Tree Fungus Treatment Guide: How To Stop Tree Diseases, Mildew, Fungus Rot

Woman wants a tree fungus treatment guide that explains how to identify types of tree fungus, how to prevent and treat tree diseases like leaf spot, powdery mildew, and yellow spots on leaves.

Trees, like all living things, are susceptible to ailments, and knowing how to properly apply tree fungus treatment can help save your trees from early demise.

Trees cannot scream out in pain or tell you they are unwell, so it is entirely up to you to know even the most subtle of signs that your tree is under a fungal attack.

There are fungi that are completely harmless; maybe the worst they can do is alter your trees’ looks, but you have to be on the lookout for the lethal ones because those can end your tree’s life.

Moreover, a weak tree becomes a hazard, especially during the bad weather when it topples over onto your property; so there is a lot more to protecting your tree than just keeping it alive.

This tree fungus treatment guide provides detailed information on how to stop tree diseases, mildew, and fungus rot and explains what you need to know when it comes to spotting deadly fungal diseases and the most effective treatment and prevention remedies.

Common Tree Fungi and How To Treat Them

Fungi diseases are a tree owner’s nemesis because you never see them coming, and they can be pretty hard to treat.

With the right tips, you will not only know how to spot them at their earliest stages but also know the best tree fungus treatment.

Graphics with images and text showing common tree fungus.

Here are some of the most common ones.

Powdery Mildew on Plants

You will easily identify powdery mildew because it causes whitish dusting on the surface of the leaves. It loves attacking perennial trees, and although it is not exactly fatal, it covers up the leaves and forces them to drop, which is the last thing you want to happen.

The best way to avoid it is to properly space your trees and weed them regularly to avoid overcrowding.

Leaf Spot Disease

Leaf spot is another fatal disease that not only affects your tree’s looks but could also kill it unless you detect and treat it on time. Apart from attacking ornamental plants, strains like the Cercospora leaf spot love attacking plants like the crepe myrtle tree, infamous for forming tan blotches with brown circles around them.

Obviously, that interferes with photosynthesis and the tree’s overall health. There are chemical methods to deal with leaf spots using fungicides, but you can also go organic, removing the affected leaf parts and disposing of them.

Black Knot Fungus

Do you grow cherries, plums, peaches, or apricots? Then you have to watch out for the black knot fungus that absolutely loves attacking such fruit trees.

You can easily tell it apart by how it forms dark galls wrapping around the tree. When it sets base, it doesn’t take long before it affects the tree’s appearance and, of course, fruit production.

Early detection is the best way to go, spotting it early, then removing the affected parts, and treating them with neem oil. But to be safe, you better plant fruit tree varieties that are known to be more resistant to black knot.

Oak Wilt Treatment

Are you a proud owner of a majestic oak tree? The deadly fungal disease caused by a fungus known as Bretziella fagacearum is no joke, especially if you have many oaks growing close to each other.

From the name, you can tell that it makes your oak wilt and later kills it. How do you spot it?

The leaves will start withering and discoloring and then later fall off.2 Considering the fact that the disease kind of spreads fast, your best shot at protecting other trees would be to remove and dispose of the affected trees.

Systemic fungicides may also work, although they are majorly used as preventative options, not for cure.

Verticillium Wilt

This is another fungal disease that is also known to cause wilting; it is just as deadly as the others. The fungi causing verticillium wilt travels through the soil, which makes it all the more dangerous.6

You can spot it early when you see the leaves curling up, drying, and discoloring, and in some cases, you can tell when your tree shows stunted growth. Given that there is no particular fungicide that can kill it, you have to pay more attention to preventing it.

Maybe start by planting the least susceptible tree varieties like the birch and arborvitae. The trees that are most vulnerable to this wilt include ash trees, magnolia, boxwood, dogwood, oak, and maple trees.


Watch out for this fungal disease that is caused by fungi from the Colletotrichum group of pathogens. You can tell an attack when you see dark soaking lesions on the parts of the tree.

In no time, the disease can turn your bountiful harvest into nothing but waste. To protect your plant, consider using fungicides or organic neem oil sprays.

Sulphur powders, or copper sprays also go a long way to prevent the disease from attacking.

Root Rot

Any seasoned tree owner is frightened by the thought of their plants contracting root rot and will do anything to stop it from happening. There is a pretty good reason why because it is one of the deadliest, near impossible to cure.

Top shot showing the bottom part of a tree trunk with root rot.

(Image: Scot Nelson9)

Guides will tell you to avoid overwatering your plant because that is one of the fastest ways to cause root rot. The roots start rotting, and without them, the entire tree is as good as dead.

Yellowing and wilting leaves are clear signs, but you may also perceive a foul smell coming from the ground; as a confirmation, the roots will be darkened and look mushy. No tree or plant is spared from the root rot wrath, from beech trees, oak, maple, fruit trees, ornamental trees, flower plants, and virtually any plant that is overwatered.


