Twigs falling from trees.

Thanks to Diane Rausch for this great question! Late last fall, twigs and small branches suddenly fell off her honey locust and on trees around the neighborhood. They looked like they’d been cut or even sawed off. What caused this?

Twig girdlers! The adults are longhorned beetles that range from ½’ to 5/8’ inch long and grayish brown in color.  They cut a circular section around the tips of the smallest branches in trees, which makes those tips vulnerable to breaking off and falling to the ground.

You’ll definitely notice an infestation after a wind storm, when the ground around trees may be completely covered with broken twigs.

Adult twig girdlers feed on the tender bark and then the females lay eggs on the tips of the branches they’ve just girdled. This is by design, and is a very specific part of the life cycle of this insect. The deposited eggs will hatch into larvae which will feed on the dead tree tissue, once it breaks off and falls to the ground.

So the best way to break this cycle is to rake up and toss all of those twigs around the trees, in the whole neighborhood, and discard them.

This isn’t usually too much of a problem for most trees, but it can negatively affect nut production in pecan trees, and repeat or heavy infestations can cause deformities in growth.