What is oak wilt?
Oak wilt is a fungal disease caused by Ceratocystis fagacearum that kills live oaks and red oaks in Central Texas through root graft connections and beetle transmission.
A fungal pathogen called Ceratocystis fagacearum causes oak wilt, a disease that kills live oaks and red oaks across Central Texas. The fungus disrupts water and nutrient transport in the tree, causing wilting, leaf discoloration, and death, often within one to two seasons for red oaks and somewhat longer for live oaks.
The disease spreads in two main ways. Root grafts connect neighboring oaks underground, allowing the fungus to move from an infected tree to healthy ones, which is why wilt often appears in clusters. Beetles, particularly the oak bark beetle, can carry spores on their bodies and introduce infection when they feed on or breed in trees during spring and early summer.
In the Hill Country and surrounding areas, oak wilt represents a serious threat to the native and established oak population. Once established in a tree, the infection is difficult to arrest, and infected oaks typically cannot recover. Property owners and tree service providers in Austin monitor for symptoms including brown discoloration on leaves, premature leaf drop, and branches dying back from the crown. Managing spread often requires removing infected trees promptly and cutting or treating root connections to adjacent oaks to prevent fungal transfer underground.