Twig girdlers are species of longhorned beetles that have a very distinctive approach to laying their eggs. The female selects a twig that is about the diameter of a fat pencil, and then chews a deep, narrow groove around it. This girdles the twig, leaving only the terminal section attached by a slender piece of heartwood. The beetle then crawls along the terminal end, making small notches in the twig. Groups of 5 to 20 eggs are deposited into the notches.
The twig terminal that contains the eggs and white legless larvae soon breaks and falls to the ground. The results of the girdler’s handiwork can be seen littering the ground under a variety of trees, including hickory, pecan, and oak. Twig pruning produces growth deformities that affect the shape and appearance of small trees, but it generally is not a problem for large trees.
Collection and destruction of fallen twigs is the most effective means of reducing the potential infestation for next year. Application of insecticides to control these insects has not been very satisfactory.
by Lee Townsend, Extension Entomologist