It's April of 2012 and spring is springing. In an effort to deter mountain pine beetles (a type of bark beetle) without deterring park visitors, Rocky Mountain National Park officials are spraying insecticide now.
“The primary objective is to spray when the visitation numbers are low, so we have fewer impacts to visitor recreation activity,” RMNP Forester Brian Verhulst told Colorado-based radio station KUNC. “And also to spray at the start of the summer season prior to the emergence of the bark beetle.”
Since the pine beetle outbreak began in 1996, more than three million acres of Colorado forests have been devastated. Spraying insecticide helps the cause, but only to a certain extent. Officials only spray five percent of RMNP’s trees, those giants that meet a specific need—whether providing shade or visual screening—as well as those that have become part of the cultural or historical landscape.
“Our objective is to allow bark beetles to remain a natural part of the ecosystem,” Verhulst said. “The spraying we do in the park (does) not change the fate of the forest, but it can protect specific trees in visitor use areas.”
Park officials primarily use two different insecticides to battle the beetles. The first, Carbaryl, is a compound that defends the trees, and though it is a neurotoxin, a 2001 study by North Carolina State University describes it as EPA-approved, safe and effective. The second insecticide, Verbenone, is a pheromone that deters beetle infestations without actually killing the insect.
Verhulst said that Memorial Day 2012 is the deadline by which RMNP hopes to have sprayed all 67,000 trees on the to-spray list.