Image courtesy Howard Russell, Michigan State University.

ARS Insect Lab Identifies Beetle Threatening Ash Trees

Of all insect species identified by the Agricultural Research Service's Systematic Entomology Laboratory (SEL) since 1999, a beetle that feeds on ash trees represents perhaps the greatest threat to become a major pest.

Since its discovery near Detroit in May 2002, the emerald ash borer, Agrilus planipennis, has decimated the ash tree population in parts of Michigan and forced quarantines to be imposed there and in parts of Ohio and Ontario.

Ash is a valuable hardwood that provides habitat for wildlife, ornamentals for landscapers, and wood for makers of handles, oars, baseball bats, furniture and baskets.

The metallic-green beetle, which feeds beneath the bark of green (Fraxinus pennsylvanica), white (F. americana) and black (F. nigra) ash trees, is indigenous to Asia. It is feared that the borer, which probably entered this country about five years ago in wooden packing material, will cause damage rivaling that caused by the Asian longhorned beetle (Anoplophora glabripennis) and Dutch elm disease.

When first found, the bug stumped authorities trying to identify it. They sought help from the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS), which, in turn, sent specimens to SEL's Communications and Taxonomic Services Unit in Beltsville, Md.

The unit, led by entomologist Robert Carlson, helps solve taxonomic problems and provides identifications needed for carrying out APHIS' Plant Protection and Quarantine program. It also assists individuals and other agencies.

Carlson sent a sample borer to Richard Westcott, a cooperating entomologist with Oregon's Department of Agriculture, who confirmed its suspected immigrant status. Eduard Jendek, an entomologist with the Academy of Sciences' Institute of Zoology in Bratislava, Slovakia, made the final identification.

The emerald ash borer is one of more than 50 species of insects and mites newly identified in the United States by SEL since 1999.

ARS is the U.S. Department of Agriculture's chief scientific research agency.