WHAT IS SPRUCE BEETLE?

Spruce beetles (Dendroctonus rufipennis) are a bark beetle species that are native to North America.

They are small (about 4-7mm long), stout-bodied beetles that range in colour from reddish-brown to black.

They occur in endemic populations, meaning they are naturally found and established in the region. They typically exist at low levels, but can erupt into outbreaks, especially in areas that experience recent damage or disturbances.

WHAT TYPE OF TREES MAY BE ATTACKED?

Spruce beetles target large diameter, mature spruce trees. Primary hosts include White Spruce (Picea glauca) and Engelmann Spruce (Picea engelmannii).

WHEN DO BEETLES ATTACK TREES AND HOW LONG DO THEY STAY IN TREES?

Outbreaks often originate in areas with weakened and recently dead trees, including areas with blowdown or logging slash. Spruce beetles breed and multiply in these areas and may begin to attack and kill healthy trees.

In Alberta, the spruce beetle typically has a 2-year life cycle.

Female spruce beetles’ tunnel into the bark of trees, creating galleries (6-23 cm long) where they lay eggs and the larvae feed. The white grub-like larvae are approximately 3-7 mm long.

Spruce Beetle Larvae

Spruce beetles must overwinter once to mature fully. Mature adults emerge and attack new host trees from late May to early June.

Outbreaks usually last between 2-5 years, and can severely deplete the large-diameter spruce within that area.

IF MY TREE IS ATTACKED, WILL IT DIE?

Spruce beetles are capable of killing trees, especially when populations are high during outbreaks. 

Larval feeding activity within the tree bark can lead to the colonization of blue-stain fungi, which disrupts the tree’s ability to transport water and nutrients within the tree, ultimately leading to tree death.

Tree mortality rates in infested areas can be extremely high, exceeding 90% in heavily impacted areas.

HOW CAN I TELL IF MY TREES HAVE BEEN ATTACKED?

To detect if spruce beetles have been damaging your spruce trees, look for the following signs and symptoms:

• Entrance holes on lower stem (late May and June)
• Light brown to red-brown boring dust on the tree trunk and at the base of the tree
• Resin (pitch tubes) -small globular masses of resin (may be reddish due to boring dust).
• Straight egg galleries (6-23 cm long) under the bark that follow the wood grain
• Foliage discoloration - yellowish-green to reddish coloured needles of trees.
• Woodpecker damage, leaving a reddish trunk due to bark scaling.

Entrance/Exit bore holes

Fan shaped galleries with beetles

Dead trees in shelterbelts after two years of infestation

 (Images courtesy of Toso Bozic, ATTS Group Inc.)

WHAT DO I DO IF MY TREE IS INFESTED?

In Alberta, spruce beetle management focuses on reducing beetle populations through prevention, early detection, and sanitation:

• Surveying mature spruce stands near areas of blowdown, logging slash, or dead and stressed trees.
• Monitoring healthy trees for signs of early beetle infestations.
• Removing infested trees before beetles emerge and fly (early May to June).
• Sanitation logging of infested stands where trees are cut, removed, and potentially burned.

WHAT IS THE CURRENT STATUS OF THE SPRUCE BEETLE POPULATION IN CLEARWATER COUNTY? HOW CAN CLEARWATER COUNTY HELP?

Clearwater County Agriculture & Community Services has recently received several calls about spruce beetles and are continuing to monitor populations. 

Clearwater County Agriculture & Community Services staff are available to assist landowners with inquiries regarding pests or tree health issues and best management or control options. Feel free to give us a call at 403-845-4444.

REFERENCES AND RESOURCES 

For more information about Spruce Budworm, visit: 

Alberta Agriculture & Forestry Website

Government of Canada - Spruce Beetle Fact Sheet

County of Wetaskiwin - Spruce Beetle Information Page

Government of B.C. - Managing Spruce Beetles…

ATTS Group Inc. Yard Whispers - Spruce beetle

Forest Tent Caterpillar

Larvae Colony/Mass

Adult Moth

WHAT IS FOREST TENT CATERPILLAR?

