Spruce bark beetles on the move
Spring and summer weather gets people out of their houses and working on their property, preparing their homes for wildfire season, clearing trees. But it is not the time to cut live spruce trees.
This is the time of year when spruce bark beetles move from infested trees and fly to new host trees. From mid-May until mid-July when temperatures are above 60° F, the beetles move from the layer between the bark and wood of infested trees, seeking new trees to lay their eggs. Howard Kent is the Fire Management Officer for the Kenai/Kodiak Office of the Division of Forestry.
"At that time we have probably the nicest weather of the year here in Alaska and people want to get out and it’s natural for them to want to take those trees down and cut, you know, get things cleaned up," he said. "But what that does is actually attract more beetles to your property.
According to the Department of Natural Resources' Division of Forestry, Recent annual statewide aerial surveys indicate that the ongoing spruce beetle outbreak in Southcentral Alaska has affected more than 900,000 acres from 2016-2018. Those dead trees increase wildfire risk.
“The drought that we’ve seen over the last several years contributes to that, the mild winters that we’ve had," Kent said. "I was kind of hoping the cooler winter we had this year would kill some of those off but it really hasn’t had much of an impact this year. Those beetles are now flying. They’re all over the place.”
The beetles prefer to attack the upper roots and lower trunk. Infested trees will show a reddish-brown dust produced by the beetles as they chew entrance holes into the bark. The dust will accumulate on the bark and ground at the base of the tree. Live attacked trees will usually produce resin where the beetle bores into the tree. Currently, two pesticides are registered for preventative use against spruce but they are for use in April and May.
Best practice is to remove the tree before more beetles move out, chipping, milling or burying the infested material, but that time has passed on the peninsula. Beetles are now on the move. DNR Division of Forestry recommends no action this time of year. They say make a plan now to remove trees in August through
For more information about spruce beetles, visit www.alaskasprucebeetle.org.