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Banded elm bark beetle

Written by V.G. Nealis Revision 2025

General information and importance

Banded elm bark beetle is native to central and northeastern Asia. It was first identified in western North America in 2003 but likely introduced a decade or more earlier. It is established in Canada from British Columbia to Quebec, and across much of the contiguous United States. Its principal hosts are elms (Ulmus).

The greatest threat from banded elm bark beetle is its potential as a vector of the introduced fungal pathogens (Ophiostoma ulmi and O. novo-ulmi) causing Dutch elm disease, a vascular wilt with catastrophic impacts on elms in North America and Europe. The more virulent O. novo-ulmi, which was introduced more recently than O. ulmi, has become the dominant pathogen that causes Dutch elm disease in Canada. Two other beetle vectors of the pathogens are already present in North America: native elm bark beetle (Hylurgopinus rufipes) and the introduced European elm bark beetle (Scolytus multistriatus). Native elm bark beetle is the most common vector in Canada but has been displaced by the European elm bark beetle in the southern portions of their shared ranges and invaded western North America outside the range of the primary host, white or American elm (U. americana). Banded elm bark beetle may be displacing European elm bark beetle in western North America and native elm bark beetle in parts of its range. Banded elm bark beetle can transmit Dutch elm disease but is no more efficient in doing so than the other two elm bark beetles. Banded elm bark beetle and European elm bark beetle are the only significant vectors in western North America, outside the native range of the primary elm host. Their populations may be sustained, in part, by elms planted in urban and park landscapes.

As with other elm bark beetles, female adults of banded elm bark beetle locate and bore through the bark of stressed, moribund, or recently dead trees where they construct galleries and lay eggs. It is not the beetle that causes tree mortality because the trees they colonize are already dead. However, if trees used for brood were infected with the pathogen causing Dutch elm disease, the beetles developing in these trees become contaminated with spores of the pathogen. When these adults move to healthy trees for their maturation feeding, spores can infect the healthy tree via the feeding scars.

Distribution and hosts

Banded elm bark beetle is native from Kazakhstan to Mongolia in central Asia, east through Siberia to northern China, and Korea. This insect is introduced to North America including Mexico. It is most common in western North America but now occurs in Canada from British Columbia to Quebec and throughout most of the contiguous United States from the Pacific coast to scattered locations in the northeastern states. It has not been verified present in the southeastern United States.

Primary native host trees in Canada and the United States are white or American elm (U. americana) and rock elm (U. thomasii), with additional susceptible elms in the United States. Most introduced elms to North America are susceptible, especially the main host in Asia— Siberian elm (U. pumila), as well as English elm (U. procera), European white elm (U. laevis), and field elm (U. minor). In its native Asian range, banded elm bark beetle is reported from several broadleaf hosts, including willow (Salix), pea-tree (Caragana), crab apple (Malus), and cherry and plum (Prunus), but these have not been recorded as hosts in North America.

Tree parts affected

Adults of banded elm bark beetle feed in the crotches of twigs on living elm trees. This is a common site of infection by spores of the fungal pathogen. Female beetles bore into bark of moribund trees, mining galleries in the inner bark where they lay their eggs. Hatching larvae construct feeding tunnels in the phloem at right angles to the egg gallery.

Symptoms and signs

Feeding activity of adults in crotches of living twigs in the canopies of healthy trees is not usually evident, especially when viewed from the ground. Boring dust may be seen around entrance holes of moribund trees. Removal of bark reveals vertical egg galleries and larval feeding tunnels radiating outward from galleries. Egg galleries are constructed vertically, along the grain of the wood. Eggs are laid along the side of the gallery and the female returns to the entrance and dies. Hatching larvae tunnel perpendicular to the egg gallery through the phloem, sometimes crossing one another. Larvae are white, legless grubs with brown heads. Pupae are frail and white with visible adult features including legs and antennae. Adults are 2.7 to 4.3 millimetres in length with a broad, transverse, dark band across the wing coverings (elytra).

Life cycle

In Asia, banded elm bark beetles have two to three overlapping generations per year. Limited information for Canada suggests no more than two generations. This insect overwinters as mature larvae, possibly as pupae or adults, although survival of these latter stages is low. Adults emerging in the spring feed in the crotches of twigs on live trees to complete maturation. This is the most likely period when spores of the pathogen causing Dutch elm disease are transmitted. Female beetles locate stressed or moribund trees through host volatiles and bore through the bark to the phloem. There is no evidence of pheromones released to initiate mass attack as in other bark beetles. The female is joined by a male and mated. Egg galleries are constructed vertically, along the grain of the wood by females. Eggs are then laid along the side of the gallery and the female returns to the entrance and dies. Hatching larvae tunnel perpendicular to the egg gallery through the phloem. Final instar larvae migrate to the outer bark, form a chamber, and pupate. Adults emerge through holes chewed in the bark.

Damage

Damage to twigs in the crowns of healthy trees by feeding adults is inconspicuous but are likely sites of infection by the pathogens causing Dutch elm disease. Broods are produced in trees and large branches that are stressed, moribund, or already dead. Tree death is caused by the transmitted fungal pathogen and not by the beetle. Dutch elm disease has caused catastrophic mortality to elm, which was once a dominant hardwood tree of eastern North America and favoured amenity tree in urban settings.

