Protect Your Trees from Oak Wilt
All oak trees are susceptible to Oak Wilt. Oaks in the Red Oak family are very susceptible, and once infected, these trees will die in a matter of weeks. Symptoms come suddenly (usually in July) and once the tree is infected it is too late to be treated.
White oaks, on the other hand, are more resilient. When diagnosed early, these trees can be treated, and the disease progression managed.
Oak Wilt is a disease that grows in the water conduction vessels of the tree. The trees respond to this infection by plugging the vessels, preventing water from reaching the trees canopy. This is a process which is part of a trees defense mechanism. Some trees like the White Oak family are very efficient at compartmentalizing the infection, thus their resilience. Red oak, on the other hand are very poor compartmentalizers, thus the infection rapidly spreads throughout the tree, killing it in a matter of weeks.
Oak Wilt is spread from Oak tree to Oak tree in two ways through grafted roots of susceptible trees growing in close proximity of one another, and over-land, by a small beetle. Over-land transmission of Oak Wilt, by the beetle, can largely be prevented!
When an Oak tree is wounded, it will leak sap on the surface of the wound. This, in turn, will attract a small beetle, commonly called a pick-nick beetle. If this beetle was feeding on an infected Oak, it can then infect the wound of another susceptible oak that it chooses to feed on.
Oak wilt can largely be prevented and or managed. Avoid pruning or otherwise wounding susceptible oaks during the months of April through September when the Pick-Nick beetle is active. If a wound occurs naturally or is unavoidable, the wound should be treated immediately by spraying the wound with aerosol tree wound paint. Tree wounds can be infected for up to several days after a wound occurs.
Within the Red Oak family, symptoms of Oak Wilt will come on suddenly, usually in early July. The foliage will begin to wilt and turn a dull olive green with browning of the leaf margins. Leaves will begin falling from the tree covering the ground beneath. Within weeks, the tree will have completely defoliated and died. This catches most homeowners off guard.
If Oak Wilt is detected in your area, treatment options are available.
Again! The over-land spread of Oak Wilt can be prevented! Avoid creating wounds on susceptible species of oaks trees. Even properly placed and made pruning cuts are considered wounds!
There is much more information concerning Oak Wilt and its management not covered here.
This paper is to highlight Oak Wilt and its possible prevention within the Red Oak family.
Consult an ISA Certified Arborist with your questions and concerns if needed. To find a Certified Arborist in your area, go to Treesaregood.org.