A mosaic virus is any virus that causes infected plant foliage to have a mottled appearance. Such viruses come from a variety of unrelated lineages and consequently there is no taxon that unites all mosaic viruses.

Problem: There are a number of mosaic viruses, but gardeners are most likely to encounter two: tomato mosaic virus and tobacco mosaic virus. The former infects tomatoes, peppers, potatoes, apples, pears and cherries; the latter infects tomatoes, peppers, cucumbers, lettuce, beets, petunias and, of course, tobacco.

Mosaic virus causes mottled yellow and green leaves that are sometimes curled and distorted. Some plants exhibit yellowing, stunted growth, malformed fruits and reduced yield. Mosaic virus is more common in hot weather.

Solution: There are no chemical controls, but resistant varieties exist. The virus can live in dry soil for some time. Remove and destroy infected plants, roots and all, and avoid planting susceptible plants in the same area for two years. Because tobacco is a carrier, smokers should wash hands thoroughly before handling plants.

Regards

Joseph Mareddy

Assistant Managing Editor

Journal of Plant Biochemistry and physiology