In 2008 one red oak hybrid (Quercus rubra × ellipsoidalis) was diagnosed with oak wilt disease (Ceratocystis fagacearum) at Starhill Forest Arboretum in Illinois. The tree was removed to below grade and burned to prevent Nitidulid sap beetle vectors from spreading the fungus. The roots were treated with butoxyethyl ester of triclopyr (Garlon-4 herbicide) to try to prevent conduction of the disease to adjacent trees via root grafting.