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

Maple > Leaves > Leaves turn completely yellow or brown

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  • Image: Branch cankers 1
    Credit: E. L. Barnard, FL Dept. of Ag. and Consumer Services, Bugwood.org
  • Image: Branch cankers 2

    Credit: Univ. of GA Plant Pathology Archive, Univ. of GA, Bugwood.org

  • Image: Branch cankers 3

    Credit: Univ. of GA Plant Pathology Archive, Univ. of GA, Bugwood.org

  • - CLICK PHOTOS TO ENLARGE -

green arrowBranch cankers
Botryosphaeria obtusa, Valsa spp. and other fungi

  • Leaves on random branches wilt, turn yellow then brown during the growing season
  • Random dead branches seen throughout canopy
  • Infected branches don’t leaf out in spring
  • Cankers are brown to black sunken areas on branch that may have cracked bark and discolored sapwood
  • Common on trees stressed by drought, winter injury, wounds, insect feeding or other factors
  • More information on Branch cankers...
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  • Image: Stem girdling roots 1
    Credit: M. Grabowski, University of Minnesota
  • Image: Stem girdling roots 2

    Credit: M. Grabowski, University of Minnesota

  • Image: Stem girdling roots 3

    Credit: M. Grabowski, University of Minnesota

  • - CLICK PHOTOS TO ENLARGE -

green arrowStem girdling roots

  • Affected trees commonly exhibit water-stress symptoms such as marginal leaf scorch, wilting, sudden leaf fall
  • Affected trees are often have branch dieback, stunted growth, exhibit poor summer color, change color and lose their leaves early in the fall
  • Affected trees commonly exhibit excessive and abnormal winter damage including frost cracks and dieback
  • A root circling the trunk of the tree may be seen at the soil line
  • Trunk may become sunken in or compressed where it contacts the root
  • If girdling root is below ground, the trunk will lack the natural widening or flare at the soil line so will go straight into the earth like a telephone pole; trees often exhibit an abnormal lean
  • More information on Stem girdling roots...
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  • Image: Verticillium wilt 1
    Credit: C. Ash Kanner
  • Image: Verticillium wilt 2

    Credit: M. Grabowski, University of Minnesota

  • Image: Verticillium wilt 3

    Credit: W. Jacobi, Colorado State University, Bugwood.org

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green arrowVerticillium wilt
Verticillium dahliae

  • Leaves are small and yellowed in chronic infections
  • Leaves turn brown from the edges and tips, wilt and die in severe infections
  • Leaf symptoms are often seen on only one or a few random branches in the canopy
  • Dark brown to black streaks often can be seen in the sapwood if the bark is peeled back, appearing as rings or arcs in a cross cut
  • Symptoms may develop over a single growing season, or over several years
  • More information on Verticillium wilt...
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  • Image: Sapwood rot 1
    Credit: M. Grabowski, University of Minnesota
  • Image: Sapwood rot 2

    Credit: M. Grabowski, University of Minnesota

  • Image: Sapwood rot 3

    Credit: M. Grabowski, University of Minnesota

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green arrowSapwood rot
Schizophyllum commune and Cerrena unicolor

  • Dead branches within the canopy
  • Groups or rows of small (<2 inches wide) semi-circle self fungi along killed branches or on the main trunk
  • Schizophyllum shelf fungi are white and appear fuzzy on top
  • Cerrena shelf fungi are white to greenish grey and have concentric rings on the surface
  • Occurs on trees with an open wound or crack
  • Wood below fungal shelves is yellowish to white, crumbly and decayed; bark around fungal shelves is killed and often falls off
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  • Image: Oystershell scale 1
    Credit: W. Seidel, University of Minnesota
  • Image: Oystershell scale 2

    Credit: W. Seidel, University of Minnesota

  • Image: Oystershell scale 3

    Credit: W. Seidel, University of Minnesota

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green arrowOystershell scale
Lepidosaphes ulmi

  • Feeding can cause foliage to yellow
  • Twig and branch dieback can occur when branches are heavily infested
  • Light to dark brown, elongated, 1/10 to 1/8 inch long, found feeding on branches
  • Heavy infestations of “shells” can completely cover bark
  • Damage occurs during summer
  • More information on Oystershell scale...
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  • Image: Heart rot 1
    Credit: L. Haugen, USDA Forest Service, Bugwood.org
  • Image: Heart rot 2

    Credit: M. Grabowski, University Of Minnesota

  • Image: Heart rot 3

    Credit: Unknown

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green arrowHeart rot
Phellinus spp., Climacodon septentrionalis, Oxyporus
populinus and others

  • 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
  • Fungal fruiting bodies arise along the stem, near a pruning wound, crack or other wound
  • Many shapes and sizes of fungal fruiting bodies may be seen
  • More information on Heart rot...
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  • Image: Armillaria root rot 1
    Credit: M. Grabowski, University of Minnesota
  • Image: Armillaria root rot 2

    Credit: M. Grabowski, University of Minnesota

  • Image: Armillaria root rot 3

    Credit: M. Grabowski, University of Minnesota

  • - CLICK PHOTOS TO ENLARGE -

green arrowArmillaria 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.
  • 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: Ganoderma root and butt rot 1
    Credit: M. Grabowski, University Of Minnesota
  • Image: Ganoderma root and butt rot 2

    Credit: M. Grabowski, University Of Minnesota

  • Image: Ganoderma root and butt rot 3

    Credit: M. Grabowski, University Of Minnesota

  • - CLICK PHOTOS TO ENLARGE -

green arrowGanoderma root and butt rot
Ganoderma spp.

  • 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 root and butt rot...

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