scholarly journals First Report of Powdery Mildew (Sawadaea bicornis) on Norway Maple (Acer platanoides) in North America

Plant Disease ◽  
2003 ◽  
Vol 87 (4) ◽  
pp. 451-451
Author(s):  
C. Nischwitz ◽  
G. Newcombe
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
Acer Platanoides ◽  
The Pacific ◽  
Norway Maple ◽  
Street Tree ◽  
White Mycelium ◽  
Northern United States ◽  
The U.S

Norway maple (Acer platanoides L.) was introduced into the continental United States around 1756 as a street tree (2). It is a widely planted shade tree in the northern United States and Canada due to its fast growth rate when young and its tolerance of pavement and dry soils. Powdery mildew is common on Norway maple in Europe with records from at least 22 countries according to the databases of the U.S. National Fungus Collections. However, there are no North American records. In September 2002, powdery mildew was observed on young Norway maple trees along the Idaho-Washington border in Moscow and Pullman, respectively. Mildew was not observed on older Norway maple trees. The mildew occurred mainly on the upper leaf surface as patches of dense, white mycelium with scattered or gregarious cleistothecia. Mean diameter of the cleistothecia was 146 (± 13.4) μm. Short stalked and subsessile asci averaged 69 (± 4.1) μm × 48 (± 5.4) μm. Ascospores averaged 27 (± 3.2) μm × 12 (±0.9) μm. Appendages were deeply cleft, simple, or one to three times dichotomously branched. This mildew fits the description of the European species Sawadaea bicornis (Wallr:Fr.) Homma (1). Also, conforming to S. bicornis were chains of macroconidia (21 (± 2.7) × 14 (± 1.5) μm) and microconida. Fibrosin bodies were seen in both. Infection of only some young trees and its absence in previous years lead us to believe that the introduction is recent in the Pacific Northwest. The susceptibility of native maples to the Norway maple mildew remains to be determined. Specimens have been deposited in the U.S. National Fungus Collections (BPI 842088). References: (1) U. Braun. A monograph of the Erysiphales (powdery mildews) J. Cramer, Berlin-Stuttgart, 1987. (2) D. J. Nowak and R. A. Rowntree. J. Arboric. 16:291, 1990.

Identification of Resistance to Powdery Mildew in Publicly Available Male Hop Germplasm

2018 ◽  
Vol 19 (3) ◽  
pp. 258-264
Author(s):  
David H. Gent ◽  
Briana J. Claassen ◽  
Megan C. Twomey ◽  
Sierra N. Wolfenbarger
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
Western United States ◽  
R Genes ◽  
Sources Of Resistance ◽  
Department Of Agriculture ◽  
Breeding Programs ◽  
The Pacific ◽  
The U.S

Powdery mildew (caused by Podosphaera macularis) is one of the most important diseases of hop in the western United States. Strains of the fungus virulent on cultivars possessing the resistance factor termed R6 and the cultivar Cascade have become widespread in the Pacific Northwestern United States, the primary hop producing region in the country, rendering most cultivars grown susceptible to the disease at some level. In an effort to identify potential sources of resistance in extant germplasm, 136 male accessions of hop contained in the U.S. Department of Agriculture collection were screened under controlled conditions. Iterative inoculations with three isolates of P. macularis with varying race identified 23 (16.9%) accessions with apparent resistance to all known races of the pathogen present in the Pacific Northwest. Of the 23 accessions, 12 were resistant when inoculated with three additional isolates obtained from Europe that possess novel virulences. The nature of resistance in these individuals is unclear but does not appear to be based on known R genes. Identification of possible novel sources of resistance to powdery mildew will be useful to hop breeding programs in the western United States and elsewhere.

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.

scholarly journals Coast-to-coast spread of SARS-CoV-2 in the United States revealed by genomic epidemiology

2020 ◽  
Author(s):  
Joseph R. Fauver ◽  
Mary E. Petrone ◽  
Emma B. Hodcroft ◽  
Kayoko Shioda ◽  
Hanna Y. Ehrlich ◽  
...  
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
The United States ◽  
International Travel ◽  
Viral Genomes ◽  
Genomic Epidemiology ◽  
The Pacific ◽  
Travel Restrictions ◽  
Novel Coronavirus ◽  
The U.S

SummarySince its emergence and detection in Wuhan, China in late 2019, the novel coronavirus SARS-CoV-2 has spread to nearly every country around the world, resulting in hundreds of thousands of infections to date. The virus was first detected in the Pacific Northwest region of the United States in January, 2020, with subsequent COVID-19 outbreaks detected in all 50 states by early March. To uncover the sources of SARS-CoV-2 introductions and patterns of spread within the U.S., we sequenced nine viral genomes from early reported COVID-19 patients in Connecticut. Our phylogenetic analysis places the majority of these genomes with viruses sequenced from Washington state. By coupling our genomic data with domestic and international travel patterns, we show that early SARS-CoV-2 transmission in Connecticut was likely driven by domestic introductions. Moreover, the risk of domestic importation to Connecticut exceeded that of international importation by mid-March regardless of our estimated impacts of federal travel restrictions. This study provides evidence for widespread, sustained transmission of SARS-CoV-2 within the U.S. and highlights the critical need for local surveillance.

