Oak wilt, a fatal fungal disease of native and non-native oaks, is the most serious threat to oak trees in North America. It is spreading throughout the country. All types of oaks, even hickory trees, can be infected by oak wilt.
White oaks can die within weeks. Red oaks can die within months. Oak wilt fungus grows within tree roots and moves up into stems and branches via water-conducting vessels in the sapwood (plant tissue where food is transported).
Fungus growth eventually clogs these conducting vessels and prevents water movement, resulting in wilting of foliage above the infected area and death of the tree. The disease causes leaves to brown and die, branches to drop prematurely or break completely off the tree and root rot that can girdle an infected tree’s trunk.
The first symptoms of oak wilt include chlorosis (yellowing) of leaves which is typically followed by browning or blackening of leaf margins, especially on new spring growth. Other symptoms include stem discoloration and bark cracking as well as death to crowns above ground level.
The fungus is carried by beetles that feed on fungal mats produced on the trunks of oak wilt center trees or recently cut oak firewood during spring or early summer. Infected beetles carry spores to fresh wounds on other nearby healthy oak trees and spread infection there.
If you see signs of oak wilt in your area, contact Joe McIlvaine Tree and Lawn service at 215-322-8394 and a certified arborist can consult.
PHOTO CAP: Oak wilt can fatally damage oak trees. Look for common symptoms.