How Arborists Treat Leaf Fungus: Step-By-Step Guide

 

When trees get leaf fungus—a disease caused by different kinds of fungi—arborists (tree experts) use a mix of approaches to treat it and prevent damage from spreading. The goal is to protect the tree's health and stop the fungus from returning. Treatment depends on the type of fungus, how bad the infection is, and the kind of tree. Here’s how professional arborists usually handle it:

 

Understanding Leaf Fungus

 

Before acting, arborists identify the problem. Leaf fungus shows up as spots, bumps, weird colors, or powdery coatings on leaves. These symptoms can be caused by many fungi, like powdery mildew, anthracnose, or leaf spot. Identifying the specific fungus helps choose the right solution.

 

Removing and Disposing of Infected Material

 

One of the first steps is to carefully remove any infected leaves, twigs, or even branches. This removal, called "sanitation," helps prevent the fungus from spreading further.

• Arborists use sharp, clean pruning tools to cut off affected areas.
• All fallen leaves and debris around and under the tree are gathered and thrown away in waste bags (not composted), because composting can allow the fungus to survive and reinfect plants later.
• Tools are cleaned with alcohol or a special cleaner between cuts, to avoid spreading the fungus.

 

Improving Airflow and Sunlight

 

Fungi thrive in damp, shady conditions. Professional arborists often thin out crowded branches to let air and sun in, helping leaves dry quickly after rain or dew.

• Selective pruning reduces dense spots so sunlight reaches more of the tree.
• This also lowers humidity, making conditions less inviting for fungi.
• Cleaning up around the tree—removing weeds and tall grass—helps with airflow, too.

 

Cutting Back on Water on the Leaves

 

Excess water on leaves makes fungus worse. Arborists may recommend watering the base of the tree instead of the leaves. This is called "soil-level watering" and is one of the simplest changes a homeowner can make.

• Water in the early morning to allow leaves to dry quickly.
• Avoid using sprinklers that spray the leaves.

 

Applying Fungicides When Needed

 

If the disease is severe or keeps coming back, arborists might use fungicides (chemical treatments that kill or stop fungi). These are selected carefully, as not all fungicides work for every fungus.

• Spraying is timed to hit the window when new leaves are most vulnerable, such as right after buds open in the spring.
• Arborists use professional-grade products and apply them safely to avoid harming the tree or nearby plants.
• Multiple applications may be needed during bad outbreaks or when rain washes the product off.
• Homeowners should avoid doing this on their own, since using the wrong type, dose, or timing can harm trees, wildlife, or people.

 

Fertilizing and General Tree Health

 

Stressed trees are more likely to get sick. Part of fungal treatment is making sure the tree stays healthy overall.

• Arborists might suggest fertilizing the tree if the soil is lacking nutrients.
• They also look for, and address, other problems—like root damage, pests, or drought—that can weaken the tree’s natural defenses.
• Healthy trees are better at resisting the return of fungal diseases.

 

Prevention and Maintenance

 

Even after treating the current infection, arborists work on preventing leaf fungus from coming back.

• Annual inspections for early signs of disease.
• Regular cleanup of fallen leaves and debris, especially in the fall.
• Ongoing pruning for good airflow and sun exposure.

 

When to Call a Professional

 

Not all leaf fungus problems can be fixed by simple actions. If the tree is large, old, valuable, or the fungus keeps returning despite your best efforts, always contact a certified arborist. They have special training and equipment to handle the problem safely and effectively.

 

In summary, arborists treat leaf fungus by properly identifying the fungus, removing infected parts, keeping the tree’s surroundings clean, improving air and light, watering carefully, applying fungicides when necessary, supporting overall tree health, and maintaining good practices for the future. This thorough, step-by-step approach helps trees recover and stay healthy over the long term.