The pecan weevil requires two to three years to complete one generation. Eggs of the pecan weevil are deposited in a pecan when the fruit is nearly hardened and contain well-developed kernels (dough state). When fully grown, pecan weevil grubs are about 3/4 of an inch long. They are creamy-white color with reddish-brown capsules. After feeding within a nut, larvae will chew "exit" holes about 1/8 of an inch in diameter in the shell, emerge from the nuts, and drop to the ground and burrow into the soil to pupate. The adult pecan weevil is a light-brown to grayish long snout beetle, measuring about 1/2 of an inch in body length. When kernel formation and expansion begin (near the end of August), adult weevils start emerging from the soil, which event is usually associated with rainfall. Three to four days following a one to two inch rainfall, weevil emergence will increase dramatically. If rainfall amounts are lower and periodic, then weevil emergence will be prolonged over time.
May begin feeding as adult weevils during the water or gel stage of pecan development, causing nuts to drop. Female weevils begin egg laying on average 6.5 days after emergence and can deposit an average of 4-4.5 eggs per pecan. Feeding damage by weevils during the gel stage can also cause "sticktights" where the shuck adheres to the nut or it can result in pitted (black spots) or moldy kernels near the feeding punctures. Larval feeding within the pecan causes complete destruction of the kernel.
Chemical insecticides are available for control of pecan weevils.