Now that it’s April, experts say don't prune oak trees until after July…if you want to keep them safe from the oak wilt pathogen. Oak wilt is a deadly fungus that gets transmitted through tiny sap beetles.
DNR Forest Health specialist Brian Schwingle says oak wilt works in a similar way as Dutch elm disease, which devastated North American elm populations in the 20th century. Both are fungal diseases spread through beetles. But Schwingle says out of the two, oak wilt is much easier to prevent.
A lethal tree disease has been found for the first time in near Woodruff. Oak wilt is prevalent in southern and central Wisconsin. But tests have confirmed its presence in the Northern Highland American Legion State Forest.
DNR Forest insect and disease Specialist Brian Schwingle says the finding is significant.
“It’s concerning that we found it on our largest state property, the Northern American Legion state forest, where oak is an extremely valuable tree.”