scholarly journals First report of Armillaria cepistipes causing root disease on Populus trichocarpa (black cottonwood) in Oregon, USA.

Plant Disease ◽  
2021 ◽  
Author(s):  
Brandon Alveshere ◽  
Patrick Bennett ◽  
Mee-Sook Kim ◽  
Ned B. Klopfenstein ◽  
Jared M. LeBoldus

Populus trichocarpa Torr. and Gray (black cottonwood) is an economically and ecologically important tree species native to western North America. It serves as a model tree species in biology and genetics due to its relatively small genome size, rapid growth, and early reproductive maturity (Jansson and Douglas 2007). Black cottonwood is susceptible to root rot caused by at least one species of Armillaria (Raabe 1962), a globally distributed genus that exhibits diverse ecological behaviors (Klopfenstein et al. 2017) and infects numerous woody plant species (Raabe 1962). However, several Armillaria spp. have been isolated from Populus spp. in North America (Mallet 1990), and the most recent report of Armillaria on P. trichocarpa used the now ambiguated name A. mellea (Vahl.) Quel. (see Raabe 1962). In April 2016, mycelial fans and rhizomorphs of an unknown Armillaria species (isolate WV-ARR-3) were collected from P. trichocarpa in a riparian hardwood stand ca. 5.5 km east of Springfield, Oregon, USA (44°3'21.133"N, 122°49'39.935"W). The host was dominant in the canopy, large in diameter (ca. 90-cm dbh) relative to neighboring trees, and exhibited minimal crown dieback (ca. < 5%). A mycelial fan was observed destroying living cambium beneath the inner bark, indicating pathogenicity. The isolate was cultured on malt extract medium (3% malt extract, 3% dextrose, 1% peptone, and 1.5 % agar) and identified as A.cepistipes on the basis of somatic pairing tests and translation elongation factor 1α (tef1) sequences (GenBank Accession No. MK172784). DNA extraction, PCR, and tef1 sequencing followed protocols of Elías-Román et al. (2018). From nine replications of somatic incompatibility tests (18 tester isolates representing six North American Armillaria spp.), the isolate showed high intraspecific compatibility (colorless antagonism) with three A. cepistipes tester isolates (78%), but low compatibility with the other Armillaria spp. (0 – 33%) that occur in the region. Isolate WV-ARR-3 yielded tef1 sequences with a 99% identity to A. cepistipes (GenBank Accession Nos. JF313115 and JF313121). A second isolate (WV-ARR-1; GenBank Accession No. MK172783) with a nearly identical sequence was collected from a maturing P. trichocarpa in a riparian stand ca. 8 km northeast of Monroe, Oregon (44°21’47.57”N, 123°13’14.415”W) along the Willamette River, downstream from the McKenzie river tributary where WV-ARR-3 was collected. Armillaria cepistipes has been reported on Alnus rubra (red alder) in Washington, USA (Banik et al. 1996) and on broad-leaved trees in British Columbia, Canada (Allen et al. 1996). It is generally considered to be a weak pathogen on broad-leaved trees in the Pacific Northwest, but it is also associated with pathogenicity on both coniferous and deciduous trees in Europe (e.g., Lygis et al. 2005). However, a recent phylogenetic study suggested that North American A. cepistipes is phylogenetically distinct from Eurasian A. cepistipes (Klopfenstein et al. 2017), butadditional studies are needed to determine the formal taxonomic status of North American A. cepistipes. To our knowledge, A. cepistipes has not been previously confirmed on P. trichocarpa in the U.S.A. or formally reported as a pathogen of any Populus species in North America. Continued studies are needed to determine the distribution, host range, and ecological role of A. cepistipes in riparian forests of the Pacific Northwest, while monitoring its populations under changing climates.

2021 ◽  
Author(s):  
Christian Schmidt ◽  
Alexandre Anctil

The geometrid moth Hemithea aestivaria (Hübner, 1789) was introduced from Europe to North America, first detected in British Columbia in 1973. Until 2019, its North American range was limited to a restricted area of the Pacific Northwest. Here, we report on the first records of H. aestivaria for eastern North America from three widely separated urban centers in eastern Canada during 2019-2020.


