Early Signs of Tree Disease

What to Look For in June and Why Early Diagnosis Matters

Introduction

June is when many tree diseases start to show up—and often go unnoticed until they’ve done significant damage. By spotting issues early, you can intervene before they spread or compromise plant health.

Here are the most common diseases we see in early summer—and what to do if you spot them.

1️⃣ Anthracnose Fungus & Leaf Spot Diseases

These fungal infections thrive in wet spring weather. Look for:

Brown or black blotches on leaves
Leaf curling or premature drop
Widespread thinning of the canopy

Common on: maple, sycamore, dogwood, oak

2️⃣ Fire Blight

A bacterial disease that causes:

Blackened, shriveled branch tips (often “shepherd’s crook” shape)
Cankers oozing sap
Rapid dieback of shoots

Common on: pear, apple, crabapple, hawthorn

3️⃣ Powdery Mildew

This shows up as a white, powdery coating on leaves, often in shady or humid areas. While not usually fatal, it stresses plants and interferes with growth.

Common on: lilac, viburnum, ninebark, dogwood

4️⃣ Why Early Detection Matters

Catching diseases early helps: ✔ Limit spread to nearby trees ✔ Prevent unnecessary decline or defoliation ✔ Guide proper treatment (if needed) ✔ Avoid over-treating or applying the wrong product

We use visual inspection + lab testing if needed to identify problems accurately.