Therefore, avoid using diseased transplants and establish plantings in non-infested soil. Soil fumigation may provide partial control, but does not completely eliminate bacteria from the soil. When infected plants are identified, remove and destroy them immediately. Virus Diseases Viruses are particles that are smaller than a single cell and not visible through a light microscope. Most viruses are spread by insects, but some are spread mechanically.
Infection occurs through wound openings made by the insects or mechanical damage.
Once inside the plant, more virus is produced which then spreads throughout the plant. Virus infection causes a wide range of symptoms including unusual color patterns in leaves and fruit, distorted growth, plant stunting, and reduced yield. Several different viruses can infect tomato, but only tobacco mosaic virus and tomato spotted wilt virus have been important in Oklahoma. Yield loss from TMV is a result of reduced number, size, and marketability of fruit. The virus may be introduced on contaminated seed, infected crop plants and weeds, and tobacco products.