The hickory shuckworm, _Laspeyresia caryana_ (Fitch), frequently causes
severe injury to pecans. In the late summer and fall the shucks are
tunneled out. As a result, the nuts are slower to mature and the kernels
do not develop properly. The shucks stick to the nuts and fail to open,
thus increasing the difficulty of harvest.
The adult shuckworm is a dark, grayish-black moth with a wing span of a
little over one-half inch. The larva is white with a light brown head.
It attains a length of three-eighths inch at maturity.
The winter is passed by the larvae in fallen pecan or hickory shucks.
They pupate in late winter and emerge as adults during the spring. The
adults deposit eggs principally on hickory trees on the leaves and young
nuts, and the larvae feed in developing nuts in early summer.
Succeeding generations develop in pecan shucks. Before pupating, the
larvae cut a hole to the outside, and then spin a cocoon. When the moth
emerges, the empty pupal skin is left projecting from the hole and can
be seen afterward on the shuck. As many as five generations may be
completed each year before the last generation larvae go into
hibernation.
_Control._—No economical chemical control for the shuckworm has been
developed. Cultural measures will aid in reducing populations. Plowing
during July and August to turn under the infested shucks is relatively
effective. The larvae are unable to mature in the decaying shucks, and
the adults cannot emerge from the soil. Care should be taken to
completely cover the fallen shucks, but the depth of plowing should be
regulated or damage to the roots will result.
[Illustration: Figure 10. Location of overwintering cocoons, or
hibernacula, of the pecan nut casebearer.]