Oak Wilt (Bretziella fagacearum) - Oak wilt is one of the most destructive tree diseases in the United States, and it 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 species of oaks (Quercus spp.) in Central Texas can be infected with the oak wilt fungus. Red oaks (Spanish oak, Shumard oak, blackjack oak) and live oaks are most commonly killed by oak wilt when compared with white oaks (post oak, bur oak, Mexican white oak) which are less commonly killed. However, those white oaks such as shin oak, chinkapin oak and Lacey oak that grow in stands with interconnected root systems also may die in large numbers from oak wilt.