Identifying Common Tree Diseases: Symptoms and Solutions

Understanding and identifying the most common ailments trees face will make it easier to manage disease impacts and empower you to take proactive steps. Early detection is the key to preventing future tree failure due to tree disease or insect infestation.

Let’s go over some of the most common tree diseases and how to identify them.

What Is Your Tree Supposed to Look Like?

One of the most vital steps in recognizing if the disease is present is knowing what your tree is supposed to look like. As a responsible homeowner, gardener, or tree enthusiast, it is helpful to research what a tree will look like through different stages of growth and what its expected size and shape will be once it reaches maturation. This information is also essential before you plant new trees, ensuring they have the suitable space and conditions to grow to their full potential.

Before we delve into common tree diseases, let’s first understand what a healthy tree looks like. Good health indicators for deciduous trees include lush leaves that are the appropriate colour for the season. For evergreens, the branches should be full of green needles. The trunk should also be in good condition. The bark on a healthy tree looks consistent without any holes, inclusions, or cracks. Branches should also grow in an even pattern from the tree’s stem.

Have There Been Any Abnormal Changes?

Knowing the factors that point to a healthy tree makes it easier to spot when something is not quite right. If you have noticed any abnormal changes in your tree’s appearance, you should not shrug it off. The typical indicators of disease are generally easy to recognize if you know what to look for.

Common Diseases & Indicators

  • Leaf Rust:

Tree rust is a fungal infection that attacks the leaves on the tree. Orange, gold, or reddish spots appear on the leaves, eventually rupturing the leaf surface. Several fungi lead to leaf rust, though they tend to be species-specific. This means there is little concern that the infection will spread to other tree types in your yard (though it will likely spread between trees of the same species, so treatment should be applied as quickly as possible).

  • Fire Blight:

Fire Blight is caused by a bacterial infection (Erwinia Amylovora). Trees infected with Fire Blight will have drooping branches and sudden withering of leaves and blossoms. Cankers often appear on the trunk, and the bark may look like it has been burnt (hence the name). Fire Blight can be a terminal diagnosis for trees and other plants (especially the Rosaceae family), and Toronto’s warm, humid climate can make it challenging to control. However, early interventions, mainly employed in winter when the bacterium is dormant, have successfully stopped the spread.

  • Dutch Elm Disease:

One of the early indicators of Dutch Elm Disease, or DED, is the wilting, curling, yellowing, and premature falling of leaves on the upper branches of an Elm tree. DED is a fungal disease spread by elm bark beetles and was introduced to North America in the early 1900s. Because the Elms here do not have any natural resistance to the disease, they have been severely impacted. Integrated pest management systems have helped to slow the spread of DED and protect the vulnerable Elm population.

  • Anthracnose:

Anthracnose is another fungal disease that affects trees. This group of fungal diseases causes dry brown or black spots on the edges of leaves. Anthracnose can spread quickly during rainy seasons, so early detection and intervention are essential.

  • Emerald Ash Borer:

The Emerald Ash Borer is an invasive insect species that affects Ash trees. Female beetles lay eggs under the bark of the tree. When the larvae hatch, they feed on the tree and usually overwinter in the prepupae stage. They entirely transform into adult beetles and emerge from the tree in spring. You can recognize the distinctive “D-shaped” holes left behind in the bark from where they exit. Another sign of Emerald Ash Borer infestation includes thinning the leaves at the crown of a tree.

Consult the expert

Remember, it is essential to address any possible infections or infestations immediately. But don’t worry, you’re not alone in this. Waiting too long to apply treatment will likely lead to the continued spread of disease and the eventual death of your trees. Like our team, certified arborists have extensive training in diagnosing tree disease and various treatment options. We’re here to support you in maintaining the health of your trees.

Remember, you play a crucial role in the health of your trees. If you suspect any disease or infestation, don’t hesitate to contact Local Arborist today. Our tree care experts are here to help you protect and preserve your trees!

Local Arborist is a professional tree care company in Toronto specializing in tree disease and pest management. Contact our friendly team today for a free estimate on tree disease treatment.