Maple tree bark diseases

Maple Tree Bark Disease – Diseases On Maple Trunk And Bark

There are many kinds of maple tree diseases, but the ones that people are most commonly concerned with affect the trunk and bark of maple trees. This is because bark diseases of maple trees are very visible to a tree’s owner and are often bring about dramatic changes to the tree. Below you will find a list of diseases that affect maple trunk and bark.

Maple Tree Bark Diseases and Damage

Canker Fungus Maple Tree Bark Disease

Several different kinds of fungi will cause cankers on a maple tree. These fungus are the most common maple bark diseases. They all have the same thing in common, which is that they will create lesions (also called cankers) in the bark but these lesions will look different depending on the canker fungus that is affecting the maple bark.

Nectria cinnabarina canker – This maple tree disease can be identified by its pink and black cankers on the bark and typically affects parts of the trunk that were weak or dead. These cankers can become slimy after rain or dew. Occasionally, this fungus will also appear as red balls on the bark of the maple tree.

Nectria galligena canker – This maple bark disease will attack the tree while it is dormant and will kill healthy bark. In the spring, the maple tree will regrow a slightly thicker layer of bark over the fungus infected area and then, the following dormant season, the fungus will once again kill back the bark. Over time, the maple tree will develop a canker that looks like a stack of paper that has been split and peeled back.

Eutypella canker – The cankers of this maple tree fungus looks similar to Nectria galligena canker but the layers on the canker will normally be thicker and will not peel away from the tree trunk easily. Also, if the bark is removed from the canker, there will be a layer of visible, light brown mushroom tissue.

Valsa canker – This disease of maple trunks will normally affect only young trees or small branches. The cankers of this fungus will look like small shallow depressions on the bark with warts in the center of each and will be white or grey.

Steganosporium canker – This maple tree bark disease will create a brittle, black layer over the bark of the tree. It only affects bark that has been damaged by other issues or maple diseases.

Cryptosporiopsis canker – The cankers from this fungus will affect young trees and starts out as a small elongated canker the looks as though someone pushed some of the bark into the tree. As the tree grows, the canker will continue to grow. Often, the center of the canker will bleed during the rising of spring sap.

Bleeding canker – This maple tree disease causes the bark to appear wet and is often accompanied by some bark coming away from the maple tree trunk, especially lower down on the trunk of the tree.

Basal canker – This maple fungus attacks the base of the tree and rots away the bark and wood beneath. This fungus looks very similar to a maple tree root disease called collar rot, but with collar rot, the bark typically does not fall away from the base of the tree.

Galls and Burls

It is not uncommon for maple trees to develop growths called galls or burls on their trunks. These growths often look like large warts on the side of the maple tree and can get to massive sizes. Though often alarming to see, galls and burls will not harm a tree. That being said, these growths do weaken the trunk of the tree and can make the tree more susceptible to falling during wind storms.

Environmental Damage to Maple Bark

While not technically a maple tree disease, there are several weather and environment related bark damages that can happen and may look like the tree has a disease.

Sunscald – Sunscald most frequently occurs on young maple trees but can happen on older maple trees that have thin skin. It will appear as a long discolored or even barkless stretches on the trunk of the maple tree and sometimes the bark will be cracked. The damage will be on the southwest side of the tree.

Frost cracks – Similar to sunscald, on the southern side of the tree cracks, sometimes deep cracks will appear in the trunk. These frost cracks will most commonly happen in late winter or spring.

Over mulching – Poor mulching practices can cause the bark around the base of the tree to crack and fall off.

Maple Diseases & Insect Pests


Leaf Scorch: On maple (Acer species) trees a number of problems cause symptoms that are generally classified as leaf scorch. Scorch symptoms are light brown or tan dead areas between leaf veins or around the leaf margins. Occasionally the leaf margins are yellow or chlorotic. Scorch symptoms tell us that one or more of the following factors are affecting the tree:

  • Physiological leaf scorch is the most common. It is caused by dry weather, combined with wind and high temperatures. When trees do not get enough water they will scorch. The symptoms are on all parts of the tree or only on the side exposed to sun and wind. Scorching due to dry soil may be overcome by proper watering.
  • A response to an undesirable soil contaminant, such as salt (applied to roads for wintertime ice control), accumulation of fluorides in containerized soil mixes with perlite, or high levels of phosphate fertilizers.
  • A reaction to a vascular pathogen, either fungal or bacterial.

Anthracnose of maple (Aureobasidium apocryptum).
Paul Bachi,

Anthracnose: This disease is caused by the fungus Aureobasidium apocryptum. Leaves and buds may turn brown and die, followed by twig and branch dieback. Infected trees may be deformed with crooked and angular branches or witches’ brooms (clusters of shoots growing from one area of a branch). This disease is most severe during wet weather.

Prevention & Treatment: The most effective control is to replant with resistant trees. Spraying three times at two-week intervals with a copper-based fungicide, mancozeb, chlorothalonil, or thiophanate methyl starting when the leaves begin to unfurl in spring will provide control (see Table 1 for specific products). Read and follow all directions on the label.

Bacterial leaf scorch of maple (Xylella fastidiosa).
John Hartman,

Bacterial Leaf Scorch: This disease is caused by the bacterium Xylella fastidiosa. Symptoms often start out as a marginal chlorosis or yellowing of the leaves before they fade to a drab green or brown color. Presumably, the symptoms develop because of water stress within the water conducting vessels. Diseased trees lose vigor, and branches or entire trees may eventually die. The symptoms are most noticeable in late summer to early fall, following extended periods of drought. The bacteria are transmitted by leafhoppers feeding and vegetatively through grafts and cuttings.

Prevention & Treatment: In general, practices that encourage root development and root function are recommended. Incorporate organic soil amendments into the soil to improve aeration and drainage of clay soils or to improve the water holding capacity of sandy soils. Irrigate during periods of drought. The disease has been suppressed by oxytetracycline injections, but not cured. A certified arborist should be contacted if chemical control is needed.

Phyllosticta leaf spot of maple (Phyllosticta cotoneastri).
Paul Bachi,

Phyllosticta Leaf Spot: This disease, also known as purple eye, is caused by the fungus Phyllosticta spp. On the leaves, spots appear with pale yellow centers and purple borders. The spots are irregularly round and ¼ inch in diameter. Black fruiting bodies of the fungus develop in a circle in the centers of the spots. These fruiting bodies occur in greater numbers on the upper leaf surface. Severe infection can result in partial defoliation of the tree. Often the disease goes unnoticed until leaf accumulation occurs under the tree.

Prevention & Treatment: The fungus survives the winter in fallen leaves. In the spring spores are produced and dispersed to the new leaves of susceptible trees. Rake up all fallen leaves. Fertilization and watering may help to reduce the disease. ‘Autumn Flame’, ‘Tilford’, and ‘Gerling’ red maple varieties are relatively resistant to leaf spot. Spraying three times at two-week intervals with a copper-based fungicide, mancozeb, chlorothalonil, thiophanate methyl, or triadimefon starting when the leaves begin to unfurl in spring will provide control (see Table 1 for specific products). Read and follow all directions on the label.

Tar spot of maple (Rhytisma acerinum).
Andrej Kunca,

Tar Spot: Tar spot is caused by the fungus Rhytisma acerinum. Spots arise in late spring or early summer after leaves attain full size. At first the infected tissue is light green or yellow. Then, during late summer, raised, shining black, tar-like dots develop within the yellow spots on the upper leaf surfaces. The lower surface of a leaf beneath a large tar spot turns brown, but the surface beneath speckled tar spots remains yellow. Leaves with multiple spots may wither and drop prematurely, but seldom so early or in such quantities as to threaten the health of the tree.

This disease is more common in the forest, but may be seen in some landscape situations. Tar spots are among the most showy and least damaging foliar diseases.

Prevention & Treatment: The fungus survives the winter in fallen leaves. Rake up and discard the leaves in fall. Spraying three times at two-week intervals with a copper-based fungicide, mancozeb, or triadimefon starting when the leaves begin to unfurl in spring will provide control (see Table 1 for specific products). Read and follow all directions on the label.

Insect Pests

Aphids: Aphids are soft-bodied insects that range from 1/16 to ⅜ inch long. They may be green, yellowish, pink, gray or black. They feed by piercing plant tissue and sucking plant sap. They prefer feeding on new growth in such areas as shoots, buds, and the undersides of leaves. As they feed on plant sap, they excrete honeydew (a sugary material). The sooty mold fungus grows on the honeydew, resulting in unsightly, dark fungal growth.

