Breeds of Oak Trees Resistant to Oak Wilt

Oak wilt kills thousands of oak trees each year.

Oak wilt is a serious fungal disease, caused by Ceratocystis fagacearum, that kills thousands of oak trees each year. According to the United States Department of Agriculture, all species in the white oak group are moderately resistant to oak wilt.

Resistance

Resistance means that the disease affects fewer trees and spreads slower. The United States Department of Agriculture notes that even though white oak trees are resistant to oak wilt, if the trees become infected, they often die within a few years.

Reason

The reason for the white oak's resistance is at least partly because the white oaks form tiny plugs, called tyloses, in their sapwood vessels when the tree is wounded or infected or as part of the natural aging process. These plugs prevent water from penetrating the wood and also appear to prevent the fungus from moving through the vascular system of the tree.

Prevention

To help prevent oak wilt, remove any infected trees immediately and avoid injuring healthy trees. Do not prune the trees during the summer, when the fungus is most active. Open wounds and other damage to oaks offer an easy route for fungal infection.

References

• United States Department of Agriculture: How to Identify, Prevent, and Control Oak Wilt
• Plant Answers: Live Oak Tree Problems And Solutions