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Exotic Wood-Boring Insects (EWBI)
Target Orders: Wood boring insects in the Coleoptera, Hymenoptera, and Lepidoptera.

Target Families: Buprestidae, Cerambycidae, Curculionidae (Platypodinae and Scolytinae); Siricidae and Xiphydriidae; Cossidae and Sesiidae.


wood-boring beetle
Sirex noctilio
wood-boring beetle
 
Target Species: There are many species of exotic wood boring insects that are targets of our surveys. A few examples are listed below.
Brown spruce longhorned beetle (Cerambycidae: Tetropium fuscum)
This European beetle was found damaging spruce in a city park of Halifax, Nova Scotia. Although other conifers are attacked, spruce is the favored host. In its native Europe, this species normally attacks severely stressed, dying, or recently dead trees. It is more aggressive here, attacking apparently healthy trees. So far, the only known North American distribution is in or near Halifax.
 
European wood wasp (Siricidae: Sirex noctilio)
This European wood wasp has been introduced into Argentina, Australia, Brazil, Chile, New Zealand, South Africa, Tasmania, and Uruguay. Although rarely known to attack other conifers, it almost exclusively attacks pines. It is not a significant pest in its native Europe. However, in those countries where it has been introduced, it has been extremely destructive, killing millions of pines in plantations, mainly Monterey pine (Pinus radiata). Unfortunately, it has now been discovered in northern New York and adjacent Pennsylvania and Ontario, Canada. Whether it will have the same impacts on our native pines as it has had on plantations of exotic pine elsewhere is unknown.
 
Granulate ambrosia beetle (Scolytinae: Xylosandrus crassiusculus)
The granulate ambrosia beetle is native to southern Asia, but has been introduced to Africa, Australia, and the southern U.S., where it was first found in 1974. Because this insect does not directly feed on wood tissue but just uses that as a medium to grow a symbiotic fungus upon which it does feed, it can attack a very broad range of woody trees and shrubs. It is known to attack over 200 hosts in 41 families, mainly broad-leafed species, but also including pines.
 
Identification: One of the challenges of this project is that there are hundreds, perhaps thousands, of potential target species throughout the world. In order to confidently ascertain whether a given specimen represents a possible exotic species, all wood boring insects captured must be identified. Considering that one trap in a two-week sampling period may collect as many as 4,000 specimens of target insects amid possibly hundreds of thousands of non-target insect specimens, this can present a formidable task. Depending upon the specific program and its extent, over a hundred thousand target specimens have been collected and identified in a single season.

Below are a few examples of the types of insects we've collected in these surveys.
Buprestis aurulenta
Scolytus schevyrewi
Semanotus amethystinus
Urocerus californicus
 
 
Images of: Buprestis aurulenta, Scolytus schevyrewi, Semanotus amethystinus, and Urocerus californicus

 
Damage: In most cases, the feeding and galleries caused by larvae are the primary damage, although adult emergence holes can also cause damage. With Platypodinae and Scolytinae, adult galleries can also be extensive and damaging. All Platypodinae and Siricidae and many Scolytinae have symbiotic fungi that also damage hosts. In fact, these pathogens may have more impact than the mechanical damage directly caused by their insect symbionts. Disruption of the water and nutrient transport mechanisms of the host can be fatal. Breakage via weakening of branches and trunks can also be severe. Other pathogens and wood boring insects may be able to take advantage of weakened hosts or may gain access through damage caused by the initial attackers. Many "wood boring" insects actually restrict their activities to the interface of the wood and the underside of the bark. These include the true bark beetles (many Scolytinae) and many Buprestidae and Cerambycidae. Other species may bore directly into the wood, such as the ambrosia beetles (Platypodinae and many Scolytinae), many Buprestidae and Cerambycidae, and the Siricidae and Xiphydriidae.
Ips galleries
X. germanus gallery
buprestid galleries
 
Images of Ips galleries, Xylosandrus galleries, Buprestid galleries.

