Emerald Ash Borer

What is it?

The emerald ash borer (EAB) is an invasive beetle species native to Asia. It's a significant threat to ash trees in North America and parts of Europe. These metallic-green beetles lay their eggs on the bark of ash trees. When the eggs hatch, the larvae bore into the tree and feed on the inner bark, disrupting the tree's ability to transport water and nutrients. This feeding eventually kills the tree.

EAB infestations have devastated millions of ash trees across the continent since their accidental introduction in the early 2000s, likely through international shipping. Efforts to control EAB infestations include the use of insecticides, biological control methods (such as introducing natural predators), and tree removal programs to prevent further spread.

The economic and ecological impacts of EAB are substantial, as ash trees are important components of many ecosystems and have significant economic value in industries such as forestry and urban landscaping. Efforts to manage and mitigate the spread of EAB continue to be a priority for conservationists and policymakers.

I have healthy ash trees, how can I protect them?

Protecting healthy ash trees from emerald ash borer (EAB) infestations requires a combination of preventive measures and vigilant monitoring. Here are some steps you can take:

1. Early Detection: Regularly inspect your ash trees for signs of EAB infestation, such as D-shaped exit holes in the bark, S-shaped larval galleries under the bark, canopy dieback, and increased woodpecker activity. Early detection allows for prompt action to prevent further spread.

2. Insecticide Treatments: Consider applying insecticide treatments to healthy ash trees, especially if EAB has been detected in your area or if your trees are in close proximity to known infestations. Systemic insecticides injected into the tree's trunk or applied to the soil around the base can be effective in protecting against EAB larvae.

3. Professional Consultation: Consult with a certified arborist or forestry expert to assess the health of your ash trees and determine the most appropriate treatment plan. They can recommend the best insecticide products and application methods based on your specific situation.

4. Tree Health Maintenance: Keep your ash trees healthy and vigorous through proper watering, mulching, and fertilization. Healthy trees are better able to withstand insect infestations and other stressors.

5. Quarantine Measures: If EAB has been detected in your area, be cautious about moving firewood or other ash wood products to prevent the accidental spread of the beetle to new areas.

6. Biological Control: In some cases, introducing natural predators or parasitoids of EAB, such as certain species of wasps, can help reduce beetle populations. However, this approach may require careful consideration and professional expertise to ensure effectiveness and minimize unintended ecological consequences.

7. Tree Removal: In situations where EAB infestations are severe or widespread, and treatment is not feasible or cost-effective, consider removing and replacing ash trees with species that are not susceptible to EAB.

By implementing these measures, you can help protect your healthy ash trees from emerald ash borer infestations and contribute to the overall efforts to manage and mitigate the impact of this destructive invasive species.

How do I identify affected ash trees?

Identifying trees affected by the emerald ash borer (EAB) involves looking for specific signs and symptoms of infestation. Here are some key indicators to watch for:

1. Canopy Thinning: One of the early signs of EAB infestation is gradual thinning of the tree's canopy, starting from the top and progressing downward. This occurs as the beetles disrupt the tree's nutrient and water transport systems.

2. Epicormic Shoots: In response to stress caused by EAB feeding, the tree may produce new shoots, called epicormic shoots, along the trunk and branches. These shoots may appear as clusters of small branches with leaves.

3. Bark Splits and Vertical Cracks: As EAB larvae tunnel under the bark, they create serpentine galleries that disrupt the flow of nutrients and weaken the tree's structure. This can lead to the formation of vertical splits or cracks in the bark.

4. D-shaped Exit Holes: Adult EAB beetles emerge from infested trees through small, D-shaped exit holes in the bark. These exit holes are a distinctive characteristic of EAB infestation and are typically found on the trunk, branches, and main stems of affected trees.

5. S-shaped Larval Galleries: Underneath the bark, EAB larvae create winding, S-shaped galleries as they feed on the tree's inner bark. These galleries can be seen by carefully peeling back the bark, revealing the larval feeding tunnels.

6. Increased Woodpecker Activity: Woodpeckers are natural predators of EAB larvae and may be attracted to infested trees. Look for signs of woodpecker activity, such as pecked or stripped bark, as they feed on EAB larvae beneath the bark.

7. Dieback and Decline: As the infestation progresses, affected trees may exhibit extensive dieback of branches and ultimately decline in overall health. This can result in a greater susceptibility to secondary pests and diseases.

If you observe any combination of these signs and symptoms in your ash trees, it's important to take action promptly to assess the extent of the infestation and implement appropriate management strategies, which may include insecticide treatments, tree removal, or other control measures. Consulting with a certified arborist or forestry expert can help you accurately identify and address EAB infestations in your area.