Skip to Main navigation Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension
We're looking for your feedback on the Extension website. Please take our survey.

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

Print Icon Email Icon Share Icon

Oak > Leaves > Brown spots or blotches on leaves

1 of 7
  • Image: Oak anthracnose 1
  • Image: Oak anthracnose 2
  • Image: Oak anthracnose 3

Oak 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...
2 of 7

Bur oak blight
Tubakia iowensis

  • Infects only bur oaks - small acorn variety
  • Spring and early summer, leaf veins on lower leaf surface have dark brown dots or short lines
  • Mid-summer and fall, random lengths of leaf vein turn brown; some expand into brown wedge shaped areas on leaves
  • Leaves may turn completely brown, some drop early
  • Small raised black dots form on the petiole (stem) of infected leaves
  • Some leaves remain attached through winter
  • Symptoms appear in lower, inner canopy first. Disease progresses upward and outward over multiple seasons
  • More information on Bur oak blight...
3 of 7
  • Image: Jumping oak gall wasp 1
  • Image: Jumping oak gall wasp 2

Jumping 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...
4 of 7
  • Image: Oak leaf miner 1
  • Image: Oak leaf miner 2
  • Image: Oak leaf miner 3

Oak 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...
5 of 7
  • Image: Oak slug sawfly 1
  • Image: Oak slug sawfly 2
  • Image: Oak slug sawfly 3

Oak 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...
6 of 7
  • Image: Oak leaf blister 1
  • Image: Oak leaf blister 2
  • Image: Oak leaf blister 3

Oak 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...
7 of 7
  • Image: Tubakia leaf spot 1
  • Image: Tubakia leaf spot 2
  • Image: Tubakia leaf spot 3

Tubakia 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...

Don't see what you're looking for?

  • © Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy