The further the selection of plants goes, the more delicate they become. Therefore, lovers of ornamental plants constantly have to deal with various difficulties.
QUICK ANSWER: To treat the fungus on a Japanese maple, remove any dead or badly damaged leaves and spray the tree with an aqueous solution of multi-purpose fungicide. Also, provide good air exchange around the Japanese Maple and avoid overwatering.
These are general recommendations that work in most cases. Next, we’ll go into more detail about the most common Japanese Maple fungal diseases and how to deal with them.
| Disease | Symptoms | Treatment |
| Verticillium wilt | Blackening of the bark. | Spray wounds after pruning with fungicide. |
| Powdery mildew | White powder on the leaves. | Spray the leaves with horticultural oil. |
| Pseudomonas | Black branches. | Cut back the branch below the site of the pathogen damage. |
| Sooty Mold | Black spots on the leaves. | Spray the leaves with a multi-purpose fungicide. |
| Anthracnose | Brown spots on the leaves. | Spray the leaves with a copper fungicide. |
| Phyllosticta leaf spot | Brown spots on the leaves. | Spray the leaves with triazole fungicide. |
| Phytophthora Root Rot | Browning of the leaves. | Plant Japanese maple only in well-drained soil. |
| Tar spot | Black spots on the leaves. | Spray the leaves with a multi-purpose fungicide. |
Verticillium wilt
Verticillium wilt is a serious disease that is not well treated. The pathogens of this disease enter through cracks in the bark or through wounds.
Once the disease enters the maple’s interior, it destroys the tissues that supply water higher up the branch. As a result, leaf petioles and leaves droop.
On branches where the disease has spread heavily, the bark turns black.
Treatment:
- Avoid unnecessary damage to the trunk and branches of Japanese Maple.
- Prune branches a few inches below the blackened area.
- Use only sterile tools for pruning. Clean the tools with rubbing alcohol.
- Spray wounds after pruning with multipurpose fungicide or copper fungicide.
- Allow free air movement around the maple tree.
Powdery mildew
Powdery mildew is one of the most common diseases among Japanese maples and most plants. Fortunately, this fungus is not as severe as the previous one.
The symptoms of powdery mildew are the blackening of the leaves, which become covered with a white coat. Over time, the leaves will shrivel up and fall off.
Treatment:
- Remove badly damaged leaves.
- Improve crown ventilation by pruning some of the branches.
- Avoid overwatering and excessive humidity around the maple.
- Spray the leaves with a fungicide designed to fight this disease.
- Avoid using Neem Oil as it can damage the delicate leaves of the Japanese Maple.
Read also: Growing and Caring for Japanese Maple.
Pseudomonas
Pseudomonas is another fungal disease that affects Japanese Maples. It usually occurs in late winter or early spring.
The pathogens enter through frost-damaged buds. At this point, the blackening of the branch occurs, and the upper part dies off. If the leaves have already appeared, they also die out.
In most cases, the lower part of the crown remains intact. Most susceptible to this disease are 1-2-year-old branches.
Treatment:
- Cut back the branch below the site of the pathogen damage.
- Use a sterile and sharp pruning tool.
- After pruning, thoroughly spray the entire Japanese Maple with Phyton 35.
- Avoid planting the maple in damp areas with poor ventilation.
- If possible, protect the maple from freezing winds over the winter.
Sooty Mold
Sooty mold is a fungal disease that develops on the sticky secretions of aphids. Aphids parasitize on the upper leaves and leave sticky secretions that fall on the lower leaves.
This is an ideal environment for this kind of pathogen. Next, the leaves affected by the fungus turn black. But at the same time, the leaf remains alive because the fungus’s food is the secretions, not the leaf.
Treatment:
- Wash off the aphids and black leaves with water from a hose.
- Remove badly damaged leaves.
- Aphids on Japanese Maple leaves can easily be controlled with insecticidal soap.
- Spray the leaves with a multi-purpose fungicide.
Anthracnose
The spores of this fungus settle on the leaves of the Japanese Maple and damage them. This disease is not capable of causing severe damage to the tree, but it can severely damage its aesthetic appearance.
The disease is most common in humid and low-wind conditions. Dark spots form on the leaves that turn brown and dry over time.
Sometimes, the leaf may turn brown along the edge. Heavily damaged leaves will fall off.
Treatment:
- Clean the fallen leaves around the maple in the fall.
- Provide good air exchange around the maple.
- Do not overwater the Japanese Maple.
- Spray the leaves with copper fungicide. Repeat the spraying after 2 weeks.
