HICKORY SHUCKWORM (HSW): Clydia caryana (Fitch) Order - Lepidoptera: Family - Tortricidae

DISTRIBUTION: HSW is found throughout the pecan belt from Georgia and South Carolina in the east to New Mexico in the west.

DESCRIPTION: Eggs (Fig 2) are small (0.5-1mm), light tan to white, flattened, and usually can be found on the surface of shucks. Larvae (Fig 3)are 9-10 mm long when mature. They have three pairs of thoracic legs and five pairs of prolegs, and are creamy-white with reddish-brown heads. Pupae (Fig 4) are 8-9 mm long, light reddish-brown, and are usually found in tunneled areas of shuck. Adults (Fig 1) are 8-9 mm long and gray to dark gray with dark and light alternating marks along the leading edge of the front wings.

HOSTS: Pecan and hickory

DAMAGE : Before nutshells harden, larvae tunnel into nuts, causing early drop. After the shells harden, larvae tunnel in the shucks and prevent kernels from developing properly. Injured portions of the shucks may stick to the nutshell, interfering with processing.

INSPECTION TIPS: Sticky-board traps are used to detect adults. Look for powdery white stains around larval entry points on shucks. Open and inspect fallen nuts for larvae and pupae. Check for pupae skins on the surface of shucks and look for adult moths resting on foliage.

LIFE CYCLE: HSW completes two to five generations per year. Mature larvae overwinter inside fallen pecan shucks. They create thin “windows” over the larval entrance holes in the shuck prior to pupation, providing an easy exit for wiggling pupae or adult moths; pupation takes place within or on the surface of the shuck. First generation moths emerge from February to May, usually several weeks before pecan nut set. These early females lay eggs on hickory nuts (if available), pecan foliage, or even phylloxera galls. Larvae issuing from eggs laid on pecan foliage rarely survive; consequently, few pecan trees are infested with first generation HSW. If an alternate host is available, later generations lay eggs on the surface of pecan shucks, often leaving a characteristic powdery white patch of body scales (Fig 5) around the eggs to seal and protect them. Larval entrance holes are often found beneath these white patches. Throughout the summer and fall, larvae continue to feed in, develop in, and pupate in or on fallen pecan nuts. Mature, last generation larvae overwinter in the fallen pecan nuts or occasionally in nuts remaining on the tree.

References