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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Oak > Brown spots or blotches on leaves

Oak > Leaves > Brown spots or blotches on leaves

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  • Image: Oak anthracnose 1
    Credit: M. Grabowski, University Of Minnesota
  • Image: Oak anthracnose 2

    Credit: M. Grabowski, University Of Minnesota

  • Image: Oak anthracnose 3

    Credit: J. O'Brien, USDA Forest Service, Bugwood.org

  • - CLICK PHOTOS TO ENLARGE -

green arrowOak anthracnose
Discula quercina

  • Leaves have scattered brown, irregular spots that can coalesce into nearly completely brown leaves
  • Affected leaves become wrinkled, cupped or curled especially around leaf edges
  • On severely infected trees, leaves fall off early in the season, trees soon sends out new leaves
  • Damage is most common on lower and interior branches
  • Damage most common in spring as leaves are growing during wet weather
  • Most affected are trees within white oak group (white oak, bur oak, swamp white oak)
  • More information on Oak anthracnose...
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  • Image: Jumping oak gall wasp 1
    Credit: T. Haugen Brown
  • Image: Jumping oak gall wasp 2

    Credit: J. Hahn, University Of Minnesota

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green arrowJumping oak gall wasp
Neuroterus saltatorius

  • Leaf upper surface has brown spots, 1/16 to 1/8 inch diameter, encircled by yellow halo
  • Growths the size of BBs or small seeds on leaf undersides
  • Foliage can be discolored or turn brown when leaves heavily infested
  • Can cause premature leaf loss
  • Commonly associated with white oaks
  • More information on Jumping oak gall wasp...
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  • Image: Oak leaf miner 1
    Credit: R. Nelson, University of Minnesota
  • Image: Oak leaf miner 2

    Credit: R. Nelson, University of Minnesota

  • Image: Oak leaf miner 3

    Credit: T. D. Leininger, USDA Forest Service, Bugwood.org

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green arrowOak leaf miner
Cameraria spp.

  • Larvae feed between leaf surfaces creating blotch-like mines
  • Canopy looks brown when heavily infested; defoliation can occur
  • Larvae 1/4 inch long with bodies that taper to rear, although larvae are rarely seen
  • Primarily attacks white oak
  • More information on Oak leaf miner...
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  • Image: Oak slug sawfly 1
    Credit: J. Hahn, University Of Minnesota
  • Image: Oak slug sawfly 2

    Credit: D. J. Moorhead, University of GA, Bugwood.org

  • Image: Oak slug sawfly 3

    Credit: T. Tigner, VA Dept. of Forestry, Bugwood.org

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green arrowOak slug sawfly
Caliroa quercuscoccineae

  • Larvae windowpane feed underside of leaf, i.e. chew leaf one layer of leaf tissue between the veins creating a lacelike appearance
  • Larvae is dark green to black and covered in slime; adult is non-stinging wasp that is rarely seen
  • Damage first visible early summer
  • Pin oak and black oak are preferred hosts
  • More information on Oak slug sawfly...
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  • Image: Oak leaf blister 1
    Credit: M. Grabowski, University Of Minnesota
  • Image: Oak leaf blister 2

    Credit: M. Grabowski, University Of Minnesota

  • Image: Oak leaf blister 3

    Credit: M. Grabowski, University Of Minnesota

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green arrowOak leaf blister
Taphrina caerulescens

  • Raised blister-like leaf spots; appear sunken from the underside of the leaf
  • Leaf blisters are initially pale green to orange, but turn brown with age
  • Blister areas range from 1/16 to 1/2 inch in length
  • Heavy infestation will cause leaf to curl after the blisters have merged together
  • Leaves do not drop
  • Damage most common in spring as leaves are growing during wet weather
  • More information on Oak leaf blister...
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  • Image: Tubakia leaf spot 1
    Credit: Purdue Univ., Plant and Pest Diagnostic Lab
  • Image: Tubakia leaf spot 2

    Credit: P. Bachi, University of KY Res. & Ed. Center, Bugwood.org

  • Image: Tubakia leaf spot 3

    Credit: Purdue Univ., Plant and Pest Diagnostic Lab

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green arrowTubakia leaf spot
Tubakia dryina

  • ¼ to ½ inch sized leaf spots or blotches that are dark brown or reddish-brown
  • Spots often restricted by leaf veins; defoliation occurs if infection is severe
  • In severe cases, the canopy appears full of brown leaves
  • Symptoms first present mid-summer but become most obvious late summer
  • All oaks are susceptible
  • More information on Tubakia leaf spot...

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