Maryland is protecting threatened hemlock trees with…beetles?

08 December 2023- During the fall of 2023, the Maryland Department of Agriculture’s Forest Pest Management program hosted inter-state collections of Laricobius nigrinus beetles at Rocky Gap State Park, MD with the goal of redistributing the beetles to states in the North East in an effort to protect Eastern Hemlock trees against the invasive pest hemlock woolly adelgid. 

L. nigrinus beetles were originally released at Rocky Gap in 2004 from lab-reared individuals as part of a pest management strategy and thanks to a long-standing collaborative effort between the department’s Forest Pest Management program and the U.S. Forest Service’s Hemlock Woolly Adelgid Initiative, Rocky Gap State Park has become one of the most successful sites on the East Coast for establishment of this biological control.  

“Since the inception of the redistribution efforts of L. nigrinus, countless Eastern Hemlock trees in the North East have been saved,” said Maryland Department of Agriculture Secretary Kevin Atticks.  “I thank our dedicated team at MDA for leading this effort and the partners who work with us to make these collection efforts possible.” 

Led by the department’s Forest Health Specialist Biff Thompson, 2023 marked the most successful collection and redistribution event to date. Over the three-week collection period that occurred in late October and early November, MDA staff, State, and Federal cooperators from seven organizations collected over 8,000 beetles for distribution throughout six states. The Maryland beetles were released across the East Coast, assisting in the protection of Eastern Hemlock trees as far north as Maine and as far south as West Virginia. In the last three years this multi-state cooperative project has moved over 19,000 beetles to imperiled Eastern Hemlock forests in Maine, New Hampshire, Rhode Island, Ohio, Pennsylvania, Maryland, and West Virginia, including sites in National Parks. 

This year’s participants included Maryland Department of Agriculture Forest Pest Management program, Maryland Park Service, Maine Department of Agriculture Conservation and Forestry, Rhode Island Department of Environmental Management Division of Agriculture and Forestry, New River Gorge National Park, Pennsylvania Bureau of Forestry Division of Forest Health, New Hampshire Division of Forests and Lands, and the U.S. Forest Service Morgantown Field Office. The department wishes to express thanks to these partners as this project could not have been completed without their cooperation, participation, and assistance.