An aphid-like insect called adelgid is killing North Carolina hemlocks, but the Lari beetle is being used to replace the chemicals once used to control them. The Linville, N.C., golf course released 14,000 Lari beetles and up to 90% of the club’s hemlocks have survived.
More than half of North Carolina’s forest hemlocks have died in the past 15 years, but the beetle Laricobius nigrinus, a native of the Pacific Northwest known as lari, feasts on the aphid-like insects that kill the trees, called hemlock woolly adelgids, the Charlotte (N.C.) Observer reported.
Lari’s proving ground is Grandfather Golf & Country Club in Linville, N.C. The 14,000 beetles released there since 2008 have replaced the chemicals once used to control the adelgid. Eighty-five percent to 90 percent of the club’s hemlocks have survived, and many have put on growth spurts, the Observer reported.
“We’re back to the point where we were before the adelgid hit,” said golf course superintendent Pete Gerdon. “We bring people in now, who know about this problem, who are stunned” by the rebound.
The beetle has scored similar, if less dramatic, success across Western North Carolina. Adelgid experts are more optimistic about the trees’ survival than they were just a few years ago, when infestations peaked, the Observer reported.
Lari’s arrival in the North Carolina high country was the work of Gerdon’s friend Richard McDonald, a Watauga County entomologist who set out to save the hemlocks. Researchers discovered in 2006, several years into the infestation, that the adelgids previously traced to Japan are also natives of the Northwest. Because hemlocks there still thrive, McDonald knew, they must have native predators, the Observer reported.
McDonald’s business, Symbiont Biological Pest Management, uses predator insects and other ecological controls on insect pests. The strategy works for broccoli fields and golf courses. McDonald convinced Grandfather’s directors to send him to Seattle for two weeks in 2008 to collect Lari beetles, the Observer reported.
Government agencies had studied Lari for six years, making sure it wouldn’t cause problems in its new territory, before approving releases in 2002. Fifty-nine trips later, McDonald has released Lari in dozens of places in the Grandfather region and as far west as Cashiers, the Observer reported.
“I thought we were doomed,” he said of the hemlocks. “The data kept telling us we were doomed until about 2009, when the trees stopped dying.”
McDonald said the nearly 150,000 beetles he’s collected in the Northwest, and from the growing North Carolina population, have multiplied into the millions. “I started finding beetles everywhere I looked.”
Jesse Webster, a forester at the Great Smoky Mountains park, says beetles are now the best long-term hope for the surviving hemlocks. He calls McDonald their Johnny Appleseed. “I have seen what he’s talking about,” Webster said, “and seeing is believing.”
Lari beetles have established a foothold in the park, Webster said, and seem to be maintaining a predator-prey balance with the adelgid. Hemlocks in the park’s half-million acres can now go longer without being treated with chemicals, and smaller amounts are needed when they are treated. Recent frigid winters, which control the pest in the Northeast, have helped by killing many adelgids, the Observer reported.
The Smokies’ hemlocks are still producing seeds for a new generation. Research is underway to help restore the species. And the search for more adelgid-munching beetle species such as Lari continues, the Observer reported.
“We see a lot of hope for the future,” Webster said. “We’ve seen that tsunami wave, and now we’re collecting the pieces and establishing the forests of the future.”
North Carolina’s agriculture department used money from an unrelated pollution settlement to start the Hemlock Restoration Initiative last year. The initiative has paid for Lari releases on state lands and this year will hire a coordinator to work with the public. Rusty Rhea, a U.S. Forest Service entomologist in Asheville, calls Lari a “major player” in saving the hemlocks, the Observer reported.
“Trees that looked bad five or six years ago are starting to come back,” he said, as the beetles spread. The service still uses chemicals to treat trees, as a short-term measure, but hopes to rely increasingly on beetles, the Observer reported.
Rhea is cautious about declaring the beetle a hemlock savior. It will take years of observation, he says, to gauge Lari’s real impact. With so many trees already lost, his hope for the hemlocks is modest: To maintain it on the landscape and restore trees where they’ve been lost. “If we could save a third of them, I’d be happy,” he said.
Grandfather Golf & Country Club, where the adelgid had been spotted in 2001, was willing to bet on Lari. A $25,000 contract it gave McDonald financed a two-week beetle collecting trip to Seattle. Course superintendent Gerdon went with McDonald and came back a believer, the Observer reported.
The adelgid’s cottony white egg sacs so covered hemlocks in the Northwest that “they looked like they had snow on them,” Gerdon said. But the voracious beetles kept the trees in perfect trim, the Observer reported.
McDonald started shipping home 10,000 Lari beetles a year and now sells them for $5 each. Collecting the beetles and releasing them among infested hemlocks is now much of his business. The country club, meanwhile, saved $100,000 a year when it stopped chemically treating its hemlocks and switched to beetles, the Observer reported.
“Anything we can do that is environmentally sound is a good thing,” Gerdon said. “And being able to control a pest without doing anything else about it is nice.”
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