Home & Garden Tips
Twig Girdler Victimizing Pecan Trees
By Roosevelt McWilliams County Extension Agent

You may notice this fall that something is cutting off limbs of young pecan trees in your back

yard. The cuts are smooth, with a point at the center. What is doing this and what can I do about it?

An insect called a twig girdler is the culprit. It's hard to believe insects can make such a smooth cut, but they can.

The adult girdles the pecan twigs in late summer and fall. This girdling causes the injured branch to break off or hang loosely on the tree.

A twig girdler is grayish brown, more or less cylindrical in shape and about an inch long with an elongated antennae extending over its back. The adult lays an egg in the twig and then cuts a deep groove around the twig. The girdled twig dies.

The adult girdles the pecan twigs in late summer and fall. This girdling causes the injured branch to break off or hang loosely on the tree. The wind breaks the twig and it falls to the ground, where the larvae develop in the dead twig.

Twig girdlers are generally present wherever pecans are grown. It is especially abundant in groves near timberland containing hickory and persimmon. The insects overwinter as eggs or grubs inside severed limbs.

The grubs grow slowly during the fall and winter months but in spring, as they begin to tunnel inside the twigs, they grow rapidly. They normally complete their growth, pupate, and emerge as beetles during the latter part of August. The adults lay eggs in the tips of twig and then girdle the twigs. Twig girdlers complete their life cycle in one year, although some individuals require a second season.

This girdling habit is important in the survival of the insect because the larvae that hatches from the egg cannot develop in the presence of the sap in a healthy twig.

The first noticed sign of attack is usually a large number of small branches and twigs lying on the ground beneath the tree or dying branches and twigs hanging on the tree, nearly broken off. Close examination of the tree reveals branches with cut ends that have been chewed almost straight across as if cut with a knife. The injury will have slightly rounded edges and will feel a little rough from the beetles chewing on it.

There is no way to spray for these pests, but you do need to gather and destroy all the infested twigs that fall to the ground to prevent the eggs from hatching. It you live in an area with a lot of other pecan or hickory trees (which they also like), you may encounter this problem every year.

While it's not good that this is happening to your pecan trees, these pests will not kill your trees.