Iowa latest state to release wasps in an attempt to stop borers that are destroying ash trees

Iowa is turning its hopes to wasps to defeat the invasive emerald ash borer that has infested ash trees in 31 of the state's 99 counties, Donnelle Eller reports for The Des Moines Register. In the coming days officials will begin releasing thousands of wasps, a natural enemy of the ash borer, to attack it. "Iowa will use two species of parasitic wasps. One lays its eggs inside the emerald ash borer egg; the other, its larvae. Both use the borer to feed its offspring." While the wasps won't be a silver bullet, the hope is that they "lessen the impact" of the ash borers, said Mike Kintner of the state Department of Agriculture. He said the wasps, which are the size of a grain of rice, are harmless to humans. (Wisconsin Department of Natural Resources photo by Bill McNee: Eulophid wasp)

The U.S. Department of Agriculture blames the ash borer for destroying tens of millions of trees nationwide, Eller writes. "Iowa has an estimated 52 million rural ash trees and about 3.1 million more ash trees in urban areas." USDA says ash borer have been detected in 25 states: Arkansas, Colorado, Connecticut, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and Wisconsin. Wasps have been used in most of those states to combat ash borer.