A Decade of Hop Powdery Mildew in the Pacific Northwest

2008 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
David H. Gent ◽  
Mark E. Nelson ◽  
Ann E. George ◽  
Gary G. Grove ◽  
Walter F. Mahaffee ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Sustainable Management ◽  
The United States ◽  
Future Directions ◽  
Loss And Damage ◽  
The Pacific ◽  
The Us ◽  
Management Approaches ◽  
First Time

Hop powdery mildew, caused by the fungus Podosphaera macularis, was confirmed for the first time in hop yards in the United States Pacific Northwest in 1997. The US hop industry experienced significantly crop loss and damage from the disease, but new knowledge, grower experience, and management approaches have allowed the industry to survive the introduction of this damaging pathogen. This review provides an overview of research on and progress towards economically sustainable management of hop powdery mildew in the US, and future directions for research and further innovation. Accepted for publication 2 January 2008. Published 14 March 2008.

scholarly journals Erysiphe trifolii Causing Powdery Mildew of Lentil (Lens culinaris)

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 797-803 ◽  
Author(s):  
Renuka N. Attanayake ◽  
Dean A. Glawe ◽  
Frank M. Dugan ◽  
Weidong Chen
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
The United States ◽  
Morphological Characters ◽  
Grain Legumes ◽  
Its Sequences ◽  
Powdery Mildew Fungus ◽  
The Pacific ◽  
Soybean Genotypes ◽  
Erysiphe Trifolii

The taxonomy of the powdery mildew fungus infecting lentil in the Pacific Northwest (PNW) of the United States was investigated on the basis of morphology and rDNA internal transcribed spacer (ITS) sequences. Anamorphic characters were in close agreement with descriptions of Erysiphe trifolii. However, teleomorphs formed chasmothecial appendages with highly branched apices, whereas E. trifolii has been described as producing flexuous or sometimes loosely branched appendages. Branched appendages have been described in Erysiphe diffusa, a fungus reported from species of Lens, Glycine, and Sophora, raising the possibility that the PNW fungus could be E. diffusa. Examination of morphological characters of an authentic specimen of E. trifolii from Austria determined that it included chasmothecial appendages resembling those seen in PNW specimens. Furthermore, ITS sequences from five powdery mildew samples collected from lentils in PNW greenhouses and fields from 2006 to 2008 were identical to one another, and exhibited higher similarity to sequences of E. trifolii (99%) than to those of any other Erysiphe spp. available in GenBank. Parsimony analysis grouped the lentil powdery mildew into a clade with Erysiphe baeumleri, E. trifolii, and E. trifolii–like Oidium sp., but indicated a more distant relationship to E. diffusa. In greenhouse inoculation studies, the lentil powdery mildew fungus did not infect soybean genotypes known to be susceptible to E. diffusa. The pathogenicity of E. trifolii on lentil was confirmed using modified Koch's postulates. This is the first report of E. trifolii infecting lentil. E. diffusa and E. trifolii have different host ranges, so the discovery of E. trifolii on lentil has implications both for determining species of powdery mildews on cool-season grain legumes, and in disease management.

scholarly journals First Report of Powdery Mildew, Caused by an Oidium sp., on Poinsettia in California

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 128-128 ◽  
Author(s):  
S. T. Koike ◽  
G. S. Saenz
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
The United States ◽  
Euphorbia Pulcherrima ◽  
American Phytopathological Society ◽  
First Report ◽  
The Pacific ◽  
Uninoculated Control ◽  
Alternative Identification

In December 1996 and January 1997, powdery mildew was observed on potted poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) plants in Monterey County, CA. Mycelia were observed on stems, petioles, mature and immature leaves, and bracts. Severely diseased leaves became twisted and bent and senesced prematurely. The white mycelia were conspicuous, epiphytic, and amphigenous; hyphae measured 4.6 to 6.9 μm in diameter. Growth initially was in patches but eventually became effused. Appressoria were slightly lobed to lobed and sometimes opposite. Conidiophore foot cells were cylindrical, sometimes bent at the base, and slightly flexuous to flexuous. Foot cells measured 30.0 to 46.2 μm × 5.8 to 6.9 μm and were followed by one to two shorter cells. Conidia were cylindrical to slightly doliform and measured 25.4 to 32.3 μm × 11.6 to 18.5 μm. The length-to-width ratios of conidia generally were greater than 2.0. Conidia were produced singly, placing the fungus in the Pseudoidium-type powdery mildew group. Conidia germinated at the ends, and no fibrosin bodies were observed. Cleistothecia were not found. The fungus was identified as an Oidium species. Pathogenicity was demonstrated by gently pressing infected leaves having abundant sporulation onto leaves of potted poinsettia plants (cvs. Freedom Red, Peter Star Marble, and Nutcracker White), incubating the plants in a moist chamber for 48 h, and then maintaining plants in a greenhouse. After 12 to 14 days, powdery mildew colonies developed on the inoculated plants, and the pathogen was morphologically identical to the original isolates. Uninoculated control plants did not develop powdery mildew. This is the first report of powdery mildew on poinsettia in California. This fungus appears similar to Microsphaera euphorbiae but has longer, slightly flexuous foot cells that do not match the description for M. euphorbiae (1,2). An alternative identification would be Erysiphe euphorbiae; however, there are no available mitosporic descriptions for morphological comparisons (1,2). In the United States, powdery mildew of poinsettia previously has been reported in various states in the Pacific Northwest, Midwest, and Northeast. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.

