Twelve or so years ago, a local rancher brought in a small twig and had a question. He couldn’t figure out how the twig, had a girdling circle cut nearly all the way through it. Further examination confirmed the perfect girdling circle. Finally, someone with more experience recognized the damage being caused by a twig girdler beetle. They haven’t been a real problem since then until now. I’m currently losing 4-6 twigs a week,
A twig girdler beetle (Oncideres pustulatus LeConte) is a small (.5”-.75”) beetle in our area that does its work during the August to October Time period. There are several girdlers named after the species they attack. In our area, however, the common name is used as the beetles like oak, pecan, hickory, hackberry, elm, honeylocust, dogwood, and other hardwood species.
A female beetle selects a small twig up to roughly the size of a pencil, girdles it, lays an egg under the bark and then moves on. In the tree or on the ground, the egg hatches, and the beetle larva overwinters in the twig. Where is dependent on what you do with the twig, such as leaving it alone, moving it to a burn pile, or putting in trash. Next July, the new adult emerges to start the cycle all over again.
So, how do we control this pest? The best way is to stop the repeating cycle. When you notice damage, your first step in controlling them should be a thorough clean-up of the yard. If you pick up and dispose all the twigs on the ground beneath trees that have been attacked, you are affecting twig girdler control. Many of the twigs you destroy will contain eggs or larva. Removing the fallen twigs is by far the best way toward eliminating the problem.