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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Annuals and Perennials > Iris > Damaged rhizomes

Iris > Damaged rhizomes

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  • Image: iris borer 3
    Credit: Michelle Grabowski
  • Image: iris borer 2

    Credit: Michelle Grabowski

  • Image: iris borer 1

    Credit: Jeff Hahn

  • - CLICK PHOTOS TO ENLARGE -

green arrowIris Borer

  • Damaged rhizomes occur mid summer through fall
  • Water-soaked looking streaks in leaves may be noticed in spring
  • Yellow or brown streaks especially near the base of the leaf mid to late summer
  • Ragged brown leaf tissue at the base of the leaf, may look tattered or have sawdust like frass
  • Pinkish or whitish larva with a dark colored head, up to 1 1/2 to 2 inches long inside rhizome
  • More information on Iris Borer...
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  • Image: soft rot 1
    Credit: Michelle Grabowski
  • Image: soft rot 2

    Credit: Michelle Grabowski

  • Image: soft rot 3

    Credit: Michelle Grabowski

  • - CLICK PHOTOS TO ENLARGE -

green arrowBacterial Soft Rot
Erwinia carotovora

  • Leaves turn brown from the tip down with a yellow border between green and brown leaf tissue
  • Browning leaves may wilt and fall over
  • Rhizome is soft when pressed on and may smell bad
  • Inside of the rhizome is soft, mushy and smells bad
  • Common in heavy wet soils, and in rhizomes damaged by borer

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