Back in mid-October the U.S. Forest Service began using a series of new approaches to save hemlock forests under attack from woolly adelgids.
The new approaches include aerial application of an adelgid-killing fungus, use of the chemical dinotefuran in high-priority areas where trees are in immediate danger of dying, expanding the number of sites that will be treated, releasing new species of predator beetles as they are evaluated, and allowing the use of the longer-lasting chemical, imidacloprid, on all treatment areas as needed.
“We are very concerned about how many hemlocks have already been killed by the hemlock woolly adelgid,” said Marisue Hilliard, forest supervisor of the National Forests in North Carolina. “It is a catastrophic pest that is continuing to kill eastern and Carolina hemlocks throughout their range. We intend to use all appropriate tools in conserving hemlocks for future generations.”
In 2005, the forest service identified 159 eastern and Carolina hemlock areas that were distributed throughout a conservation network designed to represent genetic diversity within the distribution of known hemlock stands. These areas were part of a larger conservation network of areas being treated in surrounding states. Initial treatments focused primarily on release of certain predator beetles and treatment of high-priority areas with imidacloprid.
Follow-up studies have shown that hemlocks in a number of the conservation areas have died. Hilliard decided in late August to increase the number of treatment areas. In addition, the wider range of allowed treatments will help forest managers select the treatments best suited for a specific area. The recent decision will also give the forest access to new treatments and predator options in the future.