Development of monitoring tools to detect mountain pine beetle at low densities on the eastern and northern edge of beetle expansion into Saskatchewan and NWT

The life history of the mountain pine beetle (MPB) consists of migration, colonization, and development phases. Adult beetles emerge from dead brood trees, undertake a dispersal flight, and locate new hosts. The colonization phase, during which the beetles bore into the bark of selected trees, is characterized by rapid infestation triggered by aggregation pheromones. Due to the importance of pheromones in bark beetle biology, many studies have focused on the development of synthetic pheromones for the monitoring and management of bark beetle populations, and thus pheromones are known for a number of economically important bark beetle species, including MPB. However, we currently do not know whether commercially available lures used to monitor MPB populations are effective for catching MPB at low densities in novel habitats, suggesting an urgent need for the development of such lures.

Objectives

The objective is to improve the currently available commercial lures to attract MPB in novel habitats. The project will focus on the development of an attractant that will be more attractive to female beetles and less attractive to the other bark beetle species and natural enemies of mountain pine beetle.

Overview of methodology

I will compare commercially available MPB lures from Contech-Inc. and Synergy Semiochemical with lures developed in Erbilgin’s lab using flight intercept traps. Attractiveness of lures will be tested in five sites (each with 5 blocks, each block with 4 treatments): (1) Contect-Inc MPB lure, (2) Synergy Semiochemical lure, (3) new lure developed in Erbilgin’s lab, and (4) blank control. Although these lures contain similar chemicals (trans-verbenol, exo-brevicomin, and frontalin), they differ in their release rates, particularly trans-verbenol. Traps will be suspended from 2 m-long poles. The distance between traps will be 15 m and blocks will be separated by 150 m from each other. Captured beetles will be removed from the traps every 3-4 days. The initial experiment will be conducted in July.

Based on the outcome (i.e., using a particular treatment that is superior to the others), in the subsequent experiments we will alter the release rates of individual chemical(s) in the selected treatment and field test their efficacy in July and August. We will also test whether addition of host tree volatile chemicals to MPB pheromone lure will improve the attraction of beetles, particularly females. Based on the experiments conducted in Erbilgin’s lab and published literature, the candidate tree volatiles are myrcene, terpinolene, and 3-carene. In our experiments, we will add either single (terpinolene, mycrene, 3-carene), double (terpinolene + mycrene, terpinolene + 3-carene, or mycene + 3-carene) or triple (terpinolene + mycrene + 3-carene) host tree chemicals to MPB pheromone and test their attractiveness. Earlier studies conducted in BC found that adding terpinolene and myrcene together to MPB pheromone caused a significant increase in the percentage of female MPB captured in traps, but changing release rates of MPB pheromone components and host tree chemicals has never being tested before. All these field experiments will be conducted in lodgepole pine forest stands in Slave Lake and Whitecourt.

Expected outcomes

The goal of this research is to develop an effective attractant using traps in novel habitats. The project will provide a learning environment for multiple undergraduate summer students.