U.S. Forest Service adds new treatments in fight against Hemlock Woolly Adelgid

ASHEVILLE, NC ….The Forest Service will be using new approaches to protect hemlock forests under attack by the introduced insect pest, hemlock woolly adelgid. The new approaches will give forest managers a wider array of treatment options. These 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. The use of new treatments began in mid-October.

According to Marisue Hilliard, Forest Supervisor of the National Forests in North Carolina, “We are very concerned about how many hemlocks have already been killed by the hemlock woolly adelgid. 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 hemlock 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 monitoring has shown that a number of the conservation areas have suffered mortality, and can no longer function as genetic conservation areas for the hemlock. Forest Supervisor Hilliard decided in late August to allow expansion of the treatment areas, both to replace those that were lost as well as to add more areas overall. 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.

The forest analyzed three alternatives, including continuing current treatment, expanding treatment but without using the new chemical, dinotefuran, and expanding treatment options to include dinotefuran. During the public comment period last spring, thirteen comments were received, most of which supported the alternative that was eventually selected.

The new treatment options will be available for use in the ongoing adelgid treatment program this fall. For more information about National Forests in North Carolina hemlock conservation, please go to the website: http://www.cs.unca.edu/nfsnc/nepa/final_hwa_ea_2010.pdf.,
or contact David Casey, Silviculturist, at dmcasey@fs.fed.us. Read the full article