Oak Wilt: A Threat to Our Trees
Oak Wilt is a destructive fungal disease endangering oak trees across Wisconsin, including our local area. Found in 66 of the state’s 72 counties, this disease spreads rapidly through multiple pathways.
How Oak Wilt Spreads
- Insect Transmission: Oak bark and sap beetles carry fungal spores, infecting healthy trees.
- Root Grafts: Roots of closely growing trees can fuse, allowing the disease to spread underground, especially among Red Oaks.
- Contaminated Tools: Pruning tools used on infected trees can transfer the disease to healthy ones.
Symptoms of Oak Wilt
- Leaf Discoloration: Leaves on one side of the tree may turn brown, bronze, or yellow.
- Bark Cracking: Cracks may develop where branches meet the trunk or at the tree’s base.
- Leaf Wilting and Drop: Leaves curl, wilt, and may completely fall off by mid-summer.
- Rapid Decline: Red Oaks are particularly vulnerable, often dying within a month of infection.
Controlling and Preventing Oak Wilt
- White Oak Resistance: White Oaks are more resilient and may survive infection.
- Pruning Restrictions: Avoid pruning oaks from April to July, when they are most susceptible.
- Address Storm Damage Promptly: Treat wounds immediately after storms and apply pruning seal to minimize infection risk.
- Tool Decontamination: Clean pruning tools with alcohol or disinfectant between trees.
- Tree Removal: Infected trees must be promptly removed and not used as firewood.
- Fungicide Injections: Preventative trunk injections with fungicide can protect trees for about two years, offering long-term benefits.
Concerned about your oak tree?
Our certified arborists and technicians are here to help. We provide expert pruning, removal, and preventative treatments to ensure your tree thrives for years to come.