One day, scientists hope, borer-resistant trees will provide seeds to replace some of the millions of ash that have been lost. But a very small proportion of ash trees — maybe 1 percent — seem to be resisting the beetles. These have become known as “lingering ashes,” and Wildova and Rosenthal routinely brave poison ivy for them.

https://e360.yale.edu/features/ash-tree-borers-breeding-wasps