Mountain pine beetle (MPB) are a destructive tree pest. Left unmanaged, MPB could devastate Alberta's pine forests and spread eastward across Canada's boreal region. Alberta’s MPB management program employs a short-term, beetle-focused strategy and a long-term, pine-focused strategy. The short-term strategy consists of direct population management through singe tree control treatments. The long-term strategy has focused on the reduction of MPB habitat by changing the amount and distribution of mature pine across the landscape through targeted harvesting.
Each summer, aerial surveys to detect MPB-killed trees canvas millions of hectares of forest. These surveys focus on specific areas where beetle population are still actively killing trees.
Extended periods of extreme cold can cause significant mortality of over-wintering MPB. Alberta uses an overwinter mortality model that predicts per cent mortality based on winter temperatures and location data. These mortality predictions, combined with aerial surveys and ground assessments, help the province prioritize areas for subsequent management.
The Alberta government publishes an annual snapshot of programs related to the management of forest health and adaptation in the province's forests.
Trees at risk
MPB are capable of attacking and killing all species of pine including:
- scots or scotch
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.
For more information on MPB, see Forest pests and damage agents.
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.
Prevent further spread
Disposal of infested trees
The following steps will minimize the risk of damage to forests by insects or disease:
Step 1. Stand and peel
Using a knife, carefully peel the bark away from entry holes, exposing the beetles under the bark to the cold.
Step 2. Removal and disposal
Beetle infested trees are a risk to our forests. It is extremely important to remove and dispose of infested trees prior to mid-June, when mature beetles begin to emerge and fly to new trees. Beetle infested trees cannot be transported unless they are debarked. Infested bark should be chipped, burned or buried to ensure adults and larvae are destroyed.
The transport of logs and other forest products cut from coniferous trees is regulated under provincial legislation. You can read up on the legal foundation for the management of public forests in Alberta at: Forest directives and standard operating procedures.
The following steps can be taken to minimize the risk of MPBs infesting pine trees on your property and to prevent further spread.
MPBs fly and infest new pine trees in late summer and evidence of an infestation can be seen by fall. Trees respond to attack by producing resin (pitch) at the attack location. External evidence of an infestation will be pitch tubes and reddish sawdust around the base of the tree. Once a tree is infested with MPB the needles will turn dull green, then yellow and eventually turn red the following summer.
MPBs are more likely to attack older stressed pine trees. These trees may have been topped, poorly pruned, injured, root damaged or are suffering from drought.
You may remove or thin pine stands on your property by removing trees so the crowns do not touch. You may also want to consider diversifying your tree types to include other species of trees and age classes.
Note: Before engaging in these activities, you may choose to consult your local tree professional. These actions can be potentially dangerous and are not guaranteed.
Verbenone can be used to help prevent attacks on pine trees. Verbenone is a naturally occurring chemical that mimics the scent beetles emit when a tree is heavily infested – this tricks beetles into believing the tree is occupied. The chemical can cause MPB to avoid attacking pine trees. Verbenone is specific to MPB and is not a pesticide. This tool is most effective when used to protect high value susceptible pine trees over a relatively small area when beetle populations are low.
The Verbenone Use Guidelines provide information to landowners, municipalities and forest managers on using verbenone for protection.
Mountain Pine Beetle Municipal Grant Program
The Municipal Grant Program was established in 2006 to support the costs of beetle control operations for municipalities. The program provides funding and expert advice to municipalities that support MPB management on municipal and private lands. Activities may include:
- ground surveys and mapping
- treatment of infested trees
- communication, education and outreach efforts
- prevention of additional attack
- project management
Funds may be awarded to municipalities with trees infested with MPB and whose management programs align directly with Alberta's overall objectives of:
- containing infestations and minimizing the spread of MPB north and south along the eastern slopes of Alberta
- preventing the spread of MPB eastward further into the boreal forest
How to apply
Step 1. Read the guidelines
- MPB Municipal Grant Funding Program – Program Overview and Guidelines
- MPB Municipal Grant Funding Program – Funding Priorities
Step 2. Complete the application package
Step 3. Submit the application package
The municipality must submit the completed application to the local Forest Health Officer by or before October 31, or by the extended deadline as approved by the local Forest Health Officer.
In 2007, Alberta’s MPB management program implemented both a strategy to manage MPB infestation and protect the health of our forests. The program employs a short-term, beetle-focused strategy and a long-term, pine-focused strategy. The short-term strategy consists of direct population management through singe tree control treatments. The long-term strategy has focused on the reduction of MPB habitat by changing the amount and distribution of mature pine across the landscape through targeted harvesting.
Our goal is to reduce the opportunity for MPB to spread further into our pine forests, particularly throughout the watersheds of the eastern slopes and further into the boreal forest. Through the MPB Strategy, prescribed fire, and strategic harvesting, Alberta is encouraging a more natural diversity of tree ages that will be more resilient to threats from destructive insects, disease and wildfire.
For more information on MPB, see Forest pests and damage agents.