Stingless Wasps Imported To Iowa To Fight Emerald Ash Borer

DES MOINES — Thousands of stingless wasps are being enlisted to slow the onslaught of an imported pest attacking Iowa’s ash trees.Officials with the Iowa Department of Agriculture and Land Stewardship say they are turning to stingless, parasitic wasps that are natural enemies of the emerald ash borer, a highly destructive pest of ash trees that was accidentally introduced into North America from Asia and now is present in 31 Iowa counties.Mike Kintner, the department’s EAB and gypsy moth coordinator, said the “biocontrol” effort that will begin Thursday with the release of several thousand wasps at Whitham Woods near Fairfield will not be a “silver bullet” to rid Iowa of the EAB infestation but the introduction of natural enemies will serve as a long-term management strategy to lessen the borer’s adverse impact.“They seek out the emerald ash borer larva and then the larva of these wasps actually will feed on the emerald ash borer so they basically become a parasite,” said Laura Jesse, an extension and outreach entomologist at Iowa State University’s Plant and Insect Diagnostic Clinic.This is the first release of the natural enemies of EAB in Iowa, which has roughly 52 million rural ash trees and 3.1 million urban ash trees, but Kintner expects additional sites may be treated with biological releases to suppress and slow the spread of the destructive insects.Emerald ash borer was first detected in the United States in 2002 and was confirmed in Iowa’s Allamakee County in 2010, prompting state officials eventually to quarantine the transport of firewood among all 99 counties as a way to contain the problem.“We’re doing all we can to help slow down the spread of this and using the parasitic wasp is one more component,” Kintner said.Following rigorous USDA testing and research on one or more parasitic wasp species that are native to Asia, similar releases of the Asian-based borers’ natural predators have been made in 23 of the 25 U.S.