Woolly alder aphid (Paraprociphilus tessellatus).
Bob Lepak,

Woolly alder aphid (Paraprociphilus tessellatus) is gray to black in color. It gets its name from the fluffy, white wax found on its abdomen. It requires alder and silver maple to complete its life cycle. Occasionally, it is found on red maple. Colonies of these pests are obvious because of their white, fuzzy appearance. They are usually seen on leaves, twigs, or bark. Although infested leaves shrivel and drop early, the pests cause little permanent damage. As a result of the honeydew, sidewalks and cars become sticky.

Prevention & Treatment: Several natural enemies, such as ladybird beetles (ladybugs) and lacewings feed on aphids. These predators should be allowed to reduce aphid populations as much as possible. Controlling this pest on a large tree using chemicals is expensive and often not practical. Since little permanent damage results from woolly alder aphids, tolerating some damage is a good choice. As a result of their phenomenal ability to reproduce, aphids are very difficult to control with insecticides. Leaving one aphid alive can result in the production of a new colony very quickly. In addition, the use of insecticides kills the beneficial insects that normally keep aphid populations under control.

However, if natural predators do not reduce aphid populations sufficiently, the following foliar spray insecticides are recommended: cyfluthrin, lambda cyhalothrin, permethrin, bifenthrin, pyrethrin, and neem oil. Treat when aphids appear and repeat at seven- to 10-day intervals, if needed. As an alternative, dinotefuran or imidacloprid can be applied as a drench around the root zone of aphid-infested plants and is systemically taken up by the root system for insect control (see Table 1 for specific products). As with all pesticides, read and follow all label directions and precautions.

Cottony maple leaf scale adults (Pulvinaria acericola) (Walsh and Riley, 1868).
Nancy Gregory, University of Delaware

Scale: Many scale species-including Pulvinaria acericola, Pulvinaria innumerabilis, and Melanaspis tenebricosa are pests of maples. Scales are unusual insects in appearance. They are small and immobile with no visible legs. Scales vary in appearance depending on age, sex, and species. Some are flat and appear like scales stuck to a plant, while others appear like white cottony masses. They feed on sap by piercing the leaf, stem, or branch with their mouthparts and sucking. Their feeding can weaken or kill branches. Heavily infested trees are stunted with small flowers and leaves. Leaves may yellow and drop early.

Like aphids, soft scales, such as Pulvinaria spp., also excrete honeydew. The growth of the sooty mold fungus on the honeydew results in leaves that are dark grayish-black. Armored scales, such as Melanaspis tenebricosa, do not excrete honeydew, as they feed differently than the soft scales.

Prevention & Treatment: A combination of various natural enemies, including ladybird beetles (ladybugs) and parasitic wasps, usually keeps scales under control. In small trees with light infestations, scale can be scraped off or infested branches can be removed and destroyed. In a large tree, controlling scale chemically is not always practical. The size of the tree, the need for specialized equipment, and the cost may prohibit this approach. Adult scales are relatively protected from insecticides by their waxy covering. Their immature forms, called crawlers, are susceptible, however. If it is determined that chemical control is necessary, the recommended chemicals include the following: cyfluthrin, lambda cyhalothrin, bifenthrin, or permethrin. Apply materials when crawlers appear and repeat in 10 days. Both soft and armored scales can be controlled by a soil drench with dinotefuran . Drench applications are best made in the spring as new plant growth appears. See Table 1 for specific products. As with all pesticides, read and follow all label instructions and precautions.

Ocellate gall midge (Acericecis ocellaris).
Lacy L. Hyche

Gall Makers: Maples often develop irregular growths or swellings known as galls on their leaves. Gall development is a reaction by the leaf tissue to feeding or egg laying by various mites (such as Vasates quadripedes and Vasates aceriscrumena) and insects (such as Acericecis ocellaris and Cecidomyia ocellaris). Galls vary greatly in appearance, from wart-like bumps to spindle-shaped protrusions to felt-like patches on the leaf’s surface. Each insect or mite produces its own distinctive gall shape. Often the distinctive shape allows for identification of the pest. Galls typically develop in spring at about the time that leaves are expanding. Once the gall forms, the pest is protected inside the structure. When homeowners see these growths on the leaves of their maples, they often become quite concerned. It is important to remember that while unsightly, they do not cause permanent injury to a tree.

Prevention & Treatment: Since leaf galls do little, if any, long-term damage to the tree, control efforts are typically not needed or recommended. If a tree is small, the homeowner can handpick and destroy leaves before exit holes form to allow the release of the pest.

