Not a sexy topic even for gardening, but Oak Wilt is a really lousy fungi that destroys these beautiful trees. Oak will has traveled further north, for the first time showing up in Crow Wing County, Minnesota. Wisconsin also has the disease. Oak wilt is caused by a fungus that deprives the tree of water. The fungus isn’t visible, but the symptoms are obvious: the tree’s leaves wilt from lack of water and die. Learn about the disease, "possible" treatments and WHO should do those treatments.