How to Effectively Remove Fungus from Tree Bark

Tree bark fungus is a common issue that can affect the health and appearance of trees. While some fungi are harmless others can cause significant damage if left untreated. Fortunately there are several effective methods for removing fungus from tree bark and restoring your trees.

Common Types of Tree Bark Fungus

There are many different species of fungi that can grow on tree bark Some of the most common include

• Powdery mildew – Appears as a white or gray powdery coating on leaves, shoots and stems.

• Apple scab – Causes olive-colored spots on leaves that can lead to leaf distortion and loss.

• Cytospora canker – Causes sunken, dead areas on bark that ooze resin. Can eventually girdle and kill branches.

• Armillaria root rot – White fungal mats grow under bark at soil line and in roots. Causes tree decline.

• Black knot – Rough black swellings form on twigs and branches. Causes branch dieback.

• Taphrina blister – Raised blisters form on leaves which distort, curl, and die. Affects peaches and plums.

It’s important to properly identify the type of fungus affecting your tree to select the best treatment method. An arborist can help with diagnosis if you are unsure.

Why Remove Tree Bark Fungus?

Though some fungi are harmless, most tree fungi can negatively impact the health of your trees if left unchecked:

• Fungal infections weaken trees, making them more prone to insect infestations and other diseases.

• Certain fungi cause defoliation, branch dieback, and other growth issues.

• Severe infections can girdle and kill portions of the tree or entire trees.

• Fruiting structures like mushrooms and conks indicate advanced decay in wood.

• Fungi reduce the aesthetic beauty of trees with spots, oozing, wilting, and dying foliage.

By removing fungi as soon as it appears, you can limit its damage and effects on your trees.

Natural Methods to Remove Fungus

For minor fungal infections, there are several natural and organic methods you can try to remove fungus from tree bark and foliage:

Vinegar Spray

You can create a highly effective fungicide by combining one tablespoon of vinegar with one gallon of water. The acetic acid in vinegar inhibits fungal growth. Spray infected bark and leaves thoroughly.

Baking Soda Spray

Make this spray by dissolving 1 teaspoon of baking soda into one quart of water. The alkaline baking soda disrupts fungal development. Add a small amount of liquid soap to help the spray stick to the bark.

Milk Spray

This remedy is one of the simplest! Mix 1 part milk with 9 parts water and spray onto affected areas. The proteins in milk are antifungal. Use skim milk which sticks better than whole milk.

Neem Oil

Neem oil comes from the neem tree and has natural antifungal properties. Follow label instructions and spray onto fungus-affected bark and foliage.

These homemade sprays are inexpensive and safe for the environment. Apply them liberally starting at the first sign of fungi. Repeat applications may be needed for severe cases.

Chemical Fungicide Options

For more stubborn fungus, commercial fungicides are stronger and longer-lasting options. Some OTC fungicides for trees include:

• Copper-based fungicides like copper sulfate and Bordeaux mixture

• Chlorothalonil

• Myclobutanil

• Propiconazole

• Tebuconazole

• Mancozeb

Always follow label directions carefully. Avoid treating during hot, sunny weather which can burn leaves. Fungicides work best when applied preventatively before infections start.

Remove Infected Tree Parts

Pruning out infected parts of trees can help stop fungal spread. Disinfect tools between cuts with rubbing alcohol. Remove and destroy affected leaves, shoots, and branches by cutting at least 4-6 inches below signs of infection.

For cankers, prune off outer dead bark to reveal healthy wood underneath. Large dead branches should be removed by an arborist. Preventative pruning opens the canopy for better air circulation.

Rake and Dispose of Fallen Leaves

Rake up and dispose of fallen leaves and other debris around the base of trees. Many fungi overwinter in this debris only to re-infect trees in spring. Never compost infected leaves. Burn or bag and send to landfill instead.

Improve Air Circulation

Proper spacing and pruning creates better air flow which reduces fungal growth. Avoid overcrowding trees and allow sufficient distance between branches. Thin inner branches to open up the canopy.

Water in the Morning

Watering early in the day allows trees to dry out before nighttime when humidity is highest. Wet foliage overnight promotes fungal and bacterial growth. Drip irrigation and soaker hoses are best to keep bark dry.

Use Preventative Fungicides

Applying preventative fungicide sprays when conditions favor fungal growth can stop infections before they start. Treat 2-3 times per season or after major rain events. Organic options like sulfur and Bacillus subtilis are available.

Monitor for Reoccurrence

Keep monitoring your trees for any return of fungi and retreat as needed. Some fungi require multiple applications spaced 7-14 days apart to completely eliminate them. Persistence is key to gaining control over fungal diseases.

With diligence and proper treatment, you can successfully remove fungus from your tree bark. Combining good cultural practices with the timely application of organic sprays or chemical fungicides offers the best protection.

Be sure to properly identify the specific fungus affecting your tree and treat early before it can extensively spread. Severe cases may require intervention by a professional arborist. Removing fungi keeps your trees looking their best and improves their overall health.