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Identifying & Preventing Oak Wilt Disease

In Texas, we have a green luxury that most of us take for granted. Whether in our front yards, neighborhoods, or local park, oak trees are considered to be majestic and beautiful trees that provide a lot of shade and greenery to our otherwise dull scenes. Especially in central Texas, besides the beauty of rolling hills, we have great oak trees to complement the entire scenery.

However, oak wilt is threatening that beautiful scenery quite rapidly. Oak wilt, also known as “sudden oak death,” is one of the most threatening tree diseases in Texas and continues to kill off live oak and red oak trees – including shumard oaks, Spanish oaks and blackjack oaks – spreading from one to the next. This disease is caused by a fungus called Ceratocystis fagacearum which takes over a tree’s water conducting system, thus causing the tree to die quickly. Oak wilt kills off a tree only to move on to another, spreading through the trees’ root systems. Nitidulid beetles, which are attracted to fresh wood, can also spread the disease by coming into contact with a tree’s fresh wounds (from pruning or storm damage, for example) and moving on to to another tree. Sap-feeding beetles consume the tree sap on fungal mats that develop on infected oak trees. Nitidulid beetles then unwittingly transfer fungus spores, which become attached to them, to a healthy tree where the spores are allowed to germinate and infect with oak wilt.

What are some of the things you can do if oak wilt is destroying your oak trees?

Trenching: This is an effective and natural way to thwart the oak wilt. Building trenches at least 100 feet away from an infected tree can curb the spread of oak wilt from the roots of the trees. This is not a guaranteed method of preventing oak wilt, but it is a safe way to temporarily protect other trees from becoming infected.

Cutting grass: During the fall and winter, lawn experts recommend cutting your grass a little higher than usual in order to maintain a deeper root system, which contributes to a healthier lawn. Before you mow your lawn next time, raise the deck height of your mower to a height of at least two inches for warm season grasses and about three to four inches for cool-season grasses. In the more densely shaded areas of your lawn, you should allow the grass to reach an even taller height.

Get rid of infected trees: Trees that have been infected with oak wilt and have already died from the infection should be destroyed immediately to avoid spreading infection via the tree’s root systems. Dead trees can be cut down and the wood can be either burned or covered up in plastic for six months before the wood can be dried. The edges of the plastic should be buried in the ground as well.

Fungicide Treatment (Injecting): Every two to three years, you can inject your oak trees with an effective fungicide treatment such as Alamo fungicide, which is designed specifically to fight oak wilt. Applying the fungicide will not completely stop oak wilt from spreading through the tree’s root system, but can be effective toward saving individual trees.

Trim your trees at appropriate times: To avoid nitidulid beetles, plan your trimming or tree shearing around the beetles’ off season. Although the season for nitidulid beetles varies across the United States, most of them come in droves from February to June in Texas. That makes January the best time to trim your oak trees, so take advantage of the new year and trim those oak trees now!

Paint it Red: Painting the wounds of an oak after you’ve trimmed it will close the wound off to any potential infection from nitidulid beetles who are attracted to the fungal mats on these open surfaces and will stop the beetle from carrying fungal spores with it from tree to tree. In some areas, a homeowner can get fined heavily for not painting the wounds of a tree that has just been trimmed.

Avoid infected tools: Avoid using the same tools you used to work on any infected trees. Using these tools can help spread the infection to an otherwise healthy tree that you may be just trimming or pruning. If you need to use the same tools, a safe bet would be to sterilize them before using them on the new tree.

Choose firewood wisely: By unknowingly moving firewood from infected oak trees to new locations, healthy oak trees can become infected from the exposed fungal mats on the firewood. Make sure the firewood you are transporting did not come from an infected tree.

Diversification is key: Oak wilt is a terrible tree disease that is not going to go away anytime soon. The goal for tree sustainability is to think long-term and do what is best for your yard and/or neighborhood. Live oak and red oak trees are not the only type of oak trees you can plant in your yard. Take advantage of the different types of trees that can be cultivated and planted that are not susceptible to oak wilt. Even if you wanted to only cultivate oak trees, building and development ordinances do not allow the planting of any oak susceptible to oak wilt. However, many options exist in planting oak wilt resistant types of trees. Check out the following site for more information on the many variations of tree species available to plant: Plant Species.

The Texas Oak Wilt Suppression Project assists landowners in their continued fight against this disease. Learn if you qualify for this federal cost-share program at Fight Oak Wilt Disease.

By educating yourself about what oak wilt disease encompasses, you are on your way to beautifying your home, your neighbors’, and the state of Texas.

For more information and assistance with oak wilt, schedule an appointment with one of our lawn care specialists at: Make an ABC Appointment: Make an Appointment


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