Twig girdlers are nature’s odd pruners

Published 5:00 am Friday, December 13, 2024

Have you noticed small limbs scattered on the ground beneath your pecans, hickories, persimmons, or elms? Do they look like they’ve been run through a pencil sharpener? If so, you’ve likely encountered the work of twig girdlers. These insects are common across Texas and often go unnoticed until autumn, when their handiwork becomes apparent.

Twig girdlers are a type of longhorned beetle, named for their unusually long antennae. Males have antennae nearly twice the length of their bodies, while the females’ antennae are about the same length as their bodies. These beetles measure between ½ to 11/16 inches long and are cylindrical in shape. They range in color from light to dark brown, with a gray band across their wings and sometimes speckles of pink, orange, or yellow. Despite their noticeable impact on trees, you’ll probably never see a twig girdler; they’re stealthy and rarely spotted.

Twig girdlers are active from late summer to early fall, typically August through October. After mating, the female selects a small branch on a tree and uses her mandibles to chew a ring around the branch, leaving a portion of the center intact. This partially severed branch dies but doesn’t immediately fall, giving the female time to notch the bark and deposit her eggs in these notches. She then covers the eggs with a protective secretion.

As the branch dies and drops to the ground in the fall or winter, the eggs hatch. The larvae burrow into the dead wood, feeding under the bark. By the next summer, the larvae have matured into adult beetles, completing their life cycle.

Twig girdlers are more of a curiosity than a serious threat. While their activity can make a mess, the damage they cause to trees is minimal and rarely affects tree health. Picking up the fallen limbs is more about keeping your yard tidy than protecting your trees.

If you want to minimize their impact, the most effective control method is simply to gather and dispose of the girdled limbs as soon as they fall. This eliminates the larvae before they can develop into adults. Burn or shred the limbs for added control.

Applying insecticides to the tops of trees isn’t practical or environmentally friendly, and it likely won’t provide reliable control. For me, twig girdlers are just part of the natural cycle of fall. I’ve always admired their precision handiwork and appreciated the role they play in nature.

So, the next time you see those pencil-sharpened branches on the ground, take a moment to marvel at the intricate work of twig girdlers. They’re a subtle reminder of the fascinating natural world right in our own backyards.