Attraction of Redbay Ambrosia Beetle, Xyleborus Glabratus, To Leaf Volatiles of its Host Plants in North America

Abstract

The redbay ambrosia beetle, Xyleborus glabratus, is an important pest of redbay (Persea borbonia) and swamp bay (P. palustris) trees in forests of the southeastern USA. It is also a threat to commercially grown avocado. The beetle is attracted to host wood volatiles, particularly sesquiterpenes. Contrary to other ambrosia beetles that attack stressed, possibly pathogen-infected, and dying trees, X. glabratus readily attacks healthy trees. To date little is known about the role of leaf volatiles in the host selection behavior and ecology of X. glabratus. To address this question, an olfactometer bioassay was developed to test the behavioral response of X. glabratus to plant leaf volatiles. We found that X. glabratus was attracted to the leaf odors of their hosts, redbay and swamp bay, with no attraction to a non-host tree tested (live oak, Quercus virginiana), which served as a negative control. Gas chromatography-mass spectrometry (GS/MS) analysis of leaves revealed the absence of sesquiterpenes known to be attractive to X. glabratus and present in host wood, suggesting that additional leaf-derived semiochemicals may serve as attractants for this beetle. An artificial blend of chemicals was developed based on GC/MS analyses of leaf volatiles and behavioral assays. This blend was attractive to X. glabratus at a level that rivaled currently used lures for practical monitoring of this pest. This synthetic redbay leaf blend also was tested in the field. Baited traps captured more X. glabratus than unbaited controls and equivalently to manuka oil lures. We hypothesize that leaf volatiles may be used by X. glabratus as an additional cue for host location.

α-Copaene is an attractant, synergistic with quercivorol, for improved detection of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae)

“…glabratus , including α-cubebene, α-humulene, and calamenene [38]. The monoterpene ether eucalyptol (1,8 cineole) [55] and even host leaf volatiles [56] may contribute to that signature bouquet as well. Through serendipity, it was discovered that FL-TSHB is also attracted to the α-copaene lure.…”

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

“…; Martini et al. ); however, long leaf pine does not contain eucalyptol, a known attractant of redbay ambrosia beetle (Kuhns et al. ).…”

“…,b; Martini et al. ). Additionally, lure development has focused on the sourcing and enrichment of the attractant α ‐copaene (Kendra et al.…”

Laurel Wilt in Natural and Agricultural Ecosystems: Understanding the Drivers and Scales of Complex Pathosystems

“…While in flight, females orient initially toward long-range olfactory cues; α-copaene appears to be the primary kairomone, but other terpenoids likely contribute to generate an attractive "signature bouquet" of the Lauraceae [66,82,87]. In addition to sesquiterpenes, several monoterpenes have been reported as kairomones, including eucalyptol (1,8 cineole) [91] and a blend of redbay leaf volatiles [92]. There is no evidence that X. glabratus utilizes sex or aggregation pheromones [78].…”

“…Symptoms of laurel wilt develop soon after host trees are infected by R. lauricola (usually within 2 to 3 weeks of artificial inoculation) [117]. As the disease develops, host trees increase the production of volatiles that attract X. glabratus [92], which then promotes mass attack, colonization and brood development by X. glabratus. Ploetz et al [118] hypothesized that an avocado scion's susceptibility to laurel wilt is related to its ability to conduct water.…”