Granulate ambrosia beetle (Xylosandrus crassiusculus) larvae (Motschulsky, 1866).
Will Hudson, University of Georgia

Asian Ambrosia Beetles: Japanese maples are among the more common hosts of the granulate ambrosia beetle (Xylosandrus crassiusculus), with other hosts including styrax, ornamental cherry (especially Yoshino), pecan, peach, plum, dogwood, persimmon, sweetgum, magnolia, fig, Chinese elm, and azalea. This pest is attracted not only to damaged, stressed, or transplanted trees, but to seemingly healthy trees as well. The beetle becomes active in early March (or earlier), and the female beetles bore into trunks or branch wood of thin-barked hardwood trees. Once a tree has been attacked, it becomes more attractive to further attack. Often these trees are less than four inches in diameter.

Granulate ambrosia beetle frass (Xylosandrus crassiusculus) frass protruding from bark. .
G.Keith Douce, University of Georgia,

Visible symptoms include wilted foliage, as well as the toothpick-like strands of boring dust (frass) that protrude from these small, pencil-lead size holes. The Asian ambrosia beetle does not feed upon the wood of the host, but instead carries with it an ambrosia fungus, which grows within the galleries made by the beetle. This fungus serves as a source of food, and may partially be responsible for the death of the host plant.

Prevention & Treatment: Heavily infested plants should be removed. If only a few branches are infested, they may be cut out. The life cycle takes approximately 55 days until the emergence of the next generation of beetles, so prompt removal or burning of the wood is important. Protective sprays on other susceptible plants may reduce their spread. Permethrin may be used as a trunk and scaffold limb spray beginning in March (see Table 1 for specific products). Thoroughly wet the bark. Multiple treatments may be needed during a season. Research indicates that spraying the infested trunks with permethrin may cause the beetles to leave the galleries they have already created. Since the beetles do not consume the host plant material, dinotefuran and imidacloprid systemic soil treatments are ineffective.

Other Problems

Girdling Roots: If a tree shows symptoms of poor vigor such as small leaves, death of small limbs, top dieback or leaf scorch, the condition could be due to girdling roots. This problem occurs when a root entwines around another large root or the base of the tree and prevents or hinders water and nutrient movement. Often girdling roots occur below ground level, indicated by a lack of root flare at the base of the trunk.

Prevention & Treatment: The portion of the root that is girdling the tree should be removed. The open wound can be treated with wound paint prior to covering with soil. Fertilization of the tree after root removal will aid in recovery.

Table 1. Insecticides & Fungicides for Maple Insect Pest & Disease Control.