Maritime Rivalry, Political Intervention and the Race to Antarctica: US–Chilean Relations, 1939–1949

2001 ◽  
Vol 33 (4) ◽  
pp. 713-738 ◽  
Author(s):  
JASON KENDALL MOORE
Keyword(s):  
National Security ◽  
The United States ◽  
Maritime Policy ◽  
The Pacific ◽  
The Us ◽  
Political Intervention ◽  
Domestic Affairs ◽  
The Antarctic ◽  
First Time ◽  
Us Intervention

Throughout the nineteenth century, the United States and Chile competed for dominance in the Pacific, and their maritime rivalry reemerged in the race to Antarctica during the 1940s. The US Navy was able to circumnavigate the white continent, for the first time ever, while Chile's once great navy no longer posed a threat even to its neighbours. The Chilean government expressed concern about the scope of US exploration since the Antarctic always had been an essential component of its maritime policy with national security ramifications. President Gabriel González Videla seized upon Washington's unsuccessful attempts to determine the legal fate of the Antarctic to gain acceptance for a Chilean proposal that avoided the need to renounce sovereignty claims. In doing so, he secured essentially maritime objectives by diplomatic means. This success was more profound than widely appreciated since it came at a time when US intervention in Chile's domestic affairs had reached an unprecedented level.

A REVISION OF THE GENUS TACHYPORUS GRAVENHORST (COLEOPTERA: STAPHYLINIDAE) OF NORTH AND CENTRAL AMERICA

1979 ◽  
Vol 111 (S109) ◽  
pp. 1-95 ◽  
Author(s):  
J. M. Campbell
Keyword(s):  
United States ◽  
Central America ◽  
Pacific Northwest ◽  
The United States ◽  
Central American ◽  
The North ◽  
The Pacific ◽  
Species Groups ◽  
Diagnostic Key ◽  
First Time

AbstractThe 35 species of the genus Tachyporus Gravenhorst (Staphylindae: Tachyporinae) of North and Central America are revised. Eighteen new species are described: neomexicanus, fenyesi, and howdenorum from the southwestern United States; sharpi from Mexico and the western United States; blomae from Mexico; nigripennis from California; dimorphus, pacificus, and stacesmithi from the Pacific northwest; rulomoides and browni from southeastern Canada and the northeastern United States; and borealis, canadensis, nimbicola, inornatus, ornatus, lecontei, and flavipennis, which are transcontinental in the United States and Canada. Two European species are reported for the first time from North America: abdominalis (Fabricius) and transversalis Gravenhorst. The following new specific synonymy is proposed: tehamae Blackwelder (= californicus Horn); temacus Blackwelder, oregonus Blackwelder, and alleni Blackwelder (= mexicanus Sharp); and acaudus Say, maculipennis LeConte, and chrysomelinus var. infuscatus Bernhauer (= jocosus Say). The genus is divided into 2 subgenera of which Palporus (type species Staphylinus nitidulus Fabricius) is described as new. The subgenus Tachyporus is divided into 12 species groups. Each species is described and its distribution is mapped. The male aedeagus and the pattern of elytral chaetotaxy are illustrated for each species. Major generic characters are illustrated with the aid of scanning electron photomicrographs. Neotypes are designated for the Say species faber, jocosus, and acaudus and lectotypes are designated (when needed) for the North and Central American species described by Erichson, LeConte, Horn, Sharp, and Blatchley and for a variety described by Bernhauer. A diagnostic key for all the species is given.

