Chinese Fliers Sent in to Eradicate New England Beetles

Officials in Connecticut have called up a Chinese flying unit to help fight one of the state's most destructive invaders.

To be clear, the fighters are small, stingless, parasitic wasps which are native to China but raised here in the States and released May 30 in the New England towns of Prospect and Middlebury, in an effort to control the emerald ash borer beetle.

The Emerald ash borer is responsible for the death and decline of tens of millions of ash trees from the Midwest to New York State and south to Tennessee.

Ash trees, which are common in urban areas, make up about 4% to 15% of Connecticut's forests, according to a report in the Ridgefield Press.

The wasp release is being conducted in cooperation with the United States Department of Agriculture's Animal Health Inspection Service, under specific guidelines set for the use of parasitoids against the emerald ash borer.

Parasitoids are organisms that spend a significant portion of their lifespans attached to or within another single host organism; however, unlike true parasites, which may lead a decline in the overall health of host species but don't necessarily lead to their demise, parasitoids typically sterilize, kill and frequently consume their hosts.

The female Tetrastichus planipennisi wasp lays eggs inside the beetle's larvae where the developing parasitoid larvae kill the ash borer larvae.

The destructive beetle insect was first discovered in Prospect in July 2012 and afterward found in eight other Hew Haven County towns --- Naugatuck, Bethany, Beacon Falls, Waterbury, Cheshire, Oxford, Middlebury, and Hamden.

The emerald ash borers were detected through reports from members of the public, as well as surveys conducted by the Agricultural Experiment Station, Department of Energy and Environmental Protection and the University of Connecticut Cooperative Extension.

Emerald ash borer was also identified in Dutchess County, N.Y., Berkshire County, Mass., and Merrimack County, N.H., the Ridgefield Press report said.

The release of the Tetrastichus planipennisi wasp, the beetle's natural enemy, "is another valuable approach in our efforts to manage and slow the spread of the emerald ash borer" state entomologist Kirby C. Stafford III was quoted saying by the Ridgefield Press.

Another wasp parasitoid, the Oobius agrili, which can kill up to 80 percent of all emerald ash borer eggs laid in through a summer, will be released at a later date.

So far, the two parasitoid wasps have been released in 14 of the 19 states where the emerald ash borer has been found.

The wasps were discovered in China, where the emerald ash borer also originated. They are being reared by the USDA in a laboratory in Michigan.

A quarantine was previously established in Connecticut that regulates the movement of ash logs, ash materials, ash nursery stock, and hardwood firewood from within New Haven County to any area outside of that county. The quarantine currently applies to only that part of the state and duplicates a federal quarantine also imposed on New Haven County.