Wood Boring Insects in Alaska Wood Boring Insects Are Commonly Associated Figure 2

Wood Boring Insects in Alaska Wood boring insects are commonly associated Figure 2. Adult by Edward H. Holsten, Research Entomologist, Wood Boring with diseased, stressed, or dying spruce trees metallic woodborer, USDA Forest Service, Alaska Region, State and in Alaska. Commonly encountered woodborers Melanophila sp. Private Forestry and Karen E. Post, formerly are members of two insect orders; the Coleoptera, of the Alaska Cooperative Extension Service, Insects in Alaska or the beetles, and the Hymenoptera, or the University of Alaska. wasps. The wood boring beetles are members of two families; the long-horned beetles (also Additional information on this insect can be called roundheaded woodborers) (Cerambycidae) obtained from your local USDA Cooperative and the metallic woodborers (flatheaded wood- Extension Service office, Alaska Division of borers) (Buprestidae). Adult long-horned beetles Forestry office, or from: are characterized by antennae that are at least Generally, woodborer larvae are elongate and Forest Health Protection as long as their body (Figure 1). Their larvae have whitish; they have a legged or legless body, State and Private Forestry a rounded head, and they make galleries in depending on the species, and dark brown man- USDA Forest Service the sapwood that are rounded when viewed in dibles (Figure 4). Full-grown woodborer larvae 2770 Sherwood Lane, Suite 2A cross section. Metallic woodborers are wedge- measure about 5 cm in length. Juneau, Alaska 99801-8545 shaped beetles and are often shiny in appear- Woodborers are commonly mistaken for bark Phone: (907) 586-8811 ance (Figure 2). Their larvae have a flattened head, and they make oval-shaped galleries in beetles, particularly the spruce beetle Forest Health Protection the sapwood when viewed in cross section. (Dendroctonus rufipennis) and the engraver beetle State and Private Forestry Wood wasps are large, menacing looking (Ips sp.). However, woodborer adults and larvae USDA Forest Service yellow and black wasps about 2.5 cm long are three to five times the size of bark beetles. 3301 “C” Street, Suite 522 (cover photo). Their larvae are stout, legless In addition, bark beetles feed under the bark Anchorage, Alaska 99503 grubs, about 1.5 cm long, with a darkened and do not penetrate the wood, as do most Phone: (907) 743-9455 horny protuberance on the rear end (Figure 3). woodborers. or: All three woodborers have similar life histories. www.fs.fed.us/r10/spf/fhp/fhpr10.htm Life History Adult woodborers fly in late spring through mid- The U.S. Department of Agriculture (USDA) prohibits summer, mate, and find a suitable host tree in discrimination in all its programs and activities on the basis which the female lays an egg (oviposit) under of race, color, national origin, sex, religion, age, disability, the tree bark. Eggs hatch into larvae that feed political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) throughout the summer on phloem. In late Persons with disabilities who require alternative means summer, cerambycid, wood wasps, and some for communication of program information (Braille, large buprestid larvae bore into the sapwood where print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). they overwinter, pupate and emerge in spring as adults, completing the life cycle (Figure 5). To file a complaint of discrimination, write USDA, Some buprestid larvae spend their entire imma- Director, Office of Civil Rights, Room 326-W, Whitten United States Prepared by Leaflet Building, 1400 Independence Avenue, SW, Washington, Department of Forest Service R10-TP-95 Figure 1. Adult long-horned beetle, Monochamus scutel- ture life in the phloem region. DC 20250-9410, or call (202) 720-5964 (voice and TDD). Agriculture Alaska Region August 2001 latus. USDA is an equal opportunity provider and employer. The length of life cycle depends on the species small amounts of dark, sliver-shaped sawdust Firewood gatherers often express concern about and densities of woodborers and environmental being pushed from small holes in the bark. bringing infested firewood to their homes, fear- factors such as temperature and moisture con- Larvae may be found by peeling the bark from ing that the insects will infest building structures tent of the sapwood. Some species in other parts this area. As the larvae enter the sapwood, saw- and urban or ornamental trees. The chewing of the country are said to have life cycles as long dust being pushed from the hole in the bark noises of woodborers