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Image: Coral spot canker 1

Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Birch > Leaves wilt and turn yellow or brown

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Birch > Leaves > Leaves wilt and turn yellow or brown

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  • Image: Bronze birch borer 1
  • Image: Bronze birch borer 2
  • Image: Bronze birch borer 3

Bronze birch borer
Agrilus anxius

  • Eventually twigs and then branches dieback starting at the
    top of the canopy and progressively working its way down
  • Foliage at top of the canopy first becomes sparse
  • Raised lumps or ridges can be seen on the trunk and branches
  • D-shaped exit holes can eventually be observed on the trunk
    and branches
  • S-shaped galleries can be seen under the bark
  • Preferred hosts are European white birch and whitebarked Himalayan birch; paper birch, gray birch are also attacked; river birch is rarely infested
  • More information on Bronze birch borer
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  • Image: Drought 1
  • Image: Drought 2


  • Foliage wilts and sometimes turn brown around the edges
    but more commonly turns a dull, gray-green color
  • Dried brown to gray-green leaves hang on the tree or more commonly, foliage drops prematurely and litters the ground
    under the tree
  • Severe drought stress may cause dieback of individual branches starting at branch tips
  • More information on watering trees and shrubs
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  • Image: Armillaria root rot 1
  • Image: Armillaria root rot 2
  • Image: Armillaria root rot 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 (mycelia fans) grow 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, and this may extend from the base of the tree well up into the trunk
  • 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: Heart rot 1
  • Image: Heart rot 2
  • Image: Heart rot 3

Heart rot
Polyporus squamosus, Laetiporus sulphureus, Fomes
fomentarius, Phellinus igniarius, Piptoporus betulinus

  • Canopy may show no symptoms, or may have small yellowing leaves or dead branches depending on the extent of the decay
  • In cross section of the trunk, the wood at the center is discolored, soft, crumbling, stringy or spongy
  • Fungal fruiting bodies arise along the stem; often near a pruning wound, crack or other wound
  • Many colors, shapes and sizes of fruiting bodies may be seen
  • More information on heart rot
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  • Image: Ganoderma root and butt rot 1
  • Image: Ganoderma root and butt rot 2

Ganoderma root and butt rot
(artist's conk)
Ganoderma applanatum

  • Leaves are smaller in size and turn yellow earlier than normal
  • Canopy appears thin with few leaves and multiple dead branches
  • Fungal conks, a semicircle shelf fungi, can be found from the base of the tree up to 3 feet high on the trunk
  • Conks are reddish-brown and shiny on top, white and porous underneath; a rim of white may be visible on the edge of
    growing conks
  • Infected wood at the base of the tree is white, soft, stringy
    or spongy
  • Infected trees frequently break or fall over in storms
  • More information on Ganoderma butt rot
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  • Image: Coral spot canker 2
  • Image: Coral spot canker 3

Coral spot canker
Nectria cinnabarina

  • Common on trees stressed by drought, recent transplant or
    other factors
  • Dead branches and twigs are often first observed in early spring
  • Sunken dark brown area on branch that is often cracked or has a ridge at the edge
  • Raised cushion-like bumps on affected branches, may be cream
    to orange or red, turn black with age
  • More information on canker
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  • Image: Perennial nectria canker 1
  • Image: Perennial nectria canker 2
  • Image: Perennial nectria canker 3

Perennial nectria canker
Neonectria galligena

  • Dead branches and twigs killed by girdling cankers
  • Sunken target shaped cankers on main trunk or branches
  • Cankers do not have bark and raised ridges of wood occur in target-like rings within the canker
  • Red to reddish orange raised cushion like bumps can occasionally be seen on the edge of the canker
  • More information on Perennial nectria canker

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