First Report of Powdery Mildew of Magnolia Caused by Microsphaera magnifica (Erysiphe magnifica) in the Pacific Northwest

2003 ◽  
Vol 4 (1) ◽  
pp. 37
Author(s):  
Dean A. Glawe
Keyword(s):  
United States ◽  
North America ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
Western United States ◽  
First Report ◽  
Landscape Plant ◽  
First Finding ◽  
The Pacific ◽  
First Time

Magnolia liliiflora Desrousseaux in Lamarck (orthographic variant: M. liliiflora), a species thought to have originated in China (3), is used as a landscape plant in North America. In August 2002, Microsphaera magnifica U. Braun was collected from three plants of M. liliiflora in the Magnolia collection at the Washington Park Arboretum, University of Washington, Seattle. This report documents for the first time a powdery mildew disease of a Magnolia species in the Pacific Northwest, and the first finding of M. magnifica in the western United States. Accepted for publication 14 April 2003. Published 12 May 2003.

scholarly journals First Report of Powdery Mildew Caused by Leveillula taurica on Giant Blazing Star (Mentzelia laevicaulis)

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 132-132 ◽  
Author(s):  
R. K. Sampangi ◽  
D. A. Glawe ◽  
T. Barlow ◽  
S. K. Mohan
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Host Species ◽  
The United States ◽  
Similar Species ◽  
Voucher Specimen ◽  
First Report ◽  
Leveillula Taurica ◽  
The Pacific ◽  
Native Host

Mentzelia laevicaulis (Dougl. ex Hook.) Torr. & Gray (Loasaceae; common names are giant blazing star and smoothstem blazing star) is widely distributed throughout western North America in sites ranging from lowland deserts to mountainous areas in Canada and the United States. During a plant disease survey in June 2007 in the Owyhee Mountains, Canyon County, Idaho, leaves of M. laevicaulis displaying whitish, mycelial growth were collected from plants growing on stream banks and gravelly road embankments. Diseased leaves exhibited localized, chlorotic discolorations associated with signs of a powdery mildew. Of approximately 20 plants at the site, 50% were infected. White mycelia and conidia were more abundant on the adaxial leaf surfaces than on the abaxial surfaces. Severely diseased leaves were buckled and slightly twisted. By August and through September, sporulation was greatest on mature plants, and lowermost leaves were completely covered with flocculose, dense, white mycelia. Dimorphic conidia were lanceolate or cylindrical and measured (44-) 46 to 67 (-71) × (14-) 14.5 to 20 (-21) μm. DNA was extracted and PCR was used to amplify the internal transcribed spacer (ITS) region as described previously (2), except that primers ITS 5 and P3 (4) were used. The resulting 633-bp sequence (GenBank Accession No. GQ860947) included a 616-bp region identical to a sequence reported previously for Leveillula taurica (Lév.) Arnaud from eastern Washington (GenBank No. AY912077), as well as ITS regions from L. taurica previously reported from Iran (GenBank No. AB048350) (2) and Australia (GenBank No. AF 073351) (2). Based on the ITS sequence, the present fungus grouped within Khodaparast et al. (3) Clade 1 that included L. taurica strains they distinguished from other, superficially similar species of Leveillula. On the basis of morphological and sequence data, the fungus was determined to be L. taurica (1,3). A voucher specimen was deposited in the Mycology Herbarium (WSP) at Washington State University. To our knowledge, this is the first report of a named powdery mildew species from a member of the Loasaceae. The only previous report of a powdery mildew on a loasaceous host was an undetermined Oidium sp. on a species of Mentzelia (1). The discovery of L. taurica on a previously unknown native host species is further evidence that this introduced pathogen is becoming endemic to the Pacific Northwest. Native host species, such as M. laevicaulis, may play a role in the epidemiology of powdery mildew diseases caused by L. taurica on crop and ornamental species in the Pacific Northwest. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) D. A. Glawe et al. Mycol. Prog. 4:291, 2005. (3) S. A. Khodaparast et al. Mycol. Res. 105:909, 2001. (4) S. Takamatsu and Y. Kano. Mycoscience 42:135, 2001.

scholarly journals Discovery and Genetic Mapping of PM1, a Powdery Mildew Resistance Gene in Cannabis sativa L.

