Pecan Diseases and Pests and Their Control

by David W. Rosburg; D. R. King

Control.—Infestations may be reduced by removing girdled branches from the trees and the ground and burning them.

Chemical control is also effective. The trees should be sprayed with 4 pounds of 50 percent DDT wettable powder per 100 gallons of water when the first injured branches are observed in late August or early September. Two or three applications at 2-week intervals may be required for most effective control[9].

RED-SHOULDERED SHOT-HOLE BORER

The red-shouldered shot-hole borer, Xylobiops basilare (Say), and other shot-hole borers also injure trees in a devitalized condition. The larvae feed in wood, pupate and emerge as adults through round holes about one-eighth inch in diameter in the bark. Many of these holes may be observed in close proximity to each other.

Control.—Since this insect feeds on dying or dead wood, prunings and dead limbs should be removed from the orchard and burned.

Adequate fertilizer and water will keep trees in a healthy condition and prevent injury by this pest.

FLATHEADED BORERS

The flatheaded apple tree borer, Chrysobothris femorata (Oliv.), and other species of flatheaded borers attack unhealthy or recently transplanted pecan trees by burrowing in the bark and sapwood of the large branches and trunk. Their presence is indicated by the appearance of darkened, depressed areas in the bark from which traces of frass may protrude. When these portions of the bark are removed, shallow winding burrows packed with sawdust may be observed. The burrows usually are on the sunny side of the trunk or branch, but may extend completely around and penetrate the wood to a depth of 2 inches. Young trees may be girdled by this insect.

The adult beetle is about one-half inch long, broad and blunt at the head end and tapering to a point posteriorly. Its wing covers, which have a metallic sheen, are dark colored and corrugated.

The larva, or borer, which is legless and yellowish white, attains a length of 1¼ inches when full grown. Immediately behind the head is a broad, flattened expanded area from which the insect takes its name.