Geosmithia associated with bark beetles and woodborers in the western USA : taxonomic diversity and vector specificity

Fungi in the genus Geosmithia (Ascomycota: Hypocreales) are frequent associates of bark beetles and woodborers that colonize hardwood and coniferous trees. One species, Geosmithia morbida, is an economically damaging invasive species. The authors surveyed the Geosmithia species of California and Colorado, USA, to (i) provide baseline data on taxonomy of Geosmithia and beetle vector specificity across the western USA; (ii) investigate the subcortical beetle fauna for alternative vectors of the invasive G. morbida; and (iii) interpret the community composition of this region within the emerging global biogeography of Geosmithia. Geosmithia was detected in 87% of 126 beetle samples obtained from 39 plant species. Twenty-nine species of Geosmithia were distinguished, of which 13 may be new species. Bark beetles from hardwoods, Cupressus, and Sequoia appear to be regular vectors, with Geosmithia present in all beetle gallery systems examined. Other subcortical insects appear to vector Geosmithia at lower frequencies. Overall, most Geosmithia have a distinct level of vector specificity (mostly high, sometimes low) enabling their separation to generalists and specialists. Plant pathogenic Geosmithia morbida was not found in association with any other beetle besides Pityophthorus juglandis. However, four additional Geosmithia species were found in P. juglandis galleries. When integrated with recent data from other continents, a global pattern of Geosmithia distribution across continents, latitudes, and vectors is emerging: of the 29 Geosmithia species found in the western USA, 12 have not been reported outside of the USA. The most frequently encountered species with the widest global distribution also had the broadest range of beetle vectors. Several Geosmithia spp. with very narrow vector ranges in Europe exhibited the similar degree of specialization in the USA. Such strong canalization in association could reflect an ancient origin of each individual association, or a recent origin and a subsequent diversification in North America.Czech Grant Agency (grant no. 16-15293Y), Long-Term Research Development Project (grant number RVO 67985939), Ministry of Education, Youth and Sports of the Czech Republic (grant number LO1509), USDA NIFA Western Region IPM Center and Critical Issues—Emerging and New Plant and Animal Pests and Diseases grant programs, USDA Forest Service Forest Health Monitoring Program (Detection Monitoring Grant No. INT-DM-09-01 and Evaluation Monitoring Grant No. INT-EM-B-11-03), USDA Forest Service Special Technology Development Grant R4-2011-01 (administered by A. S. Munson).http://www.tandfonline.com/toc/umyc202018-04-24hj2017Forestry and Agricultural Biotechnology Institute (FABI)Microbiology and Plant Patholog

A new and unusual host record for Hemicoelus gibbicollis (LeConte) (Coleoptera: Anobiidae)

Volume: 77Start Page: 123End Page: 12

Ernobius mollis (L.) (Coleoptera: Anobiidae): An exotic beetle colonizes Monterey pine, Pinus radiata D. Don, in northern California

Volume: 77Start Page: 51End Page: 5

Crepuscular Flight Activity of an Invasive Insect Governed by Interacting Abiotic Factors

<div><p>Seasonal and diurnal flight patterns of the invasive walnut twig beetle, <i>Pityophthorus juglandis</i>, were assessed between 2011 and 2014 in northern California, USA in the context of the effects of ambient temperature, light intensity, wind speed, and barometric pressure. <i>Pityophthorus juglandis</i> generally initiated flight in late January and continued until late November. This seasonal flight could be divided approximately into three phases (emergence: January–March; primary flight: May–July; and secondary flight: September–October). The seasonal flight response to the male-produced aggregation pheromone was consistently female-biased (mean of 58.9% females). Diurnal flight followed a bimodal pattern with a minor peak in mid-morning and a major peak at dusk (76.4% caught between 1800 and 2200 h). The primarily crepuscular flight activity had a Gaussian relationship with ambient temperature and barometric pressure but a negative exponential relationship with increasing light intensity and wind speed. A model selection procedure indicated that the four abiotic factors collectively and interactively governed <i>P. juglandis</i> diurnal flight. For both sexes, flight peaked under the following second-order interactions among the factors when: 1) temperature between was 25 and 30°C and light intensity was less than 2000 lux; 2) temperature was between 25 and 35°C and barometric pressure was between 752 and 762 mba (and declined otherwise); 3) barometric pressure was between 755 and 761 mba and light intensity was less than 2000 lux (and declined otherwise); and 4) temperature was ca. 30°C and wind speed was ca. 2 km/h. Thus, crepuscular flight activity of this insect can be best explained by the coincidence of moderately high temperature, low light intensity, moderate wind speed, and low to moderate barometric pressure. The new knowledge provides physical and temporal guidelines for the application of semiochemical-based control techniques as part of an IPM program for this invasive pest.</p></div