2007 ◽  
Vol 8 (1) ◽  
pp. 54
Author(s):  
R. Sampangi ◽  
D. A. Glawe ◽  
S. K. Mohan

This report documents the first record of Leveillula taurica on a species of Cleome (spiderflower) in North America. The introduced plant pathogen Leveillula taurica (Lév.) G. Arnaud (anamorph = Oidiopsis sicula Scalia) occurs on a range of hosts in the Pacific Northwest (PNW), including onion and was identified infecting Cleome hassleriana Chod. (common name: pink queen, family: Capparaceae). Accepted for publication 29 December 2007. Published 19 February 2007.


2021 ◽  
Vol 9 ◽  
Author(s):  
Christian Schmidt ◽  
Alexandre Anctil

The geometrid moth Hemithea aestivaria (Hübner, 1789) was introduced from Europe to North America, first being detected in British Columbia in 1973. Until 2019, its North American range was limited to a restricted area of the Pacific Northwest. Here, we report on the first records of H. aestivaria for eastern North America from three widely separated urban centres in eastern Canada during 2019-2020.


2012 ◽  
Vol 144 (4) ◽  
pp. 555-576 ◽  
Author(s):  
K.S. Pike ◽  
G. Graf ◽  
R.G. Foottit ◽  
H.E.L. Maw ◽  
C. von Dohlen ◽  
...  

AbstractApterous adult morphs of eriosomatine aphids associated with moss (Bryophyta) and/or roots of conifer (Pinaceae) or willow (Salix Linnaeus (Salicaceae)) in forests of the North American Pacific Northwest including Alaska are described, illustrated, and keyed. In total, seven species (Clydesmithia canadensis Danielsson, Melaphis rhois (Fitch) (moss only feeder), Pachypappa rosettei (Maxson), Pachypappa sacculi (Gillette), Prociphilus americanus (Walker) (fir root only feeder), Prociphilus xylostei (De Geer), and Thecabius populimonilis (Riley)) are characterised from their secondary host habitats. Secondary host forms of C. canadensis and T. populimonilis are described for the first time. The morphotypes from the secondary hosts were confirmed through deoxyribonucleic acid sequence matching with those from the primary hosts.


1994 ◽  
Vol 126 (1) ◽  
pp. 135-181 ◽  
Author(s):  
D.J. Larson

AbstractSpecies of Agabus of the lutosus-, obsoletus-, and fuscipennis-groups, as defined by Larson (1989), are revised. Members of the lutosus- and obsoletus-groups are restricted to the Cordilleran and Great Plains regions of temperate western North America. Within this region, the species of each group are largely parapatric. Three species are assigned to the lutosus-group: A. lutosus LeConte along the Pacific Coast; A. griseipennis LeConte in the Great Basin, Rocky Mountain, and Great Plains regions; and A. rumppi Leech in the southern deserts. Agabus lutosus and A. griseipennis hybridize in the Pacific Northwest; A. lutosus mimus Leech is synonymized with A. lutosus. The obsoletus-group contains five species: A. obsoletus LeConte, A. morosus LeConte, and A. ancillus Fall along the Pacific Coast and the Sierra Nevada Mountains; A. hoppingi Leech in the Sierra Nevada Mountains; and A. obliteratus LeConte, containing two subspecies, A. o. obliteratus and A. o. nectris Leech, new status, with a wide range including the Great Plains and Cordillera but not reaching the Pacific Coast. The four species of the fuscipennis-group, A. ajax Fall, A. coxalis Sharp, A. fuscipennis (Paykull), and A. infuscatus Aubé, are boreal and all except A. ajax are Holarctic. Agabus coxalis is restricted to northwestern North America, the other three species are transcontinental.For each species the following information is provided: synonymy, description, and illustrations of taxonomically important characters; notes on relationships, variation, distribution, and ecology; and a map of North American collection localities. Group diagnoses and keys to the species of each group are presented. A correction to the key to species groups of North American Agabus (Larson 1989) is made with the addition of a couplet to include the obsoletus-group. Lectotypes are designated for A. discolor LeConte and A. obliteratus LeConte.


2021 ◽  
Vol 2 (3) ◽  
Author(s):  
George Poinar, Jr.

