State officials released 500 tiny black beetles into a forest in York this morning in hopes of fighting an infestation there of the hemlock woolly adelgid, an invasive insect that has decimated hemlock forests in other parts of the eastern United States.

The beetles released today are Laricobius nigrinus, which are native to the Northwest and were raised in a laboratory in Virginia. The Laricobius beetles eat only hemlock woolly adelgids and, over time, should slow the advance of the more destructive insects, entomologists said.

The adelgids, tiny brown and black bugs native to Japan, exude a woolly substance that appears at this time of year as white masses on the underside of twigs. They kill hemlocks by gradually sucking their sap.

Woolly adelgids were found in Kittery, York, Eliot, South Berwick and Wells in 2003 and 2004. State entomologists found the pests in Saco last summer and then confirmed this fall that they had infested trees in Kennebunkport.

Their threat to Maine forests is considered limited because of the colder winters, but officials fear the adelgids could spread further north in the milder coastal region.

File photo
A Hemlock branch infested with invasive adelgids --
visible as fuzzy white patches -- found in Ferry
Beach State Park in Saco in July.

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