Pine Beetle Information

Pine Beetles in the Okanagan-Similkameen

The Okanagan-Similkameen is home to two types of Pine Beetle.

The Western Pine Beetle is a native species that often has multiple broods per year. The Western Pine Beetle primarily attacks Ponderosa Pine trees growing in the bottoms and sides of the Okanagan and Similkameen valleys. Although this beetle has seen an increase in population it has not yet become an epidemic like the Mountain Pine Beetle.

The Mountain Pine Beetle, which has ravaged the forests of the Central Interior, is a native species in the Okanagan but its population has exploded over the last few years. A number of conditions have allowed the Mountain Pine Beetle to expand to epidemic proportions. Seeking out new food supplies the Mountain Pine Beetle swarm has entered the Okanagan-Similkameen. The Mountain Pine Beetle has the potential to dramatically reduce the number of adult pine trees in our area. The Mountain Pine Beetle generally has one large brood per year and attacks all forms of pine tree including Lodgepole, Ponderosa and ornamental species.

View a copy of Pine Beetles in the Okanagan and Similkameen

1. Why inspect your pine trees regularly?

Surveying your property provides valuable information on:

  • Whether pine beetles are present.
  • What life stage beetles are at and what stage the outbreak is at.
  • Whether your trees are healthy, and what can be done to increase their health to help lower the risk of a pine beetle attack.
  • Whether specific trees should be removed to protect other trees.
'Bullet' holes created by the exit of mature beetles

2. Common signs pine beetles are present

Shot holes - Examine the tree trunk closely for small holes—most commonly found in the lower six meters and occurring in regular patterns. Pitch or frass (sawdust) may also be observed coming out of the holes.

Boring dust - The sawdust trails left by boring beetles can be seen in bark crevices and on the ground near the base of the tree.

Pitch tubes - Popcornshaped globs of yellowish gum or resin on the trunk show where beetles have tunneled into the bark. They are the tree’s response to the invasion and they push beetles out.

Pitch tubes result from the tree defending itself from a pine beetle attack

Galleries - Galleries are tunnels underneath the bark that may still contain beetles, eggs or larvae. Carefully peel off some layers of bark to see them.

Blue stains - Attacking beetles carry the spores of bluestaining fungi on their bodies and in a structure on their heads. As the fungi develop and spread, they interrupt the flow of water to the tree’s crown and reduce the tree’s flow of pitch, which aids the beetles in overcoming the tree. The combined action of the beetles and the fungi causes the needles to discolour and the tree to eventually die.

Needle discolouration - Occurs during the year after the attack, when the beetle has almost completed development. Needles fade from green to yellow and to bright red. By the time the trees appear bright red, the beetles have moved on to attack new trees.

Woodpeckers - Woodpeckers feed on the beetle larvae. Holes in the bark, dry and dead sections of bark and bark chips on the ground may be evidence of woodpeckers. If the trees are close to your home, you may also hear the familiar sound of woodpeckers at work.

3. Recognizing other insects and diseases

There are a number of other diseases that affect pine trees. Some cause trees to show symptoms similar to those experienced during a pine beetle attack.

European pine shoot moth — While infested shoots turn reddish brown at the ends of the branches, this is unlike the effect of a pine beetle infestation which turns the entire tree red.

Western gall rust — This disease is caused by a fungus which causes the formation of galls on branches and stems. Brown branch tips appear throughout the tree. While the fungus causes disfigurement, it has little effect on the tree’s overall health.

Red turpentine beetle — Pitch tubes are usually located at the base of the tree and the resin coming from the holes is white or yellowish. Borings are red. Some pitch tubes can be as large as two inches across, which is three times the size of those left by the western pine beetle.

4. Using life history to determine age or stage of attack

Lifecycle for the Mountain Pine Beetle

The pine beetle develops through four stages: egg, larva, pupa and adult. Except for a few days during the summer when adults emerge and fly to new trees, all stages are spent under the bark of the infested trees. The Mountain Pine Beetle usually takes one year to complete its life cycle. The Western Pine Beetle, more common in the Okanagan, may produce up to three generations in one year. Unmated female beetles making the first attacks in an area release chemicals called aggregating pheromones. Pheromones attract males and other females until a mass attack overcomes the tree.

Stage 1 — Egg

Under the bark, female beetles construct straight, vertical egg galleries and lay tiny, pearlwhite eggs in niches along the sides of the galleries during the summer and early fall. Eggs hatch in 10 to 14 days.

Stage 2 — Larva

The legless larvae are white with brown heads. Larvae feed on the phloem (tissue), constructing galleries that extend from the egg galleries.

Stage 3 Pupa

When mature, the larvae excavate oval cells in which they turn into pupae.

Stage 4 — Adult

Adults feed within the bark before emerging. After making an exit hole, several adults will emerge. One to two days after emerging, the beetles will attack other trees.

5. Factors affecting outbreaks

Food supply - Beetles usually select large pines that have a thick phloem (the tissue that conducts food material in plants). They need the adequate food found in large diameter trees for their population to build up.

Tree health - Healthy, vigorously growing trees are most resistant to attack. Bark beetles prefer to attack weakened trees. Trees that aren’t growing vigorously due to old age (over 80 years old), overcrowding, injury or poor growing conditions are susceptible to attack.

Tree age - Young trees under four inches in diameter are not susceptible in the early stages of a beetle attack and beetles will only attack them once the larger trees in the vicinity are dead.

Characteristic blue staining in wood caused by a fungus introduced by Pine Beetles

6. What can you do to prevent an attack?

  • Ensure trees on your property are healthy.
  • Avoid heavy pruning as this may stress trees.
  • Avoid damaging trees’ roots or the root zone around trees.
  • Remove trees that are weak or injured as they are more susceptible to attack and can become the initial host by attracting beetles. This will help ensure the survival of healthier trees.
  • Consider thinning out overcrowded stands of trees. Leave the healthiest trees and ensure they have room for sunlight, rain and air circulation.
  • Do not bring beetlekilled wood into the area for firewood. You could be importing the beetle onto your property.
  • Monitor trees regularly, noting that the active time for pine beetle is April to October.
  • If you find early evidence of an attack, call a professional for advice.

7. Time to call in a professional?

  • Professional arborists or treecare workers can selectively prune out unhealthy limbs, thin crowded stands of trees, or remove infested trees.
  • Professionals might employ techniques to help prevent attacks, such as pheromone pouches or screening.
  • Professionals may offer continual monitoring if you are unsure of the signs and symptoms, or if you need help learning how to monitor your trees.