COMMON NAMES: Hickory Shuckworm, Shuckworm
SCIENTIFIC NAME: Order Lepidoptera, family Torticidae, Cydia caryana
SIZE: Adult--3/8", wing span 1/2", larva--3/8"
IDENTIFICATION: Adults are brown to black moths. Larvae are small white worms with brown heads.
BIOLOGY AND LIFECYCLE: Eggs are deposited on leaves and young nuts. Larvae infest the shucks covering the nuts and then overwinter in the fallen debris on the ground. They pupate in late winter to early spring and emerge as adults in the summer. As many as five generations a year. Complete metamorphosis.
FEEDING HABITS: Larvae feed in developing young nuts. In the late summer and fall the larvae tunnel into the shucks of hickories and pecans, preventing the kernels from filling out.
ECONOMIC IMPORTANCE: Can cause severe injury to pecan and hickory crops. Nuts are damaged and shucks fail to open.
NATURAL CONTROL: Bats, green lacewings, trichogramma wasps and other wasps.
ORGANIC CONTROL: Beneficial nematode soil treatment. Throw compost on top of infested shucks. Larvae are unable to mature in decaying shucks and adults cannot emerge from the soil. Successive releases of trichogramma wasps.
INSIGHT: In mid-season it is sometimes hard to tell the difference between the pecan casebearer and the hickory shuckworm. When the nuts get too hard for the casebearer to penetrate, the casebearer will also tunnel in the shuck. The casebearer frass or castings will be pushed to the outside of the shuck. There it tends to build up and stick. When the casebearer is found, there is usually one per nut. The shuckworm keeps the castings in the tunnel because it eats itself a new hole to escape after it pupates into an adult moth. Usually the pupal skin can be seen hanging halfway out of the hole after the moth has flown away. Two or more shuckworms may be found in the shuck of each nut. The shuckworm is creamy white while the casebearer has an olive or gray-green color.