One simple measure that can help prevent the spread of oak wilt is to not prune any oaks during the growing season. This will prevent fresh wounds that draw in sap beetles that may be carrying the oak wilt fungus.
Cutting down a tree with oak wilt that is still partially alive can cause the disease to spread, but removing it during the least vulnerable months can prevent this.
Preventing New Infection Centers
Once an oak tree becomes infected with oak wilt, there is no known chemical treatment that is capable of “curing” the disease; however, fungicide research is continuing.
Tree Injection With Systemic Fungicide: Trees within the buffer zone can be treated with a systemic fungicide (See Photo). Alamo is the product labeled for use in the control of oak wilt. It is applied by injecting the fungicide into the root flares. Alamo is most effective when applied as a preventive treatment.
Trees in the red oak group generally die rapidly, usually within weeks or months after infection. Treatment will not save an infected red oak. Trees in the White oak subgenus, such as Burr oak and Chinkapin oak, can generally be treated for oak wilt and will recover within a year of treatment.
Biology & Symptoms:
Trees in this group completely defoliate and die within three to six weeks after initial wilt symptoms occur. Some oaks, including live oaks, develop brown veins in their leaves, although green tissue remains. Early symptoms are wilting, bronzing, and shedding of leaves at the ends of branches.
It may be burned up or taken to an approved yard waste facility.
Propiconazole is the only fungicide scientifically tested and proven effective (when properly applied prior to infection) for use as a preventative treatment to protect live oaks.
How much does treatment cost? Fungicide treatments are based on the diameter of the tree and therefore vary quite a bit. The average tree costs about $250 to treat once. However, there are discounts available for larger projects.
Finally, I'd like to note that chainsaws do not transfer oak wilt and are self-sterilizing on account of the operating temperature exceeding the temperature that the fungus can live in.
Maintenance pruning your oak trees should be done between November 1 and March 31. This is the SAFE period to prune them. It is recommended to avoid pruning any oak trees throughout the growing season which is April 1 - November 1.
If there is concern that a red oak may have been infected with oak wilt, then its wood should be immediately burned, buried, or chipped. Fire will kill oak wilt, and there is no risk of spores being transported by smoke.
Pruning between April 15 and July 15 should be strictly avoided because this is when beetle activity and viable spores are most prevalent across the landscape. If pruning an oak is absolutely necessary during this time, wounds should be immediately sealed with pruning sealer or water-based paint to prevent infection.
(Note: Burning firewood with oak wilt spores does not spread the fungus! Fungal spores burn, too. The risk comes from transporting infected firewood and storing it where the spores can be picked up by beetles and carried out to infect nearby healthy oaks.)
If you decide to cut the root and separate it from the tree you can apply glyphosate brush killer to the root section separated from the tree to kill that section.
Once an Oak has Oak Wilt there is no cure, no matter what anyone tells you. You may be able to slow the decline down for a bit by treating it with the fungicide Propiconazole but eventually the tree will succumb to the fungus. Propiconazole is a very strong fungicide and is used more as a preventative than a treatment.
To stop the spread of oak wilt through the root system, trenches can be placed around a group of trees, at least 100 feet away from the dripline of infected trees and at least four feet deep, or deeper, to sever all root connections.
Once an oak tree is infected with the oak wilt fungus, the tree will die and there is no treatment to save the tree. When an oak wilt infection is confirmed treatment can be applied to the surrounding trees to prevent the spread of this disease.
Live oak trees infected with oak wilt usually die within two to four months.
Since your trees are already dead, the curing process will have already started, and the wood should be dry enough to burn in a shorter time period. Hardwoods like oak will burn better if seasoned for more than a year.
Saving a dying oak tree requires a combination of knowledge, dedication, and professional support. By recognizing the signs of decline, identifying the underlying causes, and implementing targeted treatments, you can give your oak tree the best chance at recovery.
While the best time for tree treatment may be in the spring after the new leaves have set, successful treatments can be made at any time that there are sufficient green leaves on the tree to be treated. We've found that if the Oak Wilt threat is imminent, a treatment should happen soon to avoid major damage.
Re-fertilize all around the tree, especially the ground directly underneath the branches, to support those stressed roots. Next, apply fresh mulch in a donut shape around the base of the tree about one foot in distance away from it. This helps to prevent new diseases from taking advantage of weakened trees.
Disease Characteristics
Oak wilt is identifiable by the rapid pattern of wilting starting from the top of the tree and progressively dying down to the bottom, and on specific leaves, wilting from the edges to the base.