From: James R. Baker and Stephen B. Bambara, Extension Entomologists
The first sign of the twig girdler, a longhorned beetle that
attacks basswood, dogwood, elm, hackberry, hickory, honeylocust,
oak, pecan, poplar, sourwood, zelkovia and various fruit trees, is
fallen branches on the ground under infested trees in late
September and October. The grayish-brown beetles are about an inch
long and have long antennae. The beetles emerge in late summer and
feed on tender bark and tips of twigs. Female beetles chew grooves
around the twigs of the host trees and then poke their eggs under
the bark usually at a leaf along the girdled terminal. The girdled
portion of the branch soon dies, breaks over and then usually falls
to the ground. Several twig girdler grubs feed in a fallen branch
until the middle of the following summer. The grubs fill their
mines with wood particles and frass as they feed. Pupation occurs
in a cell formed by walling off a portion of the mine with fibrous
frass. A new generation of adults emerges in late summer and
starts to feed on the tender bark again. Dozens of branches may be
girdled and fall to the ground from a large tree. Nursery stock
become ragged and unattractive. Collecting and burning infested
twigs and branches during the fall or winter is an effective method
of control if the trees to be protected are located some distance
from infested stands. To control the adult beetles in pecans,
growers can apply Sevin during mid-September. The beetles are
active from mid September into early October. Sevin or Dursban in
early and late September should give adequate control.
Web page last updated on October 13, 1997 by Stephen J. Toth, Jr..
