The best way to prevent the spread of oak wilt is to not prune any oak tree during the growing season.

“It’s best to wait until after Oct. 15 to start pruning oak trees,” says Tivon Feeley, with the Iowa DNR’s forest health program. “You can prune your oaks all winter long with the goal to stop pruning by March 1.”

Oak wilt, caused by a fungus, has been present in Iowa for many years. Iowa’s red, black, and pin oak are more susceptible to oak wilt, but it can also infect white and bur oak. Black, pin, or red oak usually die within the same summer they are infected. White oak and bur oak can often take a number of years before they succumb to this disease.

Oak wilt can spread from infected trees to healthy trees in two ways: a small beetle that carries spores of the fungus from a disease

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