Exotic Bark Beetles: Invading Our Trees

Exotic bark beetles pose a significant threat to trees worldwide, causing extensive damage to those that lack natural defenses against them. But what are bark beetles, what specific threats do they pose, and what can be done to mitigate their impact?


Examining the Threat

Exotic bark beetle is a broad name for multiple species of insects that can cause extreme devastation to trees. Common examples of bark beetles are the Emerald Ash Borer and the Mountain Pine Beetle. While these insects are native to specific regions or ecosystems, they wreak havoc by invading new areas with tree populations that are defenseless against them. By tunneling through the bark of healthy trees, laying their eggs, and disrupting the flow of nutrients and water within the tree, bark beetles ultimately cause the tree’s decline and death. A region-wide infestation can have ecological and economic consequences, including a loss of biodiversity, negative impacts on the timber industry, increased fire risks, and costly expenses of removing infected trees.

While exotic bark beetles invade many areas of the country, certain states are particularly susceptible to their presence. Florida and California, for example, have ports that receive a large amount of imported goods and often experience an influx of beetles hitchhiking on shipping containers or wood packaging. Additionally, the emerald ash borer has made its way inland to devastate ash trees across Michigan, Nebraska, Iowa, and Wisconsin.


Identifying Infestations

Recognizing the warning signs of an exotic bark beetle infestation is crucial for early detection and intervention. Some common indicators include:

  • Dead or dying branches;
  • Discoloration of leaves and the canopy;
  • Boring holes visible on bark;
  • Sawdust near the tree; or
  • Bark splitting and peeling away from the tree’s trunk.

If any of these signs are observed, consult an arborist who can accurately identify the beetle species and develop an action plan for the affected tree. Early intervention can potentially save individual trees and prevent infestation from spreading to neighboring trees.


Taking Action

Trapping has emerged as a promising strategy for managing infestations. The process involves strategically placing traps in the forest that attract and capture adult beetles. These traps are typically made of materials that mimic the scent and texture of a healthy tree. By doing so, they lure the beetles away from the live trees and into the traps. Once trapped, the beetles are removed from the area, preventing them from reproducing and infesting healthy trees.

Trapping offers several advantages as a management strategy. Its environmentally friendly approach does not involve harmful chemicals and pesticides, making it a safe option for protecting trees without causing additional harm to the environment or other non-target species.

Trapping is also a proactive approach that can be used as part of an integrated pest management plan. Traps effectively disrupt the beetle’s life cycle and reduce their populations by trapping them before they lay their eggs.

Trapping is also a cost-effective strategy compared to other methods, such as aerial spraying or tree removal, and can be easily deployed.

Lastly, trapping can be implemented as a monitoring tool to assess the severity of infestations and track changes in beetle populations over time. This information can then help inform forest management decisions as well as the implementation of appropriate control measures.

The threat posed by exotic bark beetles requires vigilance, awareness, and proactive measures. By understanding their nature, recognizing warning signs, and seeking professional assistance, the impact of these invasive insects can be minimized, protecting our trees and ensuring their preservation for future generations.


For more information about exotic bark beetles, contact JEO's ISA Certified Arborist, Dana Genereux.

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