Author: Masen Webster, Conservation Assistant at Saratoga PLAN
On October 29th, Saratoga PLAN (PLAN) staff were joined by Cornell University’s New York State Hemlock Initiative to release hundreds of Laricobius beetles into select hemlock trees on the Snake Hill Preserve. This effort is part of an ongoing integrated pest management effort on the preserve and aims specifically to protect the preserve’s hemlock trees which serve a critical ecological role not just on the preserve but across the state.
The target of PLAN’s integrated pest management is the hemlock woolly adelgid (HWA). These tiny, aphid-like insects were introduced to the United States in the 1920s from Japan and have since spread across the country, becoming a destructive invasive pest. The adelgid has only recently spread to the northern reaches of the state, in part due to warmer winters that contribute to their survival. They are most easily detected by the white woolly masses they produce at the base of hemlock needles, where they feed on the trees’ needles. HWA poses a serious threat to the region’s hemlock trees, as an infestation can kill an eastern hemlock in as few as four years, killing the needles and preventing photosynthesis.
What makes PLAN’s approach “integrated pest management” is the use of both chemical and biological control (biocontrol) methods to establish long-lasting prevention. Starting in 2024, PLAN worked with CGL Arbor to address some of our most critical and most threatened hemlock stands with targeted chemical treatment. The release of the Laricobius beetles will act in tandem with these treatments by introducing a natural predator to HWA that eats the pest and can help control infestations. These beetles are native to the Pacific Northwest, where they feed exclusively on hemlock woolly adelgid. The population released on Snake Hill was reared by Cornell’s New York State Hemlock Initiative as part of their statewide effort to protect hemlock trees. The initiative has been releasing the Laricobius beetles across the state since 2008.
Beyond PLAN’s commitment to protecting the beauty of the natural landscape, preserving Snake Hill’s hemlocks has important ecological benefits. Well suited for steep slopes where many other species cannot grow, hemlocks play a crucial role in preventing erosion in shallow soils. Their dense shady canopies help regulate water temperatures in streams and lakes they typically grow along, maintaining habitat conditions for many aquatic species. Rising temperatures and increasingly frequent drought conditions pose major threats to New York’s hemlock populations. Preserving the ecological benefits these trees offer requires intervention. In protecting Snake Hill’s hemlocks, PLAN aims to reduce the spread of HWA through the region and demonstrate how diligent stewardship can make a difference.
Saratoga PLAN thanks Cornell’s New York State Hemlock Initiative for its technical assistance in assessing the severity of the infestation and providing the biocontrol species for release. Additionally, PLAN would like to thank Capital Region PRISM (Partnership for Regional Invasive Species Management) for providing partial funding for this project using funds from the Environmental Protection Fund as administered by the New York State Department of Environmental Conservation (DEC).
References
https://blogs.cornell.edu/nyshemlockinitiative/
https://www.epa.gov/climateimpacts/climate-change-connections-pennsylvania-eastern-hemlock
https://dec.ny.gov/nature/animals-fish-plants/insects-and-other-species/hemlock-woolly-adelgid