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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Ash > Dots, spots, blotches or rings on leaves

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Ash > Leaves > Dots, spots, blotches or rings on leaves

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  • Image: Ash plant bugs 1
  • Image: Ash plant bugs 2
  • Image: Ash plant bugs 3

Ash plant bugs

  • Damage occurs during spring but will be present remainder of summer
  • Feeding cause speckled, pinprick whitish or yellowish discoloration; does not cause leaf drop
  • Severe feeding can result in brown, dead areas, especially along edges of leaflets
  • Nymphs bright red, then turn yellowish or brownish
  • Adults brown and yellow with heart-shaped mark
  • More information on Ash plant bugs...
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  • Image: Antracnose, leaves up close 1
  • Image: Antracnose,leaves up close 2
  • Image: Antracnose, leaves on tree

Anthracnose
Discula fraxinea

  • Tan to brown irregular spots on leaves, often causing leaves to be curled or deformed
  • In severe infection leaves may wilt and fall off, part or all of the tree may lose its leaves
  • Common on young leaves in cool wet spring weather
  • Lower leaves and leaves in the inner canopy are often infected first, or most severely
  • More information on Anthracnose...
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  • Image: Rust, wart-like spot 1
  • Image: Rust, wart-like spot 2
  • Image: Rust, wart-like spot 3

Rust
Puccinia sparganioides

  • Yellow to bright orange wart like spots on leaves and green stems
  • Clusters of tiny cup like structures grow out of spots and release powdery orange spores
  • Leaves and stems may be bent or twisted where infected
  • In severe cases leaves may turn brown and fall off (very rare in MN)
  • More information on Rust...
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  • Image: Powdery mildew, leaf up close 1
  • Image: Powdery mildew, leaf up close 2
  • Image: Powdery mildew, leaf up close 3

Powdery Mildew
Phylactinia fraxini

  • Powdery white coating on leaves, green stems, and buds
  • Common on lower leaves and leaves that are shaded
  • In severe infections leaves may curl or turn yellow (rare)
  • More information on Powdery Mildew...
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  • Image: Virus, leaves up close 1
  • Image: Virus, leaves up close 2
  • Image: Virus, leaves up close 3

Virus
White Ash Mosaic Virus and many others

  • Random pattern of yellow and shades of green on leaves
  • Blocky white or yellow irregular spots or rings on leaves
  • Leaves may be distorted or unusually shaped

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