USU Extension Warns of Invasive Insect Found in Aspens East of Provo

SALT LAKE CITY – An invasive insect has been identified in the area of ​​the Uinta-Wasatch-Cache National Forest called Pole Canyon, east of Provo. And for the USDA Forest Service’s Forest Health Protection Program, the finding is alarming.

Oyster shell scales cover the bark of an aspen tree in Arizona. Photo Credit: Justin Williams, USDA Forest Service

“This pest is a significant threat to the health of our Utah forests, and management options to deal with it are limited and require further research,” said Darren McAvoy, Utah State University Extension assistant professor of forestry.

Oyster shells are motionless insects. According to Utah State University Extension, the insects are surrounded by a shell and feed on the sap just under the bark of aspen as well as ash, willow, poplar and boxwood in Utah.

It is an invasive insect that can weaken and kill aspens. And while it’s likely been affecting trees and shrubs in Utah for decades, USU Extension reports it was only recently confirmed in the aspens of Pole Canyon.

Young trees, McAvoy said, are especially susceptible to Oystershell scale. He also said that many forests in Utah already lack young aspens, which are important to the health of a forest, especially if there is a fire in the area.

“The oyster scale is known to kill large groups of native forest tree species in several eastern states,” McAVoy said. “(The insect) is currently causing significant damage to aspen trees in northern Arizona, where it has been active for the past decade, weakening and killing aspen trees below 8,200 feet in elevation.”

How you can help thwart this invasive insect

There are two ways to help. Insects are usually seen on the shady side of a tree and on the branches and not in direct sunlight. If you happen to see the oyster mealybug on a tree, note your GPS location, take a photo, and email the information to Justin Williams, USDA Forest Service, Forest Health Protection Ogden Field Office. The address is [email protected]

Additionally, McAvoy said it’s important not to bring firewood into a forest if it’s infected with Oystershell.

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