Today I peeled back the shuck of a Maramec pecan and found a couple of hickory shuckworm larvae (photo above). The red arrows point to the head of one larvae and the tail of another. These caterpillars feed on the shucks of pecans leaving tell-tale black tunnels in the shuck. The tunneling seems to be concentrated near the base of the nut but you can find tunnels throughout the shuck.
Hickory shuckworm is a minor pest in our northern pecan groves. Northern pecan cultivars fill their kernels and ripen their nuts faster than the shuckworm can destroy the shuck and cause economic damage. Hickory shuckworm populations are kept relatively low in well tended pecan groves because insecticides applied in August to control stink bugs and pecan weevils also control shuckworm.
Hickory shuckworm larvae are small white caterpillars with a red heads (photo at left). Note that these larvae are confined to the shuck and have well defined legs. Pecan weevil larvae are also white with red heads but are completely legless. Unlike shuckworm, pecan weevil larvae are usually found inside the shell of the nut.
