Scientific name: Agrilus planipennis 

Adult size: Typically about 8.5 mm (≈0.33 in) long and very narrow. 

Adult color: Bright metallic green with darker green or copper hues on the wing covers (elytra). 

Distinct feature: Only North American Agrilus species with a bright red upper abdomen visible when wings are spread. 

Body characteristics: Small spine at tip of abdomen and serrated antennae. 

Larvae appearance: Creamy white, flattened, segmented larvae that feed under ash bark. 

Signs of infestation:

• “S-shaped” feeding galleries under bark made by larvae.

• D-shaped exit holes in bark where adults emerge.

• Bark splitting, woodpecker activity, and canopy thinning

Insecticides such as azadirachtin, imidacloprid, emamectin benzoate, and dinotefuran can be used to protect ash trees from emerald ash borer. Imidacloprid and dinotefuran are systemic treatments, meaning they are absorbed into the tree and work from the inside out to kill feeding larvae. Depending on the product and tree condition, treatments may protect a tree for 1 to 3 years and require repeat applications to maintain protection. Treatment is typically considered for healthy, high-value landscape trees in urban or residential settings when caught early and before severe damage occurs. Treatments can be costly over time, must be repeated, and are often ineffective once a tree shows significant decline. For trees that are already declining, heavily infested, or located in wooded areas, removal is often the most responsible and cost-effective option. Removing infested trees helps reduce safety risks, limits further spread, and eliminates ongoing treatment expenses.