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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Cucumber > Holes in leaves

Cucumber > Leaves > Holes in leaves

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  • Image: Striped Cucumber Beetle 1
    Credit: E.C. Burkness, University of Minnesota
  • Image: Striped Cucumber Beetle 2

    Credit: E.C. Burkness, University of Minnesota

  • Image: Striped Cucumber Beetle 3

    Credit: E.C. Burkness, University of Minnesota

  • - CLICK PHOTOS TO ENLARGE -

green arrowStriped Cucumber Beetle
Acalymma vittatum

  • Feeds on flowers and directly on fruit, causing scarring
  • Beetles feed on leaves and can completely defoliate a plant
  • Shows a preference to cucumbers, certain varieties of winter squash, and zucchini
  • Vectors bacterial wilt
  • Adult is yellow-green in color, about 1/4 inch long, and marked by three black stripes
  • Active from June through September
  • More information on Striped Cucumber Beetle...
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  • Image: Anthracnose 1
    Credit: M. Grabowski, University of Minnesota
  • Image: Anthracnose 2

    Credit: M. Grabowski, University of Minnesota

  • Image: Anthracnose 3

    Credit: M. Grabowski, University of Minnesota

  • - CLICK PHOTOS TO ENLARGE -

green arrowAnthracnose
Colletotrichum obriculare

  • Somewhat circular dry brown leaf spots form near veins
  • Center of leaf spot often falls out, leaves appear ‘shot hole’
  • Circular sunken dark spots on fruit, salmon colored spores form in the center when wet
  • Commonly appears mid to late season
  • Also commonly infects melons and pumpkin
  • More information on Anthracnose...
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  • Image: Angular Leaf Spot 1
    Credit: Clemson University, Bugwood.org
  • Image: Angular Leaf Spot 2

    Credit: Clemson University, Bugwood.org

  • Image:Angular Leaf Spot 3

    Credit: T.A. Zitter, Cornell University

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green arrowAngular Leaf Spot
Pseudomonas syringae pv. Lachrymans

  • Leaves develop small, angular, brown or straw-colored spots with a yellow halo
  • Leaf spots dry and drop out, leaving irregularly shaped holes in the leaves
  • Water soaked to tan small circular spots on fruit
  • Sticky drops of whitish liquid for on the underside of the leaf when wet, dry to a crust when dry
  • More information on Angular Leaf Spot...
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  • Image: Scab 1
    Credit: M.A. Hansen, VPISU, Bugwood.org
  • Image: Scab 2

    Credit: M. Grabowski, University of Minnesota

  • Image: Scab 3

    Credit: M.A. Hansen, VPISU, Bugwood.org

  • - CLICK PHOTOS TO ENLARGE -

green arrowScab
Cladosporium cucumerinum

  • Irregular gray leaf spot with a yellow halo
  • Center of leaf spot falls out, leaves look shot holed or ragged
  • Cucumber, summer squash, zucchini, & pumpkin have sunken fruit spots are covered with greenish black velvety fungal growth
  • Winter squash have raised corky areas around fruit infections, internal rot varies depending on resistance of variety
  • Watermelon is very resistant
  • More information on Scab...
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  • Image: Spotted Cucumber Beetle 1
    Credit: Susan Ellis, Bugwood.org
  • Image: Spotted Cucumber Beetle 2

    Credit: Whitney Cranshaw, Colorado State University, Bugwood.org

  • - CLICK PHOTOS TO ENLARGE -

green arrowSpotted Cucumber Beetle
Diabrotica undecimpunctata howardii

  • Beetles feed on leaves, flowers, and fruit
  • Vectors bacterial wilt
  • Adult is 1/4 inch long, bright yellow-green body with 12 black spots
  • Active from June through September

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