Telling pine beetles 'this tree is full' at Great Basin

Forest health staff prepare a funnel trap on a dead tree to detect when mountain pine beetles are flying. NPS photo.

Wheeler Peak Campground, high in Great Basin National Park, has lost many of its limber pines to the mountain pine beetle. To protect the trees that are left, the park and the U.S. Forest Service turn the beetles' own chemical language against them — and a two-year trapping study showed when to do it.

"This tree is full"

Mountain pine beetles talk in pheromones. When they attack a tree, one compound, verbenone, builds up; as it rises it tells other beetles the tree is taken — go somewhere else. Hanging synthetic verbenone on a healthy pine sends the same message, and beetles pass it by.

The catch is timing. The pheromone has to be in place when the beetles are flying, and at high elevation that can differ from the textbook dates.

When the beetles fly

In the summers of 2019 and 2020 the Forest Service's Forest Health Protection program and the park trapped beetles around the campground:

What it changes

With those dates, Forest Service entomologists and park staff can put the pheromone out at the right moment for the best protection of the campground's limber pines.

Sources

Written from Justin Williams, U.S. Forest Service, "Mountain Pine Beetles Camping out near Wheeler Peak", The Midden (Great Basin National Park), vol. 23, no. 2 (Winter 2023), a work of the United States government in the public domain. The full study is in Western North American Naturalist.