City of Austin Oak Wilt Suppression Program - Information on the deadly oak wilt disease. Fire Blight - Fire blight is a bacterial disease that affects apple trees, pear trees and rosebushes. About several tree diseases that can stunt or injure a tree over time. From University of Illinois Extension. Gypsy Moth - The gypsy moth is a serious threat to trees including maples, oaks and elms.
Caterpillars feed on leaves, weakening the tree.
Oak Wilt - Oak wilt is a devastating fungal disease that attacks red oaks, white oaks and live oaks of North America. Learn how you can identify and control this oak tree disease. Powdery Mildew - Powdery mildew is a fungus that attacks the leaves of various plants including poplar and willow trees and roses. Tent Caterpillars - The Eastern tent caterpillar affects black cherry trees and other fruit and shade trees. The forest tent caterpillar infests hardwood trees such as sugar maple and oak.