Identification and Control of Oak Wilt in Texas Urban Forests
David N. Appel
Abstract: Oak wilt, caused by Ceratocystis fagacearum, annually causes losses of epidemic proportions in towns and cities throughout central Texas. Live oaks (Quercus fusiformis and Q. virginiana) are the most seriously affected Quercus spp. because of their prevalence and subsequent high values. Oak wilt epidemiology is influenced by host characteristics, climate, and reproductive traits of the pathogen. These factors have been studied to develop the key elements of a comprehensive, integrated oak wilt management program. Under most conditions, this program can be used in Texas to successfully minimize losses. The program relies on disruption of root connections, intravascular injection with propiconazole, proper pruning and wound treatments (including dressings), and various sanitation practices. Preventative measures are the most effective means of reducing losses, making prompt, reliable diagnoses of new oak wilt infection foci essential. A five step protocol is recommended to distinguish oak wilt in live oak from other diseases in Texas and facilitate disease control. Cooperation among federal, state, and local agencies working with commercial arborists has had a dramatic impact on public understanding of oak wilt and resulted in significantly controlling the disease.