How an Invasive Beetle Almost Changed America’s Pastime

Pitchers are on the mound and warming up for this season's opening day of baseball. Ninety feet away, batters, armed only with a wooden stick, prepare to face them. Many parts of America's national pastime have changed over the years, but the two key elements - putting bat to ball - have remained at its core.

Until recently, though, this was taken for granted. An invasive beetle, the emerald ash borer (EAB), has been bearing down on North American forests like a pitch from Justin Verlander. This pest beetle has killed hundreds of millions of ash trees since they were discovered near Detroit in 2002. Ash is one of the main sources of wood for bats used in Major League Baseball.

But there is hope: scientists from the U.S. Department of Agriculture's (USDA) Agricultural Research Service (ARS), Forest Service (FS), and Animal & Plant Health Inspection Service (APHIS) have found and unleashed several predators of the EAB that unsettle the insect like a high-and-tight fastball.

"We have four parasitic wasps from the pest's native home (Northeast Asia) approved and released," said Jian Duan, entomologist with the ARS Beneficial Insects Introduction Research unit in Newark, DE. "The beauty of these wasps is that they are specialized to feed only on the eggs or larvae of the EAB. They do not feed on the ash tree itself, or any other trees or crops, and they haven't bothered pollinators or other beneficial insects."

While the wasps alone will not eradicate the EAB, they have controlled them to the point that they are killing far fewer trees. That's a win for baseball because it may keep bats in the hands of hitters from T-ball through the big leagues for years to come.