Oak wilt, one of the most destructive tree diseases in the United States, is killing oak trees in central Texas at epidemic proportions. Oak wilt is an infectious disease caused by the fungus Bretziella fagacearum, which invades and disables the water-conducting system in susceptible trees. All oaks are susceptible to oak wilt to some degree, but some species are affected more than others. The successful management of oak wilt depends on correct diagnosis and an understanding of how the pathogen spreads between different oak species.
White oaks include post oak, bur oak, Mexican white oak, white shin oak, Durand oak, Lacey oak, and chinquapin oak. Although white oaks show some tolerance of the disease, all oaks are susceptible to the fungus.
Live oaks and Texas live oaks are intermediate in susceptibility to oak wilt, but are most seriously affected due to their tendency to grow from root sprouts and form vast interconnected root systems that allow movement (or spread) of the fungus between adjacent trees.