The forest tent caterpillar (Malacosoma disstria) is a native defoliating moth species found throughout North America.

Greatest foliage damage occurs during the larval stage of development.

Young caterpillars (larvae) are roughly 3 mm long and black and hairy in appearance. They can often be found clustered together on the trunks or branches of trees when they are not feeding on foliage.

Mature caterpillars (larvae) are roughly 5 cm long and can be identified by their characteristic blue stripes and white keyhole shaped dots down the back.

Forest tent caterpillar infestations are easily identifiable due to the large cluster populations that can blanket entire areas.

Adult moths are a yellow-brown colour and a have a wingspan of about 3-4.5 cm.

WHAT TYPE OF TREES MAY BE TARGETED? 

Forest tent caterpillars target broadleaf trees and shrubs. They primarily attack Trembling Aspen (Populus tremuloides), but they can also feed on poplar, birch, ash, maple, fruit trees, and even garden crops when infestations are severe.

WHEN DO FOREST TENT CATERPILLARS ATTACK TREES AND HOW LONG DO THEY DAMAGE TREES?

Forest tent caterpillars are common in Alberta, with outbreaks occurring approximately every 10 to 12 years and lasting upwards between 3 to 6 years. 

Outbreaks are considered a natural disturbance, much like a fire or flood, as forest tent caterpillars have an important role to play in the recycling of forest nutrients.

Forest tent caterpillars have one generation per year, and follow a typical moth lifecycle of egg to caterpillar to pupae to adult. 

After overwintering, eggs hatch and larvae will begin to feed on new foliage in late April to early May. During this time, larvae from one egg mass will cluster until they begin to wander in search of more food. The most damage to foliage occurs in the 5^th larval stage. In mid to late June, larvae are fully grown and begin to pupate into moths. Adults (moths) emerge in early July, when they will then begin mating and lay about 150-200 eggs in an egg band.

Egg Band

IF MY TREE IS ATTACKED, WILL IT DIE?

Defoliation of trees by forest tent caterpillars do not typically lead to tree mortality, however, heavy defoliation over 2 or more years can result in a decline in health. 

This weakened state can make trees susceptible to drought, disease, or attacks by other insects or pests. They can also cause branches to die back.

Healthy trees can withstand light defoliation and are often able to leaf again after minor infestations.

HOW CAN I TELL IF MY TREES HAVE BEEN ATTACKED?

To detect if forest tent caterpillars have been damaging your trees, look for the following signs and symptoms:

• Minor to complete defoliation (holes, damage, etc.) of host trees depending on outbreak severity.
• Masses/colonies of larvae (caterpillars) blanketing surfaces
• Branch and crown dieback due to tree stress/disease susceptibility.
• Presence of egg bands in fall to spring when leaves are absent.

Severe defoliation

Masses/colonies of Larvae (caterpillars)

WHAT DO I DO IF MY TREE IS INFESTED?

Due to the short timing of outbreaks, management of forest tent caterpillars is not typically necessary. Birds, as well as other insects and predators are usually able to keep populations in check.

However, due to the increasing populations due to recent outbreaks, the following management practices can be used:

• Removal of egg bands or caterpillars (larvae) by hand or with pressurized water.
• Biological insecticides such as Bacillus thuringiensis var kurstaki (Btk) can be applied in May when larvae are small.
• As a last resort, Malathion contact insecticide can be used on small populations for ornamental trees (read and follow label correctly).

WHAT IS THE CURRENT STATUS OF THE SPRUCE BUDWORM POPULATION IN CLEARWATER COUNTY? HOW CAN CLEARWATER COUNTY HELP?

Forest tent caterpillar infestations have been reported in neighbouring counties, with an increase in calls being made to Clearwater County Agriculture & Community Services about growing populations within the county. 

Clearwater County Agriculture & Community Services staff are continuing to monitor populations and are available to assist landowners with inquiries regarding pests or tree health issues and best management or control options. Feel free to give us a call at 403-845-4444.

