Tree Health - Emerald Ash Borer

ISA Certified Arborists are expertly trained to treat emerald ash borer (EAB) infestations, ensuring effective management of this destructive beetle. Using our International Society of Arboriculture credentials, we assess ash trees and apply targeted treatments, such as trunk injections with insecticides like emamectin benzoate, to protect trees with minimal environmental impact. Our professional approach maximizes treatment success, helping preserve valuable ash trees.

Identifying Emerald Ash Borer

The Emerald Ash Borer (EAB) (Agrilus planipennis) is an invasive beetle devastating ash trees across North America. Early identification is crucial to manage infestations and protect trees. Below are key signs and characteristics to identify EAB activity and confirm its presence.

Adult Beetle Identification

Appearance: Metallic green, bullet-shaped body, about 1/3 to 1/2 inch long and 1/16 inch wide.
Active Period: Adults emerge from trees in late spring to early summer (May–July), often seen on ash tree leaves or bark.
Distinctive Features: Bright, iridescent green wings; flattened back; and a slightly golden or coppery abdomen visible when wings are spread.

Signs of Infestation

Look for these symptoms on ash trees as EAB larvae feed under the bark, disrupting nutrient and water flow:

Canopy Dieback: Thinning or yellowing leaves, starting at the tree’s top and progressing downward, often indicating 30–50% infestation.

D-Shaped Exit Holes: Small, D-shaped holes (1/8 inch wide) in the bark, left by adult beetles emerging from the tree.

S-Shaped Galleries: Winding, serpentine patterns under the bark, created by larvae feeding. Peel back loose bark to check.

Epicormic Shoots: Sprouts or small branches growing low on the trunk, a stress response to EAB damage.

Bark Splits: Vertical cracks in the bark, often exposing larval galleries, due to feeding activity.

Woodpecker Activity: Increased woodpecker damage or “flecking” (light patches on bark) as they feed on EAB larvae.

Treatment

1. Recommendation: Based on tree health, size, and value, we will advise on treatment or removal. Healthy or lightly infested trees (under 30% canopy loss) are candidates for treatment; severely damaged trees are recommended for removal.

2. Treatment Selection:

Trunk Injection: Preferred for larger trees (over 15 inches diameter at breast height, or DBH). They inject systemic insecticides like emamectin benzoate (e.g., Tree-age) into the trunk, providing 2–3 years of protection. This method is highly effective (up to 90%) and minimizes environmental impact.
Soil Drench: For smaller trees (under 15 inches DBH), they may apply imidacloprid-based soil drenches in spring (mid-April to mid-May), ensuring proper soil moisture for uptake. They advise homeowners on DIY options if appropriate.

3. Application: As licensed pesticide applicators, we use specialized equipment (e.g., injection systems) to ensure safety and efficacy. We wear protective gear and adhere to state regulations.

4. Monitoring and Maintenance: We can schedule follow-up inspections and retreatments every 1–3 years, as EAB protection is ongoing. We will monitor tree recovery, looking for improved canopy density and reduced EAB signs.

5. Environmental Considerations: Here at Treetec we prioritize low-impact methods (e.g., trunk injections over sprays) to protect pollinators and aquatic ecosystems.