Ernobius mollis (L.) (Coleoptera: Anobiidae) established in California

Volume: 69Start Page: 36End Page: 4

Extended development of Polycaon stoutii (Leconte) (Coleoptera: Bostrichidae)

Volume: 69Start Page: 33End Page: 3

Daily <i>Pityophthorus juglandis</i> catches from 8 May to 17 September, 2012.

<p>(A) 0600–1000 h; (B) 1200–1600 h; (C) 1800–2200 h. Time intervals: 0600 h (2200 h of the previous day–0600 h the current day); 0800 h (0600–0800 h); 1000 h (0800–1000 h); 1200 h (1000–1200 h); 1400 h (1200–1400 h); 1600 h (1400–1600 h); 1800 (1600–1800 h); 2000 h (1800–2000 h); and 2200 h (2000–2200 h). Green arrow points to 3 September, 2012 when <i>P. juglandis</i> flight activity stopped between 2000 and 2200 h for the season. <i>N</i> = 133 days.</p

Effects of time interval of the day and <i>Pityophthorus juglandis</i> sex on <i>P. juglandis</i> catches (mean + SE).

<p>(A) Effect of time interval; (B) Effect of <i>P. juglandis</i> sex. Time intervals: 0600 h: 2200 h the previous day–0600 h the current day; 0800 h: 0600–0800 h; 1000 h: 0800–1000 h; 1200 h: 1000–1200 h; 1400 h: 1200–1400 h; 1600 h: 1400–1600 h; 1800: 1600–1800 h; 2000 h: 1800–2000 h; and 2200 h: 2000–2200 h. Different lower-case letters above bars denote significant difference between time intervals (A) or between <i>P. juglandis</i> sexes (B) at <i>α</i> = 0.05. <i>N</i>_{time interval} = 268 except the time interval 0800 when <i>N</i> = 266. <i>N</i>_sex = 1205 for both sexes. Means plotted in (B) represent catches per 2 h interval.</p

Weekly <i>Pityophthorus juglandis</i> total trap catches (A) and percentage of males in selected catches (B) from 29 August, 2011 to 2 June, 2014 in five Lindgren funnel traps.

<p>Hash marks along the x-axis denote the first day of each week. Percentages of males are presented for weeks when more than 50 <i>P. juglandis</i> were trapped. Inset in (A): rescaling of weekly <i>P. juglandis</i> catches from 29 August, 2011 to 31 December, 2012 to facilitate comparison of seasonal flight pattern with 2013 and 2014 when flight responses were higher.</p

Sum of <i>w_i</i> (an indicator of relative importance in the model) for variables (terms) from selection of models predicting flight of <i>Pityophthorus juglandis</i> in response to ambient temperature (T), light intensity (L), wind speed (W), and barometric pressure (P) and their interactions.

<p>A total of 94 models (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945.s002" target="_blank">Appendix S2</a>) were tested. <i>w_i</i> indicates the relative likelihood of the model <i>i</i> being the best model given the data. Computation and interpretation of statistics followed <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945-Burnham1" target="_blank">[29]</a>. Superscripted numbers in parentheses denote ranks of the sum of <i>w_i</i> across terms appeared the same number of times in the models. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945.s003" target="_blank">Appendix S3</a> (Female) and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105945#pone.0105945.s004" target="_blank">S4</a> (Male) for detailed statistics.</p><p>Sum of <i>w_i</i> (an indicator of relative importance in the model) for variables (terms) from selection of models predicting flight of <i>Pityophthorus juglandis</i> in response to ambient temperature (T), light intensity (L), wind speed (W), and barometric pressure (P) and their interactions.</p