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Extension > Fruit > Apple > Spots/blotches are smooth

Apples > Fruit > Spots/blotches are smooth

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  • Image: Plum Curculio 1
    Credit: T. McCamant, Northland Community and Technical College
  • Image: Plum Curculio 2

    Credit: J. Hahn, University of MN

  • Image: Plum Curculio 3

    Credit: E. Levine, The Ohio State University, Bugwood.org

  • - CLICK PHOTOS TO ENLARGE -

green arrowPlum Curculio
Conotrachelus nenuphar

  • Fruit can drop prematurely
  • Adult weevils lay eggs in the apple resulting in distinctive crescent shaped tan spots on the apples
  • Adult weevil is small (1/5" in length), dark brown with whitish-gray patches, bumps on the wings, and a distinctive downward-curved snout
  • Mature larvae are yellow-white, ¼" long, and c-shaped (rarely seen)
  • Adults active in early spring (during bloom)
  • More information on Plum Curculio...
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  • Image: Sooty Blotch 1
    Credit: Clemson Univ. Bugwood.org
  • Image: Sooty Blotch 2

    Credit: Clemson Univ. Bugwood.org

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green arrowSooty Blotch
(many species of fungi)

  • Fruit develops gray, green, brown, or black blotches on the surface of the fruit that can easily be washed off
  • Infection is superficial and does not rot the fruit
  • Commonly occurs with fly speck
  • Common in August and September
  • More information on Sooty Blotch...
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  • Image: Flyspeck 1
    Credit: M. Gleason, IA State Univ.
  • Image: Flyspeck 2

    Credit: Clemson Univ. Bugwood.org

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green arrowFlyspeck
(many species of fungi)

  • Fruit develops distinct clusters of pin-point size black dots that do not wash off
  • Infection is superficial and does not rot the fruit
  • Commonly occurs with sooty blotch
  • Common in August and September
  • More information on Flyspeck...
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  • Image: Black Rot 1
    Credit: G. Sundin, Michigan State University
  • Image: Black Rot 2

    Credit: G. Sundin, Michigan State University

  • Image: Black Rot 3

    Credit: M. Grabowski, University of Minnesota

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green arrowBlack Rot
Botryosphaeria obtusa

  • Fruit is rotted but remains firm
  • Fruit may become mummified and remain on tree
  • Round leaf spots with a purple border & tan center
  • Large brown spots with brown rings form on fruit
  • Branch cankers can be sunken, reddish brown or rough looking or cracked bark; cankers may remain small or enlarge to become several feet long
  • Leaves on girdled branches wilt, die and turn brown
  • Common on stressed trees & trees infected with fire blight
  • More information on Black Rot...
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  • Image: White Rot 1
    Credit: University of Georgia Plant Pathology Archive, University of Georgia, Bugwood.org
  • Image: White Rot 2

    Credit: University of Georgia Plant Pathology Archive, University of
    Georgia, Bugwood.org

  • Image: White Rot 3

    Credit: University of Georgia Plant Pathology Archive, University of
    Georgia, Bugwood.org

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green arrowWhite Rot
Botryosphaeria dothidea

  • Sunken brown spots on fruit, can grow to rot part or all of fruit
  • Fruit rot is soft, watery and extends to the core of the apple
  • Small blister like spots on branches exude, watery fluid
  • Branch infections grow to cracked, flakey, orange canker
  • Leaves on girdled branches wilt, die and turn brown
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  • Image: Sunburn
    Credit: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org
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green arrowSunburn

  • White, tan or yellowed patches found on the sun exposed side of the fruit
  • More common on fruit on the southwest quadrant of the tree
  • Can be more pronounced under drought-like conditions

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