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The addition of a trap baited with manuka oil or longer lasting cubeb oil lures (Hanula et al. 2013) along with those baited with ethanol for surveys targeting detection of non-native, invasive Curculionidae could improve these surveys by also targeting the destructive redbay ambrosia beetle. [ABSTRACT FROM AUTHOR]

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, vectors laurel wilt, Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva, that quickly kills all large diam (> 2.5cm) redbay trees [ Persea borbonia (L.) Sprengel] in an area but smaller diam trees (< 2.5cm) survive for years. We measured densities of X. glabratus attacks on hanging bolts of freshly cut mature redbay annually for 5 yr (2007-2011) at 7 locations varying in age of infestation from newly infested in 2007 to those that were among the oldest infested areas (infested in 2002 or earlier), to determine if populations persist after mature host trees are gone. Attack densities on redbay bolts at the field sites varied from 10-25 X. glabratus attacks/100cm2 where large dying redbay trees were still present, to < 1 attack/100cm2 at sites where few or no trees > 2.5 cm diam near ground level were still living at the beginning of the study in 2007. Despite having no large trees available, populations of the beetle persisted at 2 of the 3 oldest infested sites throughout the 5-year survey period (2007-2011). In 2012 we studied X. glabratus utilization of small diam redbay wood as a possible explanation of how populations might survive in these areas in the absence of larger trees. In laboratory trials, X. glabratus produced 27.8 ± 6.63 adults/gallery (± SE) from 18 galleries constructed in portions of redbay trees that averaged 3.2 ± 0.02 cm diam at the point of attack. The smallest stem section to support a successful gallery was 1.7 cm diam but it produced only 2 adults. In field trials no attacks occurred in portions of stems < 1.6 cm diam. Upon stem dissection, more brood was found in stem sections near the ground (0-10 cm) than in those over 80 cm above ground. In addition, brood abundance in10 cm long tree sections exhibited a positive non-linear relationship (cubic polynomial; R2 = 0.21) with section diam. Our data suggest that X. glabratus can maintain low populations in areas devoid of large redbay by utilizing 2-3 cm diam portions of small trees primarily near ground level. [ABSTRACT FROM AUTHOR]

The redbay ambrosia beetle, Xyleborus glabratus Eichoff, (Coleoptera: Curculionidae: Scolytinae) is a severe pest of North American trees and shrubs in the family Lauraceae. Supercooling point (SCP) is an important physiological baseline for cold tolerance studies and could provide useful insights into the invasive potential of X. glabratus in northern latitudes of North America. The supercooling point (SCP) of X. glabratus was experimentally determined on field-collected and artificially cold hardened specimens. Field-collected beetles were captured in Jackson County, Mississippi using Lindgren funnel traps baited with manuka oil lures. Testing was conducted from June through August 2011. The mean SCP for field-collected X. glabratus was -21.7 ± 0.5 °C (± SE). A significant negative trend in the SCPs of field-collected beetles occurred over the summer testing period. Xyleborus glabratus specimens were reared from redbay (Persea borbonia (L.) Sprengel bolts in June 2012 and artificially cold hardened in a low temperature incubator at a thermo-photoperiod of 7 °C:2 °C (10:14 h L:D) for 31 days. Artificially cold hardened X. glabratus supercooled to a mean temperature of -23.9 ± 0.4 °C (± SE), which was significantly lower than that of field-collected beetles. Biometric indices of beetles (size, weight, and size x weight interaction) had no effect on the mean supercooling SCPs of either field-collected or artificially cold hardened beetles. Results from environmentally conditioned beetles suggest that X. glabratus has a high degree of thermal plasticity. Based on the artificially cold hardened mean SCP, X. glabratus and laurel wilt disease have the possibility to impact sassafras and northern spicebush throughout eastern North America. The data, although preliminary, suggests that a previous spatio-temporal model based on climate match data may have substantially underestimated the geographical area that may be affected by X. glabratus. This study will help form the basis of building and validating models to better predict the North American invasion potential of X. glabratus. [ABSTRACT FROM AUTHOR]

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring pest that vectors Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), the etiologic agent of laurel wilt. To date, all confirmed U.S. hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. However, in previous research, an unknown variety of lychee, Litchi chinensis Sonn. (Sapindales: Sapindaceae), was found to be highly attractive to X. glabratus and elicited boring behaviors. Therefore, a study was undertaken to evaluate two commercial cultivars of lychee, 'Brewster' and 'Mauritius', for susceptibility to attack by X. glabratus, for transmission of R. lauricola, and for development of laurel wilt disease. In no-choice laboratory bioassays, 35 and 44% of females bored into cut bolts of 'Mauritius' and 'Brewster', respectively. Similar boring was observed on the trunks of two live 'Brewster' trees; but after 3 mo, there was no evidence of beetle reproduction, no symptoms of laurel wilt, and no recovery of R. lauricola from tissue associated with beetle galleries. Lychee trees artificially inoculated with an isolate of R. lauricola (RL4) that kills lauraceous hosts of this pathogen were asymptomatic after 1 mo, and assays for R. lauricola were negative. Chemical analysis indicated that lychee emits several sesquiterpene constituents in common with the Lauraceae, but at lower levels. Based on these data, we conclude that L. chinensis, although attractive to female X. glabratus, is not a likely reproductive host. This may be due to the inability of lychee wood to support growth of R. lauricola, the presumed primary nutritional symbiont of X. glabratus. [ABSTRACT FROM AUTHOR]

Semi-artificial diets consisting of redbay (Persea borbonia (L.) Spreng.; Laurales: Lauraceae) sawdust and various nutrients were tested for rearing Xyleborus glabratus Eichoff (Coleoptera: Curculionidae: Scolytinae) in vitro. Comparison of 2 media, modified and standard, adapted from Biedermann et al. (2009) showed that the more solid consistency of the modified medium resulted in greater rates of successful brood production in cultures. A 2-layered medium structure with a nutrient rich lower layer and a nutrient poor upper layer proved to be superior to a single-layered structure. Using a 2-layered structure, 72.5% of foundresses successfully produced brood, which was similar to or greater than success rates of X. glabratus under natural field conditions. The most successful media recipes used finely ground wood from redbay, but some successful brood production also occurred when wood from pondberry (Lindera melissifolia) (Walter) Blume; Laurales: Lauraceae) and California bay laurel (Umbellularia californica (Hook. & Arn.) Nutt.; Laurales: Lauraceae) were used instead of redbay. A 2-layered structure with nutrient levels slightly higher than those in the modified medium of Biedermann et al. (2009) is recommended for rearing X. glabratus in vitro. [ABSTRACT FROM AUTHOR]

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is a wood-boring pest that transmits the fungal pathogen Raffaelea lauricola, the causal agent of laurel wilt disease in American Lauraceae. This study documents the gallery formation patterns of X. glabratus as well as its life cycle and development at 25 ± 2 °C in logs of 3 natural hosts: avocado (Persea americana), redbay (P. borbonia) and swampbay (P. palustris). Females were observed to excavate galleries perpendicular to the tree trunk; galleries were characterized by a main entrance tunnel, from which branched secondary tunnels that, in turn, gave rise to tertiary tunnels. By dissecting infested logs daily, the length of time was determined for each developmental stage, and found to be comparable in all 3 hosts. Eggs were first encountered in avocado, redbay, and swampbay at 7, 11, and 10 days after gallery initiation (agi), respectively; larvae at 14, 20, and 14 days agi; pupae at 24, 26, and 26 days agi; and teneral adults at 31, 30, and 27 days agi. Despite comparable rates of development in all hosts, there were fewer progeny per female produced in avocado. Oviposition by the founding female extended over a broad time-span, and all stages were observed in the gallery at 1 month agi. Three larval instars were present, with mean head capsule widths of 0.21, 0.26, and 0.37 mm, respectively. Long term rearing of X. glabratus was achieved on swampbay logs soaked in water prior to infestation. Emergence of new females from logs was first observed at 60 d agi, indicating that teneral adults remain in hosts for ~1 month prior to dispersal. Emergence continued for up to 240 days, with maximum emergence observed between 120-150 days agi. [ABSTRACT FROM AUTHOR]

The redbay ambrosia beetle Xyleborus glabratus is unusual among ambrosia beetles because of its host specificity to Lauraceae, but it isn't clear whether this is only a feature of the invasive American population. Our examination of the extensive collection in the Chinese Academy of Sciences suggests that Xyleborus glabratus strongly prefers Lauraceae also in its native Asia. These are also the first published records of the species from continental China, which highlights the value of entomological collections. [ABSTRACT FROM AUTHOR]