Phyllosticta Leaf Spot
Phyllosticta is very similar to the previous disease because it causes leaf spots. The characteristic feature is that the spots can turn into tiny holes. If there are many holes, the leaf will die.
Usually, the spores of this fungus are found in plant debris on the ground. When wet and warm weather arrives, the spores become active. As a result, the leaves may be severely damaged, but the tree will not suffer much.
Treatment:
- Keep the surface around the maple tree clean of leaves and other plant debris.
- Use well-drained soil for planting maple trees.
- Spray the leaves with triazole fungicide.
- Do not plant Japanese Maple in areas that are too dark and poorly ventilated.
Phytophthora Root Rot
Root rot is the most common disease of Japanese maple. It is a serious problem that should not be neglected.
It is usually caused by overwatering, poorly drained soil, or planting the maple in a wet location. As a result, the roots soften and experience oxygen deprivation.
The root system then begins to rot. The external symptoms are yellowing and falling leaves.
Treatment:
- Stop watering too often; water only if the soil is 1-2 inches dry.
- When planting, use well-drained soil.
- Do not plant Japanese Maple where water collects or stagnates.
Tar spot
This disease is not very serious and rarely leads to the tree’s death. However, it can ruin the aesthetic appearance of your maple tree.
When the warm season arrives, spores of the Rhytisma fungus begin to germinate on the leaves. At first, faint yellowish spots appear on the leaves, but they turn dark black over time. The spots resemble tar, hence the name.
Treatment:
- Collect fallen maple leaves and discard them far from your garden each fall.
- If only a few leaves have spots, rip them off and discard them.
- If the infection is severe, spray the maple with a multi-purpose fungicide 2-3 times monthly.
🍁Ask me anything in the comments!🍁
Share This Post
This looks like tar spots but results in the branch loosing all if its leave and dying. This is the second year for the problem.
I have a japanese maple on the east side of my house. It has been there for several years. a few days ago it was fine, then yesterday when walking around I saw all the leaves are all curled up. What gives with this. It was all at once.
Hi Linda! It’s hard to say without a photo and context, so please attach a photo if possible. First of all, check your maple for pests and diseases. If necessary, treat it with remedies.
If the weather was hot, it may be a maple’s reaction to the heat. In this case, water it once with enough water.
I hope this information will be useful to you. Be sure to write if you managed to solve your problem. All the best to you!
I have a Bloodgood Japanese Maple that starts out each spring beautiful, almost perfect. Then around mid-summer the leaves begin to wilt, curl up, turn brown, and eventually fall off prematurely. It’s done this probably the last 5-6 years. I had it looked at by a knowledgeable tree person. He suspected I had a soil fungus and said there wasn’t much I could do but maybe fertilize it, which I did, with little success. I live in northern Indiana. The tree is 18 years old. I really would like to find an answer.
Hi Denny,
In my opinion, the problem is an excess of sunlight. In the summer heat, the leaves burn and curl.
The best thing to do about it is to provide the maple with some shade in the midday heat during the summer months.
Also keep it watered during the summer. This should reduce the heat stress a bit, but avoid overwatering. Let the soil dry out 2 inches between waterings.
I would also recommend fertilizing your maple tree with a fertilizer that is designed for the roots. This will help the tree to develop a strong root system and it will be able to extract the necessary amount of water on its own. In addition, the roots play the role of a cooling system, so the larger the root system, the more comfortable the tree feels in the heat.
I hope these tips will help you. Be sure to write if you managed to solve the problem. I wish you success!
The bark is turning white on tree. The top center branch is dying.
Hi Linda,
It could be a disease. Remove dry branches and treat the tree with a copper fungicide including cracks in the bark. Repeat the spraying every month until winter.
Also water the maple with liquid fertilizer. There is a chance that the tree will recover after a while.
I hope this helps. I will be happy to answer your other questions.
Looking for solution to fungus on bark. What can I treat this fungus with?
Hi Ken,
It looks more like a pest than a fungus to me. I recommend spraying the maple with insecticidal soap and using a sponge and toothpick to gently remove the white stuff from the branches. After that, spray the tree with a copper fungicide.
After a month, repeat the treatment with insecticide and fungicide. I look forward to hearing from you and will be happy to answer any other questions you may have.
Hi Igor, I’m trying to figure out what’s going on with my Japanese Maple. Is it dead or what? Normally at this time it’s has beautiful leaves and is very healthy but not this year. Any advice would be appreciated.
