Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension

Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Poplar > Scattered dead branches in canopy

Print Icon Email Icon Share Icon

Poplar > Trunk/Branches > Scattered dead branches in canopy

1 of 9
  • Image: Hypoxylon canker 1
  • Image: Hypoxylon canker 2
  • Image: Hypoxylon canker 3

Hypoxylon canker
Entoleuca mammata

  • Leaves on one or more branches are undersized, turn yellow then to brown and remain attached to stem
  • Cankers begin near wounds or at the base of a branch
  • Infected bark initially turns yellowish-orange; older infections are black at center with yellowish-orange margins
  • Bark first appears blistered and raised, then falls off to reveal blackened wood
  • Clusters of raised buff white to black bump like fungal stromata can be seen on 3 year old cankers
  • Damage most common on trembling aspen
  • More information on Hypoxylon canker
2 of 9
  • Image: Valsa and Leucostoma cankers 1
  • Image: Valsa and Leucostoma cankers 2
  • Image: Valsa and Leucostoma cankers 3

Valsa and Leucostoma cankers
Valsa sordida and Leucostoma niveum

  • Random dead branches seen throughout canopy
  • Sunken irregularly-elongated cankers with cracked bark at the edges occur on branches or the main trunk
  • Leaves on random branches wilt, turn yellow then brown
  • Cankers are brown to black at the center with salmon to orange discoloration of the bark at the edges
  • In wet weather curled tendrils of orange spores emerge from pimple like fungal structures within infected branches
  • Common on trees stressed by drought, winter injury, wounds, insect feeding or other factors
  • More information on canker
3 of 9
  • Image: Cryptodiaporthe canker 1
  • Image: Cryptodiaporthe canker 2
  • Image: Cryptodiaporthe canker 3

Cryptodiaporthe canker
Cryptodiaporthe populea

  • Random dead branches caused from girdling cankers seen throughout canopy
  • Bark on cankers may or may not be discolored, but the tissue beneath the bark will be brown to black
  • Leaves on infected branches turn yellow and drop prematurely
  • Multiple thin weak adventitious shoots develop
  • Callus tissue formed around edges of cankers causing bark to fall off and expose the wood beneath it
  • Common on Lombardy poplars
4 of 9
  • Image: Bronze poplar borer 1
  • Image: Bronze poplar borer 2
  • Image: Bronze poplar borer 3

Bronze poplar borer
Agrilus granulatus

  • Branch die back and death caused by larvae feeding under bark
  • Creates serpentine S-shaped galleries underneath bark
  • "D" shaped exit holes present in affected branches
  • Adults have black bodies with a tinge of metallic green; approximately 3/8th inch long
  • Larvae are whitish, slender, 1- 1 ½ inch long with 2 dark brown tail-like structures at the end of the body
  • More information on Bronze poplar borer
5 of 9
  • Image: Poplar-gall saperda 1
  • Image: Poplar-gall saperda 2
  • Image: Poplar-gall saperda 3

Poplar-gall saperda
Saperda inornata

  • Branch tips die and/or break over above the gall
  • Twig bulges or becomes round where longhorned beetle larvae are feeding
  • Fully grown larvae are up to 1" long, creamy-white and legless
  • Common on quaking aspen
  • More information on Poplar-gall saperda
6 of 9
  • Image: Trunk and limb rot 1
  • Image: Trunk and limb rot 2
  • Image: Trunk and limb rot 3

Trunk and limb rot
Phellinus tremulae

  • The canopy may show no symptoms or may have small yellowing leaves/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
  • Fruiting bodies are up to 8 inches wide to 6 inches thick; lower surface at 45 degree angle
  • Fungal surface is pale brown when young to black and crusted when aged
  • More information on Trunk and limb rot
7 of 9
  • Image: Deicing salt injury 1

Deicing salt injury

  • Run-off salt kills roots which results in die-back of branches
  • Soil salt damage causes leaf edges or margins to appear burnt or scorched progressing toward the mid-vein
  • Affected trees leaf out later than other non-infected trees
  • Damage most noticeable in spring and the summer growing season
  • More information on Deicing salts
8 of 9
  • Image: Ganoderma root and butt rot 1
  • Image: Ganoderma root and butt rot 2

Ganoderma root and butt rot
(aka. 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 tree base is white, soft, stringy or spongy
  • Infected trees frequently break or fall over in storms
  • More information on Ganoderma butt rot
9 of 9
  • 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

Don't see what you're looking for?