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Black Walnut > Nuts > Dark spots or blotches

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  • Image: Husk maggots 1

    Credit: Ken Gray Image Courtesy of Oregon State University

  • Image: Husk maggots 2

    Credit: Ken Gray Image Courtesy of Oregon State University

  • Image: Husk maggots 3

    Credit: Washington State University

  • - CLICK PHOTOS TO ENLARGE -

green arrowHusk maggots
Rhagoletis spp.

  • Larvae (maggots) feed inside the husk during mid-summer
  • Larvae feeding causes husks to become slimy, dark and stick to the shell
  • Do not harm nutmeat but fruit becomes unappealing and difficult to handle
  • More information on Husk fly maggots...
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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: Andrej Kunca, National Forest Centre - Slovakia, Bugwood.org

  • - CLICK PHOTOS TO ENLARGE -

green arrowAnthracnose
Gnomonia leptosyla

  • Leaflets have circular brown spots surrounded by yellow tissue
  • Infected leaves turn yellow, then brown on the margins, curl and eventually fall off
  • Dark brown to black spots or blotches form on nut husks
  • Nuts drop prematurely
  • More information on Walnut Anthracnose...

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