Garden Column for the Salisbury Post

Darrell Blackwelder

November 25, 2003

I always receive numerous inquiries about pecans during the holidays. The crop is especially valuable during the Christmas Holidays. Unfortunately, many have complained about the quantity as well as the quality of this season’s crop.

This tree species is extremely durable, but the nut crop itself is subject to over 20 insect and disease pests, not mentioning a host of animal pests including squirrels, crows, blue jays, sap suckers and occasional deer damage.

    There are 4 major insects, which damage to the nut. The pecan weevil is one of the most serious insect pests. The weevil has the characteristic a "boll weevil" type snout, which is actually a tool to feed and bore into the pecan shell. The weevil punctures nuts in early August causing premature drop. Later by depositing eggs, the larva chews a circular hole through the shell and as the nuts fall to the ground, it exits the nut, and burrows into the soil. Homeowners often find empty pecans shell void of kernels.

Stink bugs attack both before and after shell hardening. Early feeding causes premature nut drop. This insect causes black spots to develop on the kernel. Black spots on the kernel are bitter and referred to as bitter spot. The southern stinkbug over-winters as adults in orchard debris. Eggs are then laid on grasses and soybeans and then move to pecans as adults in late summer.

Limbs and twigs found on the ground that seem to be cleanly cut is the work of the twig girdler. Twig girdlers are beetles, which girdles twigs and small branches in September and October. Females lay eggs in slits the girdled branches. Windy conditions breaks the girdled branch and the limb falls to the ground where the larvae feed in the severed branch and pupate into the soil. These beetles produce only one generation a year.

Other strategies to control insects are:

**Locate new plantings 200 feet from wooded areas to discourage insects, birds, squirrels and other pests

**Do not grow soybeans or vegetables close to pecan trees. These plants encourage stinkbug populations

**Control broadleaf plants under trees in late winter on the entire orchard floor.

**Gather destroy fallen twigs during September to reduce twig girdler populations.

**There are pheromone traps that can be purchased to monitor insect populations. Timing of these sprays is important in controlling emerging beetles in August and September.

The major disease of concern in pecans this season is pecan scab. It was a serious problem eliminating much of this season’s crop. It is a fungus that attacks both the foliage and the pecan shuck. Scabby lesions on the nut’s shuck appear to be small, sunken black spots. Severe infestations experienced this fall caused the entire shuck encasing the pecan to turn black and fall off the tree. Fungicidal sprays are impractical for large trees. This disease is best managed through selecting resistant varieties. But with the unseasonable amount of rain and humidity experienced this season, resistant pecan varieties cannot overcome this disease.