Canadian Forest Service Publications
Maximizing bark and ambrosia beetle catches in trapping surveys for longhorn and jewel beetles. 2020. Marchioro, M.; Rassati, D.; Faccoli, M.; Van Rooyen, K.; Kostanowicz, C.; Webster, V.; Mayo, P.; Sweeney, J. Journal of Economic Entomology 113 (6): 2745-2757.
Issued by: Atlantic Forestry Centre
Catalog ID: 40543
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Bark and ambrosia beetles are commonly moved among continents within timber and fresh wood-packaging materials. Routine visual inspections of imported commodities are often complemented with baited traps set up in natural areas surrounding entry points. Given that these activities can be expensive, trapping protocols that attract multiple species simultaneously are needed. Here we investigated whether trapping protocols commonly used to detect longhorn beetles (Coleoptera: Cerambycidae) and jewel beetles (Coleoptera: Buprestidae) can be exploited also for detecting bark and ambrosia beetles. In factorial experiments conducted in 2016 both in Italy (seminatural and reforested forests) and Canada (mixed forest) we tested the effect of trap color (green vs purple), trap height (understory vs canopy), and attractive blend (hardwood-blend developed for broadleaf-associated wood-boring beetles vs ethanol in Italy; hardwood-blend vs softwood-blend developed for conifer-associated wood-boring beetles, in Canada) separately on bark beetles and ambrosia beetles, as well as on individual bark and ambrosia beetle species. Trap color affected catch of ambrosia beetles more so than bark beetles, with purple traps generally more attractive than green traps. Trap height affected both beetle groups, with understory traps generally performing better than canopy traps. Hardwood-blend and ethanol performed almost equally in attracting ambrosia beetles in Italy, whereas hardwood-blend and softwood-blend were more attractive to broadleaf-associated species and conifer-associated species, respectively, in Canada. In general, we showed that trapping variables suitable for generic surveillance of longhorn and jewel beetles may also be exploited for survey of bark and ambrosia beetles, but trapping protocols must be adjusted depending on the forest type.
Plain Language Summary
Bark beetles, ambrosia beetles, and wood boring beetles are frequently moved among continents in wood-packaging materials used to pack globally traded commodities, and some of these species can establish populations in Canada and potentially become damaging invasive pests. Annual trapping surveys are conducted by the Canadian Food Inspection Agency at high-risk locations (e.g., urban forests near ports and industrial parks) to detect introduced non-native forest insects as early as possible. The sooner an invasive pest is detected the more likely it can be eradicated or contained. This study tested the effects of trap color (green vs. purple), trap height (understory vs. tree canopy), and trap lure on detection of bark- and ambrosia beetles in Italy and Canada, to determine the most effective protocol for early detection surveys. Most ambrosia beetles were detected in understory traps but results were mixed for bark beetles: some species were detected mainly in the canopy and others were detected mainly in the understory. Trap color affected catch of only a few species, with purple traps usually outperforming green traps. Two lure blends previously found effective at detecting longhorned wood boring beetles were also effective at detecting bark and ambrosia beetles: the conifer lure blend attracted beetles that feed in conifers and the broadleaf lure blend attracted beetles that feed in broadleaf trees. Overall, the study concluded that for detection surveys in broadleaf stands, all traps should be baited with the broadleaf lure blend, with green traps in the canopy and purple traps in the understory. In mixed conifer-broadleaf stands the same mix of trap heights and color should be used but half of the traps should be baited with the conifer lure blend and half with the broadleaf lure blend.