Asian Longhorned Beetle

asian longhorned beetle
Anoplophora glabripennis
Last updated by:

Faith Campbell, June 2020

  • The Asian longhorned beetle attacks dozens of species from 15 plant families, especially maples, elms, and willows
  • Forests dominated by vulnerable species make up more than 10% of all U.S. forests.
  • The Asian longhorned beetle has been introduced to North America and Europe at least 35 times beginning in the early 1990s. The pathway of introduction has been wooden crates and pallets.
  • Asian longhorned beetles continue to be detected in wooden packaging, despite regulations intended to prevent their presence.

Outbreaks of the Asian longhorned beetle (ALB) outside its natural range have been found 36 times – nine in North America (U.S. seven; Canada two); 26 in Europe (especially Austria, France, Germany, and Italy); and one in Japan. Seventeen of these outbreaks have been detected since 2012 (Eyre & Haack 2017). Ten of these outbreaks have been eradicated (Eyre & Haack 2017; supplemented by APHIS press release October 2019 and APHIS announcement May 2020).

In North America, Asian longhorned beetle outbreaks have been detected in the New York City metropolitan area (including northern New Jersey), Chicago, Toronto metropolitan area, central-eastern Massachusetts, southern Ohio, and South Carolina (Charleston Post and Courier 2020). Several of these outbreaks have been eradicated – Chicago in 2008; New Jersey in 2013; both the original and secondary Toronto infestations (Eyre & Haack 2017, 2020); and New York City in 2019 (APHIS press release October 2019). As of 2016, 85% of the New York infestation had been eradicated; 34% of the Massachusetts infestation; but only 15% of Ohio infestation (USDA APHIS annual report for 2016). In 2017, APHIS eradicated some of outlying infestations in Ohio (2018 APHIS annual report).

All of the North American infestations were first found by local residents (Haack et al. 2010) with the notable exception of the very small infestation in Boston, which was found by a groundskeeper. Additionally, the Chicago infestation was found by an off duty parks employee. All detections in North America have occurred between 2 and 10+ years after the beetle became established.

These eradication efforts are expensive; USDA APHIS spent approximately $640 million on ALB eradication efforts between the first detection in New York in 1996 and 2017 (Eyre & Haack 2017 for expenditures through 2013; annual appropriation levels for more recent years — $30-40 million per year). Cooperators have spent additional funds (USDA APHIS 2015). As of September 2018 authorities had removed more than 180,000 trees in Ohio, Massachusetts, New York, New Jersey, and Illinois. (USDA APHIS September 2018 press release). Tree removals are ongoing in the active eradication areas (Ohio, Massachusetts, and now South Carolina) so the total is constantly shifting upwards- and well exceeds 200K as of June 2020.

Canadian authorities had cut more than 26,000 trees by 2010 (Haack et al. 2010). Between 2001 and 2010, the European countries have cut more than 1,700 trees and spent nearly 550,000 Euros (Haack et al. 2010).

The risk of new introductions remains. Beetles in the family to which ALB belongs – the Cerambycidae – have been repeatedly detected in wood packaging moving internationally. Both U.S. and European data show rising numbers of Cerambycids detected in wood packaging in more recent years (Eyre & Haack 2017). In the course of studying pests detected in wood packaging entering the United States over the years 2012 – 2017, scientists found six ALB – all in Populus wood originating from a single wood-treatment facility in China (Krishnankutty et al. 2020b).

Upon detection of the second known North American outbreak in 1998, U.S. and Canadian authorities moved to prevent additional introductions. Their efforts resulted initially in tightened regulations governing wood packaging from China (USDA APHIS, 1998); then, in 2002, to adoption of an international standard requiring treatment of all wood packaging used in international trade (International Standard for Phytosanitary Measures #15). Widespread adoption of the standard (the U.S. and Canada began full implementation in 2006) has resulted in a reduction of the incidence of live insects in wood packaging by an estimated 32 – 56%. Nevertheless, the estimated 0.1% infestation rate of wood packaging entering the U.S. still amounted to 13,000 shipments per year in which the wood packaging is probably infested with a “quarantine pest” entering the U.S. (Haack et al. 2014).

