Some diseases of the live oak tree are leaf blister, oak wilt, anthracnose, tubakia leaf spot, powdery mildew, sooty mold and crown gall. Live oak is frequently affected by leaf blister, a fungal infection that ruins leaves but does no lasting harm to the tree.
Oak wilt is a fungus that can kill infected trees within a year. Tubakia leaf spot causes brown or red spots on leaves, premature dropping of leaves and problems with twigs in severe infections. Lesions may cause leaves to shrivel and may restrict movement of water. Anthracnose causes leaves and shoots to become brown and shriveled, and young leaves become deformed with lesions.
Powdery mildew is a white growth on the top of leaves. The infection does not appear to affect the long-term health of a tree. Sooty mold causes crusty or powdery black growth on stems and leaves. It does not penetrate leaves and does not cause long-term damage. Crown gall causes large lesions on stems and roots. The affliction may kill trees that are under severe stress or have other diseases.
Live oaks are also referred to as evergreen oaks and primarily grow in warmer areas of the United States, including the South, the Gulf Coast and the Southwest. Colder climates can kill the trees.