Louis
Hi Louis,
Crush some buds from different parts of the tree. If at least one of them is alive and juicy, the maple should come back to life. However, if all the buds are dry, the tree did not survive the winter and there is nothing you can do.
I hope this helps. I will be happy to answer your other questions.
Hello Igor, My young Japanese maple has what looks like green lichens growing on a few of the branches and wherever they are the branches are dead beyond the lichen like growths. Should I pluck off these growths and cut back the dead maple branches? What could I put on topically to kill this green stuff? I should try to get a picture of it. Perhaps it’s a fungus. It looks rather hard and has jagged edges and encircles the stem, especially around joints. Thank you for any help you can give me.
Hi Jennifur,
Most likely it is lichen and it is not harmful. I recommend you remove the dead branches and spray the tree with a copper fungicide.
I hope this will help. I will be happy to answer other questions.
Hello I’m not sure whats wrong with my Japanese maple tree
Hі Lee,
It looks like Verticillium wilt or some other trunk disease.
I recommend treating the cracks in the bark with a copper fungicide. After 2 weeks, treat the cracks with a multi-purpose fungicide.
Repeat this treatment in the second half of summer.
The mulch around the trunk does not look healthy, so I recommend removing it. Also fertilize the maple with a liquid fertilizer.
I hope this helps, I look forward to hearing from you.
Hi.
These black “spots” are spreading though I’ve sprayed a fungicide on it.
Appreciate your thoughts.
Hi, Igor
It was a hard, cold winter here in western Mass. When our Japanese cutleaf maple leaved out recently, there were leaves on only about 30% of the branches. Never happened before. The tree appears otherwise healthy, with no damage to limbs or bark and no apparent infestations of anything. The tree has been here for about 8 years, in a somewhat protected site (but evidently not protected enough!).
Is freezing weather the likely cause of the damage and, if so, will the tree recover? Are there any steps I might take to hasten its recuperation and to forestall damage in the future?
Thank you so much for all the help you give lovers of momiji!
Dale
Hi Dale,
Yes, a late frost can cause damage to maple. Young leaves are particularly susceptible.
If the branches are healthy, I recommend that you water the tree with a liquid multi-purpose fertilizer. This will give it some energy to recover. Repeat this in about a month.
The only way to protect the maple from frost is to cover it with a frost protection fabric. If the size of the tree allows, cover it next spring before the arrival of late frosts.
I hope I have helped you. I will be happy to answer your other questions.
Hi I have a Bene mesume Japanese maple that has been healthy up until the last month. The leaves have brown spots and some are dying. I suspected spider mites and sprayed with a mild solution of soapy water. It did not help with the leaves condition. I have kept it out of the direct sun because it is very hot where I live. Please advise, I love my Bene
Hi Geoff,
You did the right thing by moving the maple to the shade. Most likely the leaves were burned by the sun. Water the maple with a generous amount of water. Excess water should flow out through the drainage holes.
After a week, water the tree with a liquid multi-purpose fertilizer. In the future, avoid placing it in full sun. Partial shade is the best place for it. This avoids sunburn and overheating of the pot.
Also check for pests on the leaves, if necessary, use a magnifying glass. If there are pests, spray the leaves with horticultural oil.
I hope I have helped you. I will be happy to answer your other questions.
WHY ARE MY LEAVES CURLING AND FEELING DRY AROUND THE EDGES AND FALLING OFF? IT’S A YOUNG TREE BEEN IN THE GROUND ABOUT 3 WEEKS. IT FIRST STARTED WITH OFF WHITE SPOTS ON THE LEAVES.THEY ARE MUCH WORSE NOW.
THANKS
Hello PENNY
Most likely, the white spots are pests, although it is possible that it is a fungus. Newly planted maples are very susceptible to diseases and pests.
Spray the leaves and branches with insecticidal soap. After a week, spray with a copper fungicide. Repeat the spraying after a month.
In addition, shade the maple from direct sun for the rest of the season and water it with liquid fertilizer. I hope I have helped you, I look forward to hearing from you.
THANK YOU SO MUCH…..
UNFORTUNATELY ALL THE LEAVES HAVE DRIED UP AND FALLEN OFF.
THE ONLY GOOD NEWS IS WHEN I SCRAPE A LITTLE BARK OFF IT IS STILL GREEN AND WET!
I WILL DO AS YOU HAVE ADVISED AND HOPE FOR THE BEST.
THANKS AGAIN!