can be quite loud and as seven years. may change to a mixed yellow and dark colored sound potentially destructive. To oviposit, wood Some woodborers overwinter as larvae in the sawdust. Chewing sounds can be heard quite boring beetles need wood that has bark on it; phloem of standing trees either below or above distinctly at this time. Bark peeled from the log therefore, they cannot infest structures or peeled the snowline, depending on species. Others, may expose the irregularly shaped feeding gal- logs. Once established in suitable habitat, the such as the buprestid Chrysobothris trinervia, lery in the phloem and a hole leading into the larvae will not move to other locations. If hom- Figure 5. Roundheaded woodborer gallery, sapwood. eowners have spruce trees on their property presumably overwinter as adults. Pupation usu- Monochamus sp. ally occurs during a short period in the spring for The tunneling galleries in the sapwood may be that are stressed, weak, diseased, or dying, there those borers with one-year cycles. as large as 1-inch in diameter and penetrate to the may be a potential for borers that emerge in bodies. Melanophila sp. (Figure 2) oviposits in center of the tree, depending on the woodborer the spring from infested woodpiles to attack the Forest fires have a significant effect on wood- large roots exposed by fire and around the species. weakened trees. This problem can be alleviated borer activity. Some species are attracted to base of burned trees, not higher than a meter by burning the firewood before the beetles fly fire, using infrared sensors located on their above ground. High densities of a cerambycid, Wood boring beetles usually are not a primary in the spring, by keeping yard trees healthy and Monochamus scutellatus (Figure 1), were found agent of tree mortality, but may cause a structural vigorous through fertilization and watering, and Figure 3. Wood ovipositing in burned trees from the bases to weakness or susceptibility to pathogens such as by avoiding physical injury or damage to the tree. wasp larva. about 10 m aboveground. decay fungi. Lumber products manufactured from infested woodborer material may be struc- There are contact insectides that may be applied Wood boring insects may be considered ben- turally weaker than uninfested wood due to to the stems of trees to prevent woodborer infes- eficial in the forest, where they aid in the the nature of the winding larval galleries in the tation, but it will not kill woodborers once they breakdown and decomposition of dead woody sapwood. have gained entry into the phloem. Check with material. Their larval galleries in the wood create you local Alaska Cooperative Extension office entryways for pathogens to become established, for insecticides that are currently labeled for which further break down the cellulose and Control Measures prevention of woodborer attack. Figure 4. Wood borer larvae: fibers within the trees and replenish the soil with Mechanical control may be applied by peeling A. Roundheaded borer nutrients for new plant growth. Woodborers are the bark off recently felled logs that are to be (Cerambycidae); detrimental when they cause economic losses in used for lumber products or house logs. This will CAUTION: Pesticides can be injurious to humans, B. Flatheaded borer the form of wood degradation and volume loss. domestic animals, desirable plants and fish, or other prevent oviposition and remove young larvae wildlife—if they are not handled or applied properly. (Buprestidae). under the bark; however, it will not kill larvae Use all pesticides selectively and carefully. Follow Detection and Damage once they have entered the sapwood. Peeling of recommended practices for the disposal of surplus the logs should be done immediately after cut- pesticides and pesticide containers. Mention of a Woodborers can be detected in trees in a number pesticide in this publication does not constitute a ting the tree if the tree is felled in early spring of ways, depending on the developmental stage recommendation for use by the USDA, nor does through midsummer, which is the flight period it imply registration of a product under Federal of the beetle. In their early stages when the of adult woodborers. Trees felled in late summer Insecticide, Fungicide, and Rodenticide Act, as larvae are feeding in the phloem, a loud, should be peeled before the next spring flight amended. Mention of a proprietary product does not squeaky noise may be heard. There may be constitute an endorsement by the USDA. period. .

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