The hemlock woolly adelgid is a tiny, aphid-like insect that derives its name from the covering of wool-like wax filaments that it forms as it matures to protect itself and its eggs from natural enemies. A native of Asia, the adelgid has decimated hemlocks across western North Carolina since it was discovered in the state in 1995. The insect settles at the base of a needle and sucks out juices, causing bud mortality, twig dieback and defoliation. Under high infestation rates, the adelgid can cause tree death in as little as four to seven years.
In 2009, Commission employees combatted adelgids by chemically treating hemlock trees on Sandy Mush Game Land, which is located in Buncombe and Madison counties. Staff released the beetles last month because research indicates that biological control, combined with chemical control, yields the best results. This particular species of beetle, Laricobius nigrinus or Lari beetle, controls adelgids well because it is a voracious predator that feeds exclusively on woolly adelgids. Lari beetles, which are native to the Pacific Northwest, are winter feeders and can eat up to six adelgids per day before laying 200 to 400 eggs in the adelgid egg sacs. Each larva can consume 200 to 250 adelgid eggs or crawlers before they pupate in June. Once established, Lari beetles can advance up to 2 miles per year.
“Right now the trees that were chemically treated are very healthy and growing vigorously but are still infested with adelgids at low densities, while the untreated hemlocks in the same stands are highly infested with adelgids and have more than a 50-percent leaf defoliation and twig dieback with most of the lower branches dead,” said Joe Tomcho, a conservation technician with Commission who helped with the initial treatments. “We are hopeful that the Lari predator beetles will take hold and provide long-term control of the adelgids and help save the remaining hemlock stands on our game lands.” So why is saving a few trees so important to the Commission? The hemlock is excellent cover for all manner of wildlife. It’s a favorite haunt for my gamebird, the grouse, during cold and snowy or rainy weather. I’ve found them there many times. Let’s hope this works.
Regular readers of this column have repeatedly heard me expound on the importance of early successional, or young forest, growth for wildlife. If you really want to learn more about it, I encourage you to visit The Young Forest Project by the Wildlife Management Institute (WMI). WMI has been around since 1911 and was started by sportsmen and businesses worried about the loss of wildlife species. This is just one of their many projects. The WMI does scientific research and publishes results on the importance of young forest growth for a variety of wildlife. It recognizes that young forests are needed as part of a diversity of habitat needed as much as are mature forests and wetlands which we already protect.
Their website, www.youngforest.org, is an invaluable resource for anyone wanting to learn more about the role young forests provides for wildlife and how it is established. There are 42 species of birds alone that depend on young forest growth to include golden-winged warblers, Blue Grosbeaks, ruffed grouse, and woodcock. If you go to their resources page on their website there are numerous downloadable publications that you can read and share with friends to help their understanding of young forests.
Why do I mention this? After the latest round of Forest Service meetings about the Pisgah/Nantahala plan revising, and the resulting misinformation being perpetuated by environmentalists, it is clear that the general populous does not understand the important role young forests play not just for wildlife but also as part of a diverse landscape that leads to a healthy forest. I encourage anyone who is interested in all aspects of forest management to visit their website and learn more about young forest as part of our National Forests in North Carolina.