What's wrong with my plant? : Garden : University of Minnesota Extension

Poplar > Leaves > Leaves wilt, then turn yellow or brown

1 of 6

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 6

Leaves on random branches wilt, turn yellow then brown
Random dead branches seen throughout canopy
Sunken irregularly-elongated cankers with cracked bark at the edges occur on branches or the main trunk
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 6

Leaves on infected branches turn yellow and drop prematurely
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
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 6

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

5 of 6

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

6 of 6

Dried brown to gray-green leaves hang on the tree or foliage drops unseasonably and litters the ground under the tree
Foliage sometimes turn brown around the edges but more commonly turns a dull, gray-green color
Severe drought stress may cause dieback of individual branches starting at branch tips
More information on watering trees and shrubs