Trap trees: an effective method for monitoring mountain pine beetle activities in novel habitats

Abstract

Mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins) has recently expanded its range into the lodgepole pine forests in Alberta, Canada. However, it is unknown whether semiochemical tools developed in the beetle’s historical range are suitable for monitoring MPB in the new environment. Thus, we conducted a 3-year study to test new MPB monitoring tools in Alberta. A field trial selected a combination of MPB pheromones and two host volatiles. Using this combination, we baited different numbers of trees in triangular, square, or rectangular formations (spatial arrangements of trees) to determine how the densities of baited trees affect MPB attraction. Three plots, each made up of three formations, were arranged in a linear transect at various distances between formation boundaries. The proportion of baited trees mass-attacked was highest in the square formation. However, the proportion of spillover trees mass-attacked (attacks on non-baited trees) was lower when formations were 1 km apart compared with 4 or 8 km apart. In a follow-up test of the square formation alone, there was no difference in trap tree effectiveness between distances of 8 and 12 km. We suggest that four baited trees spaced 50 m apart in a square formation at a 12 km distance can be used in the field.

A Pine in Distress: How Infection by Different Pathogenic Fungi Affect Lodgepole Pine Chemical Defenses

“…For instance, it was reported that upregulation of 3-carene restrict the growth of G. clavigera [24]. Conversely, upregulation of terpinolene may increase mountain pine beetle attraction to its aggregation pheromone [30]. All these results demonstrate that upregulation of host tree monoterpenes can be seen as defense strategy while such upregulation may also bene t bark beetles, suggesting that we need to consider the subsequent effects of plant defenses on the bark beetle-fungal symbiont complexes [8, 24,31,32].…”

Understanding bark beetle outbreaks: exploring the impact of changing temperature regimes, droughts, forest structure, and prospects for future forest pest management

“…Once attracted, beetles can be killed with pesticides or by removing the infested trees or logs. Limited scientific evidence supports the efficacy of using trap trees to effectively reduce beetle populations or the number of attacked trees (Klutsch et al 2017). However, there is a shortage of research on the efficacy of trapping techniques in reducing the risks of outbreaks and rates of damage, particularly for large-scale applications.…”