Mosaic, << moh ZAY ihk, >> disease is the name of a group of plant diseases caused by certain viruses. The leaves or fruit of affected plants become mottled with blotches of light and dark green. Many mosaic viruses are spread by such insects as aphids, beetles, and leafhoppers. Others are transmitted by mites or by worms called nematodes. People may transmit the tobacco mosaic virus by smoking infected tobacco and then handling tomato or tobacco plants before washing with soap and water.
Mosaic diseases infect such crops as beans, blueberries, potatoes, raspberries, soybeans, and strawberries, and such ornamental plants as tulips and petunias. No cure exists for diseased plants, and crop yields are severely reduced. Mosaic diseases can be avoided by selecting naturally resistant varieties, through insect and weed control, and by using virus-free plant cuttings when starting new plants.