 
Impacts: Exotic wood borers have the potential to cause substantial damage. Examples of high profile wood borer problems in the U.S. include: Asian longhorned beetle (Anoplophora glabripennis), which can feed in and eventually kill many North American hardwood trees. Its discovery in cities such as Chicago, IL, New York, NY, and Worcester, MA has necessitated large scale eradication efforts including the destruction of thousands of trees. The European woodwasp (see above), which has demonstrated the ability to be a significant pest, has recently been found in New York state. Finally, Emerald ash borer (Agrilis planipennis), originally found in Michigan, has brought about the destruction of millions of ash trees and has resulted in a quarantine on movement of ash tree material from Illinois, Indiana, Michigan, and Ohio.

These introduced species can have adverse impacts on Oregon’s forestry and nursery industries not only due to damage and death of trees and shrubs, but also due to trade restrictions, such as quarantines, on Oregon products. In addition, these insects can become pests of landscape plants around homes and businesses, as well as cause environmental degradation.

Host plants: Woody shrubs and trees, sometimes nuts, large seeds, or fruit pits. Specific wood borers may attack only one or a few species of hosts, all hosts in a given genus or family, a wide variety of coniferous or broad-leafed hosts, or both coniferous and broad-leafed hosts (the latter host range is rare). Some wood borers, mainly ambrosia beetles, are very non-specific and are known to attack hundreds of species in many genera and families.
 
Distribution: Highly variable due to the large number of species involved.

distribution maps
 
Biology and Life Cycle: Although there is a large degree of variability because of the number of insect groups involved, there are some general statements that can be made about the biology of wood boring insects. Wood boring insects undergo complete metamorphosis as they develop (egg, larva, pupa, and adult). The adult is the vehicle by which the insect spreads to new hosts. Once a suitable host is found (usually a stressed, dying, or dead host, although healthy hosts are sometimes attacked by exotic wood borers) the adult either lays eggs in the bark or in some species may actually bore through the bark, making elaborate nursery chambers for their offspring. If a species is associated with a symbiotic fungus, it will be established at the time when eggs are being laid (Platypodinae, Siricidae, and some Scolytidae). Larvae hatch and (depending on the species) either begin feeding on the introduced fungus, phloem, xylem, or the wood itself. Larval feeding generally causes the most damage. As the larvae feed they shed their exoskeleton as they grow. Next, a pupa is formed in which the change will be made to an adult. The adult emerges from the pupa and chews its way out of the host plant so that it can find a mate and produce offspring.
 
Pathways: Wood boring insects can be introduced to Oregon in a number of ways. One of the most challenging to monitor is the movement of solid wood packing material such as pallets, crates, and dunnage (used for bracing cargo on ships). Other pathways include nursery stock, untreated wood products such as raw logs and lumber, and decorative crafts made with untreated wood, especially when with bark.

What ODA is doing: Each year, ODA performs visual surveys and places Lindgren funnel traps baited with a variety of lures at high-risk sites across the state. In 2005 of exotic wood borers were detected in The Dalles from imported raw railroad ties. A subsequent eradication effort was successful to eradicate the Asian Ambrosia beetle. 
 
What you can do to help:
1. Buy firewood locally. Obtain firewood near your home or the campground you are staying. Do not transport firewood from out of state into Oregon.
2. Use caution when buying untreated wood materials from outside of the U.S., especially carvings and other decorations that still have bark.
Unfortunately, many native species closely resemble the species that are targets of our surveys, so the best thing to do when damage is identified that could be caused by an exotic species is to capture and preserve the insect (link?) or call ODA to inspect the damage.
 
 
Links:
2010 annual report
 
Photo credits:
Agrilus planipennis gallery photo by Josh Vlach, Oregon Department of Agriculture
Insect photos by Steve Valley, Oregon Department of Agriculture
Ips gallery photo by Ronald F. Billings, Texas Forest Service, www.forestryimages.org
Xyleborus gallery photo by Daniel Adam, Office National des Forêts, www.forestryimages.org