Sun Valley, ID – After a forest fire like the 75 square-mile Castle Rock blaze that encroached upon Sun Valley’s ski runs in 2007, Douglas fir bark beetles often move in, destroying not only fallen timber but healthy trees as well. The U.S. Forest Service is hoping that aerial spraying a pheromone on Sun Valley’s slopes will prevent the deforestation.nThe pheromone, called methylcyclohexenone (MCH), is naturally produced by the beetles to tell other beetles that a tree is occupied. Forest Service officials hope that the spraying of MCH flakes last week will trick beetles into finding their feast elsewhere.

Forest Service officials cited the importance of Sun Valley ski area to the local economy in justifying the spraying.

The MCH flakes are effective for approximately 55 days. Therefore, a second helicopter application of MCH flakes is planned beginning June 28, weather permitting.

“We appreciate that Sun Valley Company is allowing us the use of their parking lots for staging the helicopter flights. We also appreciate the understanding of Bald Mountain recreationists who may be inconvenienced by the temporary closure of Bald Mountain access while the helicopter is in operation,” said Kurt Nelson, Ketchum District Ranger with the Sawtooth National Forest.