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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous > Ironwood (Ostrya)
> Leaves small and discolored yellow to brown

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Ironwood (Ostrya) > Branch > Leaves small and discolored yellow to brown

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  • Image: Fire Blight 1
  • Image: Fire Blight 2
  • Image: Fire Blight 3

Armillaria root rot
Armillaria spp.

  • Infected trees have poor growth, dead branches in the upper canopy, undersized and/or yellow leaves
  • Flat white sheets of fungal growth (mycelial fans) between the bark and sapwood at the base of infected trees
  • Thick black, shoestring-like fungus can sometimes be seen under the bark, around roots and in the soil around the base of the tree
  • Wood is decayed, white, soft and spongy; this may extend from the base of the tree well up into the trunk
  • Trees frequently break or fall over in storms
  • Clusters of honey-colored mushrooms may grow at the base of the tree in fall
  • More information on Armillaria root rot...
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  • Image: Black Rot 1
  • Image: Black Rot 2
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Heart rot
Phellinus spp. and Oxyporus populinus

  • Fungal fruiting bodies arise along the stem, near a pruning wound, crack or other wound
  • Phellinus fungi grow are up to 8" across, hoof-shaped and dark gray above, tan below with a white margin
  • Oxyporus shelf fungi are 6" across, almost as thick and often covered with green moss
  • The canopy may show no symptoms or may have small yellowing leaves or dead branches depending on the extent of the trunk decay
  • In cross section of the trunk, the wood at the center is discolored, soft, crumbling, stringy or spongy
  • More information on Heart rot...
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  • Image: White Rot 1
  • Image: White Rot 2
  • Image: White Rot 3

Sapwood rot
Cerrena unicolor

  • Dead branches within the canopy
  • Yellowing to brown leaves may be present
  • Groups or rows of small (<2 inches wide), thin, semi-circle shelf fungi along killed branches or on the main trunk, often near cracks or wounds
  • Shelf fungi are white to greenish gray and have concentric rings on the surface
  • Wood below fungal shelves is yellowish to white, spongy, crumbly and decayed
  • Bark around fungal shelves is killed and often falls off
  • Common on trees stressed by drought, winter injury, wounds, mechanical injury or other factors
  • More information on Sapwood rot...

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