Insecticides & Fungicides Examples of Brand Names & Products
Acephate1 Bonide Systemic Insect Control
Bifenthrin Ferti-lome Broad Spectrum Insecticide Concentrate
Hi-Yield Bug Blaster Bifenthrin 2.4 Concentrate
Monterey Turf & Ornamental Insect Spray
Chlorothalonil Bonide Fung-onil Concentrate
Ferti-lome Broad Spectrum Landscape & Garden Fungicide
Garden Tech Daconil Fungicide Concentrate
Hi-Yield Vegetable Flower Fruit & Ornamental Fungicide
Ortho Max Garden Disease Control
Southern Ag Liquid Ornamental & Vegetable Fungicide
Tiger Brand Daconil
Copper-based Fungicides Bonide Liquid Copper Concentrate
Camelot O Fungicide/ Bactericide Concentrate
Monterey Liqui-Cop Fungicide Concentrate
Natural Guard Copper Soap Liquid Fungicide Concentrate
Southern Ag Liquid Copper Fungicide
Cyfluthrin Bayer Advanced Vegetable & Garden Insect Spray Concentrate; & RTS
Dinotefuran Ortho Tree & Shrub Insect Control Ready to Use Granules
Valent Brand Safari 2G Insecticide Granules
Valent Brand Safari 20SG Insecticide
Gordon’s Zylam Liquid Systemic Insecticide
Gordon’s Zylam 20SG Systemic Turf Insecticide
Horticultural Oil2 Bonide All Seasons Spray Oil Concentrate
Ferti-lome Horticultural Oil Spray Concentrate
Monterey Horticultural Oil Concentrate
Southern Ag Parafine Horticultural Oil
Summit Year Round Spray Oil Concentrate
Imidacloprid Bayer Bio Advanced 12 Month Tree & Shrub Insect Control Landscape Formula
Bonide Annual Tree & Shrub Insect Control with Systemaxx
Ferti-lome Tree & Shrub Systemic Insect Drench
Martin’s Dominion Tree & Shrub
Monterey Once A Year Insect Control II
Insecticidal Soap3 Bonide Insecticidal Soap Concentrate
Espoma Earth-tone Insecticidal Soap Concentrate
Natural Guard Insecticidal Soap Concentrate
Safer Brand Insect Killing Soap Concentrate
Garden Safe Insecticidal Soap Concentrate
Lambda Cyhalothrin Spectracide Triazicide Insect Killer for Lawn & Landscapes Concentrate
Martin’s Cyonara Lawn & Garden Concentrate
Mancozeb Bonide Mancozeb Flowable
Southern Ag Dithane M-45
Malathion4 Bonide Malathion 50% Insect Control
Gordon’s Malathion 50% Spray Concentrate
Hi-Yield 55% Malathion Insect Spray
Martin’s Malathion 57% Concentrate
Ortho Max Malathion Insect Spray Concentrate
Southern Ag Malathion 50% EC
Spectracide Malathion Insect Spray Concentrate
Tiger Brand 50% Malathion
Neem Oil5 Bonide Neem Oil Fungicide, Miticide, Insecticide Concentrate
Ferti-lome Rose, Flower & Vegetable Spray Concentrate
Garden Safe Fungicide 3 Concentrate
Garden Safe Neem Oil Extract Concentrate
Monterey 70% Neem Oil Concentrate
Natural Guard Neem Concentrate
Southern Ag Triple Action Neem Oil
Permethrin Bonide Eight Insect Control Vegetable Fruit & Flower Concentrate
Bonide Total Pest Control – Outdoor Concentrate
Hi-Yield Indoor/Outdoor Broad Use Insecticide Concentrate
Tiger Brand Super 10 Concentrate
Martin’s Vegetable Plus Concentrate
Pyrethrin Bonide Garden Insect Spray Concentrate
Southern Ag Natural Pyrethrin Concentrate
Monterey Bug Blaster-O
Monterey Pyganic Gardening
Thiophanate-methyl Cleary’s 3336-WP Turf & Ornamental Fungicide
Southern Ag Thiomyl Systemic Fungicide
Important Notes: Chemical control of diseases and insect pests by sprays on large trees is usually not feasible since adequate coverage of the foliage with a pesticide cannot be achieved.

1Acephate may damage red and sugar maples.
2Horticultural oil may injure Japanese, amur, and red maples. May not injure silver maple.
3Insecticidal soap should not be applied to Japanese maples.
4Malathion may cause slight injury to many maple species.
5Neem oil may cause injury to Japanese maples.
Spinosad may cause injury to Japanese Maples.
Follow label directions for all insecticide rates (strength in solution).
Do not apply insecticidal soap, horticultural oil, or neem oil if temperature is greater than 85 ºF., and apply these three insecticides in early morning or evening.

Note: Pollinating insects, such as honey bees and bumblebees, can be adversely affected by the use of pesticides. Avoid the use of spray pesticides (both insecticides and fungicides), as well as soil-applied, systemic insecticides unless absolutely necessary. If spraying is required, always spray late in the evening to reduce the direct impact on pollinating insects. Always employ cultural controls first, then use less toxic alternative sprays for the control of insect pests and diseases. For example, sprays with insecticidal soap, horticultural oil, neem oil extract, spinosad, Bacillus thuringiensis (B.t.), or botanical oils can help control many small insect pests and mites that affect garden and landscape plants. Neem oil extract or botanical oil sprays may also reduce plant damage by repelling many insect pests. If soil applied insecticides are used, make applications immediately after flowering to reduce the amount of insecticide exposure to pollinating insects. For more information, contact the Clemson Home & Garden Information Center.

Why is Bark Falling off My Tree (Oak, Pine, Ash, Maple)?

Full canopies, plump fruit, thick bark—all these things describe a healthy tree. But what happens when one is missing?

If your tree is missing chunks of bark, it may not look so hot. But does it mean something’s wrong?

If you spot peeling bark on your tree, help it out by learning about the causes—and solutions—below.

Why is my tree losing its bark?

Usually, it’s normal for a tree to lose bark. For some species, like sycamore, silver maple, and birch, shedding large chunks of bark is just one of their charms! Other trees, like oak, pine, ash, and maple, develop from the inside out, so the older bark on top chips away to make room for new bark.

