Pest Management

The North Carolina Cooperative Extensions Services offers this advice on pest management.

Pecans are subject to attack by more than 20 insects and mites. It is important to be able to recognize damage caused by these insects and to understand their life history to know when to monitor for their presence and control them using integrated pest management strategies.

You can contact your county Cooperative Extension Center for help in identifying pests and for recommended control measures.

Here are some pest management strategies to consider

  • Establishing new plantings at least 200 feet from wooded areas to discourage insects, squirrels, birds, and other potential pests
  • Not growing soybeans or vegetables close to pecan orchards as these plants support stink bug populations
  • Using herbicides to control broadleaf weeds in late winter on the entire orchard floor; also control all vegetation in a strip down the tree row to destroy weed hosts and competition for nutrients and moisture
  • Top-working neglected older trees or thinning out trees to ensure adequate spray coverage and light penetration
  • Monitoring for aphids and their natural enemies; use an aphicide should populations increase
  • Gathering and destroying fallen twigs during September to reduce twig girdler populations
  • Gathering and destroying weevil-infested nuts as they fall
  • Keeping areas around the orchard free of debris that may harbor overwintering insects

You can also call the Georgia Hotline 1-800-851-BUGS (2847) to get the most recent scouting report from Georgia.

You can also access the Georgia Spray Guide via this link. 2014-Pecan-Spray-Guide

Monitoring your crops

Monitoring in a systematic way provides valuable information on the populations of pests and beneficial insects in an orchard. The results can be used to time pesticide applications properly. Two monitoring techniques used in pecan orchards are field surveying and insect trapping. In sampling for foliar insects, randomly select five compound leaves and five nut clusters from five trees in a 10-acre block. Record observations on a weekly basis and refer to these records regularly to make comparisons and identify trends. Marking trees with numbers is helpful in establishing permanent reference points.

Insect traps are used to catch pests, monitor their development, and indicate when additional sampling is required. A black-light insect trap can be used for moths, beetles, and stink bugs. Pheromone traps containing a sex attractant also are available for many insects. These pheromone traps are very species specific. There are two ways to monitor for pecan weevils using traps. The first is to place cone cage traps under the tree’s drip line and record the number of adult weevils collected. A second way is to use trunk band traps. Burlap bags can be wrapped in overlapping flaps around the trunks of several trees in an orchard. Daily collections of male and female weevils indicate when to spray, and destroying the weevils collected provides some physical control 

Another method of monitoring pests is to place a sheet of plastic or cloth on the ground under the trees. Shake the trees and count the insects on the sheet. Trees also can be sprayed with a commercial pesticide and then checked later for the number and species of insects found on the sheet. In the case of twig girdlers, fallen twigs can be examined for the smooth, cut surface caused by adult beetles. The best management strategy for these insects is sanitation by removing and burying or burning these twigs as soon as they fall from the tree.

Insects which can harm Pecan crops

Aphids

Across the Aphid family, there are three types of Aphids that you should watch out for when growing your pecans:

  1. Yellow Pecan Aphids
  2. Blackmargined Aphids
  3. Black Pecan Aphids

Yellow Aphid

The yellow pecan aphid is smaller, pale to bright yellow, and has red eyes. It is bullet-shaped and has few black markings and many long setae (hair) that are visible under magnification.   

Blackmargined Aphid

The blackmargined aphids have a yellow background color and heavy
black margin along the front of the wings and on the edge of the head
and thoracic areas. 

Black Pecan Aphid

Black aphids are pear-shaped, pale to dark olive-green in the nymphal stages and black as adults. Early summer forms of the pest, which include the stem mother and one or two generations of their offspring, are yellow-green with relatively little dark pigment. Winged adults are jet black with transparent wings and several snow-white waxy spots on the upper surface of the body. They hold their wings tent-like over their abdomens at rest.


Other General Insects

Hickory Shuckworm

Hickory shuckworm moths are small, dark brown to smoky black moths about 0.35 inch long. Adults are not often seen because they are most active at night. Larva are small, cream-colored and burrow into the shuck. Full grown larvae are about 0.5 inch long and have light brown to dark brown heads and small inconspicuous black spots over their entire abdomens. The pupae are found within the tunneled area of the shuck or protruding from small exit holes made by the larvae. They are golden brown to dark tan, and all of their appendages are tightly
molded to their bodies.

Pecan Nut Casebearer

The adult pecan nut casebearer is a small brown moth about 0.33 inch long. It has a ridge or tuft of dark scales extending across the middle of the forewings. Full grown larvae are about 0.5 inch long with
olive-green to dark green bodies and yellowish brown heads. The larvae spin silken webs around the nuts they feed in and make small cases within the web. The silk webbing and case are distinctive signs of this pest.

Pecan Weevil

Adult pecan weevils are hard-shelled beetles with long slender snouts and thin legs. They are reddish-brown to gray and between 0.3 to 0.5 inch long. The snout is longer than the body on the females and slightly shorter on the males.

The pecan weevil larvae are creamy white, legless grubs with soft, fleshy bodies and reddish brown heads. They molt four times and upon maturity may be nearly 0.35 inch long.

Pecan Leaf Scorch Mite

The pecan leaf scorch mite is a tiny, pale green pest usually found feeding on the underside of the leaflet midline. The dark spots on the mite’s body are actually internal organs that are visible through its almost transparent integument. Adult mites have a smaller, bright red spot on
each shoulder. Mites have eight legs; the front pair is usually carried forward and can be mistaken for antennae. Female scorch mites have fuller bodies than males and are always much more numerous.

Walnut Caterpillar

Walnut caterpillars are dark red when young, becoming black near maturity, and have silver hairs along their bodies. These larvae feed within the canopy without forming silken webs and migrate back to the trunk or scaffold limbs in groups when molting.

Pecan Budmoth

The adult budmoth is gray with blackish brown patches on each forewing and a wingspan of about 0.66 inch. Its fringed hindwings are dark gray-brown with iridescent scales on the undersurfaces. The adult lays iridescent eggs that hatch into dirty-white larvae or caterpillars.
When the larvae are fully mature, they are yellowish-green, have dark brown heads, and are about 0.5 inch long.

Nut Curculio

The nut curculio lays eggs on immature nuts from June through early August. The single egg is deposited in the shuck, and the legless grub hatches and tunnels into the nut to feed. Damaged nuts bleed brown sap through the puncture and the nuts usually drop from the tree after infestation.

Phylloxera

The adults and nymphs of phylloxera are tiny (0.1 to 0.2 inch long), soft-bodied insects that resemble aphids without cornicles (the protruding dorsal tubes found on aphids). They usually are cream-
colored to pale yellow, having sucking mouthparts, and can rarely be seen without magnification.

Plant and Stink Bugs

Southern green stink bug is a large, green, shield-shaped insect about 0.5 inch long. the adults have wings and can fly well; the nymphs are wingless.

Spittlebugs

Adult spittlebugs are active hopper and fliers that resemble plant hoppers to which they are related. All forms have piercing -sucking type mouthparts and are identified by two rings of spines around the hind legs. Adults are about the size of curculios, 0.18 to 0.25 inch long, and are heavy-bodied in appearance.