Summary: Climate change has contributed to rising numbers of forest insect pests including the Douglas-fir beetle, which will start its flight as early as April in Pacific Northwest and Rocky Mountain states.

If the mountain pine beetle is the current superstar of the forest pest world, the Douglas-fir beetle is its lesser-known--but gaining in notoriety--younger sibling. Like the mountain pine beetle, current conditions have led to an increase in Douglas-fir beetles in the last few years, but unlike the mountain pine beetle which starts its flight in mid-summer, the Douglas-fir beetle will be out in force starting as early as April.

As its name suggests, the Douglas-fir beetle attacks Douglas-fir trees and sometimes downed western larch. It is prevalent throughout the Pacific Northwest and Rocky Mountain states including Arizona, Colorado, Idaho, Montana, New Mexico, North Dakota, South Dakota, Oregon, Utah, Washington and Wyoming. On the coast, the Douglas-fir beetle can infest downed trees, logs and stumps. It readily attacks living trees in the interior. Populations may build up on fallen trees and logs and then switch to standing trees the next year.

“Just like mountain pine beetle, the Douglas-fir beetle is responding to climate change,” said John Borden, Professor Emeritus at Simon Fraser University in Vancouver, B.C. and chief scientific officer for Contech Enterprises. “In past years, the beetles and larvae were killed off during cold weather. Recent temperate conditions have allowed the larvae to overwinter in the trees, ready to attack as soon the weather starts to warm.”

Like most of its bark-boring counterparts, the Douglas-fir beetle kills trees by boring into the bark and cutting off the tree’s supply of water and nutrients. If a tree is already stressed by drought, disease, or another pest, it is particularly susceptible.

The first step to managing a Douglas-fir beetle infestation, according to Borden, is identification. He suggests looking for dripping resin on the tree as well as red or orange “boring dust” in the bark crevices or at the tree's base. To confirm attack, remove a section of the bark to look for long tunnels that run parallel to the wood grain and larval tunnels that fan out laterally to the main tunnels. Once a tree has been infested, it will likely die within a year.

Boring dust found in crevices and at base of Douglas-fir. Photo credit: Kenneth E. Gibson, USDA Forest Service, Bugwood.org	Larval tunnels fanning out from main tunnels. Photo credit: Doug Page, USDI Bureau of Land Management, Bugwood.org

To help protect against infestations, Borden recommends an integrated pest management program including removal of infested trees and logs, regular hydration, and the use of MCH—a naturally occurring beetle pheromone that is very effective in repelling the Douglas-fir beetle. The repellent, attached to living trees, tricks the beetles by sending a false message that the tree is already full and that they should look elsewhere for a suitable host. It is environmentally friendly and non-toxic to humans, animals, and even the beetle themselves.

For more information on the Douglas-fir beetle:
BC Ministry of Forests
For more information on pheromone treatments for the Douglas-fir beetle:
Integrated Pest Management & MCH
For more information on why trees are important:
Arbor Day Foundation

Contact:
Tracey Robertson
Media Relations, Contech Enterprises
www.contech-inc.com
1-800-767-8658 ext 124