Tobacco Mosaic Virus (TMV) and Your Employees

Tobacco mosaic virus can be introduced into a greenhouse production area on infected plugs and cuttings or on the hands and clothing of employees who are tobacco users. Greenhouse operators should prohibit the use and carrying of tobacco products into the greenhouse or headhouse by employees to prevent the accidental introduction of the tobacco mosaic virus into the production area. All employees should be required by the employer to wash their hands frequently to prevent the spread of tobacco mosaic virus to susceptible crops.

Employee clothing can be a significant carrier of the tobacco mosaic virus. The tobacco mosaic virus is long-lived and has been known to exist in the environment for over 40 years. Clothes contaminated with tobacco mosaic virus will remain a carrier of the virus until the contaminated clothing has been laundered. Once the tobacco mosaic virus has been introduced into the greenhouse production area, it can be easily spread in plant sap from contaminated hands and tools to uninfected plants.

Tobacco mosaic virus symptoms can be quite variable, and their appearance may be somewhat dependent on the host plant, the age of the plant, environmental conditions, and the strain of the virus causing the infection. Commonly observed symptoms include leaf mottling, leaf necrosis, mosaic-like symptoms, yellowing, stunting, leaf curling, flower breaking, delayed fruit ripening, distorted fruits, poor yield, and nonuniform fruit coloration.

Tobacco mosaic virus infections can be prevented in the greenhouse by:

• Sanitizing all tools with a 10% chlorine bleach solution. Make sure that the chlorine bleach being used is labeled for this practice.
• Discarding TMV-contaminated media away from the growing area and downwind from the greenhouse range or growing area. TMV can cling to dust and organic debris. It can be transported by wind into growing areas and infect wounded plants.
• Encouraging workers to hold flats away from their bodies when carrying them in the greenhouse. TMV-laden plant sap that accumulates on clothing can infect wounded plants that brush up against the clothing while being transported.
• Requiring handwashing before starting work in the morning and after all breaks to prevent the mechanical transmission of the tobacco mosaic virus by workers to susceptible species.
• Prohibiting all tobacco use in and around growing plants/crops.
• Providing nitrile gloves to workers and requiring their usage when handling susceptible species.
• Using milk to deactivate tobacco mosaic virus. Consider having your workers dip their hands in milk before handling plants. Milk sprays can also be used to deactivate the tobacco mosaic virus on benches and floors.
• Carefully remove dry or dead leaves from the greenhouse. If these residues can be blown around in the greenhouse, they can infect wounded plants. Dispose of dead plants and/or leaves carefully by placing them immediately into a plastic trash bag. Do not carry dead or dry plants through the greenhouse, or you may risk spreading the tobacco mosaic virus.