No gardener or farmer wants to hear the term blight because it is one of the most problematic fungal diseases ever. There is absolutely no cure, so the best that you can do is either prevent it or at least stop it from spreading to other trees.

First off, there are various forms of blight, including the infamous early and late blight. They manifest as lesions on the tree parts, causing defoliation and ruining harvests.

What you can do is prevent it by rotational planting, picking the tree types that are least susceptible, and watering directly on the ground.

Canker Disease

Canker, which can be bacterial or fungal is pretty easy to spot, no thanks to how it leaves behind long lesions that have a sort of reddish tint on the branches and bark.3 As with many other fungal diseases, the best way to deal with it is by prevention, you may want to go for the tree varieties that you are certain are immune to canker, and if by chance one gets affected, you will start by removing the affected parts or the entire tree to protect the rest.7

Tree Fungus Treatment for Shot Hole Fungus

Think of leaf spot and how it leaves behind blotches and marks all over the leaves, now, shot hole fungus goes a little beyond that by also leaving holes in these spots. An unsuspecting tree owner would immediately think that it is a case of a pest attack, where they eat through the leaves, but that’s not it.

You can confirm that it is the fungi when you see red-brown spots around the holes. Later on, the affected leaves start discoloring and dropping prematurely.

At Home and Professional Tree Fungus Treatment

It is understandable that seeing your tree under attack makes you panic, trying to find ways to save it from impending doom. Good news.

Graphics with illustrations and text showing possible home remedies for minor tree fungus.

You can actually keep it alive using at-home or DIY remedies, especially if the case is not that bad. If it is a new infection and you have fortunately caught it before it spreads to most parts of the tree or to others around, you can use natural remedies.

First of all, you can start off by identifying the parts that are affected. Given how fast the fungi spread, you will have to chop off these parts, collect them, and then burn them, this way, there will be no chance of them spreading again through the air or water.

If you are dealing with a massive infection, then you will have to call in a tree trimming service or in the worst-case scenario, opt for tree removal. The latter may be the last resort in some cases where there is no chance of survival.

To avoid getting to that point, it is crucial to call in tree doctors whenever you suspect that there is something off. A professional will take a look, diagnose your tree, and treat it right before the situation escalates.

Apart from that, you can try the following at-home remedies as minor tree fungus treatment.

  • Baking Soda: All you need is a teaspoon of this kitchen item mixed with a couple of drops of insecticidal/ liquid soap, and spray that on the tree leaves. It works wonders in cases of leaf blight, powdery mildew, and anthracnose.4
  • Vinegar: Just another common kitchen item but one that is pretty effective when it comes to sensitive plants like flowers. Spray a tablespoon mixed with about a gallon of water to keep off fungi.
  • Chamomile: This is not just for tea. You can also brew it and drizzle it on top of your plants the second they start showing signs of infection.

What Causes Tree Diseases? What Are the Signs You Need Tree Fungus Treatment?

Trees are some of the best features of a home, and it is no wonder you prize yours and want to protect it at all costs.

Unfortunately, all living things are vulnerable to diseases, and in this case, tree fungus.

Graphics with illustrations and text showing various visual indicators of fungal infection in trees.

While some are harmless, only messing up the tree’s aesthetics, others are fatal and fast spreading, so you have to keep an eye out for them. Are you wondering how on earth your tree gets infected in the first place?

Fungi have a unique way of spreading through the air, water, soil, and insects, so there is no way to see them coming. They move through spores, and there is little to nothing that you can do to stop them.

There are also chances that they will spread through your gardening tools, so you have to be very careful not to unknowingly transmit them. They can attack whatever lies in their way, but wounded and weak trees are even more susceptible.1

Fungi will find the slightest opening in the bark and roots and then attack the interior. Stressed trees are their favorites, say those deprived of food or water and even those under attack by pests and weeds (overcrowded).

If this is your very first tree, of course, you want to know the telltale signs. How do you know that it has contracted a disease?

First of all, fungi are different, manifesting in plenty of ways depending on the particular case. What you will look out for are any abnormalities, no matter how small, in your tree’s looks and growth patterns.

If you see anything out of the ordinary, take that as your sign, but below are some of the most common symptoms.5

  • Stunted growth regardless of proper care and maintenance
  • Premature falling of pines and leaves
  • Leaf discoloration
  • Spots on the top or bottom parts of the leaves
  • Leaf wilting and curling
  • Spots on the fruits
  • Dusting on the tree
  • Growth in the tree’s bark
  • Wetness at the ground level near the trunk

What Do You Call the Red Fungus on Tree?

One of the most common red fungi that you will likely spot on your tree is called the wood ear, a gelatinous jelly-like fungus that is thick and takes a coppery red color. It looks just like any other mushroom apart from the red color and is actually used as food in plenty of cultures.

