The Asian Longhorned Beetle (ALB) and the Emerald Ash Borer (EAB) are two of the most destructive invasive forest pests introduced to North America. Both insects, originating from Asia, share a common history of introduction and have inflicted catastrophic ecological and economic damage. The connection between Anoplophora glabripennis (ALB) and Agrilus planipennis (EAB) lies in their status as non-native, wood-boring insects that kill millions of healthy trees. Their parallel invasions have forced governments and scientists to develop coordinated strategies to protect North American forests.
Shared Origin and Introduction Pathway
Both the Asian Longhorned Beetle (ALB) and the Emerald Ash Borer (EAB) are native to the Far East; the ALB originates in China and the Koreas, and the EAB is from Northeast Asia. They were introduced to North America unintentionally through the same mechanism: solid wood packaging material (SWPM) used in international trade. This packaging, including wooden pallets, crates, and dunnage, was often made from raw, untreated wood that harbored the insects during shipping.
The ALB was first discovered in New York in 1996, and the EAB was found near Detroit, Michigan, in 2002. Their arrival highlighted a significant flaw in import screening processes, demonstrating that global trade provided a direct pathway for forest pests. This common mode of introduction led directly to the implementation of new regulations for international commerce.
In response to the threat posed by these and other wood-borne pests, the International Plant Protection Convention (IPPC) developed the International Standards for Phytosanitary Measures No. 15 (ISPM 15). This global standard requires that all non-processed solid wood packaging material used in international trade be treated, either by heat or fumigation, and marked with a certified stamp.
The treatment involves heating the wood core to 56 degrees Celsius for a minimum of 30 continuous minutes, a process designed to eliminate living insects or pathogens. The earlier arrival of ALB and EAB demonstrated the devastating consequences of the unprotected trade route before ISPM 15 was widely adopted and enforced.
Similarities in Ecological Impact and Host Specificity
The primary similarity in the destructive potential of the ALB and EAB lies in the feeding behavior of their larval stages. Both are wood-boring insects whose larvae tunnel extensively just beneath the bark, feeding on the tree’s phloem and cambium tissues. This tunneling creates winding galleries that effectively girdle the tree, interrupting the flow of water and nutrients and ultimately resulting in the tree’s death.
The two beetles differ in host specificity, but both cause high mortality rates for specific tree genera. EAB is a specialist, targeting almost exclusively ash trees (Fraxinus species), and has caused the death of hundreds of millions of ash trees across North America. North American ash species lack the co-evolved defenses found in Asian ash, leading to nearly 100% mortality in infested areas.
The ALB, by contrast, is a more generalist pest, with a host range that includes over 12 species of hardwoods, showing a preference for maples (Acer species). Maples are a dominant genus in North American forests and urban landscapes, placing them at extreme risk from ALB infestation.
The ALB’s wider host range threatens a greater variety of ecological niches and industries, including the maple syrup and timber trades. Both insects attack and kill healthy trees, triggering rapid forest decline and causing substantial economic losses related to tree removal and replacement costs.
Coordinated Management and Regulatory Response
The federal and state responses to these two invasive borers developed a shared framework, representing their most significant regulatory connection. The initial management strategy for the ALB focused on eradication through the immediate removal and destruction of infested trees, a tactic that successfully eliminated isolated infestations in places like Chicago and New Jersey. This aggressive approach set the precedent for handling similar high-risk invasive wood borers.
The USDA Animal and Plant Health Inspection Service (APHIS) plays a central role in managing both pests, utilizing quarantines to restrict the movement of host materials, particularly firewood and nursery stock. The experience with ALB heavily influenced the initial response to EAB, leading to a federal domestic quarantine for EAB established in 2003. However, due to the EAB’s widespread distribution and the quarantine’s ineffectiveness in stopping long-distance spread, APHIS rescinded the national domestic quarantine in January 2021.
This regulatory shift for EAB redirected resources toward non-regulatory control methods, primarily the rearing and release of biological control agents, such as specialized parasitoid wasps from Asia. While eradication remains the goal for ALB, the EAB response has evolved into a long-term management and containment strategy. This strategy integrates state-level quarantines, chemical treatments, and biocontrol. This unified, multi-faceted approach applies lessons learned from the earlier ALB infestation to the EAB threat, representing the core of their coordinated regulatory response.