REFERENCES AND RESOURCES

For more information about Forest Tent Caterpillars, visit: 

Alberta Agriculture & Forestry Website

Government of Canada -Forest Tent Caterpillar

Government of Canada -Forest Tent Caterpillar by J.P. Brandt

County of Wetaskiwin - FTC Information Page

Parkland County – FTC in the County

WHAT IS MOUNTAIN PINE BEETLE?

The Mountain Pine Beetle (MPB) is a small, black beetle about the size of a grain of rice. It is a naturally occurring insect found in pine forests.

WHAT TYPE OF TREES MAY BE ATTACKED?

Mountain pine beetles attack and kill pine trees, usually mature ones aged 80 to 120 years old. All species of pine, including lodgepole, jack pine, scotts pine and ponderosa pine are vulnerable. Mountain pine beetles do not attack aspen, spruce or fir trees.

WHEN DO BEETLES ATTACK TREES AND HOW LONG DO THEY STAY IN TREES?

Beetles fly in search of new trees in July and August. Once a beetle has found a suitable tree, it will live in that tree for the remainder of its life and lay eggs. The new generation of beetles will not emerge from the tree for at least one year.

IF MY TREE IS ATTACKED, WILL IT DIE?

Trees successfully attacked by mountain pine beetles usually die within one year, however if the beetle has made an attempt to enter the tree but is "pitched out” before completing reproduction, the tree may survive.

HOW CAN I TELL IF MY TREES HAVE BEEN ATTACKED?

Look for creamy globs that look like crystallized honey, called pitch tubes, and sawdust at the base of the tree and in the bark’s crevices.

WHAT DO I DO IF MY TREE IS INFESTED?

Scout out the pine trees on your property, wrap survey tape around each tree that has been attacked. It is recommended that a tree with more than 40 pitch tubes be removed. In the winter months, trees can be sold and transported to sawmills and debarked on their site. Other options are to hire an arborist with a chipper to come on to your property and leave the material on site or burn the mass attacked trees before July when the developing beetles could emerge to attack nearby trees.

WHAT IS THE CURRENT STATUS OF THE MOUNTAIN PINE BEETLE POPULATION IN CLEARWATER COUNTY? HOW CAN CLEARWATER COUNTY HELP?

Clearwater County has worked diligently with the provincial government to address the Mountain Pine Beetle infestations over the last few years by monitoring the spread and providing control efforts on private land. 

Due to diligent work, boots on the ground efforts and with the help of mother nature’s frigid winters, officials recently stated the province has had "striking progress" against the pests – the most destructive problem facing pine forests. 

Mountain Pine Beetle populations have declined 98 per cent since the beetle’s peak in 2019 with populations expected to decline even further next year, says the province. Providing less worry for landowners which is great news, especially for those with large pine forests or specialty pine trees around the homestead.

Though populations of the Mountain Pine Beetle have declined, this is not to say that you should turn a blind eye to MPB going forward or other possible tree issues that may arise or be found. Doing so could save your woodlot, shelterbelt, or the trees in your yard. 

Here are some steps residents and visitors can take to eliminate the spread of pests and tree disease:

1. Be careful with firewood. If you bring firewood home from an infected tree you risk spreading a pest on to trees on your property and in your neighborhood.
2. Keep trees healthy, as any tree stressed by a lack of moisture, poor pruning, trunk or root injury and topping, are at greater risk of disease.        
3. Diversify your wooded areas with different tree species. Always be planning for the next generation of trees.
4. Be realistic about life expectancy. Every tree is ultimately terminal. An end-of-life strategy for trees includes knowing when to remove them. Assess your trees before they become a problem.  
5. Take responsibility for trees on your own property. A landowner is ultimately responsible as the provincial government does not control trees on private or municipal land.

Clearwater County Ag and Community Services staff are available to assist landowners with inquiries regarding pests or tree health issues and best management or control options. Feel free to give us a call at 403-846-4040.

For questions about MPB on public (crown) land contact Alberta Agriculture and Forestry.

For more information visit the Alberta Agriculture & Forestry website.