Mosaic virus

Affecting a wide variety of horticultural and vegetable crops — roses, beans, tobacco, tomatoes, potatoes, cucumbers and peppers — mosaic is a viral diseases found throughout the United States.

Plant viruses can be difficult to detect as symptoms look similar to many nutrient deficiencies and vary depending on the age of the plant when infection occurs. Look for:

  • Yellow, white or green stripes/ streaks/ spots on foliage
  • Wrinkled, curled or small leaves
  • Pronounced yellowing only of veins
  • Stunted growth and reduced yields
  • Infected fruit appears mottled and develops raised “warty” areas

Mosaic virus overwinters on perennial weeds and is spread by insects that feed on them. Aphids, leafhoppers, whiteflies and cucumber beetles are common garden pests that can transmit this disease. Soil, seed, starter pots and containers can be infected and pass the virus to the plant. Cuttings or divisions from infected plants will also carry the virus.


There are no cures for viral diseases such as mosaic once a plant is infected. As a result, every effort should be made to prevent the disease from entering your garden.

  1. Fungicides will NOT treat this viral disease.
  2. Plant resistant varieties when available or purchase transplants from a reputable source.
  3. Do NOT save seed from infected crops.
  4. Spot treat with least-toxic, natural pest control products, such as Safer Soap, Bon-Neem and diatomaceous earth, to reduce the number of disease carrying insects.
  5. Harvest-Guard® row cover will help keep insect pests off vulnerable crops/ transplants and should be installed until bloom.
  6. Remove all perennial weeds, using least-toxic herbicides, within 100 yards of your garden plot.
  7. The virus can be spread through human activity, tools and equipment. Frequently wash your hands and disinfect garden tools, stakes, ties, pots, greenhouse benches, etc. (one part bleach to 4 parts water) to reduce the risk of contamination.
  8. Avoid working in the garden during damp conditions (viruses are easily spread when plants are wet).
  9. Avoid using tobacco around susceptible plants. Cigarettes and other tobacco products may be infected and can spread the virus.
  10. Remove and destroy all infected plants. Do NOT compost.