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Pest Profiles - Diseases

Fusarium Wilt

  • About

    Photo: Courtesy UC Regents
    Photo: Courtesy UC Regents
    Fungus that only infects tomatoes. Like verticillium, causes leaf yellowing and discoloration of water-conducting tissues. Fungi spread in soil water, on equipment, transplants, or tubers. Once inside the root, the fungus grows until it reaches the water-conducting cells, inside which it spreads upward through the plant, restricting water flow.

  • Category
    • Fungi
  • Signs/Symptoms

    Plants turn yellow starting with one side or branch and gradually spreading through the plants, eventually killing them. 

    Growth is typically stunted, and little or no fruit develops. 

    Browning of the water-conducting tissue compared to healthy ivory color of uninfected plants.

    Verticillium and Fusarium discoloration are extremely difficult to distinguish, although Fusarium discoloration tends to be darker. 

  • Where

    Fusarium tends to occur more in warmer soils and Verticillium in cooler ones.

  • When

    When temperatures are between 80 and 90 degrees F.

  • Prevent

    Plant resistant varieties, which are indicated by the letters F or FF. If you wish to grow susceptible varieties, problems can sometimes be minimized by removing all residue, including roots, which may be susceptible, and using soil solarization before you plant.

    Avoid using too much nitrogen fertilizer.


  • Manage

    Remove infected plants.

    Do not plant any Solanaceae plants in the infected area for four years.

    Sanitize stakes and tomato cages at the end of the season.

  • More Information