Before You Prune That Oak Tree…

Oak wilt can kill some oaks within weeks

Keep oak trees healthy by helping prevent oak wilt disease

During the period between April 15 and July 15, beetles actively carry spores of fungus from tree to tree, meaning oak trees are at high risk for infection with oak wilt. Oak trees with wounds in their bark are susceptible to the disease, which can weaken white oaks and kill red oaks within a few weeks.
“Oak trees should not be pruned between April 15 and July 15. These pruning guidelines can help keep infection from spreading,” said Simeon Wright, forest health specialist in the DNR’s Forest Resources Division. “Once a tree is infected there is no cure. Without expensive treatments the disease spreads to other trees and may in time kill all nearby oaks.”
If you have an oak tree that gets damaged during the high-risk period from April 15 to July 15, immediately cover all wounds with tree-wound paint or latex-based paint. Painting tree wounds is not recommended for other trees species as it can reduce the effectiveness of the healing process.
Besides being carried by the nitidulid beetle, which is active in spring and early summer, oak wilt also can spread from tree to tree through roots that are grafted, or grown together underground. Spores also can be carried long distances to living trees when you move firewood cut from an infected tree and beetles pick up the spores.