Oak Wilt

Disease

High Threat

Affects: Red oak group (red, pin, scarlet, black - usually fatal). White oak group (white, bur, swamp white - slower, sometimes survivable).

Photo: Robert L. Anderson / USDA Forest Service (CC-BY-3.0-US (Bugwood))

Identification & Biology

Fungal disease (Ceratocystis fagacearum) that clogs water-conducting vessels. Red oaks can die within weeks. Spreads through connected root systems between nearby oaks and via beetles attracted to fresh wounds.

Current Status

Established in NY, PA, NJ. Spreading through root grafts and nitidulid beetles.

States affected:

Connecticut Delaware Maine Maryland Massachusetts New Hampshire New Jersey New York Pennsylvania Rhode Island Vermont Virginia

What Homeowners Should Do

NEVER prune oaks between April and October - beetles carry the fungus to fresh cuts. If an oak shows sudden wilting/browning, get a certified arborist assessment immediately. Root barriers can prevent spread between adjacent trees.