In the Boulder Heights area up Lee Hill Drive, tree care professionals have been running ragged the last few weeks trying to stem the damage caused by moth larvae munching their way through Douglas Firs.
“The tree damage is pretty significant,” Sam Dilettoso, a local manager for Bartlett Tree Experts, told Boulder Reporting Lab.
As of Aug. 1, however, Dilettoso said the caterpillars seem to be done feeding and are now using their energy to spin cocoons. The damage may be done for this year, but the moths will likely be back, and trees will die in the meantime.
Moths tend to go through boom-and-bust cycles based on a multitude of factors, from pathogens to weather. Dilettoso said viruses will periodically come through and wipe out populations, causing years-long recovery periods before damaging levels are reached. Whatever took them out last time, the moths have recovered. Hot and dry weather is also preferable for the moths, and Boulder has been very hot and dry this year.
Dilettoso and his team, along with other companies, have been applying full-canopy sprays around Boulder Heights that essentially force larvae to stop eating, causing them to starve and die off before they reach their cocoon stage. Although tree professionals have been working to stop as many of the moths as they can, there’s only so much they can do in the face of the hundreds of acres Dilettoso estimates have been affected.
While tussock moths are not like bark beetles, where they’re inside the tree, eating foliage is still a stressor on trees already stressed by the heat and the drought in the area.
“Trees are going to die,” Dilettoso said.
This is not good for a neighborhood situated in Boulder’s flammable foothills. Dead trees become tinder that raises the heat and intensity of future wildfires. Because each female moth lays 300 eggs, however, Dilettoso thinks this year is just a preview of what’s to come.
“I think it’s going to be bad next year,” he said. “I think it’s going to be worse.”
