Tree diseases and climate stress: What Michigan homeowners need to know

Southeast Michigan’s trees are facing growing threats from disease, pests, and climate change.

Zach Lacombe with Davey Tree Expert Company in Canton, says tree health issues are on the rise, affecting both residential and urban landscapes. Fungal infections, extreme weather, and environmental stressors are making trees more vulnerable than ever.

Common Tree Diseases in Michigan

Local trees are particularly susceptible to three major infections:

• Apple Scab – A fungal disease that weakens apple and crabapple trees, causing leaf loss and reducing their ability to absorb sunlight.
• Oak Wilt – A deadly vascular infection that spreads through beetles and root grafts, cutting off water and nutrients to oak trees.
• Dutch Elm Disease (DED) – A persistent fungal disease that has devastated American elm populations in Michigan for over a century.

“These infections often go unnoticed until it’s too late,” says Lacombe. He says thinning foliage, premature leaf drop, and unusual discoloration can all be warning signs of tree disease. 

Rising temperatures and shifting weather patterns are also increasing the spread of tree pests and diseases, according to Lacombe. 

Milder winters mean fewer insect die-offs, allowing pests like the picnic beetle (which spreads oak wilt) to thrive. Stronger storms and heavy rainfall can cause tree root damage, increased fungal growth, and weakened trees. Road salt runoff forces trees to release moisture from their leaves, leading to drought stress and weakened defenses.

Preventative care and early intervention can go a long way, Lacombe advises.