Tomato Mosaic Virus




Tomato mosaic virus (ToMV) is a member of family tobamoviridae and belongs to the genus tobamovirus, which is a plant pathogenic virus. It is found worldwide and affects tomatoes and many other wide host range plants including many agricultural crops and weeds such as tobacco and beans, all of which can serve as inoculum sources. The tomato crop is highly susceptible to the Tomato mosaic virus (ToMV). The symptoms vary from tiles, wrinkle, reduction and curvature of leaflets, and irregular ripening of fruits. This disease requires attention because of its easy dissemination by contact, cultural practices, or contaminated seed.

Tomato mosaic virus symptoms can be found at any stage of growth and all parts of the plant may be infected. ToMV causes yellow mosaic symptoms on the leaves and tomato fruits. Tomato mosaic virus symptoms are seen as a general mottling or mosaic appearance on foliage. Light and darker green mosaic leaf mottle, sometimes with distortion of younger leaves; this is the most common reaction in summer in glasshouses. In winter, with low light intensity, short days and temperatures not above 20°C, plants are often severely stunted and leaves distorted to ‘fern-leaf’ or tendril shape, but mottling may be slight. Plants are less vigorous, and fruit yield is reduced by 3 to 23%. Tomato mosaic virus strains occur in Chenopodium murale in the USA, causing severe stunting, distortion and necrosis , and in pear associated with a diffuse chlorotic leaf spotting.

Virus Control

This viral disease is able to overwinter on perennial weeds and is then spread by several insects including aphids, leafhoppers, whiteflies and cucumber beetles. Both cuttings and divisions from infected plants will be infected. The disease is spread into the plant via small wounds caused by mechanical injury, insect chewing, and grafting. Leftover plant debris is the most common contagion. Tomato mosaic virus of tomatoes can exist in the soil or plant debris for up to two years, and can be spread just by touch – a gardener who touches or even brushes up against an infected plant can carry the infection for the rest of the day.  You should wash your hands with soap and disinfect tools after handling tomato plants to keep the disease from spreading. Treating mosaic virus is difficult and there are no chemical controls like there are for fungal diseases, although some varieties of tomato are resistant to the disease, and seeds can be bought that are certified disease free. Sanitation is the most important application to practice when controlling tobacco mosaic virus. Tools should be boiled for 5 minutes and then washed with a strong detergent. Bleaching doesn’t work for viral decontamination. 

Destroy any seedlings that appear stunted or distorted and then decontaminate tools and hands. Keep the area around the tomatoes weeded and free of plant detritus to minimize areas the disease can harbor. Control insects as well to lessen the chances of contamination. If you spot the disease in your garden, you should immediately dig up and burn infected plants. Don’t plant tomatoes, cucumbers or other plants that are susceptible to mosaic virus in that same area again.






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