The Push-Pull Tactic for Mitigation of Mountain Pine Beetle (Coleoptera: Curculionidae) Damage in Lodgepole and Whitebark Pines

Abstract

In an attempt to improve semiochemical-based treatments for protecting forest stands from bark beetle attack, we compared push-pull versus push-only tactics for protecting lodgepole pine (Pinus contorta Douglas ex Loudon) and whitebark pine (Pinus albicaulis Engelm.) stands from attack by mountain pine beetle (Dendroctonus ponderosae Hopkins) in two studies. The first was conducted on replicated 4.04-ha plots in lodgepole pine stands (California, 2008) and the second on 0.81-ha plots in whitebark pine stands (Washington, 2010). In both studies, D. ponderosae population levels were moderate to severe. The treatments were 1) push-only (D. ponderosae antiaggregant semiochemicals alone); 2) push-pull (D. ponderosae antiaggregants plus perimeter traps placed at regular intervals, baited with four-component D. ponderosae aggregation pheromone); and 3) untreated controls. We installed monitoring traps baited with two-component D. ponderosae lures inside each plot to assess effect of treatments on beetle flight. In California, fewer beetles were collected in push-pull treated plots than in control plots, but push-only did not have a significant effect on trap catch. Both treatments significantly reduced the rate of mass and strip attacks by D. ponderosae, but the difference in attack rates between push-pull and push-only was not significant. In Washington, both push-pull and push-only treatments significantly reduced numbers of beetles caught in traps. Differences between attack rates in treated and control plots in Washington were not significant, but the push-only treatment reduced attack rates by 30% compared with both the control and push-pull treatment. We conclude that, at these spatial scales and beetle densities, push-only may be preferable for mitigating D. ponderosae attack because it is much less expensive, simpler, and adding trap-out does not appear to improve efficacy.

Volatile Organic Compounds Emitted by Fungal Associates of Conifer Bark Beetles and their Potential in Bark Beetle Control

“…Pest beetles are deterred by using push stimuli placed within target stands or on their perimeter, and simultaneously attracted by using stimuli attached to baited traps placed outside the target stand. Stimuli can be delivered in a number of ways in this strategy, as described above, and push-pull methods have been successfully tested against the mountain pine beetle, D. ponderosae and Ips paraconfusus Lanier attacking Torrey pine ( Pinus torreyana ), an endangered species growing in a limited area of California (Gillette et al 2012; Shea and Neustein 1995). The choice of traps (baited trees or baited traps), plot size, and trap spacing was shown to influence the method’s efficacy (Borden et al 2006).…”

Evaluation of repellents for the redbay ambrosia beetle, Xyleborus glabratus, vector of the laurel wilt pathogen

“…Furthermore, a 'push-pull' system (Cook et al 2007;Gillette et al 2012) combining the best repellents identified in this study to 'push' the vector away from susceptible hosts, in combination with the best available attractant (i.e. 50% a-copaene lure; Kendra et al 2016a,b) to 'pull' them to areas of non-hosts, may increase the effectiveness of these semiochemicals than if used alone.…”

“…; Gillette et al. ) combining the best repellents identified in this study to ‘push’ the vector away from susceptible hosts, in combination with the best available attractant (i.e. 50% α ‐copaene lure; Kendra et al.…”

Applied Chemical Ecology of the Mountain Pine Beetle

“…Shea and Neustein (1995) tested pushpull on the California five-spined ips, Ips paraconfusus Lanier, and while their treatments were successful, that study was not replicated or controlled, and was complicated by the sudden end of drought conditions that had precipitated the initial outbreak (Littrell 1992). Gillette et al (2012b) conducted a two-phase study to determine whether adding perimeter traps to verbenone-treated stands further reduced levels of tree mortality attributed to D. ponderosae. They reported that at two different levels of spacing, adding a pull component had no effect.…”

“…Not surprising, push-pull tactics are currently under scrutiny to assess whether the added effort and cost of an attractive component is merited. The scale at which effectiveness can be balanced with efficiency has yet to be defined (Gillette et al 2012b) and dose-range tests (Miller et al 1995) may need to be incorporated in related studies to aid in decisions about which combinations of semiochemical treatments best meet management objectives and desired levels of tree protection.…”