With no parasitic wasps — like we have for emerald ash borer — and no miracle fungal pathogen — as with gypsy moth — our control options for the nonnative insect threatening Eastern hemlock forests, the hemlock woolly adelgid, have been tricky. Hemlock forests, and the hemlocks in your yard, are paying the price.

Related Research:

• "Hemlock Woolly Adelgid: A Non-Native Pest of Hemlocks in Eastern North America" (2018)
• "Mitochondrial DNA from Hemlock Woolly Adelgid Suggests Cryptic Speciation and Pinpoints the Source of the Introduction to Eastern North America" (2006)
• "Vegetation and Invertebrate Community Response to Eastern Hemlock Decline in Southern New England" (2012)
• "Hemlock Canopy Arthropods Biodiversity On A Threatened Host" (2009)
• "Spring Bird Migration as a Dispersal Mechanism for the Hemlock Woolly Adelgid" (2019)

Scientists:

• Nathan Havill, Research Entomologist, Northern Research Station, Hamden, Connecticut
• Talbot Trotter, Research Ecologist, Northern Research Station, Hamden, Connecticut

Produced by the USDA Forest Service Northern Research Station.

Want more information? Visit us at https://www.fs.usda.gov/research/nrs/products/multimedia/podcasts/forestcast-season-1-balance-and-barrier-episode-4-when-single

Questions or ideas for the show? Connect with Jon at: jonathan.yales@usda.gov