More often than not, the fungus will grow on the branches of dying or already dead trees or on the woods on the forest floor.

Tree Fungus Prevention

Did you know that trees have evolved to find ways to protect themselves against fungi diseases? A strong healthy tree will easily fight off attacks, but you also have a part to play to boost your tree’s defenses. Here is what a caring tree owner does to help prevent fungal infections.8

  • No matter what, make sure that you apply fungicides on your tree, especially when the weather is dry.
  • Since insects can spread infections, you should also use insecticides and pesticides.
  • Avoid overwatering your trees else they become susceptible to root rot.
  • Be sure to trim and prune your trees correctly.
  • Take care of wounded and damaged trees, uproot if you have to.
  • You can also make it a point to conduct regular (annual) tree inspections.

What Are Common Peach Tree Diseases?

There are quite a number of diseases that attack the peach tree, so you have to keep an eye out for them lest your entire harvest goes to rotten waste. Peach trees, like other fruit trees, are susceptible to black knot fungus, brown rot, peach leaf curl, root rot, leaf spot, canker, crown gall, anthracnose, and so many more.

For most of these diseases, there is no known cure, so the best that you can do is prevent them from occurring in the first place.

What Are the Types of Citrus Tree Diseases?

Citrus trees are an absolute favorite among homeowners, and it is a plus that there are so many fruit types to choose from. You will do anything to keep your plant safe, and one of them is to watch out for the common fungal diseases, the likes of foot rot, dry root rot, mal secco, and even post-harvest fungi like sooty mold, caused by poor weather and a particular variety of citrus.

The goal is to keep your tree strong and healthy; otherwise, there will be nothing to harvest.

Are There Specific Tree Bark Diseases?

Fungal diseases don’t only manifest on the tree’s leaves and branches; there are also instances where it is the bark that is affected. In many cases, this means that the infection is in its advanced stages, and it is even worse because it’s not like you can chop off the entire stem.

Many bark diseases are fatal, so you have to look out for any abnormalities on the bark, like lesions and swelling. The most common fungal disease that attacks the tree’s bark is the canker, and you can easily tell by the massive wound that forms on the tree.

How Do You Treat Yellow Spots on Apple Tree Leaves?

There are so many fungal and bacterial diseases that cause yellow spots on your apple tree. The most common culprits include leaf spot and cedar-apple rust, both equally deadly because of how fast they spread and how there is no foolproof cure.

The second you see your apple tree leaves showing signs of such diseases, you have to chop off the affected parts and dispose of them, then apply chemical or homemade fungicide as a precaution.

Close up image of yellow spots on apple tree leaves.

(Image: Matt Borden10)

Do you have some of the most stunning trees and plants in your home? Then, you will do anything to keep them healthy and strong at all times.

There is one hurdle though: deadly, unforgiving tree fungi. Fungal, viral, and bacterial tree diseases are not to be taken lightly because they could kill your plant in the blink of an eye, and sometimes even wipe out an entire plantation.

You need to know how to identify the most common ones. To be safe, maybe look out for any irregularities in the growth pattern/ rate and the appearance of your tree.

Discolored leaves, premature leaf loss, spots, wounds, swelling barks, all that should never be taken for granted. It could be a matter of life and death for your tree, so you have to act fast before it’s too late.

Tree fungus treatment could be organic homemade remedies or chemical methods, but if you are not sure, speak to a plant pro to help identify and treat the fungus.

Read More About Tree Fungus Treatment


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3Coelho, S. (2021, June 23). 7 Common Tree Diseases and How to Treat Them Before it’s Too Late. Bob Vila. Retrieved November 23, 2023, from <>

4Tree_Wiz. (2023). Fungus on Trees – How To Get Rid of It. Fast Tree Removal Services. Retrieved November 23, 2023, from <>

5Isleib, J. (2012, December 19). Signs and symptoms of plant disease: Is it fungal, viral or bacterial? Michigan State University. Retrieved November 23, 2023, from <>

6Iowa State University Extension and Outreach. (2023). Verticillium Wilt. Iowa State University. Retrieved November 23, 2023, from <>

7University of Arkansas Division of Agriculture. (2023). Common Forest Disease Problems. University of Arkansas Division of Agriculture. Retrieved November 23, 2023, from <>

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9Hibiscus Root Rot Photo by Scot Nelson. CC0 BY 1.0 DEED | CC0 1.0 Universal. Resized, Adjusted Color Balance, and Adjusted Brightness and Contrast. Flickr. Retrieved January 16, 2024 from <>

10Cedar apple rust (Gymnosporangium juniperi-virginianae) on apple (Malus domestica) Photo by Matt Borden. CC BY-SA 2.0 DEED | Attribution-ShareAlike 2.0 Generic. Resized, Adjusted Color Balance, and Adjusted Brightness and Contrast. Flickr. Retrieved January 16, 2024 from <>