Good Bugs Good News For Hemlocks First Results From Banner Elk Test Site Promising By Miles Tager High Country scientists are optimistic that the predator beetle, Laricobius nigrinus, will prey on the Hemlock woolly adelgid. Photo courtesy of Dr. Richard McDonald of Symbiont Biological Pest Management A year ago on another cold High Country day, a half-dozen scientists gathered at a wooded spot on the Lees-McRae campus in Banner Elk to release barely visible beetles on old-growth hemlock trees, some thought to have been growing there since the age of Columbus. And virtually all showing sign of the dreaded Hemlock woolly adelgid, an invasive species capable of reducing the old growth to no growth. Then, as now, the hope was that the introduced predator beetle, the Laricobius nigrinas, would feed on the adelgid in the field as they had in university studies. That hope has now been raised to cautious optimism, according to consulting biologist Dr. Richard McDonald, one of a team that took the Virginia Tech-raised beetles and released them in the area’s only test site in December, 2003. The first-ever in North Carolina, the Hemlock Hill experiment with the Laricobius has now brought in enough data for the scientists to consider the status of the good bugs and the trial protocol “in a very good spot,” McDonald said. The three-hundred adult predator beetles, like their prey natives of Asia, were set on their hemlock branches a year ago; researchers had to wait through the hard 2004 winter until April to see whether the next generation would hatch in the wild, and in the cold. The spring brought the good news of “recovery of adult beetles,” McDonald said; a ‘native’ generation of “our very own bugs.” Further examination in October and November, after more extreme weather, revealed good bugs in three out of the ten hemlocks on the test site, including survival at the two different locations at the base of the hill and a half-mile up the slope. “They basically survived two hurricanes,” McDonald said. “What this means is that they are trying to set up on this site, and in the next round of the cycle should, or could, multiply like crazy.” Each female beetle can lay “between 200-400 eggs,” McDonald said. Laricobius unusually “feeds from October to March, covering a unique period, McDonald said; further, both the larvae and adults prey on the adelgid. McDonald cautions that the progress, though encouraging, represents only the first stages of a process that may take another year to claim success; for example the group is “just beginning the process of determining the ratio of pest populations to number of predators released.” Data “will be analyzed to determine the possibilities of single-tree releases for urban situations,” McDonald said. But good groundwork has been laid with the good bugs; the Lees McRae site represents “the first field recovery of Laricobius in the Eastern United States.” Other local sites are being considered for testing, McDonald said. The timing of the news has the scientists excited for another reason; McDonald and others will be leaving for Asheville, North Carolina in a few weeks to attend a national conference on saving the hemlocks, and hope to present their findings to date with a view to garnering additional support. “We have been trying to save our hemlocks on a shoestring,” McDonald said, and now have enough results to “be a leading edge” in the national effort to control the destructive work of the adelgid. “It is still too early to know,” McDonald said; “but we have reason to hope that we will see suppression on Hemlock Hill.”