9 Insects and Diseases Destroying Canada’s Trees and Forests

July 19, 2019

Canada is famous for a great number of things given everything from dedicated hockey fans to maple syrup lovers, friendly folks and fantastic forests. With a maple leaf adorned on the country’s flag, trees are synonymous with this proud nation. Along with supporting many types of wildlife, trees also can become infested or inhabited by a number of different diseases and insects that threaten their existence. These are nine of the most problematic pests that damage and often destroy trees along with thinning forests in one of the most beautiful northern regions of the world.

1. Asian Longhorned Beetle (Anoplophora glabripennis)

Native to China and the Korean peninsula, the Asian longhorned beetle has no natural enemies in this part of North America only appearing in Ontario. Mainly attacking the treasured Canadian maple trees, it’s also destructive to other species such as the poplar, birch, willow and elm. The beetles were first discovered near Toronto in 2003 and were eventually eradicated by the government. However, a second population sprouted up in 2013 and the war wages on to rid the region of this destructive pest.

2. Birch Leafminer (Tenthredinidae family)

Birch leafminers, also known as sawflies are native to Europe and first introduced to Canadian forests sometime after 1920. They are also a problem in nearby Alaska according to the USDA (United States Department of Agriculture). This species of leafminers attack all species of birch trees and can adversely affect up to 90% of a tree’s leaves. These pests have been found feasting on birch foliage in all provinces of Canada except the expansive northern territory of Nunavut.

3. Brown Spruce Longhorn Beetle (Tetropium fuscum)

Red, white, black and Norwegian spruce trees are all potential victims of the brown spruce longhorn beetle native to Russia, Japan, northern and central Europe. Other than a small population near Calhoun, New Brunswick, this pesky beetle has only been found in Nova Scotia. It’s believed this longhorn beetle arrived inside wood packaging material delivered by container ships docked at the Port of Halifax during the 1990s.

4. Butternut Canker (Ophiognomonia clavigignenti-juglandacearum)

The first fungus on this roster, the Butternut canker is an infection mostly affecting the namesake Butternut trees. Scientists are puzzled by the origin of this disease and it’s been a part of Canada’s Species at Risk Act since 2005. The fungus causes a canker (or wound) that causes small, long, black, sunken blemishes. First appearing in Quebec in 1990, later in Ontario and New Brunswick, the fungus has decimated up to 80% of the Butternut tree population in this country.

5. Emerald Ash Borer (Agrilus planipennis)

This metallic, wood-boring beetle is native to regions of the Far East including China and Russia. Similar to the brown spruce longhorn beetle, it’s believed the emerald ash borer arrived in wood packing materials in the 1990s. Many species of ash trees found in North America are particularly vulnerable to an infestation of this bug and has led to millions of flora deaths in both forested and urban areas of Canada. Even though predators include woodpeckers, insects and parasites that are known enemies of this boring bug, they haven’t been able to slow the spread of this destructive pest. 

6. Forest Tent Caterpillar (Malacosoma disstria)

Native to North America, the forest tent variety of these wormlike creatures is one of three tent caterpillar species including the eastern tent caterpillar (Malacosoma americanum) and the western tent caterpillar (Malacosoma californicum pluviale). These campy critters have destroyed millions of hectares of Canadian forests feeding mostly on the trembling aspen, oak, ash, maple and white birch. Outbreaks have been recorded in the boreal forest since the 1930s and other infestations have crippled tree populations in Alberta, Ontario and Quebec.

7. Mountain Pine Beetle (Dendroctonus ponderosae)

Western North America is home to the mountain pine beetle that attacks a wide variety of pine trees including lodgepole, ponderosa, western white, whitebark, limber and jack but doesn’t have a taste for the Jeffrey pine. This boring beetle’s enemies in the wild include other insects, parasites and woodpeckers but these predators aren’t having a significant impact on controlling outbreaks, their population and devastation. Like other Canadian bugs, their invasion began in British Columbia circa the early 1990s and migrated north and eastward into the boreal forest of north-central Alberta.

8. Eastern Spruce Budworm (Choristoneura fumiferana)

These little worms cause big problems with outbreaks regularly occurring in the boreal, Great Lakes and Acadian forests of Canada even though they’re an integral part of these ecosystems. Unfortunately, major outbreaks cause tens of millions of hectares of spruce and fir trees to be destroyed or defoliated by these destructive budworms. Those injured or dead trees cause significant losses for the timber industry, become fuel for forest fires, brood and food for other insects.

9. Western Spruce Budworm (Choristoneura freemani)

Similar to their eastern cousins, the western spruce budworms are equally as problematic but in a different way. Instead of feasting on leaves, these worms feed on the growing shoots of host trees leaving them distorted and discoloured. Needle fragments are often encased in silk and some trees become stripped of needles in their entirety. These little buggers are found in coastal and interior parts of British Columbia, south and west of the Fraser River, in the foothills of Alberta, east to the Cypress Hills and on the Alberta-Saskatchewan border. 

Important Closing Comments

Trees weakened by any of these insects and/or diseases often become more susceptible to other adverse conditions such as the drought that continues to be present and problematic in many parts of Canada. It’s unknown whether or not global warming is a factor or even an issue with the growing populations of these pests who often enjoy warmer climates. In any case, outbreaks and infestations continue to be an enormous problem for Canada, North America and other parts of the world. 

In conclusion, if there are dead, diseased or otherwise distressed trees that are in need of removal, be sure to contact the professionals at Pevach Corp for a free quote about this vital service. As experts in the tree removal industry, our motto is “working with nature to make nature work.” Our more-modern, environmentally-friendly techniques do less harm to Mother Nature and do more to help preserve our forests for the future.