The adult twig girdler, _Oncideres cingulata_ (Say) (_O. texana_ of some
authors), girdles twigs and branches, weakening them so that they fall
off or die on the tree, Figure 22. This insect is active during the late
summer and early fall. Many twigs may be found on the ground under a
severely infested tree. Secondary branching may occur and the number of
bearing twigs is reduced.
The twig borer is a grayish brown beetle one-half to five-eighths inch
in length with a broad gray band over the middle of the wing covers. Its
head is reddish brown and bears a pair of long antennae, which extend
beyond the abdomen on the male.
The larva is a white legless grub about three-fourths inch long when it
reaches maturity.
This insect overwinters as a partially grown larva in a twig on the tree
or ground. It develops rapidly in the spring feeding in the twig.
Following pupation, the adult emerges in late August or early September.
The female systematically girdles twigs and deposits eggs in the severed
portion since the larva is unable to develop in healthy sapwood. The
eggs hatch in a few weeks into larvae which remain small until the
following spring when they complete development, pupate and emerge as
adults in the late summer and fall. There is one generation annually,
although some individuals require 2 years to mature[1].
_Control._—Infestations may be reduced by removing girdled branches from
the trees and the ground and burning them.
Chemical control is also effective. The trees should be sprayed with 4
pounds of 50 percent DDT wettable powder per 100 gallons of water when
the first injured branches are observed in late August or early
September. Two or three applications at 2-week intervals may be required
for most effective control[9].