Monday, February 4, 2008

Greenhouse - Tobacco Mosaic Virus (TMV)

Tobacco mosaic virus is a common virus disease that affects many greenhouse plants. It is transmitted mechanically, often with handling of plants by smokers. The following is information on this disease.

Symptoms of tobacco mosaic virus (TMV) on calibrachoa.
Photo: Margery Daughtrey and Maria Tobiasz

Watch for tobacco mosaic virus (TMV) on calibrachoas and petunias this season. TMV has a wide host range and can also infect many other common greenhouse crops such as begonia, impatiens, lobelia, nicotiana, osteospermum, torenia, and verbena. Symptoms of TMV vary depending on the host, but look for yellowing, mosaic patterns, necrotic leaf spots, overall stunting, or leaf distortion. TMV can be spread by contact and handling and via infected seed, but unlike other common greenhouse viruses is not transmitted by insects. Remove and discard any infected plants; don’t forget to consider that weeds might also be infected. Also, do not handle healthy plants after handling infected plants or contaminated equipment, or disinfest tools and hands after handling infected plants or contaminated material. If infected plants or contaminated equipment or pots were handled, hands can be disinfested by washing with milk (instant non-fat dry mild can be used) – strangely enough this will degrade virus particles. Flats, pots, doorknobs, propagation equipment, gloves, clothing, and etc., can also become contaminated with virus particles if contacted by infected plants. Disinfest the greenhouse with a commercial disinfestant such as Green-Shield, Oxidate, Physan, Triathlon, or ZeroTol.

Extracted from the March/April 2007 edition of the Northeast Floriculture IPM Notes from Cornell and Rutgers University Cooperative Extension.

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