Tree Pests and Diseases

Mountain Pine Beetles

The mountain pine beetle is a member of the bark beetle family and is the most damaging insect pest of pine trees in western North America. Left unmanaged, the Mountain Pine Beetle could devastate Alberta pine forests. Lacombe County has found several cases in the western portion of the County.

Prevention

Please take the time to inspect your pine trees. Look for these signs and symptoms:

• Likely the easiest sign indicating the presence of Mountain Pine Beetle is boring sawdust found in bark crevices and around the base of the tree.
• Secondly, look for pitch tubes (small nodules of sap that look like crystallized honey on the bark).
  • Peel back the bark and look for live larvae. If you do find live larvae under the bark, your healthy trees are at risk.
  • From the air, you'll notice patches of completely red-brown or yellow-green pine trees.
• Burn infested trees immediately (make sure to get a Fire Permit, if necessary).
• Keep your green trees as healthy as possible; water is key since a drought-stressed tree is less capable of resisting a beetle attack.

The following prevention information contains links to information about sprays and treatments that have been used in other provinces in an attempt to control the spread of Mountain Pine Beetle.

Lacombe County provides this information as a resource only and is in no way endorsing their use. Persons can use these chemicals on their private lands as per instruction, at their own risk and cost. These are potent chemicals that do have inherent health risks for all humans, in particular children.

Verbenone

 Verbenone has been used in spot applications to try and stop beetles from attacking valued trees. Verbenone pouches can be attached to specific high-value trees chosen to be protected; however, they are not a guarantee that pine beetles will not infest the tree.

• Verbenone is SOLD AT LACOMBE COUNTY for a 10-pack of Verbenone. This cannot be sold in smaller quantities at this time)

How Verbenone works 

The product is a repellent or anti-aggregation pheromone. Application of repellent pheromones must be completed before the beetles emerge to look for new host trees.

• Pouches should be nailed or stapled to the north side of a tree or vertical object at maximum reach from the ground, an additional pouch may be placed on the same tree on the north side as well at least 2.5 meters high from the ground.
• Additional pouches can be added in a  4-5 meters perimeter around the protected area.
• Hang on the tree between June 15 – July 1. Pouches should be placed on the tree before MPB takes flight; emerging from under the bark and leaving the effected tree to infect a new tree
• For the best results, a fresh pouch should be placed on the tree partway through the year.

Regardless of what you do, there is no guarantee you can save your trees. It depends upon the intensity and duration of the beetle flight in July and August. To find out more about the health effects and chemicals permitted for use in Canada we recommend you visit Health Canada's Pest Management Regulation Agency.

Black Knot

Black Knot is a fungal disease that can be found in commercial, municipal, private, and natural plantings throughout Alberta. 

What Trees does it affect?

Black Knot is common among plants in the genus Prunus. This includes Chokecherry's, Mayday Trees, and Flowering Plums, to name a few.

What are the Risks?

Black Knot reduces the aesthetics of affected trees, and high levels of infection can lead to the death of the plant.

What to Look For

The most common way to characterize Black Knot is by its black, tar-like swellings that grow on infected branches. These swellings begin as small, green galls that develop at a growing point or fruit spur and grow until reaching maturity.

Prevention

Here are some methods prevention methods you can implement to help control Black Knot:

• Remove all knot-bearing branches to reduce a build-up of the disease
• Prune infected branches far below knots, sanitize the blades after pruning, and immediately destroy diseased wood
• Monitor regularly and keep plants healthy and stress-free
• Practice proper pruning techniques to allow adequate canopy ventilation

Related Links

Black knot Alberta

Dutch Elm Disease

To help keep Alberta Dutch Elm Disease free, please remember that there is a provincial elm pruning ban from April 1st to September 30th every year.

• Elm trees are susceptible to Dutch Elm Disease, carried by the Elm Bark Beetles. Dutch Elm Disease is killing trees east of Alberta, resulting in complete urban deforestation of elm species in some areas. 
• Elm Bark Beetles carrying Dutch Elm Disease could be transported to this area by the movement of firewood or by winds. These beetles are attracted to wounds from pruning or damage to elm and if infected, they could cause the death of the tree in a few years.
• As a result of this threat, the Province has instituted an elm tree pruning ban from April 1st to September 30th of each year. If you need to get rid of damaged limbs, or if the elm is too close to the house, prune them after September 30th and before April 1st to ensure any wounds dry off prior to beetle activity in late spring.