The Park realized it was being blamed for the ladybugs during a public comment period on what to do about hemlock woolly adelgids. Hemlock woolly adelgids are an exotic insect that have infested hemlocks across the Southern Appalachians and will quickly lead to their demise without action. As a form of defense, the Park is breeding and releasing a beetle that eats the hemlock woolly adelgid in hopes of slowing its march.
During an environmental assessment on the Park’s hemlock strategy, some residents turned in public comments complaining about what happened the last time the park released bugs — the lady bug — which now are a nuisance when they congregate en masse on the side of houses.
Only it wasn’t the park that introduced the ladybug. The beetle was indeed introduced in the 1970s by agriculture to control crop pests.
Park biologists said they have thoroughly researched the predator beetles being released to eat hemlock woolly adelgids and have found no negative side effects. They do not congregate in large numbers and do not leave the forest during their summer dormant period, park biologists said.
In addition to breeding and releasing predator beetles, park biologists also spray organic pesticides on hemlocks and inject hemlocks with a chemical pesticide to save certain stands.
The National Park Service approved an environmental analysis of the Park’s hemlock strategy. Of the 20 comments submitted, all support the plan expect for the few concerned about the side effects of the predator beetles.
The park’s three-pronged plan gives the park flexibility. The use of biological controls such the predator beetles allows the treatment of trees in the backcountry, in old growth stands and along waterways. Chemical controls are more feasible for treating trees accessible from roads. While pesticides may be used in the backcountry, this option is not feasible on a landscape scale.
“Large scale hemlock mortality has not yet been observed in the Park, but we are beginning to see areas of decline and can expect scattered areas of mortality throughout the Park in the near future,” said Park Superintendent Dale Ditmanson. “The varying methods will give us the flexibility needed to proactively and safely address this long-term threat to our forest environments. Our best hope for success is to reduce hemlock mortality in order to sustain stands of healthy, viable trees, particularly in old growth forests and in high visitor use areas.”