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Bacterial wilt

In cucurbits, bacterial wilt is spread by cucumber beetles and blocks the plant's water-conducting tissue. Leaves wilt on one runner, then the whole plant, and do not recover overnight. In warmer climates a related bacterium wilts tomatoes and ginger.

Bacterial diseases
A cucumber vine wilting suddenly from bacterial wilt
A cucumber vine wilting suddenly from bacterial wilt

What it looks like

A sudden, green wilt.

  • One runner flops while the rest looks fine.
    Wilting runner One runner flops while the rest looks fine.
  • Leaves stay wilted in the evening and after watering.
    No recovery Leaves stay wilted in the evening and after watering.
  • Leaves wilt green, then brown and shrivel.
    Green, then brown Leaves wilt green, then brown and shrivel.
  • Cucumber beetle feeding on leaves nearby.
    Beetle damage Cucumber beetle feeding on leaves nearby.

How to confirm it

Try the string test.

  1. Cut a wilted stem

    Press the cut ends together and pull apart slowly.

  2. Sticky strands

    Fine, slimy threads confirm bacterial wilt.

  3. Beetles present

    Striped or spotted cucumber beetles in the crop.

What to do

Remove and control the beetles.

  1. Remove wilted plants

    Pull and bin infected plants at once.

  2. Control beetles

    Cover young plants and hand-pick beetles.

  3. Grow resistant varieties

    Some cucumber varieties resist wilt.

  4. Rotate

    In warm-climate tomatoes and ginger, avoid replanting in the same soil.

Prevent it next time

  • Protect seedlings with row cover until flowering.
  • Keep cucumber beetles in check from planting.
  • Use clean ginger rhizomes.

What not to do

Do not wait for plants to recover; they do not.

In the growing guides

Where the guides mention it, with plant-specific advice.

Sources

  1. Bacterial wilt of vegetables, University of Maryland Extension
  2. Bacterial wilt of cucurbits, University of Minnesota Extension