Oak Wilt
Bretziella fagacearum (formerly Ceratocystis fagacearum)
Overview
A lethal fungal disease of oaks, particularly devastating to red oak species which can die within weeks of infection. Spread by sap-feeding beetles and through interconnected root systems.
Symptoms
Red oaks: rapid wilting and browning of leaves from the outer edges inward, starting at the top of the crown. Defoliation and death within 4-6 weeks. White oaks: slower decline over several years with branch dieback.
Environmental Conditions
Variable
Prevention
Do not prune oaks from April through July (beetle activity period). Paint wounds immediately if pruning is necessary. Disrupt root connections between trees with trenching. Remove infected trees promptly.
Management
Propiconazole injection can protect high-value trees. Trench to sever root grafts (at least 100 feet beyond symptomatic trees). Remove and destroy infected red oaks. Debark and chip wood.