The pecan weevil causes two types of damage to the nut crop. First, the adult weevil punctures the immature nuts and causes many to fall. This damage is not easy to recognize and may be confused with damage from sucking bugs or the shuckworm.
Another type of damage occurs when the female weevil deposits eggs in the nuts after the kernels form. The eggs hatch and the larvae then devour the interior of the nut. This damage is most noticeable at harvest time by the lightness of the nuts or by the prominent exit hole where the grub has escaped.
The large grubs (larvae) emerge from the nuts in the fall and early winter and enter the soil. The larva prepares a cell in the soil (often 4 to 12 inches under the soil surface) and remains either 1 or 2 years. Pupation occurs during the fall of the year and the new adults remain in the soil until the following summer. The complete life cycle may require 2 or 3 years.