Europe has had a similar experience. Interception records included in EUROPHYT show 306 Cerambycidae interceptions on wood packaging over the period 1998 – 2013. The number of interceptions recorded in 2012 and 2013 are double those of all previous years. Each year, the majority are on wood packaging from China (over the full period, 84% of the interceptions were in association with wood packaging from China). In Austria in 2013-2014, 8% of 451 consignments of stone imports contained live Cerambycidae, including ALB (Eyre and Haack 2017).

A two-year intensive survey of wood packaging associated with shipments of stone from China to the 28 European Union countries during 2013-2016 disclosed that quarantine pests were detected in 0.9% of the consignments – somewhat higher than the U.S. number, as could be expected because of the focus on a high-risk commodity. The data also indicated that the problem is not decreasing. Austria detected pests in nearly one-fifth (19.6%) of inspected shipments in 2016 – the final year of the study (Eyre et al. 2018, p. 712). The authors of the European study concluded that the ISPM-15 mark was of little value in predicting whether harmful organisms were present (Eyre et al. 2018).

The reason for the expensive eradication efforts is the expectation that the Asian longhorned beetle would cause considerable damage if allowed to spread. The beetle attacks dozens of species from 15 plant families. In North America, the beetle attacks most commonly maples (Acer), elms (Ulmus) and willows (Salix) (Haack et al. 2010). Northern hardwood forests reaching from the Atlantic to the Great Lakes and beyond are made up of vulnerable species – approximately 48 million acres in the United States plus the majority of Canada’s hardwood forests (USDA APHIS & Forest Service, 2000).

Forest types dominated by ALB hosts (maple-beech-birch and elm-ash-cottonwood) make up 45% of the forests in the 20-state region reaching from Maine to Minnesota and Maryland to Missouri.  At the national level, these forests represent 10% of all U.S. forests. Additional maples, elms, willows, sycamores and poplars grow in the South and West.  Thus, the Asian longhorned beetle threatens more than 10% of all U.S. forests.

Economic losses would be greatest to the urban forest. A study of seven cities in the northeast and north central regions (Baltimore, Boston, Chicago, Jersey City, New York City, Philadelphia, and Syracuse) found that half of their trees are vulnerable to Asian longhorned beetle. The estimated cost to remove and replace the trees killed (called compensatory value) would vary from $72 million in Jersey City to $2.2 billion in New York City. Nationwide, the Asian longhorned beetle could kill a third of urban trees, which have a compensatory value of $669 billion (Nowak et al., 2001).

In rural areas, the Asian longhorned beetle would damage a range of commercial interests. One obvious impact would be on timber production. Discounted monetary losses for timber resources around Chicago and New York would range from $1 million to $10 million 30 years after introduction (USDA APHIS & Forest Service, 2000). Other industries likely to be affected include maple syrup production, nursery production, and “leaf peeper” tourism. In 2019, maple syrup production was valued at nearly more than $129 million (USDA NASS 2020). In Vermont alone, the multiplier effect of the maple sugar industry to related equipment, manufacturing, packaging, and retail sectors equals $105 million annually and represents 4,000 seasonal jobs (USDA National Ag. Statistics Service, 2009; Andrienne Wojciechowski , pers. comm. December 2008). Autumn “leaf peeper” tourists spent close to $2 billion in just two states (Vermont and Maine) (USDA APHIS 2015).

USFS scientists and managers developed a conservation priority-setting framework for forest tree species at risk from pest & pathogens and other threats, published in 2017. The Project CAPTURE (Conservation Assessment and Prioritization of Forest Trees Under Risk of Extirpation) uses FIA data and expert opinion to group tree species under threat by non-native pests into vulnerability classes and specify appropriate management and conservation strategies. The scientists prioritized 419 tree species native to the North American continent. Given the 2020 discovery of an ALB infestation in South Carolina, it is concerning that of the 35 most vulnerable species identified, 24 are southeastern tree species. 


Charleston Post and Courier 2020. First SC Sighting of Invasive Beetle Reported in Charleston County Accessed 6/16/2020

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