Oak Wilt Treatment

How to Identify, Prevent and Provide Treatment for Oak Wilt fungus:

Before we can talk about the effective treatments for oak wilt fungus, we need to discuss what the disease is and how it is spread.  Once you have a full understanding, it will be much easier for you not only to care for your trees but to make sure you are not spreading the disease on your property.    

Oak wilt is a vascular disease caused by a fungus called, ceratocystis fagacearum that spreads locally from infected trees to nearby healthy trees and can cause the death of the trees relatively in a very short period of time, within a few months to one year. 

Primarily transmitted through root grafts, it causes sudden wilting within the oak tree species (especially in the red oak group), and leaf symptoms include; early leaf drop, discolored or browning leaves, defoliation, and sometimes, vascular streaking in the sapwood.

Oak wilt affects the red oak group (red, black, and pin oaks) as well as live oaks. The white oaks is less severely affected than any of the other oak species.   As the disease progresses, limbs will die off. Fungal mats may develop under the bark, pushing the bark out and causing cracks in the wood.

The disease is also called oak blight fungus.  It is important that we keep our trees healthy, not only for our curb appeal, but also for the wildlife like the birds, squirrels, and insects that enjoy the acorns of these trees in nature.

What Does it Look Like?

Oak wilt can be difficult to identify because it shares many symptoms with other problems and diseases, such as drought stress or nutrient deficiency in oaks. However, there are some distinctive signs of oak wilt that can help you to diagnose the problem.

One of the most obvious is the sudden wilting of leaves, which usually happens within a few days of infection. Oak wilt can also cause the leaves to turn brown or red, and they may drop off the tree prematurely. If you see these oak wilt symptoms on an oak tree, it’s important to contact a certified arborist for diagnosis and treatment. Early detection is crucial for preventing the spread of this devastating disease.

It is easy to confuse this disease with bur oak blight because they look very similar. Bur oak blight is a fungal disease that started popping up in the Midwest in the 1990s. In late summer and early fall, the petioles (the stalk that joins the leaf to the stem) develop black pimples, which contain fungal spores that can be seen upon close inspection. It’s the presence of these black spots that will help you confirm your tree has bur oak blight. It’s easier to spot when the sunlight is shining on the trees and can sometimes be seen in the forest. 

Anthracnose is another common fungal disease often confused with oak wilt but affects shade trees that result in leaf spots, cupping or curling of leaves and early leaf drop.  Because oak wilt can resemble many other tree features, seeking laboratory confirmation is important. For laboratory confirmation of this disease, send samples of a cross section  1/2”-diameter branches that show symptoms, but are still green. Take the branches from an area near the wilting portion of the canopy. 

How does oak wilt spread?

Oak wilt beetles are a serious threat to oak trees. These destructive insects burrow into the bark of oak trees, causing them to wilt and die. Unfortunately, oak wilt beetles are very difficult to control once they become established in an area. They can quickly spread from tree to tree, devastating entire populations of oak trees.

The best way to prevent oak wilt beetles from damaging oak trees is to avoid transporting them. If you suspect that oak beetles are present in an area, do not move oak trees or firewood from that area. Bark beetles can also be controlled by using pesticides, but this should only be done by a trained professional.  It is vitally important that you never use wood or firewood from trees that have been infected.  Burning wood from the infected tree will infect healthy trees.

When to cut down the infected trees

When treating oak wilt, it is important to cut down the affected trees or diseased trees as soon as possible. This will help to prevent the spread of the disease to other trees. Furthermore, it is important to avoid pruning oak trees during the summer months, as this can also help to spread the disease. If you have oak trees on your property, it is important to be vigilant for signs of oak wilt and to take action immediately if you suspect that a tree is infected.

Treatment and Prevention Options

There is no cure for oak wilt disease, but there are oak wilt treatment options available that can help to prolong the life of an infected tree. One of the products for treatment is the tree injection or application of a fungicide called propiconazole into the trunk of the tree that will travel to the roots and root systems. This fungicide helps to prevent the spread of the oak wilt fungus and can extend the life of the tree by several years.

In addition, regular pruning and removal of diseased branches can also help oak wilt prevention, to keep the oak wilt fungus in check, and control the formation of new oak wilt infection centers. However, to manage oak wilt, avoid trimming and pruning trees in spring and early summer as fresh wounds or wounds develop during this season, attracting sap-feeding beetles which can spread the fungus to healthy trees.  The beetles can pick up the infected spores and carry them to healthy trees to then infect them.  

It is also recommended that you treat non-infected oaks in close proximity to the infected trees to slow the spread of the disease. Oak Wilt is an aggressive vascular wilt disease; treat trees when the disease has been diagnosed in your area. Applying Propizol Fungicide in advance of infection will greatly reduce or eliminate the likelihood of oak wilt infection. When treating multiple trees, it is recommended to disinfect your equipment in between applications.  

Timing is critical and the best seasons to inject healthy trees with fungicide are in Fall and Spring. The environmental conditions that favor uptake are adequate soil moisture, water, and relatively high humidity. Soil temperature should be above 40°F for trunk injection. Hot weather or dry soil conditions will result in a reduced rate of uptake, so trees should be watered if applications are made when soil is extremely dry.  

It is important to be familiar with oak wilt management, the signs and symptoms of oak wilt so that treatment can be initiated as soon as possible. Early detection and treatment are essential for preventing the spread of this disease development and helping with recovery. In addition, it is essential to carefully monitor the untreated trees that are very next to the treated area.

If you wish to use fertilizer for your trees a ratio of either 12-4-8 (12% Nitrogen, 4% Phosphorus, and 8% Potassium) or 12-6-6 is recommended. A fertilizer that releases nitrogen too quickly can cause more harm to the soil and trees than good. 

By following these treatment options, it is possible to keep an infected oak tree alive for many years.  Be sure to call our arborists today for more information. 

Top 7 Facts You Need to Know:

1. Oak wilt is a fungal disease that affects oak trees in the United States.

2. The disease is caused by the fungus Ceratocystis fagacearum, which is native to North America.

3. Oak wilt is most common in the Midwest and the eastern United States but can be found in other parts of the country as well.

4. The disease affects all species of oak trees but is most common in red oaks.

5. Oak wilt can spread quickly through a forested area, as the fungus can be transmitted by beetles that carry the spores from tree to tree.

6. Once a tree is infected with the fungus, it will usually die within two to three months.

7. There is no known cure for oak wilt, and the only way to prevent the disease is to avoid wounding oak trees during the spring and summer months.