Oak Wilt - What to do

Oak wilt can be transported by several insects, but it isn't the insect that is doing the damage.  Instead, it is simply transporting the fungal spores to other trees.  From there, the fungus can spread through root grafts (tree roots of separate trees that are interconnected).  This is why it is not uncommon to see trees infected in groups.  The two major groups of oaks are red and white.  Red oaks form the fungal mat (pictured above), which insects are attracted to, feed on, and pick up the fungal spores.  They then go to other oaks spreading the infection.  Red oaks can die very quickly once infected often within weeks of infection.  White oaks do not form the fungal mat, allowing them to survive longer.  This has given the misperception that white oaks are resistant to this disease, they are not.  Symptoms on white oaks include large portions of the trees dying without notice, eventually the entire tree will succumb to the fungal disease.

Symptoms of oak wilt include: wilting of leaves (hence the name), leaves turning fall colors unseasonably, half dead leaves with a distinct line between live and dead, and die back in the canopy.  Red oaks may also show signs of the fungal mat, typically this is found underneath loose bark.  

The best action is to be proactive.  Prevention is far more effective than therapeutic treatment.  The treatment consists of a fungicide injected into the tree.  Healthy trees will uptake and spread the fungicide far better than infected trees.  Once symptoms show, the likelihood of successful treatment diminishes rapidly.  If you have oak trees that you cherish or don't want to pay the high cost of removal, it is best to act sooner than later.   

The Green Advantage's ISA certified arborists can help with this and all ornamental diseases.  We are here to answer your questions, find solutions, and make honest assessments on how to move forward.  We look forward to hearing from you.