Green Ash Trees That Survive Beetle Infestation Pass on Their Resistance Through Propagation and Planting
The emerald ash borer (EAB) invasion of North America has left behind tens of millions of dead ash trees, leading many to wonder if our native ash species will become extinct. Monitoring ash trees in natural areas long infested by EAB led to the discovery of a small number of trees (less than 1 percent) that survived EAB attack. When Forest Service scientists grafted branches of some of these surviving trees and tested them by placing EAB eggs on them or by releasing adult beetles into cages containing leaves from different trees, they found that there may be more than one mechanism responsible for the increased resistance to EAB. Some trees weaken or kill larvae feeding on inner bark tissues, while others have leaves that are less preferred by adult EAB for feeding. Careful selection and breeding of these trees may lead to even larger increases in EAB resistance by combining the different defense responses. The researchers are propagating and planting clones, or copies, of more than 40 surviving ash trees to continue to test their EAB resistance and preserve them as a resource for further breeding.
Forest Service Partners