Ash trees in the Allegheny National Forest are declining and dying due to the presence and spread of the emerald ash borer.
To conserve ash on the ANF, the U.S. Forest Service is proposing to release wasps that feed on emerald ash borer larvae. Releases could begin as early as May, after which sites would be closely monitored.
There are no effective landscape scale treatment options, the Forest Service says. Wasp releases are becoming an integral part of the strategy for suppressing emerald ash borer on a smaller scale. The Pennsylvania Bureau of Forestry has released more than 40,000 of these wasps since 2011 in counties across the state.
Emerald ash borer was first found on the national forest in June 2013. Nearly 100 percent ash mortality is likely to occur on the ANF over the next 10 years, posing risks for forest health, biodiversity and public safety.
Three types of non-stinging, parasitic wasps are available — Oobius agrili, Tetrastichus planipennisi and Spathius agrili. Initial releases would be this spring in areas in the national forest, and may continue in future years at similar forested sites. Infested ash trees will provide abundant emerald ash borer hosts for these wasps, which will facilitate their establishment in treated area. Post-release monitoring will be performed.
Comments are requested by April 7. More information is available on the Forest Service’s website.