Fall is such a beautiful time of year, and it’s always a pleasure to done a knit sweater and stroll through the golden canopy of downtown Edmonton, soaking in the autumn colours and the crisp air. But fall can be hard on trees, and can bring with it a variety of threats. Continuing our in-depth examination of tree dangers, today we’re examining the spruce beetle, which is native to Western North America as well as Arizona and Alaska, and can be detrimental to white and Engelmann spruces throughout Alberta. The spruce beetle is the most serious six-legged threat to mature and over-mature interior spruce in the province of Alberta.
Rather than emerging in the spring as most pests do, the spruce beetle emerges in late summer. Over the long winter months, adults construct egg tunnels for their brood in June, and a second set of tunnels in late July for a second batch. At the end of the summer, the two broods emerge and begin to feed on weakened Spruce species, which can spell trouble for any yard. Larvae hibernate, then resume development the following June, pupate over the summer, and emerge as adults in later summer or early fall. The adults generally emerge, fall or crawl to the ground, and re-enter the same tree to hibernate, often clumping together under the bark. The initial attack usually happens in the lower trunk and is indicated by the red boring dust in the bark crevices and by pitch tubes. Some species of fungi such as Leptographium abietinum may help beetles to overcome the defenses of weakened trees which help them with their mass borings. Though difficult to spot, these symptoms spell trouble, and if you notice them, you should contact a tree care specialist immediately.
The spruce beetle is one of many beetle species that have recently increased their breeding times, which is all the more reason to be on the lookout. The overpopulation of beetles in some forests in Kenai, Alaska, has damaged several spruce species to the extent that they are no longer able to dwell there. The spruce beetle has destroyed millions of acres of spruce populations in North America in the 1990s, totaling more than 30 million trees per year. The spruce beetle epidemic killed an estimated 350,000 hectares of forest in the in the Yukon before petering out a few years into the new millennium. The infestation peaked around 2004, when beetles destroyed an area of forest about two-thirds the size of Prince Edward Island.
Because the spruce beetle’s life cycle can vary from one to three years, and because of the complexity of their maturation process, it can be difficult to spot or treat an infestation. Discoloured bark and collections of fungi near the bottom half of the spruce are strong indicators of beetle activity. If you see any of the above symptoms, don’t delay — contact a tree specialist who understands the particulars of Alberta’s vast arboreal stratum, and who can pinpoint the problem and find the right solution. Our arborists here at Chipps Tree care are certified and trained to deal with problems specific to Edmonton’s particular ecosystem. We’re more than capable of taking on the spruce beetle as well as any other pest of disease issues, so contact us today and we’ll send a specialist out to look into the issue right away!