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 Ceratocystis fagacearum, which invades and disables the water-conducting system in susceptible trees.

All oaks (Quercus spp.) are susceptible to oak wilt to some degree, but some species are affected more than others. Red oaks, particularly Spanish oak (Q. buckleyi), Texas red oak (Q. texana), Shumard oak (Q. shumardii), and blackjack oak (Q. marilandica), are extremely susceptible and may play a unique role in the establishment of new oak wilt infections.

White oaks, including post oak (Q. stellata), bur oak (Q. macrocarpa), Mexican white oak (Q. polymorpha), white shin oak (Q. sinuata var. breviloba), Durand oak (Q. sinuata), Lacey oak (Q. laceyi), and chinkapin oak (Q. muehlenbergii), are resistant to the fungus and rarely die from oak wilt

Live oaks (Q. virginiana and Q. fusiformis) 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.

The successful management of oak wilt depends on correct diagnosis and an understanding of how the pathogen spreads between different oak species.