By Sarah Cox, Originally published on October 16, 2019 at The Narwhal
Retired B.C. government forester Judy Thomas bushwhacks down a steep incline in B.C.’s Anzac River valley, north of Prince George, in search of a spruce beetle the size of a mouse turd.
To find one of the marauding insects Thomas has to chop through the coarse bark of an old-growth spruce to its soft inner layer, where a single beetle lays as many as 1,200 eggs. Extended ‘galleries’ of beetle larvae feed on the sapwood, killing the tree in tandem with an associated blue stain fungi.
“Let’s see if they’ve flown the coop,” says Thomas.
She points to telltale signs that the tree, still green and healthy-looking, has been under siege as part of the largest spruce beetle infestation B.C. has witnessed in 30 years.
Frass — a reddish brown sawdust-like substance that is a mixture of beetle poop and chewed tree debris — is sprinkled in bark crevices. The bark also has pitch tubes, appearing as tiny blobs of sap, that form as the tree tries to expel its miniature attackers.