Prevention and management

The life history, area of invasion, and habits of banded elm bark beetle are similar to that of European elm bark beetle, and so are prevention and management strategies. Direct control of both Dutch elm disease and beetle vectors is costly and often insufficient. It takes only a few adult beetles to transmit the pathogen and once present, the rate of infection is magnified rapidly as subsequent generations of beetles are exposed to more pathogen and presented with an increasing number of dying trees available for their brood.

Monitoring susceptible stands, maintaining vigorous trees, rapid removal of dead, damaged, and infected trees, and preventing movement of infected wood are the main methods of prevention and management. Traps baited with general bark beetle attractants (α-pinene and ethanol) or with commercial pheromone lures used for European elm bark beetle can be used to detect and monitor populations of banded elm bark beetle. Pruning diseased branches has been effective, although more likely to retard rather than stop progress of the disease. Removal and destruction of dead and dying trees is important as are restrictions on movement of firewood or any wood with bark out of infected areas.

Elms have been planted extensively as urban amenity trees outside their native ranges where they may be stressed from seasonal droughts and local urban conditions, making them more susceptible to attack by elm bark beetles. Replacement of infected trees with non-susceptible species is an option. There appears to be a genetic basis to vulnerability, so collecting seed from young elms that are apparently resistant to Dutch elm disease would be a step toward establishing resistant stock.

Pest management strategies for a particular pest vary depending on several factors. These include:

Decisions about pest management strategies require information about each of these factors for informed decision-making. These various factors should then be weighed carefully in terms of costs and benefits before action is taken against any particular pest.

Pheromones and pesticides are defined as pest control products and are regulated in Canada. Products registered for use against banded elm bark beetle under specific situations may change from year to year. Therefore, please search Health Canada’s Pesticide Product Information Database for currently registered pesticides and product information for use against this insect. The application of any registered product should be based on population size and applied only when necessary and against the approved life stage. It is also recommended to consult a local tree care professional. Chemical pesticides may be toxic to humans, animals, birds, fish, and other beneficial insects. Apply registered products only as necessary and according to all directions and precautions noted on the manufacturer’s label. In some jurisdictions and situations, only a licensed professional can apply pesticides. Consulting relevant local authorities to determine local regulations that are in place is recommended.

Selected references

Davis, R.S. 2011. Elm bark beetles and Dutch elm disease. Utah Pests Fact Sheet. ENT-147-11. 3 p. https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1895&context=extension_curall [Accessed September 2024]

EPPO. 2020. Pest information sheet: Scolytus schevyrewi (Coleoptera: Scolytinae). Pages 139–144 in EPPO Study on the risk of bark and ambrosia beetles associated with imported non-coniferous wood. EPPO Technical Document No. 1081. 218 p. https://www.eppo.int/media/uploaded_images/RESOURCES/eppo_publications/TD-1081_EPPO_Study_bark_ambrosia.pdf [Accessed March 2024].

Lee, J.C.; Negrón, J.F.; McElwey, S.J.; Williams, L.; Witcosky, J.J.; Popp, J.B.; Seybold, S.J. 2011. Biology of the invasive banded elm bark beetle (Coleoptera: Scolytidae) in the western United States. Annals of the Entomological Society of America 104(4): 705–717. https://doi.org/10.1603/AN10150

Humble, L.M.; John, E.; Smith, J.; Zilahi-Balogh, G.M.G.; Kimoto, T.; Noseworthy, M.K. 2010. First records of the banded elm bark beetle, Scolytus schevyrewi Semenov (Coleoptera: Curculionidae: Scolytinae), in British Columbia. Journal of the Entomological Society of British Columbia 107:21–24. https://journal.entsocbc.ca/index.php/journal/article/view/13/12 [Accessed October 2024]

Martín, J.A.; Domínguez, J.; Solla, A.; Brasier, C.M.; Webber, J.F.; Santini. A.; Martínez-Arias, C.; Bernier, L.; Gil, L. 2023. Complexities underlying the breeding and deployment of Dutch elm disease resistant elms. New Forests 54:661–696. https://doi.org/10.1007/s11056-021-09865-y

Martín, J.A.; Sobrino-Plata, J.; Rodríguez-Calcerrada, J.; Collada, C.; Gil, L. 2019. Breeding and scientific advances in the fight against Dutch elm disease: Will they allow the use of elms in forest restoration? New Forests 50: 183–215. https://doi.org/10.1007/s11056-018-9640-x

Negrón, J.F.; Witcosky, J.J.; Cain, R.J.; LaBonte, J.R.; Duerr II, D.A.; McElwey, S.J.; Lee, J.C.; Seybold, S.J. 2005. The banded elm bark beetle: a new threat to elms in North America. American Entomologist 51(2): 84–94. https://doi.org/10.1093/ae/51.2.84

Smith, S.M.; Hulcr, J. 2015. Chapter 12 - Scolytus and other economically important bark and ambrosia beetles. Pages 495–531 in F.E. Vega; R.W. Hofstetter, editors. Bark beetles: biology and ecology of native and invasive species. Elsevier, Amsterdam. https://doi.org/10.1016/B978-0-12-417156-5.00012-5

Cite this fact sheet

Nealis, V.G. 2025. Banded elm bark beetle. In J.P. Brandt, B.I. Daigle, J.-L. St-Germain, A.C. Skinner, B.C. Callan, and V.G. Nealis, editors. Trees, insects, mites, and diseases of Canada’s forests. Natural Resources Canada, Canadian Forest Service, Headquarters. Ottawa, Ontario.