Mosaic-like symptoms are characterized by intermingled patches of normal and light green or yellowish colors on the leaves of infected plants. The virus almost never kills plants but lowers the quality and quantity of the crop. TMV can be spread by burning tobacco, planting tobacco near other plants, using infected plants as mulch or just touching tobacco and then touching other plants without washing your hands. Be sure to wash your hands acrefully if you do smoke and of course never smoke around your heirloom plants.