Oak trees are a defining feature of the Michigan landscape. Unfortunately, a devastating fungal disease known as Oak Wilt (Bretziella fagacearum) poses a serious threat. Once established in an area, this disease can wipe out entire stands of oak, particularly the highly susceptible **Red Oak** varieties, in a single season.
Understanding the Risk: How Oak Wilt Spreads
Oak Wilt spreads primarily in two ways, both of which we work to manage here in Livingston and Oakland Counties:
1. Above Ground: Picnic Beetles (Sap Feeders)
The fungus produces spores under the bark of an infected tree. These spores emit a sweet smell that attracts small insects known as Picnic Beetles. When these beetles feed on an infected tree and then fly to an uninfected tree that has a fresh wound, they can transmit the spores directly into the tree's vascular system.
🚫 Key Prevention Rule: DO NOT PRUNE OAKS DURING RISK SEASON
The absolute most critical action homeowners can take is to avoid pruning or wounding any oak tree between April 15th and July 15th. This is the time when the Picnic Beetles are most active, and the fresh cuts are like an open invitation for the fungus.
2. Below Ground: Root Grafts
In neighborhoods and forested areas, the roots of neighboring oak trees often grow together, forming **root grafts**. If one oak tree becomes infected, the fungus can travel through these connected roots and infect the adjacent trees, leading to a cluster of dead or dying oaks.
Our Top 3 Prevention Strategies
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Time Your Pruning Carefully
Always schedule trimming and pruning work for the dormant season (late fall through winter). If a tree sustains damage during the active season, we immediately treat the wound with a commercial tree wound dressing to create a physical barrier against the beetles.
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Root Barrier Management
In cases where Oak Wilt is confirmed nearby, we can help break the underground root connections between healthy and infected trees using trenching or deep vertical vibratory plowing to prevent spread through the soil.
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Fungicide Treatment (High-Value Trees)
For high-value, uninfected oak trees (especially Red Oaks) that are near confirmed wilt cases, a **systemic preventative fungicide injection** is the only reliable option. This treatment, applied by a Certified Arborist, provides protection against the fungus for up to two years.
If you suspect your tree has Oak Wilt (look for rapid browning of leaves from the top down), contact us immediately. Early diagnosis is essential.