Fifteen species of insect herbivores were discovered on ferns growing along the Pacific northwest coast of North America. These included insects from the orders: Diptera in the families Anthomyiidae, Cecidiomyiidae and Syrphidae: Lepidoptera in the families Erebidae, Tortricidae and Noctuidae: Hymenoptera in the family Tenthredinidae: Hemiptera in the family Aphididae and Coleoptera in the family Curculionidae.  The present study illustrates these associations that provides new world and North American host records of fern herbivores. The fossil record of these families is used to determine if the most ancient of these insects (dating from the Mesozoic) are now mostly restricted to ferns and the most recent ones (dating from the Cenozoic) are mostly polyphagous, feeding on ferns as well as various angiosperms.  Results indicate that the insect clades belonging to the most ancient families, such as Aneugmenuss and Strongylogaster in the Tenthredinidae and Dasineura and Mycodiplosis in the Cecidiomyiidae, appear to be monophagous on ferns.


2016 ◽  
Author(s):  
Ellynne Kutschera ◽  
Aslam Khalil ◽  
Andrew Rice ◽  
Todd Rosenstiel

Abstract. Although the dynamics of methane (CH4) emission from croplands and wetlands have been fairly well investigated, the contribution of trees to global CH4 emission and the mechanisms of tree transport are relatively unknown. CH4 emissions from the common wetland tree species Populus trichocarpa (black cottonwood) native to the Pacific Northwest were measured under hydroponic conditions in order to separate plant transport mechanisms from the influence of soil processes. Roots were exposed to CH4 enriched water and canopy emissions of CH4 were measured. The average flux for 34 trials (at temperatures ranging from 17 to 25 °C) was 2.8 ± 2.2 μg CH4 min−1 (whole canopy). Flux increased with temperature. Compared to the isotopic composition of root water CH4, δ13C values were depleted for canopy CH4 where the warmest temperatures (24.4–28.7 °C) resulted in an epsilon of 2.8 ± 4.7 ‰; midrange temperatures (20.4–22.1 °C) produced an epsilon of 7.5 ± 3.1 ‰; and the coolest temperatures (16.0–19.1 °C) produced an epsilon of 10.2 ± 3.2 ‰. From these results it is concluded that there are likely multiple transport processes at work in CH4 transport through trees and the dominance of these processes changes with temperature. The transport mechanisms that dominate at low temperature and low flux result in a larger fractionation, while the transport mechanisms that prevail at high temperature and high flux produce a small fractionation. Further work would investigate what combination of mechanisms are specifically engaged in transport for a given fractionation of emitted CH4.


2021 ◽  
Vol 13 (14) ◽  
pp. 2647
Author(s):  
Julia Tatum ◽  
David Wallin

Practical methods for tree species identification are important for both land management and scientific inquiry. LiDAR has been widely used for species mapping due to its ability to characterize 3D structure, but in structurally complex Pacific Northwest forests, additional research is needed. To address this need and to determine the feasibility of species modeling in such forests, we compared six approaches using five algorithms available in R’s lidR package and Trimble’s eCognition software to determine which approach most consistently identified individual trees across a heterogenous riparian landscape. We then classified segments into Douglas fir (Pseudotsuga menziesii), black cottonwood (Populus balsamifera ssp. trichocarpa), and red alder (Alnus rubra). Classification accuracies based on the best-performing segmentation method were 91%, 92%, and 84%, respectively. To our knowledge, this is the first study to investigate tree species modeling from LiDAR in a natural Pacific Northwest forest, and the first to model Pacific Northwest species at the landscape scale. Our results suggest that LiDAR alone may provide enough information on tree species to be useful to land managers in limited applications, even under structurally challenging conditions. With slight changes to the modeling approach, even higher accuracies may be possible.


2004 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Dean A. Glawe

Chinese matrimony-vine (Lycium chinense Mill.) is a traditional medicinal plant grown in China and used as a perennial landscape plant in North America. This report documents the presence of powdery mildew on L. chinense in the Pacific Northwest and describes and illustrates morphological features of the causal agent. It appears to be the first report of a powdery mildew caused by Arthrocladiella in the Pacific Northwest. Accepted for publication 10 November 2004. Published 8 December 2004.


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