Friday, February 17th, 2017
As a homeowner or business owner, you need to care for your trees just like you would with any other part of your landscape. Part of tree care involves recognizing the signs of diseases and other issues, such as tree fungi. When it comes to the types of pathogens affecting trees in central Texas, tree fungi is fairly common while bacteria are uncommon and viruses are very uncommon. There are multiple types of fungus that can affect your trees, but some are more common than others. An arborist will help you diagnose the particular fungi in question and come up with a course of treatment, but it helps to be familiar with the possibilities.
Oak wilt is the most concerning tree fungi that you can get in central Texas as red oaks and live oaks are susceptible while white oaks tend to be a bit more resistant. You can recognize oak wilt by the leaves dropping or turning brown. In the case of live oaks, there will also be veinal chlorosis and in all species, oak wilt can lead to tree death. Oak wilt spreads through root grafts and certain beetles that feed on trees. Your arborist can provide treatment and preventative methods for oak wilt.
In the case of armillaria, foliage of the tree can turn yellow or thin. You may also see reduced shoot growth or mushrooms growing around the base of the tree. This tree fungi can lead to crown die back and white rot that creates spongy wood. If you look underneath the bark in affected areas, you will notice white fungal growth. To reduce the risk of armillaria, prevent tree stress and ensure that mulch and sod stay back from the tree trunks.
Ganoderma is a tree fungi that affects the lower trunks and roots of various trees, including elms, ash, and oaks. Eventually, trees with ganoderma may die, but this can take as long as three or five years for the entire tree to fail. In the meantime, the tree may show yellowing, branch dieback, undersized leaves, wilting, and general decline. Prevent the spread of this tree fungi by looking for conks and then removing any trees that have them. Take care to avoid wounding the trunks and roots since the infection is spread by spores in the wind that enter through the open wounds.
Hypoxylon cankers attack weakened trees and tend to be more common during times of drought. They affect elms, oaks, pecan trees, and sycamores in addition to numerous other trees. Trees with hypoxylon cankers may experience thinning of their crowns and branch dieback. There is also decaying of sapwood and this particular tree fungi can kill trees rapidly.
You may not realize it, but leaf spots that you find on your central Texas trees are actually a type of fungus as well. While they can affect trees, they don’t do any serious damage. Instead, they are mostly a cosmetic issue. Unfortunately, however, they affect many different types of trees. Leaf spots are more common during the wet years but you can prevent reinfection by raking up leaves in a timely manner.