Trees are some of the most valuable features in a landscape. They provide shade, beauty, privacy, and environmental benefits—but like any living thing, they can become sick. Recognizing the signs of tree diseases early on can help you take action before serious damage occurs. Left untreated, diseases can weaken or kill even the strongest trees, leading to safety hazards and costly removals.
Diagnosing and understanding common tree diseases, their symptoms, and available treatments can help you keep your trees healthy and thriving.
Common Tree Diseases
While many diseases can affect trees, here are five of the most common seen in Ontario:
- Dutch Elm Disease
This fungal disease spreads through bark beetles and root grafts, causing wilting, yellowing leaves, and eventual branch dieback. - Cedar Apple Rust
Affecting both cedar and apple trees, this fungal disease causes bright orange spots on leaves and can lead to premature leaf drop. - Anthracnose
Affects many hardwood species, including maple, ash, and oak. It causes irregular brown spots and curled, dying leaves in spring and summer. - Fire Blight
Common in apple and pear trees, this bacterial disease causes a scorched appearance—blackened leaves and shoots that look like they were burned. - Tar Spot
Often seen on maple trees, this fungal disease creates raised, black spots on leaves. While not usually fatal, it can weaken trees over time.
Signs of Tree Diseases
Identifying early tree disease symptoms is key to preventing serious damage. Here are some red flags to watch for:
- Discoloured, spotted, or wilting leaves
- Early leaf drop
- Cracked, peeling, or oozing bark
- Cankers or dead patches on branches
- Stunted growth or dieback of limbs
- Mushrooms or fungal growth at the base of the trunk
- Black or tar-like spots on leaves
If you notice one or more of these symptoms, your tree could be fighting off a disease.
What You Can Do About Tree Diseases
When it comes to tree disease treatment, timing and proper care are essential. Here’s what you can do:
- Remove and dispose of affected limbs to prevent spread.
- Improve airflow by thinning dense branches.
- Keep the area clean by removing fallen leaves or debris that may harbor fungi or bacteria.
- Avoid overwatering or damaging roots, which can make trees more susceptible to infection.
- Apply fungicides or treatments if appropriate—but only with proper diagnosis.
Because misidentifying a disease can lead to ineffective treatment, consulting a professional is the safest option.
Get Professional Tree Care Help
Diagnosing and treating tree diseases isn’t always straightforward. A certified arborist can assess your tree’s health, recommend the right treatment plan, and help you prevent future issues.
At Baum Tree Care, we specialize in identifying and treating common tree diseases in Ontario. If you’ve noticed any troubling signs of tree diseases, don’t wait—contact us today for a professional evaluation and customized care plan.