Emerald Ash Borer | Facts

An accidental import from Asia discovered in the United States in 2002, the borer has killed millions of ash trees in several U.S. states and Canadian provinces. The insect is predicted to cause an unprecedented $10 billion to $20 billion in losses to urban forests over the next decade.

Ash trees are valued for their shade and represent anywhere from 10 percent to 40 percent of all trees in urban areas of Ohio, the Ohio State University Extension Service says.

An emerald ash borer adult is green, about one-half inch in length and lives June through August. The larvae live year-round.

Exit holes: Native ash borers have round or oval exit holes one-fourth of an inch across in the tree bark. The emerald ash borer has a “D” shaped exit hole one-eighth of an inch in size.

Ash trees are identified by being “opposite-branched,” meaning twigs come out directly opposite one another on a branch. Maple trees are also opposite-branched.

Source: Ohio State University Extension Service