Ant Infestation in an Oak Tree
Discovering a colony of ants in one of your yard's oak trees can be a distressing find. There's a good chance that the tree is already beginning to show some signs of disease or damage, so blaming the ant colony for the tree's demise can be hasty. Ants that nest in trees typically only do so when there is already some kind of distress present, and these ants can act instead as an early warning sign. Does this Spark an idea?
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Types of Ants
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Not all types of ants will make their nests in an oak tree, so determining what kind of ant is in your tree will help in getting rid of them. Carpenter ants are one of the most common pests that nest in landscaping trees, especially those that already have damage from disease or trauma. The telltale sign of these ants is the pile of dust outside the opening of the nest made by ants pushing out chewed up pieces of wood.
Less common is the velvety tree ant, which makes its home in dead wood and whose presence can indicate the tree is already dying. Also, the thief ant can make its home alongside other colonies and steal food from them.
Associated Problems
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Ants -- including the common carpenter ant -- generally will not invade a tree unless something is already wrong with the tree. Ants that nest by chewing through the interior of the tree look for soft wood that will be easy to chew and easy to create elaborate tunnels in. The presence of an ant nest inside an oak tree usually indicates that a disease or wounded tissue was present originally, and the ants are simply taking advantage of the situation.
Cracks in the tree can lead to moist wood inside the structure, making it perfect for ants. Disease can also start to kill areas of the tree and make them vulnerable. Canker is a common oak tree disease that begins by killing branches before spreading through the rest of the tree.
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Control
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Bait traps can be an effective way to control ants, especially those that nest in areas well away from where they forage. Unlike most sprays, bait traps don't kill ants on contact. Instead, the worker ants return to the nests with the poison bait, introducing it to the queen and other ants that may never leave the nest. If the queen doesn't die, she will continue laying eggs to create new workers. Sprays can have an effect on the number of ants directly on or around the tree, but bait traps are better for completely eradicating the colony.
Cut back any branches that may touch adjoining trees or the home. This will eliminate any foraging paths the ants may have to other trees or into the home. Infestations in oak trees are difficult to eliminate because of the elaborate nests, and they may persist throughout numerous treatments.
What Not To Do
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Although some courses of action might seem like a good idea, they can end up doing more harm than good. Sealing the entrances to the nests and the holes in the trees will simply make the ants chew through more of the tree to create a new entrance. Getting rid of the tree is also highly inadvisable, because not only will this take a valuable landscape oak from the yard, but the ants are likely to just pick up and move to another nearby tree.
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References
- University of Rhode Island GreenShare Factsheets; Carpenter Ants in Trees; 2001
- Iowa State University Extension: Carpenter Ants in Trees; Donald Lewis; June 2009
- University of California Integrated Pest Management Program; Ants; February 2007
- Neighborhood Association of Southwestern Williamson County: Oak Tree Diseases
Resources
- Photo Credit Thinkstock/Comstock/Getty Images
