Study shows that pine beetle management isn't working

A new study out of UBC shows that pheromone baiting, a method to control the spread of mountain pine beetles, may actually be helping the pest’s population increase.

Rebecca Tyson, an associate professor at UBC-O, examined several mountain pine beetle strategies used in Banff National Park over a two-year simulation.

She compared four separate management strategies for the study: no management, pheromone baiting, tree removal and both pheromone baiting and tree removal combined.

“What our study found is that where the beetle population is low, the pheromone is actually attracting more beetles and thus helping the beetle population increase,” explained Tyson.

Each summer, the adult beetle emerges from a tree and finds a new one that it can nest, emitting a pheromone to attract beetles to the same tree once it’s found. Once more beetles arrive, they release more pheromone and the tree is attacked by the beetles drilling into the bark to make tunnels for their eggs.

The following summer, those eggs will hatch and turn into adult beetles, leaving the now dead tree in order to repeat the same cycle.

The idea of pheromone baiting is to attract those beetles to a specific tree or set of trees before cutting them down in the winter. If all goes well, the beetle population is so severely reduced that it dies out, but according to Tyson it’s not working as expected.

“From the field work done in Banff, we know that baiting didn’t stop the beetle epidemic.”

When the beetle population is so low, like it is right now, they have a hard time finding each other and the additional pheromone, placed by humans, helps the beetles find each other and attack a tree.

“With pheromone baiting this means that humans have put strong signals in the forest that help the beetles find each other,” explained Tyson. “They can then collect in sufficient numbers to attack a tree.”

Tyson describes the mountain pine beetle as an endemic pest that is capable of killing significant number of mature pine. She adds that the beetles may have a short lifespan, but climate change and warmer winters have helped the population increase during an epidemic that started in the late 90s.