Larvae are small, legless creamy white grubs and are found inside the nuts. The nut curculio attacks immature pecan nuts from late June through early August.
Adults puncture the young nuts with their snouts and larvae consume the insides of the nuts.
The insects cause premature nut drop. Infested dropped nuts normally contain only one legless larvae. Within a few days the egg hatches, the larvae begins to feed, and the nut falls to the ground. The creamy white, legless larva continues to feed in the dropped nuts for about two weeks before leaving the nut. The larva then forms a pupal cell under the nut in the upper 2 to 4 inches of the soil.