Oak wilt, a devastating disease that attacks and kills both Read and Live Oaks has been diagnosed in Bent Tree North.   Oak wilt is a fungal disease that has killed thousands of oaks in over 100 counties in Texas, and literally left some neighborhoods tree-less in Austin. This impacts the value of our property.
Oak Leaves Infected with Oak Wilt
The disease is actually a fungus that invades and causes the plugging of the water conducting tissues of oaks, and causes almost certain death.   It attacks and kills healthy, mature live and red oaks, just as easily as it kills stressed ones. 
Oak wilt is initially introduced into an area, by the trimming of trees at the wrong time of the year.  Tree sap from fresh wounds attract sap-feeding beetles carrying the oak wilt spores. When these spores are introduced to the wound, a new oak wilt infection is created.   Once a tree is infected, the disease then spreads to nearby trees through the root systems.  This is how whole neighborhoods of oaks have been killed throughout Austin.   Nearby there are large outbreaks in the Prestonwood area and Bent Tree Country Club.
Live Oak Leaves Infected with Oak Wilt
Symptoms are most often typically seen in leaf patterns during the summer and fall.  Leaves on diseased live oaks often develop chlorotic (yellow) veins that eventually turn brown.  Defoliation may be rapid, and dead leaves with brown veins often can be found under the tree for months after defoliation. Leaves may exhibit other patterns of chlorosis and necrosis, marginal scorch, or tip burn. 
Most live oaks defoliate and die over a 1- to 6-month period following initial appearance of symptoms. Some live oaks take longer to die, and a few untreated trees may survive many years in various stages of decline.
Red oaks seldom survive oak wilt and often die within 3 to 4 weeks following the initial appearance of symptoms. During summer months, diseased red oaks often can be spotted from a distance because of their bright autumn-like coloration in contrast to the surrounding greenery.
Oak wilt is best prevented, by using a certified arborist not your lawn care provider who will
1) NOT prune or wound oaks from February through July in Texas.  Wait until the heat of the summer or the cold of the winter. 
2) immediately paint cuts or wounds on oaks, regardless of season. This is critical.
3) remove oaks killed by the disease should be removed immediately, as the pathogen often survives in the dead tree.
If a live oak gets the disease in the early phases of the infection, it can be saved through injections of the fungicide propiconazole (AlamoTM) into the trunks of the tree.  Red oaks almost never can be saved.    This fungicide can also be used to help prevent the disease, however, cost for treatment in both situations in not inexpensive. 
Oak Wilt has been diagnosed on several of our streets in Bent Tree North, mainly Phase 1 and 2 where our most mature oaks reside.  The critical areas, are River Hill, the middle area of Harbor Town, Tamaron Drive and Tamaron Court.   Additionally, we have a long stand of Red Oaks along Spyglass that is critical.   Many BTN residents routinely treat their oaks with the preventative level of Alamo, which needs to be done every 20 months.   
Treatment is complex. Propiconazole is the only fungicide scientifically tested and proven effective.  It is injected into tree’s roots over a period of 20-36 hours allowing the tree to uptake the chemical. Additionally, if the infected tree is close to the oaks of the white oak family, trenching around the affected tree may need to be done to eliminate the spread.  
Treatment is typically performed by trained certified arborists.  Also, recently a few on-line DYI sources have begun offering both the fungicide and also the application equipment.  Texas A&M Extension Service has also released several videos on Youtube providing guidance.
For much more detailed information, on Oak Wilt, please CLICK HERE.
Our trees are a very important component of making Bent Tree North the beautiful neighborhood it is and retaining our property value.  Let's all do our part in keeping them healthy!