Oak Wilt

Oak wilt fungus blocks the movement of water and nutrients throughout the tree, causing leaves to wilt and fall off. Red oaks can be killed within a few weeks to six months, whereas white oaks take years to die.

Common Name: Oak Wilt

Scientific Name: Bretziella fagacearum

Native Range: Unknown

map of unknown

Background

Oak wilt symptoms are much more noticeable in red oak species than in white oak species. Symptoms of the disease include brown coloration that starts on the outer leaf edges and progresses toward the center, branch dieback that begins at the top of the tree and progresses downward, and leaves that suddenly wilt and sometimes fall off the tree in spring and/or summer. After the tree dies, fungal spores may develop under the bark. Oak wilt can be spread above ground by beetles or below ground by grafted roots.

Habitat

All oaks are susceptible to oak wilt but species in the red oak group often die much faster than those in the white oak group. Oaks grow under a wide range of conditions, although they do not thrive in the high forests of the Adirondack mountains.

NYS Distribution Map

NOTE: If you receive a “sign in” message, click cancel to continue. Confirmed observations of Water chestnut submitted to the NYS Invasive Species Database. For more information, visit iMapInvasives

Identification

Trees affected by oak wilt display brown coloration that begins on leaf edge and progresses inward. Sudden leaf drop occurs in spring or summer.

  • oak wilt
  • oak wilt
oak wilt

Impact

Oak wilt fungus blocks the movement of water and nutrients throughout the tree, causing leaves to wilt and fall off. Red oaks can be killed within a few weeks to six months, whereas white oaks take years to die. Transmission between red oaks occurs quickly but the disease usually cannot spread between white oaks.

Prevention and Control

To help protect oak trees from oak wilt, it is recommended to avoid pruning or wounding them in spring and summer when spore mats are present and beetles that facilitate spread are most active. Also help prevent spread by not moving firewood and obeying the rule of oak wilt quarantine districts.

Management of trees infected with oak wilt is being conducted by NYSDEC. If you find a tree that shows signs of being affected by oak wilk, please report it to NYSDEC Forest Health at or 1-866-640-0652.

Additional Information