How do I know if a tree is diseased?

What’s the best way to tell if a tree is diseased? The question may seem like an easy one, but it can be tricky. There are many different types of diseases that affect trees and they each have their own symptoms. In this article we’ll explore some common tree diseases, what causes them, how to identify them and what you can do about them. We’ll also go over ways you can ensure your trees stay healthy!

What is a tree disease and how do they form

A tree disease is a disorder that affects the health of a tree. Diseases can be caused by various things, including pathogens, insects, environmental conditions, or injuries. There are many types of tree diseases, and they can occur at any time during the year.

The most common way for a tree disease to form is when a pathogen infects the tree. Pathogens are tiny organisms that can cause diseases in plants. They can be carried by wind, rain, insects, or animals. Once a pathogen enters a tree, it can spread quickly and cause serious damage.

Insects can also cause tree diseases. Some insects feed on the sap or bark of trees, while others viruses or bacteria into the tree. Insects that feed on a tree often carry diseases from one plant to another.

Environmental conditions also play a role in tree disease. Limited water and nutrients can create stress in the tree, which can make it more likely for a pathogen to infect the tree. Extreme weather such as drought or flooding can lead to tree damage, which allows pathogens or insects an easier entry point into the tree.

Injuries allow pathogens and insects direct access to the inside of the bark and woody tissue of a tree. These injuries come from machines like lawn mowers and weed eaters and animals like rabbits and deer that chew on trees. When you cut or injure a part of a tree, pathogens or insects may enter through these openings and cause dissease.

How to identify tree diseases

One of the easiest ways to identify a tree disease is by checking the leaves. If you see any of the following symptoms, then your tree might be diseased:

– Leaves that are wilting or drooping

– Leaves that are discolored (e.g. brown, yellow, black)

– Leaves that are covered in fungus or mold

– Leaves that are falling off the tree prematurely

– A sudden change in the leaves color, size, shape or number

If you’re still unsure whether a tree is diseased or not, it’s best to look up any information on common diseases for that particular species of tree, and get a second opinion from us, or another local arborist.

Treatments for tree diseases

There are many different treatments for tree diseases. The most important thing is to catch the disease early, before it does too much damage. Some common treatments include:

-Removing the affected part of the tree

-Applying a fungicide or pesticide

-Spraying the tree with water

If you think your tree is diseased, call a professional who can provide further treatment options.

Keeping your trees healthy

Keeping your trees healthy is important for a few reasons:

-A healthy tree can resist disease and pests better than a sick tree

-Trees that are well-maintained look nicer and add value to your property

-Trees provide shade and cooling in the summer, and can help reduce energy costs

To keep your trees healthy, make sure to:

-Water them regularly, especially during hot summers

-Fertilize them at least once a year

-Prune them regularly

-Watch for signs of disease and pests and treat them as soon as possible


A tree disease is a term used to describe any plant disorder that affects the health of trees. Tree diseases can form as a result of environmental factors or through contact with other plants and animals, such as fungi, bacteria, insects and viruses. There are many different types of tree diseases which include: air pollution-induced bronzing (browning) on leaves; wilt caused by fungus gnats; dieback from oak root rot disease; leaf scorch from drought stress in sugar maple trees among others. Keeping your trees healthy starts with planting them properly so they have enough space for their roots to grow deep into the soil without competition from neighboring plants.

You should also keep an eye out for signs of insect infestation – if you see ants, caterpillars or other insects on your tree, you should contact your local nursery to get rid of them. Also, make sure that the trees are exposed enough sunlight – leave around 5-6 feet between each tree to avoid competition for food/sunlight. Tree diseases can be difficult to diagnose without close observation by a professional Arborist. If you think your trees may have a disease, please contact us, and let us take a look at your trees. We’re happy to help!

Learn More

Tree diseases: How to Identify Tree Ailments – Arbor Day Blog

We have forestry consulting services available: Forestry Consulting – Oregon Forestry Consulting