Mountain pine beetle in Alberta

Current status

Mountain pine beetles (MPBs) are attacking the province's pine trees. Left unmanaged, MPB could devastate Alberta's pine forests and spread eastward across Canada's boreal region.

Surveys conducted by the Alberta government forecast the MPB population in Alberta:

• MPB population forecast
• Mountain Pine Beetle Aerial Survey (Heli-GPS)

Beetle facts and biology

The MPB, or Dendroctonus ponderosae Hopkins, is a small bark beetle about 4.0 to 7.5 mm in length – about the size of a grain of rice. The MPB is the most destructive pest of mature pine forests in North America. When beetle populations are small, they prefer stressed, mature or over-mature (80+ years) pine. As populations grow, any pine over 12.5 cm in diameter can be killed, even healthy trees.

MPB lifecycle – In Alberta, MPB normally has a 1-year life cycle. In higher elevation areas though, it may take 2 years to complete their life cycle.

Adults – In mid-July to mid-August, the stout, black adults bore exit holes through the bark and fly to attack new trees. The female beetle releases an aggregate pheromone to initiate mass attack and to attract males. The females then begin to tunnel through the bark and make vertical egg galleries.

Eggs – In the galleries, females mate with males in mid-summer and lay eggs individually along the sides of the gallery. Female beetles will lay approximately 60 eggs.

Larvae – About 2 weeks after eggs are laid, white, grub-like larvae with brown heads hatch and mine horizontal galleries under the bark. Here they overwinter, protected from cold temperatures by the bark. The beetle spends the winter in the larval stage and resumes feeding in the spring. The larvae grow up to 7 mm in length. Mature larvae are the most cold-tolerant lifestage but 50% will die if under bark temperatures are lower than -37.5 degrees. For more information, see MPB and Cold Temperatures – The facts.

Pupae – By late June to early July, the larvae create oval-shaped chambers at the end of the larval galleries. Here they develop into adult beetles.

Trees at risk

MPB are capable of attacking and killing all species of pine including:

• lodgepole
• jack
• ponderosa
• scots or scotch, plus the endangered;
• whitebark
• limber

The MPB kills pine trees by clogging and destroying the conductive tissue of the tree by introducing a blue-stain fungi when attacking the tree. Its larvae feed in the phloem of the tree. The action of blue-stain fungi and larval feeding can kill the tree within one month of the attack.

Publications

A series of 12 printable MPB information cards are available. They cover topics ranging from cause, identification, lifecycle, affected zones and prevention to Alberta's strategy and zones what you can do to help control infestation.

Contact

Email: [email protected]