Searcy, Ark. –
Lately we have been receiving several calls about a curious phenomenon occurring in many White county yards. It seems there are many tree limbs from hardwood trees that tend to look as though they have been cut off and fall to the ground. Believe it or not this damage is caused by an insect - not a miniature beaver, not squirrels and not long legged rabbits.
Twig girdlers (Figure 1) are common throughout most of Arkansas and it is their characteristic damage to tree limbs that either causes complaints or evokes curiosity. Damage is most evident in the fall when leaves prematurely turn brown, die and the girdled limbs drop to the ground beneath infested trees. Small branches accumulating on the ground and the presence of clean-cut twigs, and in some cases dangling (flagged) branch tips within a tree, indicate the presence of beetle pests referred to as twig girdlers. These long-horned beetle species (Cerambycidae) attack numerous types of shade, nut and fruit trees. Heavily damaged trees appear ragged and unattractive, and young trees can become deformed by repeated attacks.
Twig girdler (Oncideres cingulata)
Common hosts of the twig girdler include persimmon, pecan, elm, hickory, oak, honey locust, hackberry, poplar, linden, redbud, basswood, dogwood and various fruit trees.
The adult beetle is about three-fourths of an inch long, stout, grayish-brown with a lighter colored band across its elytra (wing covers) and has antennae as long as its body.
Adult beetles typically begin to emerge in mid-August and continue through early October. During this time, the adult female chews a V-shaped groove around a small twig, girdling it (see Figure 2). She then deposits an egg beneath the bark in the twig section beyond the cut (severed portion). This is because the larva is unable to develop in healthy sapwood. The cut made by the adult female is deep enough around the twig so that the girdled portion dies quickly and usually falls to the ground, either because of wind or its own weight.
During the egg laying period, large numbers of girdled twigs often accumulate beneath the tree each day. After hatching from the egg, the developing larva bores into the dead twig to feed. The small larva will over winter in the fallen twig. During the following spring, the larva resumes feeding, consuming most of the wood.
As the larva grows it bores further down into the twig and fills the tunnel with wood shavings and waste. Pupation occurs in a cavity within the twig. Adults emerge in late summer and early fall. Twig girdlers produce one generation a year.
Homeowners should collect and destroy infested twigs and branches they find on the ground, beginning in September or no later than May. If practical, prune infested twigs still in the tree.
Owners of commercial pecan orchards should look for severed twigs, beginning in August. Apply insecticide carbaryl to trees only if you see damage. In severe cases, you may need to apply insecticide two to three times at two-week intervals. Be sure to follow label rates and directions.
The Extension Service is part of the University of Arkansas, Division of Agriculture. The University of Arkansas System, Division of Agriculture is an equal opportunity/equal access/affirmative action institution.
For additional information, contact your county office of the University of Arkansas Cooperative Extension Service or visit the website at https://www.uaex.edu/ .
By Sherri Sanders
County Extension Agent - Agriculture
The Cooperative Extension Service
U of A System Division of Agriculture
Media Contact: Sherri Sanders
County Extension Agent - Agriculture
U of A Division of Agriculture
Cooperative Extension Service
2400 Old Searcy Landing Road, Searcy AR 72143
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