We spent a week in Colorado the beginning of June. My family has had a cabin in Estes Park since 1932. My Dad’s father built it by hand when my Dad was just a couple of years old. This is on the east slope of the Rockies. There are trees starting to die on that side.
The real surprise was when we drove to the western slope. Entire square miles of forest are dead and brown. The pines have been killed by the Pine Beetle. The Pine Beetle is the most destructive forest pest in North America. The Canadian Forest Service describes the current pine beetle epidemic as the largest insect infestation in North American history.
Mountain Pine Beetles have a one year life cycle. In late summer (usually July-Aug in Rocky Mountain States) the newly hatched adults leave the tree of their metomorphosis, seeking out larger trees (usually over 13″ diameter if possible) in the surrounding area. (In areas with heavy infestation, beetle hatchlings may take even smaller trees as pressure to get ANY tree increases). When the adults arrive, they begin tunneling under the bark, lay eggs, which turn to larvae and live through the winter to produce more egg-laying adults to attack more trees. Colorado State University guesses that one infested tree will kill at least two or more trees. Thus the massive expansion occurs.
Beetles and almost all other animals communicate using pheromones. Verbenone, a synthetic pheromone treatment for high value pine trees, replicates the beetle pheromone, sending a message that the tree is full and that the food supply is insufficient for additional beetles. Arriving beetles receive the “message” that they should look elsewhere for a suitable host. BeetleBlock is the most well-known of the verbenone products. It has the advantage of just once-a-year application compared to other brands. That saves both time and money