I have a Japanese maple (bloodgood) that’s about 4 years old now & until recently was doing well. This past week I noticed some leaves on the left side were wilting & curling up. The rest of the tree looks fine. On those branches I noticed some unusual areas that likely is the issue. (picture included of that area) I took pictures to a local nursery & someone thought it was some kind of bug infestation under the bark. He sold me Bioadvanced Tree & Shrub Protect & Feed to treat the soil with. He said it will kill the bugs present & prevent any more from appearing. He said the affected branches should be fine next spring. I’ve included pictures & also one of the trunk, which I’m not sure is OK or not. I failed to take one of the trunk when I went to the nursery. Your thoughts on everything?
Hi Bruce,
From the photo I can conclude that the trunk has a little bit of lichen on it and it is not harmful. I noticed that the trunk is a little deep in the mulch and this may be the reason for the curling of the leaves.
I recommend that you remove the mulch near the trunk so that the place where the roots and trunk are connected is not buried in the mulch.
Also spray the entire tree including the trunk with copper fungicide and insecticidal soap.
I hope this helps. I am waiting for other questions from you.
I have an acer tree in a pot which has been fine for years but suddenly I’ve noticed one of the branches seems to have just died.
Hi Glen,
It looks like Verticillium wilt. Cut off the diseased branch below the point of damage. Spray the tree with a copper fungicide, repeat this in a month.
Make sure the pot has drainage holes and avoid overwatering.
I hope this helps. If you have more questions, I will be happy to answer them.
Thanks will give that a try👍
We have been having a lot of frequent and heavy rains in our area of South Carolina. The Japanese Maple limbs touch the ground. I found mold and mushrooms growing under the tree.
I was going to remove the moldy/mushroom soil and dispose of it. The replace with fresh soil and mulch. I was also going to trim the tips of the branches back to allow more air under the tree.
Does that seem reasonable? Is there something else I should do?
Hello
You did everything right. If you see brown spots on the leaves, spray the tree with a copper fungicide.
I hope your maple will be fine! Good luck with your gardening!
How do I get rid of the fungus that causes a white powder on the leaves?
Hi Clark,
The best way to get rid of this is to spray the leaves with a copper fungicide. Repeat the spraying in a few weeks.
To prevent this disease from reappearing in your garden, spray all plants several times per season with a multi-purpose fungicide.
Nice site and responses! I have a 15 year old Osakazuke that was doing great until this year. This Spring a lot of the smaller branches (like less that 1/4”) didn’t leaf out and some of the leaves on higher branches were already turning red (leaves are green in summer).
I went away for a week and came back to what looks like a dead tree. Spot is somewhat shaded, not wet (tree has done well there). Doesn’t look salvageable but would love to get your thoughts on what happened and if there’s anything to be done.
Hi Andrew,
Thanks for the kind words! Sorry to hear about your Osakazuki — that sounds heartbreaking, especially after 15 good years.
From your description, I can assume that your maple tree had a problem with the root system or a vascular clogging. Unfortunately, neither of these options can be treated.
If it is vascular clogging, it is caused by Verticillium wilt. This disease slowly kills tree. The best way to avoid this is to plant healthy seedlings and regularly spray them with fungicide, avoiding overwatering.
Hi there! My new Japanese maple looks unhappy. It gets full sun all day. Is it too much?
Hello Cee,
Your maple needs some shade especially on a hot day. Shade it from the midday sun for the summer.
I noticed traces of pests or fungus on the leaves. I recommend that you spray the maple with insecticidal soap and a week later with a copper fungicide.
Also, do not forget to water the newly planted maple after the soil has dried out by 1-2 inches. At the same time, avoid overwatering.
We had two Japanese maples, both were 2-3 decades old, and had seemed healthy most of that time. The smaller one in the backyard died a couple years ago.
The bigger one in the front yard had several branches die around the same time, and we cut them out. Since then, there has been a good bit of new growth. However, more branches are dying, some leaves have brown edging, and something like a canker appeared on the trunk.
The brown edging on the leaves might be from sunburn, since a large pine tree fell down this year, giving the maple more sun. The other problems started a couple years ago.
Should we keep cutting out branches? Is there anything else that is likely to save the tree?
Thank you!
Hi Carl,
It looks like your maple tree has a fungal disease. Unfortunately, all that can be done is to remove dead branches and treat the maple with a copper fungicide, including the places where the liquid is coming from. Also, water the tree once or twice with liquid fertilizer.
There is not much chance that the tree will survive, but there are exceptions.
I’m seeing these underneth my Akane’s leaves. Not sure if this is sooty mold or tar spot.
