Jim McKay can’t stand to look at the bloodstains on these gorgeous quaking aspen trees. He wants to stop the bleeding.
The blood isn’t real blood, of course. It’s sap. And it’s not a good sign for aspen trees in Montana.
Last week, McKay, who inspects and treats trees for invasive insects, pointed out several groves of quaking aspens in between Kalispell and Whitefish that have been damaged by a long-horned beetle called the poplar borer. Poplar borers burrow into aspens and lay their eggs, which produce larvae that live inside the tree and feed voraciously on everything except the bark, McKay said.
If given enough time, the larvae will kill the tree.
“They’re literally consuming everything to the skin,” he said.
To make room, the larvae dig holes through the bark and push out excess material from inside the tree, McKay said. The result is wood shavings spilling out of the hole. Sap also pours out and bleeds down the outside of the tree, leaving stains. Bees like to swarm around the wounds and taste the sweet sap.
McKay advises homeowners with quaking aspens on their property to take note of these sure signs of poplar borers before it’s too late. A hole with wood shavings or sap coming out of it is bad news. In highly infested aspens, the borers leave piles of wood shavings and dust at the tree’s base. If it isn’t treated early enough, the aspen will die and fall to the ground.
The problem is, the tree stays alive and its leaves continue to grow while being consumed from the inside out. So it’s of utmost importance to carefully look for the signs, McKay said.
“(The trees) look nice and they will continue to until the last minute and then they just fall over,” McKay said.
McKay treats a variety of trees for different kinds of pests throughout the Flathead Valley. Terminal weevils wreak havoc on spruces, bronze birch borers ruin birch trees and mountain pine beetles – which have been all over the news in recent months – destroy pine trees.
But the poplar borer has significantly increased its presence in Montana in recent years, McKay said. McKay, who has been in the tree treatment business for 12 years, said he began consistently dealing with poplar borers three years ago. Now he sees evidence of the borers in aspens all throughout the Flathead. They are found elsewhere in Montana too, especially in the Bitterroot Valley.
The larvae, McKay said, are the biggest culprits; the adult beetle dies shortly after laying its eggs. But the larvae spend roughly three years inside a tree, McKay said, feeding and maturing through the pupae stage until they become adults. As an adult, they will move to another tree and start the process over again.
To treat an infested aspen, McKay injects an insecticide called imidacloprid into the tree’s cambium layer. Carried by water, the insecticide quickly travels to the rest of the tree, killing the poplar borers. McKay switched to the injection after first trying a method in which he applied the imidacloprid into the underground roots.
In Whitefish last week, McKay showed off a healthy grove of aspens lining the outer yard of a home. Last spring, the trees were growing weak because of borers, McKay said. The homeowners were worried about losing the trees, which served as their privacy block. McKay conducted the injection treatment and today they are borer-free.
“This was a mess,” McKay said. “Now they’re happy as a clam.”
If the tree is already too damaged and in the advanced stages of its demise, all McKay can do is cut it down. Last week, he and Arnold Deans sawed an aspen down and split pieces of it open to reveal several writhing larvae, plump after gorging on the trees innards. In bad cases, McKay has seen as many as a dozen larvae in a six-inch sample of a small-diameter aspen.
Not only are the larvae destructive, they’re ugly. They can grow as big as a finger, McKay said.
“Great for fishing, gross as hell,” he added.
To contact McKay, call (406) 250-1883.