Mountain Pine Beetle

Female beetles bore into the bark of pine trees in mid-summer, awaiting the arrival of males to mate and deposit eggs.  In August, the larvae hatch and begin mining horizontal galleries, destroying the conductive tissue of the tree and disrupting the water and nutrient flow of the host tree. Within one month of the attack, a pine tree can be killed by the larvae. The larvae overwinter in the tree, protected from the cold by the bark. In late June to early July, the larvae develop into adult beetles. Adult beetles exit the trees in mid-July to begin their flight to new pine trees.

The most recognizable sign that MPBs have attacked is the presence of red trees.  However, red trees alone do not necessarily equate to a beetle attack. Needle discoloration is also a common sign of environmental damage caused by drought, flood, injury, or soil deficiency to name a few. When looking for beetle activity, the first question to ask is “Is it a pine tree?” Signs of MPB include pitch tubes oozing cream-coloured resin as the tree fights to “pitch” the beetle out, and boring dust around the base of the tree from the beetles boring under the bark.  Under the bark, you will see J-shaped galleries where eggs are deposited.