The leaves surface previously seem to have some marks and after spraying water off the surface and black marks a month ago, the surfaces marks are gone but black spots still appears spontanously on different leaves.
Hi Alvin
Looks like insect tracks to me. Spray the leaves with an insecticide and repeat the spraying after a few weeks.
Thank you
Hello!
My Japanese maple was purchased from a Canadian Tire about a month ago. Its been in a pot and ive been moving it in and out from our balcony over that time to help it manage with the heat we’ve been having since i saw some of the leaves curling. This seemed to help. Then it got way too hot for the last week and has been indoors only near a west facing window. Now im noticing these brown spots on the leaves. Is this just from the heat/sun or does it look like an insect or fungus problem?
Thank you!
Hello Luis,
Protecting the Japanese Maple from the heat was a wise decision, but you should not bring it indoors as this can cause the leaves to turn brown. It is best to place it outside somewhere cool without direct sunlight.
After the heat wave, place it in a location with 6 hours of direct sun. Also water it additionally, with enough water.
Hi we have two Red Coral Japanese maples. One we’ve had four years. the second was planted early summer 2025. The older one has done very well despite being in a sunny yard with windy conditions. Zone 7b. That is until the newer one was planted 30 feet away (which came with Japanese beetles). We spayed both for beetles, noticed some dead leaves and small branches which I pruned using rubbing alcohol on the pruning shears. Now both trees have dead leaves with brown spots and leaf ends curled. Also some dead branches. I don’t see insects like aphids or beetles. We deep water both as indicated on our moisture meter, with the new tree watered more frequently. Our yard is irrigated. Is this fungus?
Hi Deborah
You should definitely spray your maples with a fungicide. However, the climate is the cause here. It is too hot and there is a lot of direct sun. I have the same problem.
Unfortunately, watering alone does not solve it. The best thing to do is to create shade for the tree during the heat, if possible.
Hi, my Japanese Maple is having some issues. It was planted two months ago with heat around 95 most of that time. I kept it well watered. It does get a lot of sunshine. Is it maybe just from transplant shock? Should I wait to see how it is in spring?
Hi Bill,
What you’re seeing is a result of transplant shock. The first mistake was to plant the maple in the summer in hot weather. It is best to do this in early spring.
Now what you can do is shade it from direct sun for a few weeks until it gets cooler.
Your maple is still looking pretty good so there is a good chance that it will thrive next year.
I have a 30 year old Bloodgood which is showing signs of distress which may be caused by hot humid weather we have had this summer (located coastal SE North Carolina). Of more concern are major cracks and separation of the bark near base of tree. Have lost several JM in last few years and don’t want to lose my old friend. Any help and advice would be appreciated
Hi Sam,
If these cracks appeared in the summer, then it is most likely the result of intense heat. Maple trees do not like overly hot climates. Extreme heat can cause the bark to crack and the branches to dry out.
The best way to avoid this is to temporarily shade the tree during hot weather, if possible. You should also water the soil around the Japanese maple thoroughly, as this will slightly reduce temperature stress.
I recommend treating the cracks with a multi-purpose fungicide to prevent trunk rot.
You are very knowledgeable about Japanese Maples. I’ve a very large one, it has been very healthy. A few months ago I noticed white tips on the lacy leaves that progresses upward on each leaf. The photo I have attached is very accurately showing the condition. This plant is over 6 ft tall and probably 8 ft+ wide. Please tell me necessary steps to rectify the problem.
Thank you.
Hi Ann,
It looks like fungus. Spray the entire tree with a copper fungicide. Repeat spraying in a few weeks.
Also check the leaves and branches for pests. If there are any, spray with insecticidal soap.
Thank you for your reply and your help. I’m going to pick up the copper fungicide.
Any thoughts on what’s going on with our Japanese maple… planted this past spring…
Thanks!!
Hello Julianne,
This is normal because it is the end of the season. The leaves are changing color and falling off.
Check the branches. If they are alive, then everything is fine.
Hi Igor,
Firstly thank you for the post is very informative!!
I bought a japanese maple a few months ago, everything was fine and it was thriving really well but for the last 2 months it hasn’t changed much some leaves are getting curled up, turning grey.
Any advice?
Thanks
Hi Juan,
What you’re seeing is perfectly normal. As maples prepare for winter, their leaves change and eventually fall off, leaving bare branches. The tree will remain dormant through the winter and start producing new leaves again in the spring.
We have a large Japanese maple about 40 yrs. old. It has developed a large hard mushroom like growth on the side of a large branch. What could it be?
Hello, Tom,
I need a photo to determine your problem.