plant contact, contaminated tools, and tobacco products. Once a plant is infected, TMV spreads quickly through the vascular system.
Recognizing Symptoms of TMV
Be on the lookout for these common TMV symptoms on balsam plants
- Mottled light and dark green patterns on leaves (mosaic)
- Leaves may be distorted, curled, or stunted
- Yellow spots, rings, or line patterns on leaves
- Overall stunted growth
- Flowers may be discolored or deformed
- Reduced flowering
These symptoms can easily be confused with other viral infections, nutrient deficiencies, or herbicide damage. Lab testing is required for accurate diagnosis.
Preventing Tobacco Mosaic Virus
Prevention is the most effective disease management strategy against TMV on balsam plants:
- Start with certified, disease-free plants and seeds
- Quarantine new plants before introducing to your garden
- Disinfect tools, pots, and surfaces with 10% bleach solution
- Avoid smoking around plants – tobacco carries TMV
- Control weeds and remove debris that may harbor TMV
- Wash hands thoroughly after handling infected or suspicious plants
Managing TMV Through Cultural Practices
If TMV is detected in your garden, implement these cultural practices to control spread:
- Immediately remove and destroy infected balsam plants
- Sterilize tools after every cut when pruning diseased plants
- Increase spacing between plants to improve air flow
- Stake plants to avoid plant-to-plant contact
- Avoid overhead watering to reduce foliar contact
- Remove weeds which may provide overwintering sites for TMV
- Keep the garden free of plant debris
Disinfecting Tools, Surfaces, and Equipment
Meticulous sanitation is vital to prevent TMV spread via contaminated tools, pots, greenhouse benches and other surfaces
- Soak tools for 5 minutes in 10% bleach or Lysol solution
- Use disposable gloves and sanitize between plants
- Sterilize pots and trays in hot water (180°F for 30 minutes)
- Wash hands thoroughly with soap before and after handling plants
- Clean greenhouse benches and floors with 10% bleach solution
Managing Insect Vectors
While TMV is not directly transmitted by insects, they can spread TMV between plants through minor feeding. Control aphids, thrips, and other sap-sucking insects to reduce vector potential. Use insecticidal soaps, neem oil, or narrow-range oils. Avoid broad-spectrum insecticides that will harm beneficials.
Rogue Out Diseased Plants Promptly
Walk your garden frequently looking for telltale mosaic patterns on leaves. At first signs of TMV, immediately remove and destroy infected plants. Double bag plant debris and dispose of off-site. Carefully dig up the entire root system to eliminate virus reservoir in the soil.
Control Broadleaf Weeds
Many weeds can host TMV, serving as a green bridge between seasons Hand pull weeds or use selective herbicides to eliminate broadleaf weeds like groundsel, chickweed, mallow, and shepherd’s purse that can harbor the virus.
Promote Overall Plant Health
Healthy, vigorous balsam plants are less susceptible to infections. Use preventive care measures to promote robust plant health:
- Fertilize regularly with a balanced organic fertilizer
- Water early in the day so foliage dries completely
- Mulch beds to retain soil moisture and reduce water splash
- Prune congested interior growth to increase airflow
Be Diligent About Inspections
TMV symptoms can be subtle early on. Conduct frequent thorough inspections of your balsam plants for signs of mosaic patterns or leaf distortion. Catching TMV early allows quicker removal to protect the rest of your garden. Don’t delay – infected plants won’t recover.
Know When to Start Over with Clean Stock
If TMV becomes widespread in your garden, you may need to remove and destroy all plants and start over. Replant with clean stock from reputable nurseries confirmed as TMV-free. Take every precaution to avoid reintroducing the virus on tools, shoes, hands, or water. With vigilance, you can maintain a TMV-free balsam collection.
Staying on top of prevention, cultural practices, sanitation, prompt removal, and overall plant health is the key to successfully managing tobacco mosaic virus on treasured balsam plants. Pay close attention, implement preventive care, and remove infected plants without delay to protect your garden from this destructive virus.
Frequency of Entities:
Balsam plant: 21
Tobacco mosaic virus: 18
Leaf/Leaves: 12
Tool(s): 7
Plant(s): 22
Virus: 16
How to manage plant viruses in the greenhouse
Insect management is critical for managing tomato spotted wilt virus and impatiens necrotic spot virus, while sanitation is the critical management strategy for tobacco mosaic virus.
In Part 1 of this article, Michigan State University Extension reviewed the background about some of the most common viruses (tobacco mosaic virus, tomato spotted wilt virus and impatiens necrotic spot virus, Photos 1-3) that affect floriculture crops. Details of insect transmission of Tospoviruses were explained. The type of virus and its method of transmission impact the methods of management that should be implemented when a virus is detected on plants in a greenhouse.
Growers should inspect all incoming plant material for symptoms of viruses, including speckling, modeling, leaf curling, vein clearing, chlorosis and stunting. Unfortunately for growers, viruses can be present in plants that are asymptomatic or may not show symptoms for weeks after infection. If there is a known possibility of infected plant material coming into your facility, be extra vigilant when inspecting the plant material and randomly sample plants within each shipment and variety.
