Hickory Borer Goes pulcher (Haldeman)

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Order	Coleoptera
Suborder	Polyphaga
Infraorder	Cucujiformia
Superfamily	Chrysomeloidea
Family	Cerambycidae
Subfamily	Lamiinae
Tribe	Monochamini
Genus	Goes

Scientific Name

Goes pulcher

Common Name

living-hickory borer

Solomon, J. D.; Payne, J. A. A guide to the insect borers, pruners, and girdlers of pecan and hickory. Gen. Tech. Rep. SO-64. New Orleans, LA: USDA Forest Service. Southern Forest Experiment Station; 1986. 31 p.

Importance

The hickory borer, Goes pulcher (Haldeman), is found from southern Canada throughout the Eastern United States, and although primarily a pest of the hickories, will occasionally attack pecan (Barker 1972, Beal and others 1952, Solomon 1974). The larvae tunnel in the sapwood and heartwood of young trees 2 to 14 cm in diameter, mostly from groundline up to about 5 m. Attacks in large trees are infrequent and usually restricted to the branches. Borer injuries in vigorously growing trees usually heal within a few months after the borers emerge, but in trees of poor vigor, up to 3 years are required. Galleries that heal slowly are frequently occupied by ants for nesting sites and sometimes kept open indefinitely, thus permitting the establishment of stain and decay fungi. Trunks weakened by tunnels, woodpecker excavations, and decay occasionally break during windstorms. The holes, together with the associated stain and decay, degrade the wood for any commercial use.

Description

The adult is a typical long-horned beetle with a prominent lateral spine on each side of the pronotum (Solomon 1974). The beetle is light brown with dark elytral bands at the base of just beyond the middle of the wing covers (fig. 9A). They are miderately robust, elongate, and range from 17 to 25 mm long and 5 to 8 mm wide. Females are slightly larger than males and have heavier abdomens but slightly shorter antennae. The eggs are yellowish white, elongate, and average 4 mm long and 1 mm in diameter with a parchment-like surface texture. The larva is slightly robust, fleshly, and generally cylindrical but very slightly flattened dorsally and ventrally; the thoracic segments are slightly broader anteriorly (fig. 9B). The color varies from white to yellowish except for prominant dark-brown mandibles and amber spiracles. Larvae average 4 mm long when newly hatched and reach 18 to 28 mm at maturity. The pupa is white to greenish initially, but gradually becomes yellowish, and its eyes, mandibles, and appendages darken as adult transformation approaches.

Evidence of Infestation

The earliest signs of infestation are single or small groups of niches 4 to 8 mm in diameter chewed in the bark exposing the yellowish-brown phloem beneath (fig. 10A) (Beal and Massey1942, Solomon 1974). However, the most obvious evidence is the sap-stained bark and yellowish frass protruding from the elongate entrance hole (fig. 10B). Sap oozing from the point of attack initally darkens the bark, but in succeeding years the stain becomes bleached or yellowish brown. The frass extrudes from the entrance in curved shapes or ribbon-like pieces that accumulate on the ground below. Numerous excelsior-like wood fibers 8 to 12 mm long in the frass signal larval maturity and approaching pupation. Each borer leaves two holes, an elongate entrance hole and a 7-mm round exit hole (fig. 10C). As these wounds heal, the bark scar at the entrance site appears slightly sunken, with a small bulge around the periphery. The exit hole heals in much the same way that a branch stub is overgrown. The bark scars remain in evidence for several years. Wormholes 10 to 13 mm in diameter in sawn lumber provide good evidence of hickory borer infestation (fig. 10D).

Biology

The adults emerge during May and June (Solomon 1974). After feeding on tender twigs, leaf petioles, and leaf midribs and then mating, the female begins ovipositing. She chews an oval niche in the bark, then forces her ovipositor through the opening and downward between the bark and sapwood to lay a single egg. One female will deposit up to 14 eggs under experimental condition on caged trees but would probably deposit many more under natural conditions. Adults live from 11 to 32 days. Females usually deposit their eggs singly, although clusters of two or three egg niches are sometimes found. Open-grown trees and those growing near openings are most frequently selected for oviposition, with a preference shown for branch crotches. The larvae produce small mines 1 to 2 cm in diameter under the bark and then bore directly into the sapwood. The galleries extend horizonally or obliquely upward in the sapwood and heartwood for 2 to 5 cm, rise vertically for another 6 to 12 cm, then turn horizonally back to the surface. By the time the larva pupates, galleries range from 9 to 16 cm long and 10 to 13 mm in diameter. The life cycle is 3 to 5 years. During late fall and early spring of the final year of the life cycle, the mature larva prepares a pupation chamber at the uppermost portion of the gallery by plugging the gallery tightly with long excelsior-like fibers. Pupation lasts for 15 days. The new adult chews a round exit hole at the upper end of the pupal chamber to emerge.

Control

Woodpeckers, one of the most important natural enemies, may capture up to one-third of the larvae (Solmon 1974). Some natural mortality is found in vigorous trees that produce heavy sap that oozes from the oviposition sites. Direct controls have not been investigated, but borers in individual trees can be controlled by injecting a fumigant into the galleries, then plugging the entrance holes with clay or putty. Where problems exist in plantings near or adjacent to forests, removal of brood trees in the adjacent woodland is advised.