Defoliation by Pandora moth caterpillars not enough to cause fires, C.O. expert says
(Update: Adding video, comments from USFS entomologist)
BEND, Ore. (KTVZ) -- Pandora moths have returned to Central Oregon, but this year as caterpillars.
Central Oregon saw Pandora moths nearly everywhere last summer. Now, they have laid eggs and their eggs have hatched, revealing 3-inch-long caterpillars.
The caterpillars will then crawl down from the trees and burrow into the soil to cocoon themselves.
Robbie Flowers, an entomologist with the U.S. Forest Service, said Monday one adult moth can lay up to 100 eggs, although not all of the larvae will survive.
He said the outbreaks are allowed to subside naturally.
“Typically, with this insect, we don’t see a relationship between increased fire effects or increased fire severity,” Flowers said.
He said the low risk for wildfires is because Pandora moth caterpillars do not lead to a high number of tree deaths.
Flowers said bark beetles usually cause more damage to trees than Pandora moth caterpillars.
He said the evidence of the impact the caterpillars have on Ponderosa pines can best be seen while driving south of Bend along Highway 97.
“There’s nothing to worry about, in terms of human health factor, no risk to your pets,” Flowers said.
The defoliation happens every other year, because the moths require two years to complete a life cycle.
Flowers said this is the sixth year of the Pandora moth outbreak, with adult moths observed in 2015, 2017 and 2019.
The Forest Service first observed Pandora moth larvae and pine defoliation in Central Oregon in 2016. Flowers said there was more severe defoliation in 2018, with more than 145,000 acres of defoliation recorded during an aerial survey last summer.
Flowers said his team is currently studying the impact climate change has on native insects like Pandora moths, and how it could affect their population patterns.
For more information about the Pandora moths and their impact on Central Oregon forests, visit the USFS website here.
