One of the most recognizable features of the Texas landscape is the oak trees that decorate the state. Can you imagine the countryside without them? Ceratocystis fagacearum, a fungal disease known as oak wilt, is the perpetrator behind the dwindling oak population. These magnificent trees are being singled out by this fungal disease and rapidly reducing the oak population. Properly identifying oak wilt and utilizing successful oak wilt management techniques can help reduce tree loss.
So how do you identify oak wilt? Patterns of tree mortality such as defoliation during different seasons are one way to identify oak wilt. While exceptions have been documented, live oaks generally lose their leaves and die within six months of being infected. Red oaks display autumn-like coloration that sets them apart from surrounding foliage. They never survive the fungus, usually dying within three to four weeks after being infected.
The oaks leaves can paint a disturbing image of the damage being done. A live oak’s leaves often develop yellow veins in early stages of infection. The yellow veins turn brown as the infection eats away at the tree, a symptom called veinal necrosis. Oak wilt symptoms on the red oak are harder to recognize. In early spring, the young leaves wilt and turn a pale green and brown, remaining attached for some time, while the mature leaves will develop dark green symptoms or turn pale green or bronze. The most effective way to identify oak wilt in red oaks is to chip away at the bark of oak trees with foliar symptoms and looking for fungal mats—spore producing formations that often develop in the spring.
So how do you help control the spread of oak wilt? Red oaks that die in late summer, early winter or fall should be cut down and burned or buried to prevent the fungal mats from developing on the wood. Herbicide, deep girdling, stripping the tree of bark and drying the wood are also techniques that can help prevent the spread of oak wilt.
Distributing unseasoned firewood from red oaks infected with oak wilt can spread the fungus. While oak wilt will not survive burning, it can spread to healthy firewood in storage. Currently there are no proven transmitters from the insect world, but taking proper precautions by keeping your healthy wood free of wood-dwelling insects is smart management of your firewood.
For further details about this deadly fungus, visit texasoakwilt.org.
ABC lawn care specialists in Austin, Texas use techniques that remove infected trees safely without spreading the fungus. Looking to prevent or reduce the chances of your oaks being infected by oak wilt? We offer lawn care and landscaping for Austin residents, and we will help you identify signs of oak wilt as well as ways to prevent its spread.