US Forest Service Research & Development
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  • 1400 Independence Ave., SW
  • Washington, D.C. 20250-0003
  • 800-832-1355
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Leah Bauer, Research Entomologist

Leah Bauer

Research Entomologist, Emeritus
3101 Technology Blvd., Ste. F
United States

Phone: 517-884-8059
Fax: 517-355-5121
Contact Leah Bauer

Current Research

My research has focused on key mortality factors that regulate populations of the emerald ash borer (EAB) [Agrilus planipennis (Coleoptera: Buprestidae)] in North America, where this invasive beetle is killing native ash (Fraxinus) trees, and in its native range in Asia where it is considered only a minor ash pest. A better understanding of EAB population dynamics may facilitate the development of safe, long-term, and sustainable management strategies to better protect ash from EAB in North America. Biological control is the generally accepted method for managing invasive pests, mainly insects and weeds, in environmentally sensitive ecosystems such as forests. USDA began an EAB biocontrol program in 2007, with the approval for release of three parasitoid species from China [Tetrastichus planipennisi (Eulophidae), Oobius agrili (Encyrtidae), Spathius agrili (Braconidae)] in the U.S.  A fourth species from Russian Far East [Spathius galinae (Braconidae)], was approved for release in 2015. These four parasitoid species are currently being reared and shipped by USDA APHIS for release in the U.S. by researchers, forest managers, and landowners. Research continues on the establishment and prevalence of native and introduced EAB parasitoids, as well as the impacts of biocontrol on EAB population densities, ash health, and forest recovery in the aftermath of EAB. 

Research Interests

My collaborative research continues at long-term study sites in Michigan where we are evaluating parasitoid establishment, spread, impacts on EAB population dynamics, and impacts on ash regeneration and survival.

Why This Research is Important

Emerald ash borer (EAB), an invasive beetle from Asia is spreading in North America, causing widespread mortality of native ash (Fraxinus) trees. EAB was first discovered in southeast Michigan in 2002 and likely arrived during the 1990s in EAB-infested solid-wood packaging materials used for international trade with Asia. Despite early efforts by regulatory agencies to eradicate EAB, infestations are known in 35 states, the District of Columbia, and four Canadian provinces as of August 2018. The ecological impacts of the EAB invasion are rapidly changing the biodiversity, species composition, hydrologic processes, and nutrient and carbon cycles in our forests. The survival of ash species native to North America may require a combination of both biocontrol and the discovery or development or EAB-resistant ash genotypes.


  • University of Kentucky, Ph.D. Entomology 1987
  • University of Maine, M.S. Entomology 1977
  • University of Michigan, B.S. Natural Resources 1974

Professional Organizations

  • Entomological Society of America
  • Society for Invertebrate Pathology (SIP)
  • International Organization for Biological Control
  • Michigan Entomological Society

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Citations of non US Forest Service Publications

Research Highlights


A suite of Introduced and Native Enemies Reduces Populations of the Emerald Ash Borer

Originally from Asia, the emerald ash borer (EAB) is an invasive wood-boring beetle that attacks and kills ash trees in the United States. The l ...


Biocontrol of the Emerald Ash Borer pest improves outlook for ash trees in North America

The invasion of forests by the emerald ash borer (EAB) has resulted in the death of hundreds of millions of ash trees throughout much of the U.S ...


Emerald Ash Borer Biocontrol Benefits the Health of Young Ash Trees

Forest Service research results from a multi-year study of ash trees in Michigan forests found that an introduced natural enemy of the emerald a ...


Emerald Ash Borer Natural Enemies Becoming Established in the United States

Optimism increasing for long-term management of the emerald ash borer


Guidelines for Release and Recovery of Emerald Ash Borer Biocontrol Agents

Biological control is a sustainable and long-term management tool for invasive species and is now being used to control the emerald ash borer (E ...


Mitigation of Invasive and High-Risk Wood-Boring Insects in China

The number of accidental introductions of wood boring insect pests to U.S. forests from Asia has escalated dramatically during the last two deca ...


Natural Enemies of Emerald Ash Borer are Fighting the Good Fight in North America

The emerald ash borer (EAB) continues to sweep across the North American landscape, leaving dead and dying ash trees in its wake. To reduce popu ...


Last updated on : 03/25/2021