Emerald Ash Borer: Symptoms and Treatments

Ash trees are susceptible to a number of pests and diseases, including anthracnose, yellows, and rust, but the Emerald Ash Borer is by far the most destructive. The EAB is a serious threat that essentially strangles the tree, causing rapid decline and death. Young or stressed trees may succumb in as little as a season or two, while even robust, mature trees may die within four to five years. Over the last few decades, EAB has caused extensive damage to the woodland systems throughout the northeast. It is important that businesses and homeowners have their trees inspected regularly for signs of EAB. Most infestations, when caught early, are treatable and reversible. However, many homeowners end up being too late.

What are the warning signs of the EAB?



Emerald Ash Borer Treatment Options

There is little to be done to save an infected tree, however, control measures can be taken to reduce damage to infested trees and prevent infestation from spreading.

The following are the most effective Emerald Ash Borer treatment and control methods:

Trunk injection –

• Who applies treatment: Licensed pesticide applicators (LPAs)
• Treatment process: An LPA will drill through the bark and into the outer sapwood of the ash tree, where they will inject the insecticide.
• Frequency: 1-3 years, depending on the selected product
• Effectiveness: When properly administered by an LPA, some trunk injections have shown to be 90 percent effective at controlling EAB, making this treatment the most effective method by far
• Drawbacks: Cost and potential drilling wounds. While the most effective, trunk injections that last multiple years are typically more expensive than other EAB treatments.

Soil Drench –

• Who applies treatment: LPAs, or property owners (if ash tree is under 12” diameter at chest height)
• Treatment process: Though soil drenches vary, they’re typically applied in the form of liquid or as granules that are then watered into the bare soil around the, thus allowing the product to take hold in the roots of the tree
• Frequency: The ideal frequency varies by product and the size of the ash tree being treated. However, soil drench treatments should not be applied more than once a year.
• Effectiveness: Inconsistent. In some trials, EAB control was excellent, while others yielded poor results. That said, soil drenches administered by tree professionals proved to be more effective.
• Drawbacks: Effectiveness and environmental impact. While they proved to be better EAB control than no treatment at all, soil drenches are significantly more likely to fail than trunk injections. They’re also more likely to impact other plants, insects, and animals that may be near the tree.

Bark Spray –

• Who applies treatment: LPAs
• Treatment process: This formulated insecticide is sprayed on the bottom five to six feet of the ash tree using a common garden sprayer. That insecticide then penetrates the bark and is transported systemically throughout the tree.
• Frequency: Once annually
• Effectiveness: Inconsistent. The results of effectiveness testing on bark sprays have yielded similar results when compared to the testing on soil drenches.
• Drawbacks: Effectiveness and environmental impact. Pesticides can blow onto adjacent plants, potentially impacting plants, insects, and animals nearby.

Remove and Replace –

• Who applies treatment: Licensed tree care professionals
• Treatment process: While some property owners may be savvy enough to plant a tree on their own, removing a tree is a complicated process that requires a tree professional – oftentimes for permitting or safety reasons
• Frequency: Just once
• Effectiveness: 100 percent. While getting a new tree to take hold presents its own challenges, removing and properly disposing of an ash tree is 100 percent effective at controlling the spread of EAB.
• Drawbacks: Losing a tree that may have intrinsic value to the property owner

If you have ash trees, it is very important that you have your trees inspected on a regular basis and treated to prevent infestations. The impact of EAB has been significant, but ongoing efforts in research, management, and public participation aim to mitigate the damage and protect ash tree populations for future generations.

References:

How to Treat Ash Trees for Emerald Ash Borer Damage - Prince Gardening

How To Identify Emerald Ash Borer: Symptoms And Prevention (rwhendricksenco.com)

Emerald Ash Borer Treatment Options | Be a Smart Ash

How To Identify Emerald Ash Borer: Symptoms And Prevention (rwhendricksenco.com)

Images - Canva