Soil-borne Mosaic (virus): Symptoms of soil-borne mosaic appear early in the spring, usually when weather is cool and damp, but are rarely seen in fall or winter. Fields observed from a distance have irregular patches of light green or yellow plants. Symptoms on plant leaves range from mild green to yellow mottling and striping, giving the mosaic appearance. Stunting varies from moderate to severe and may be accomplished by rosetting. Symptom expression favors temperatures below 68o F. Symptoms gradually disappear before harvest time if normal temperature persists. A soil-borne fungus, Polymyxa graminis, which is a parasite of roots of many grass plants, is the vector of this disease. Virus particles are either inside spores of the fungus or are attached to the spores. The fungus invades the roots in the fall, when soils are cool and wet, carrying the virus particles with it. There is no practical way to rid the soil of the soil-borne mosaic virus. Rotation out of wheat to other crops will reduce losses.