Adults emerge from late May through early August, with emergence peaking in early July. As adults emerge, they leave small (one-eighth of an inch), distinctly D-shaped exit holes in the trunk and main branches, which is a sure sign of infestation. Adults feed on foliage for one to two weeks prior to mating. Females produce about 50 to 100 eggs, which are laid individually on the bark surface or within bark cracks and crevices.

As larvae hatch, they tunnel into the tree, where they feed through the summer and early fall on the phloem and outer sapwood, excavating S-shaped, serpentine galleries just under the bark. Larvae continue to feed through summer and into the fall, with most completing their development prior to over-wintering in the outer bark or just under the inner bark within the outer inch of sapwood. Pupation occurs in mid- to late-spring. Adults emerge soon thereafter to complete the typical one-year cycle.

The larva is the damaging stage, girdling the tree as it tunnels under the bark where it feeds primarily on phloem and xylem tissue. Adult beetles feed on foliage, resulting in irregular, jagged-edged patches of missing tissue along the leaf margin, the impact of which is negligible.

Ash trees are also used to make baseball bats, office furniture, tool handles, electric guitars and even drums.

Larval feeding on the inner bark of ash trees disrupts the tree's ability to transport water and nutrients, resulting in dieback and bark splitting. Emerging adults create D-shaped emergence holes.

The negative effects of EAB infestation don’t end with the death of the tree. Often, tree services must be hired to remove the dead tree, which can cost hundreds and even thousands of dollars.