KINGSTON, N.Y.  — Forestry experts say a major infestation of the destructive emerald ash borer in New York’s Hudson Valley is the farthest east discovered so far and they’re trying to map its extent.

They’ve been searching a 225-square-mile area near Kingston for any sign of the invasive Asian beetle since February and expect to wrap-up this month.

The infestation found in July is much closer to New England than the leading edge of the main population spreading from the southern Great Lakes region. Foresters think the first insects arrived in logs or firewood as long as five to seven years ago.

About a dozen state and federal agencies have sent teams to examine ash trees in the area.

The borer was first found near Detroit in 2002. It has killed tens of millions of trees in 15 states and two Canadian provinces.