Oak Wilt is a fungal disease that clogs the vessels inside the cambium layer of a tree. This blocks the water ways of the tree resulting in wilted leaves and soon after death. It can attack and kill trees very quickly, within weeks even. It mostly affects the red oak group; white oak seems to be semi resistant and can fight against it. It spreads by sap sucking beetles called Nitudulid which carry the spores from an infected tree to a healthy (but freshly pruned or injured tree). Another way the disease spreads is through the root system. Oaks root graft underneath and can then infect each other.
Precautions
April 15th-July 15th DO NOT prune, injure, or cut your oaks. This is a critical period set where the sap beetles are alive and cycling through the oaks looking for sap. If Injury does occur from storm or by accident IMMEDIATELY treat with a dressing or tree paint.
Do Not Move FireWood! Spores can be moved from one area to another though firewood
Chemical Treatments can be applied. Alamo is a preventative treatment for oaks. It can be costly and is not 100% proven but can help to save some valuable trees.
Control
Control is on a site to site basis because of its complexity of 2 ways to transfer the disease (overland and root grafts)
Trenching around the tree (based on math) can be done to break up the grafts and spread. Trenching should be 5 feet down.
Fall- removed all confirmed oak wilt trees by cutting them, taking out the stump and flipping it or burning it all. All tree parts need to be disposed of, branches, trunk, stump and roots.
Burn, chip or tarp it.
DO NOT PRUNE APRIL 1st - JULY 15th DO NOT MOVE FIREWOOD
Oak Wilt can be confused for many other diseases that affect our Oaks. It is best to consult a local arborist, Conservation District Forester, or other tree companies before assuming it is Oak Wilt. We have Oak Decline, Anthracnose of oaks, Leaf Scorch, and Two-Lined Chestnut Borer. Call your Forester, Joe, at (989) 539-6401 if you suspect this on your property.
First two photos are "flagging" trees. They are showing a very common symptom of oak with (but also that of oak decline). The leaves are wilting and falling. Second two photos are examples of pressure pads that form the following spring. If not cut down after the tree "flags" it then produces these pads that are the spores that are the cause in overland spread of the disease. The beetles smell these pressure pads, get in the bark and then go to a healthy tree. Fourth photo is a branch section and the outer ring where the fresh cambium layer (living tissue) is a black ring where the fungus has clogged the vessels. Last Photo is a large oak wilt pocket- all dead, oak wilt is not biased it will kill all red oaks- weak, strong, young, old, large, small- takes them all .