2021 ◽  
Vol 3 ◽  
Author(s):  
Paul D. Mihalyov ◽  
Andrea R. Garfinkel
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Cannabis Sativa ◽  
Genetic Resistance ◽  
The United States ◽  
Snp Markers ◽  
The Pacific ◽  
Powdery Mildew Pathogen ◽  
Lrr Protein

Powdery mildew is among the most common diseases of both hemp- and marijuana-type cultivated Cannabis sativa. Despite its prevalence, no documented studies have characterized sources of natural genetic resistance in this pathosystem. Here we provide evidence for the first resistance (R) gene in C. sativa, represented by a single dominant locus that confers complete resistance to an isolate of the powdery mildew pathogen Golovinomyces ambrosiae, found in the Pacific Northwest of the United States. Linkage mapping with nearly 10,000 single nucleotide polymorphism (SNP) markers revealed that this R gene (designated PM1) is located on the distal end of the long arm of one of the largest chromosomes in the C. sativa genome. According to reference whole genome sequences and Sanger sequencing, the marker was tentatively placed in a cluster of R genes of the nucleotide-binding site (NBS) and leucine-rich repeat (LRR) protein type. PM1's dominant behavior, qualitative penetrance, and a co-segregating qPCR marker to track its inheritance were confirmed in two separate genetic backgrounds totaling 185 recombinant F1 plants. The goal of this study is to provide a foundation for the discovery and characterization of additional sources of genetic resistance to pathogens that infect C. sativa.

scholarly journals Genetic evidence for the invasion of Cymbella janischii (A. Schmidt) De Toni in Japan

2021 ◽  
Author(s):  
Yoko Kato-Unoki ◽  
Akira Kurihara ◽  
Toshihiro Kuge ◽  
Yohei Shimasaki ◽  
Yuzuru Suzawa ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Genetic Relatedness ◽  
The United States ◽  
Genetic Evidence ◽  
Pairwise Distance ◽  
Rrna Gene ◽  
28S Rrna ◽  
The Pacific ◽  
Rapid Spread ◽  
The Us

Abstract Cymbella janischii (A. Schmidt) De Toni, an endemic diatom of the Pacific Northwest, was found in 2006 in Japan, and since then, its distribution has been expanding. It was identified on the basis of morphology in Japan, however, molecular analyses have not yet been performed, with no sequences known of genes derived from the Japanese isolate. Here, we analyzed rbcL, psaB, psbA, 18S rRNA, and 28S rRNA gene sequences (6526 bp in total) of the C. janischii specimens from several locations in Japan and explored their genetic relatedness with C. janischii from its country of origin (the United States) and its closely related species. We showed that all Japanese specimens had the same sequences, regardless of geographical distance, and formed a clade with the US C. janischii. The identities and the pairwise distance between the sequences of the Japanese and the US diatoms were 99.937% and 0.0003, respectively, indicating that these diatoms are extremely similar. These results provide potential genetic evidence of the recent invasion and rapid spread of C. janischii from the US in Japan.

First Report of Powdery Mildew of Kalanchoe blossfeldiana caused by Sphaerotheca fuliginea (Podosphaera fuliginea) in the Pacific Northwest

2003 ◽  
Vol 4 (1) ◽  
pp. 39
Author(s):  
Dean A. Glawe ◽  
Rita Hummel ◽  
Grace Jack
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Sphaerotheca Fuliginea ◽  
First Report ◽  
Major Disease ◽  
The Pacific ◽  
Kalanchoe Blossfeldiana ◽  
Extension Center ◽  
Kalanchoë Blossfeldiana

Kalanchoe blossfeldiana Poelln. is a common ornamental houseplant. Although powdery mildew is a major disease of this species, there are no published reports of it in the Pacific Northwest. In August, 2002, powdery mildew was observed on six indoor K. blossfeldiana plants in an office and adjacent laboratory at the Puyallup Research and Extension Center. Accepted for publication 25 March 2003. Published 17 April 2003.

scholarly journals Radiocarbon Calibration around AD 1900 from Scots Pine (Pinus Sylvestris) tree rings from Northern Norway

Radiocarbon ◽  
2019 ◽  
Vol 61 (6) ◽  
pp. 1775-1784
Author(s):  
Helene Svarva ◽  
Pieter Grootes ◽  
Martin Seiler ◽  
Terje Thun ◽  
Einar Værnes ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Pacific Northwest ◽  
Scots Pine ◽  
Tree Rings ◽  
Fossil Fuels ◽  
Pacific Coast ◽  
Northern Norway ◽  
Pine Tree ◽  
The Pacific ◽  
The Us

ABSTRACTTo resolve an inconsistency around AD 1895 between radiocarbon (14C) measurements on oak from the British Isles and Douglas fir and Sitka spruce from the Pacific Northwest, USA, we measured the 14C content in single-year tree rings from a Scots pine tree (Pinus sylvestris L.), which grew in a remote location in Saltdal, northern Norway. The dataset covers the period AD 1864–1937 and its results are in agreement with measurements from the US Pacific coast around 1895. The most likely explanation for older ages in British oak in this period seems to be 14C depletion associated with the combustion of fossil fuels.

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