As long as there’s healthy bark underneath the peeling layers, your tree is OK. But if you see these other signs, your tree needs a bit more help:

  • Bark falls off after frost, which usually happens on the tree’s south or southwest side. Any sudden swing in temperature can make trees shed bark and crack under stress.
  • Bark falls off after excessive heat, which, like frost damage, strips bark down to the wood.
  • Bark falls off an unhealthy tree, which means you’d see other signs of stress such as cankers, sap, or dead leaves and twigs.

If bark is falling off my tree, is it dying?

Sadly, there’s no easy yes or no to this question. But, if the tree appears overall healthy, there’s a good chance it’s just peeling for growth. If your tree lost bark after an unusual weather incident, you can usually save it with the below steps! The biggest question is if you spot other worrisome signs that point to other bigger problems.

What to Do About Pine, Maple, Oak or Ash Tree Bark Falling Off

If bark is peeling with no other symptoms, it’s likely because of weather stress. Stressed trees love water and mulch! So, hydrate the tree when its soil is dry and apply organic mulch in spring and fall.

If your tree looks unhealthy, give it a closer look. A host of tree pests and diseases can affect your ash, pine, oak or maple. There’s the infamous EAB that burrows underneath ash tree wood and the smooth patch disease, a fungus that attacks the outer layer of oak bark.

If you find any signs of pest or disease—sawdust, oozing cankers, dead leaves, or a fuzzy fungus—have a professional arborist check it out. He’ll let you know if you can treat the problem or if you need to remove it to keep other plants on your property out of harm’s way.

Eutypella canker

How does Eutypella Canker survive and spread?

Black, spore-producing structures

  • Eutypella canker is caused by the fungus Eutypella parasitica.
  • During rainy weather spores are ejected into the air from infected wood. These spores can travel more than 75 feet on the wind.
  • The fungus infects recently wounded or newly pruned small branches.

Once in the tree, the fungus makes itself at home underneath the bark. There, it grows into the wood and expands outward up to 1 inch per year.

As the fungus spreads, it kills the phloem (vascular cells that transport sugars from the leaves throughout the tree), the cambium (undeveloped cells that grow into new vascular cells).

The fungus also infects the sapwood of the tree, causing it to decay. This decay can extend up to a foot into the tree and greatly weakens the tree. Many trees infected with Eutypella canker break during strong storms and high winds.

Each year during the growing season, the tree tries to defend itself by creating a layer of wound wood around the edge of the canker. When the tree goes dormant for the season, the fungus breaks into this barrier and continues its progress. This back and forth growth can continue for decades. In very old cankers where the bark has finally fallen off, rings of growth can be seen that reflect this annual battle between fungus and tree.

White Spots on Maple Tree

It is difficult to tell from the picture. Here are some possible causes:
Lichens- these are usually of various colors- white-ish to green-ish, tan or brown. They are harmless and nothing to worry about. This is the most likely cause of your patches. You can search the internet for color pictures of lichen on trees and compare with what you are seeing.
Birds (sapsuckers or woodpeckers) punch holes in the trunks of various trees, and the milky exudate you are seeing is simply the sap and usually causes no harm. The tree will heal naturally.
A rot fungi or canker fungi (there are many)- these usually start near a wound, crack or pruned area. From your picture, this does not appear to be the case. I am giving you general descriptions of these two diseases so you can look closely at your tree and compare.
Young cankers appear as round flattened, bark covered areas on main trunk or larger branch. Branch stub or other wound is often visible at center of the canker. As cankers age, the flattened surface turns black and bark begins to fall off revealing decaying wood in a target shape pattern below.
Rot fungi- 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.
If your tree is one that has high value for you, you will want to get a definite diagnosis. Here are a couple options to do that: To consult a certified arborist for an on site diagnosis, see and search under their ‘Find a Tree Care Service’ tab at the top of the page. Call 2-3 in your area for pricing. Be sure to ask for a certified arborist, not just a tree trimmer.
Scrape the area lightly and see what is under the white patch. Take more pictures of the areas affected. Try to get a sample of the white patch and take it to your MSU Extension office. If that is not practical, you can send pictures and the sample to MSU Diagnostics Lab in East Lansing. For instructions on how to do that, and their fees, see
I hope this gives you some help with your tree. Remember, if the tree has lichen growing on it, there is no treatment or other action required. Thank you for using our service.

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