Semiochemicals for management of the southern pine beetle (Coleoptera: Curculionidae: Scolytinae): successes, failures, and obstacles to progress

Abstract

The southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae), is among the most destructive bark beetle pests of pines (Pinaceae) of the southeast and mid-Atlantic United States of America, Mexico, and Central America. Numerous volatile compounds can stimulate or reduce attraction of the beetle, but efforts to incorporate these into effective, practical technologies for pest management have yielded mixed results. Attractants have been incorporated into lures used in monitoring traps that are employed operationally to forecast outbreaks and detect emerging populations. The attraction inhibitor, verbenone, shows efficacy for suppressing southern pine beetle infestations but has not yet been adopted operationally. No effective semiochemical tree protectant has been developed for the beetle. We discuss complexities in the chemical ecology of the beetle that likely have impeded research and development of semiochemical management tools, and we describe basic science gaps that may hinder further progress if not addressed. We also report some supporting, original experimental data indicating (1) that a verbenone device can inhibit the beetle’s response to sources of attractant in a radius of at least several metres, (2) similar olfactory responses by the beetle to both enantiomers of verbenone, and (3) that pheromone background can cause conflicting results in semiochemical field tests.

How Effective Are Push–Pull Semiochemicals as Deterrents for Bark Beetles? A Global Meta-Analysis of Thirty Years of Research

“…Push-pull semiochemical treatments significantly reduced the population of Dendroctonus species, with reductions ranging from 34 to 69%. This significant reduction in the population of the Dendroctonus species is aligns with the findings of Bedard, et al [46]; Cook et al [14]; Liu et al [47]; Seybold et al [41], Seybold and Fettig [48]; and Sullivan and Clarke [49] for Dendroctonus brevicomis (LeConte), Dendroctonus pseudotsugae (Hopkins), D. valens, D. ponderosae, D. rufipennis, and D. frontalis, respectively. Moreover, using S-(-)-verbenone in combination with 1-hexanol and (Z)-3-hexanol caused about a 60% reduction in D. ponderosae attacks on trees [45].…”

“…Verbenone is a compound produced by oxidation of alpha-pinene by males of several Dendroctonus and Ips species as an anti-aggregation pheromone [67]. In field-trapping experiments, this semiochemical has been found to be effective in reducing the attraction of several bark beetles like D. frontalis toward lures [49] and D. ponderosae attraction to trans-verbenol, cis-verbenol, and exo-brevicomin [44].…”

Composition of Attractant Semiochemicals of North American Species of Dendroctonus Bark Beetles: A Review

“…Importantly, attractants that mediate massaggregation are essential to the ability of the more aggressive species to colonize healthy trees [18,19], since only with sufficient numbers of attacks can the beetles neutralize the resin defenses of vigorous hosts [20,21]. Due to the potential of semiochemicals to alter bark beetle behavior in beneficial ways, there have been extensive efforts to incorporate synthetic semiochemicals into technologies for pest management [22][23][24]. Bark beetle attractants are used for delimiting the range of individual species [25,26], assessing diversity of bark beetles and their natural enemies [27][28][29], detecting inadvertent introductions of exotic pest species [30][31][32][33], forecasting beetle population trends [34][35][36], mass trapping and "trap tree" procedures for population reduction [37][38][39][40], "push-pull" tactics with both attractants and repellants for protecting resource patches [39,41,42], creating snags for wildlife habitat [43,44], and addressing a wide range of research questions.…”

New Records of Southern Pine Beetle (Dendroctonus frontalis Zimmermann; Coleoptera: Curculionidae) in New York, New Hampshire, and Maine, USA Indicate Northward Range Expansion

“…SPB was identified in these trees, which represented the northernmost collections of SPB at that time (Dodds et al 2018). The finding of SPB on Long Island motivated pheromone-baited trapping efforts in New York and in New England, using standard methodology that has been developed in the southern US to monitor for SPB (Sullivan and Clarke 2021). As of 2016, SPB was collected from frontalin-baited Lindgren funnel traps in low numbers in Connecticut, Rhode Island, Massachusetts, and New York, with the furthest north detections in west-central Massachusetts (Dodds et al 2018).…”