Growers can buy virus testing supplies for rapid in-house testing. This allows growers to easily test suspect material identified during scouting. Plants with ambiguous symptoms can yield a positive test result. Alternatively, samples can be sent to a local diagnostics lab, such as MSU Diagnostic Services. Continue to scout the plants during the crop cycle. If possible, quarantine the susceptible or suspicious plant material. If plants test positive for viruses, immediately throw them out as virus-infected plants cannot be cured.
When there is a virus present on plants in the greenhouse, sanitation of benches, floors, watering wands and any other equipment that may come in contact with plant material is critical. Be sure to remove all weeds under any benches in the greenhouse. The primary method of spread of tobacco mosaic virus is by plants touching each other or by hands carrying the virus after touching infected plants. It is critical that those who are touching the plants are regularly washing their hands with soap and water and after touching any suspicious plants or using tobacco products.
When sticking cuttings or transplanting plugs, make sure the plants are only touching non-permeable surfaces and regularly sanitize all surfaces the plants make contact. All employees sticking cuttings should regularly use an alcohol-based hand sanitizer. MSU Extension recommends using a fresh solution of the disinfectant; be sure that the active ingredient of the product is stable enough to remain active while using it throughout the day.
Soaking areas is likely to be more effective than a “spray” or “spritz” application. Some growers use diluted dry milk, which has been shown to be effective in disinfecting tools and surfaces. Spraying milk directly onto plants to prevent virus transmission has also been shown to be effective. To read more about research findings with using milk as a disinfectant, read “Can applying milk to tools or plants be effective in reducing virus transmission?” For more information on other sanitation strategies read, “Sanitation Strategies for Greenhouse Growers.”
When trying to manage an occurrence of Tospoviruses (e.g., tomato spotted wilt virus or impatiens necrotic spot virus), management of aphid, whitefly and thrip populations are critical. As discussed in Part 1, these viruses are readily spread by insects. Western flower thrips are one of the primary vectors of these viruses. For conventional control, MSU recommends the following products for thrips control:
- Aria
- Distance
- Hachi-Hachi (do not use on impatiens or New Guinea impatiens)
- Mesurol
- Orthene 97
- Overture
- Pedestal
- Pylon
- Sanmite
For more information on how to manage tomato spotted wilt virus or impatiens necrotic spot virus, visit “Impatiens Necrotic Spot Virus.” For more information on insecticide recommendations without using neonicotinoids, read “Greenhouse insect management without neonicotinoids.”
Insect control is not as critical in an outbreak of tobacco mosaic virus because insects are not the main vector of the virus. However, according to H.J. Walters, chewing insects like grasshoppers can vector tobacco mosaic virus, but those are not common in greenhouse production. Okada et al. reported that tobacco mosaic virus could be spread to non-infected plants by bumblebees after pollinating heavily infected plants. Also, if infected leaves have exposed sap or if insects break leaf hairs, aphids have been shown to be a possible vector of tobacco mosaic virus, but it is not a major method of spread.
For more information on tobacco mosaic virus, read “Tobacco Mosaic Virus of Tobacco” or “Tobacco mosaic virus.”
To learn more about tomato spotted wilt virus, tobacco mosaic virus, or impatiens necrotic spot virus on a greenhouse crop, please see Part 1 of this article, “Common types of viruses of floriculture crops and their modes of transmission.”
The author would like to thank Dave Smitley, Zsofia Szendrei and Jan Byrne for their reviews.
How to Tell Mosaic Virus Infection from Variegation with Live Plant Examples
FAQ
Can you save a plant from mosaic virus?
How can we control the tobacco mosaic virus?
How can you reduce the spread of tobacco mosaic virus?
Does tobacco mosaic virus stay in soil?
What is tobacco mosaic virus?
One of several mosaic virii out there, the tobacco mosaic virus (or TMV for short) has a somewhat misleading name. The virus was named after one of the first host plants it was discovered on but can infect 9 different plant families and over 325 different species, mainly in the Solanaceae family.
Can balsamic vinegar help to remove mucus?
Some studies suggest that the intake of balsamic vinegar helps to eliminate some bacteria in the mouth and throat, improving your conditions in case of sore throat and cough. It is also effective for eliminating phlegm from bronchi. It can also treat congestion by adding a few drops of vinegar to steaming water and breathe in the vapor.
How do you know if a tobacco plant has mosaic disease?
Light and dark green areas on leaves, forming the typical mosaic pattern, are the most distinctive macroscopic symptom of the mosaic disease caused by TMV in tobacco ( Fig. 4 ). Leaf distortion and vein clearing on young leaves and line patterns and necrotic areas on older leaves are less common symptoms.
How to prevent mosaic virus?
To help prevent the mosaic virus spread, it’s important to wash your hands with a disinfectant soap after handling any tobacco products, especially if you hand-roll. Avoid using tobacco products near plants. Finally, only buy seeds or plants from a reputable seller who inspects their stock regularly.