Working to save Catskill Hemlocks from Hemlock Wooly Adelgid, the Hemlock Initiative introduces silver flies in a controlled release.


A new friend in the rally to save New York’s hemlocks arrived on Overlook Mountain in Woodstock this past Tuesday — the silver fly. The New York State Hemlock Initiative, with partners at the Catskill Center for Conservation and Development and the New York State Department of Environmental Conservation, released Leucopis spp. silver flies on hemlock trees on Overlook Mountain. The health of these trees is at risk due to an invasive insect from Japan, the hemlock woolly adelgid (HWA).

The NYS Hemlock Initiative is releasing these flies onto heavily-infested hemlock branches wrapped in fine mesh bags. The bags help to establish an initial persistent population of the silver flies. The hope is that the silver flies will spread in the area after the bags are taken down, moving into other HWA-infested areas in the state.

These released flies feed specifically on hemlock woolly adelgid, coming to New York from the Pacific Northwest where they are native predators of HWA. These newcomers are an important next step in preserving the New York hemlock forests in our landscape.