Prevent oak wilt by waiting to prune oaks
To minimize oak wilt infection risk, wait until November to prune oaks.
April 13, 2012 - Author: Jan Byrne, MSU Diagnostic Services, Department of Plant Pathology
Oak wilt, caused by a fungal pathogen, Ceratocystis fagacearum, is present in Michigan. Impacts of this disease can be devastating, causing rather rapid death of large oak trees in landscapes and natural areas. One of the most effective ways to prevent infection of healthy trees is proper timing of any oak pruning. The months of April, May, and June are considered the months with the highest risk for above ground oak wilt infection. As a result, oaks should not be pruned at this time.
The months of November to March are the safest time to prune oaks, when there is no to extremely little risk of oak wilt infection.
For more information on pruning and associated oak wilt risks, visit the following University of Minnesota websites: