Brown Spruce Longhorn Beetle - Video


The brown spruce longhorn beetle is an invasive insect which measures 1 to 1.5 centimeters and is native to Europe. Since its discovery in 1999 in Halifax, Nova Scotia, this beetle has killed thousands of spruce trees in that province. Experts believe the brown spruce longhorn beetle first arrived in North America in wood packaging aboard container ships from Europe.

The brown spruce longhorn beetle attacks all species of spruce that we know of, that we’ve tested. In Canada it’s attacking red spruce primarily but also white spruce and black spruce and even Norway spruce which is not a native tree but there are some planted in North America. And it damages the trees, kills them eventually by, it feeds on what’s called phloem which is a tissue underneath the bark between the bark and the wood that transports the food from the leaves down to the rest of the tree. So it’s full of sugars and goodies. The larvae feed on that phloem that goes around the tree, and when there’s enough larvae feeding on that phloem they essentially girdle the tree. So this might take 2,3,4 years before the phloem is cut off. But as the phloem gets gradually cut off, the flow of food to the roots is cut off, so the roots begin to die off, the tree gets weaker, it gets progressively weaker, it gets re-infested year after year. Depending on the health of the tree when the beetle attacks it, it may take a year to kill it or it might take 5 years.

Signs of infestation include streams of resin down the trunk, holes in the bark about 4 millimeters across and L-shaped tunnels in the wood.

Because the beetle spends most of its life cycle inside the live bark or wood of its host tree, it is both difficult to control and is easily transported accidentally in logs or firewood. In an effort to reduce the artificial spread of the beetle, the Canadian Food Inspection Agency restricts the movement of raw logs and bark out of the infested area.

Natural Resources Canada scientists, in collaboration with their partners, are developing tools for slowing the spread of the brown spruce longhorn beetle. Their discovery that the beetle uses an aggregation pheromone has led to an improved survey tool as well as some innovative control methods. Research trials have shown that aerial application of non-toxic bio-degradable pheromone flakes to infested forests disrupts the beetle’s communication and reduces mating success by about fifty per cent.

That’s a technique called mating disruption in which what we’re doing there is broadcasting the sex pheromone, the synthetic sex pheromone of the brown spruce longhorn beetle of fairly large areas, 5-10 hectares with the view of disrupting their mating, so that essentially when you broadcast the synthetic material out, males and females can’t find each other. I mean we’ve got some good success in that, we’ve got some good mating interruption in spreading that material around.

Dissemination of fungal pathogens using a pheromone trap is another promising method being tested. Brown spruce longhorn beetles are attracted to the pheromone trap and come into contact with spores of the fungus before they exit the trap. The fungal pathogen is spread from adult beetle to adult beetle via mating, and infected insects die sooner and lay fewer eggs. An added advantage of this technique is that it greatly reduces the exposure of non-target species to the fungus.

Natural Resources Canada researchers continue to work on developing environmentally friendly tools that reduce the impact of invasive species.

We can all help slow the spread of invasive insects by not moving firewood. On its own, the brown spruce longhorn beetle does not appear to move very far. Hiding in firewood, though, it can travel vast distances.