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.

Information and Emigrants: Interprefectural Differences of Japanese Emigration to the Pacific Northwest, 1880–1915

1991 ◽  
Vol 51 (1) ◽  
pp. 125-147 ◽  
Author(s):  
Yuzo Murayama
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
The United States ◽  
Information Networks ◽  
Regression Equations ◽  
Long Distance ◽  
The Pacific ◽  
The Family ◽  
Alternative Means ◽  
The U.S

This article examines the determinants of interprefectural patterns of Japanese emigration to the U.S. Pacific Northwest, using a multiple regression analysis. In estimating the regression equations, new proxies are introduced for the “family- and-friends” effect that are free of the statistical problems common in previous studies on long-distance migration. The result shows that the information networks that developed between pioneer immigrants and their home districts played a central role in shaping emigration patterns. The lack of an alternative means of obtaining reliable information about conditions in the United States appears to be responsible.

Interannual Variability of the Cyclonic Activity along the U.S. Pacific Coast: Influences on the Characteristics of Winter Precipitation in the Western United States

2009 ◽  
Vol 22 (21) ◽  
pp. 5732-5747 ◽  
Author(s):  
Boksoon Myoung ◽  
Yi Deng
Keyword(s):  
United States ◽  
Interannual Variability ◽  
Pacific Northwest ◽  
Pacific Coast ◽  
Storm Track ◽  
Winter Precipitation ◽  
Western United States ◽  
Cyclonic Activity ◽  
The Pacific ◽  
The U.S

Abstract This study examines the observed interannual variability of the cyclonic activity along the U.S. Pacific coast and quantifies its impact on the characteristics of both the winter total and extreme precipitation in the western United States. A cyclonic activity function (CAF) was derived from a dataset of objectively identified cyclone tracks in 27 winters (1979/80–2005/06). The leading empirical orthogonal function (EOF1) of the CAF was found to be responsible for the EOF1 of the winter precipitation in the western United States, which is a monopole mode centered over the Pacific Northwest and northern California. On the other hand, the EOF2 of the CAF contributes to the EOF2 of the winter precipitation, which indicates that above-normal precipitation in the Pacific Northwest and its immediate inland regions tends to be accompanied by below-normal precipitation in California and the southwestern United States and vice versa. The first two EOFs of CAF (precipitation) account for about 70% (78%) of the total interannual variance of CAF (precipitation). The second EOF modes of both the CAF and precipitation are significantly linked to the ENSO signal on interannual time scales. A composite analysis further reveals that the leading CAF modes increase (decrease) the winter total precipitation by increasing (decreasing) both the number of rainy days per winter and the extremeness of precipitation. The latter was quantified in terms of the 95th percentile of the daily rain rate and the probability of precipitation being heavy given a rainy day. The implications of the leading CAF modes for the water resources and the occurrence of extreme hydrologic events in the western United States, as well as their dynamical linkages to the Pacific storm track and various atmospheric low-frequency modes (i.e., teleconnection patterns), are also discussed.

scholarly journals First Report of Sawadaea tulasnei Powdery Mildew of Norway Maple (Acer platanoides) in Wisconsin

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 485-485
Author(s):  
B. Hudelson ◽  
D. Smith ◽  
G. Stanosz ◽  
M. Hanson
Keyword(s):  
New York ◽  
Powdery Mildew ◽  
Acer Platanoides ◽  
Rdna Its ◽  
Powdery Mildews ◽  
Beaver Dam ◽  
Norway Maple ◽  
Leaf Surfaces ◽  
White Mycelium ◽  
Powdery Mildew Pathogen

Leaves affected by powdery mildew were collected from a Norway maple tree in early October 2007 in Beaver Dam, WI (Dodge County). Diseased leaves were present throughout the crown of this tree, with white mycelium in irregular and often vein-associated spots and often covering as much as 50% of the upper surfaces of leaves. Examination of the lower surfaces revealed necrosis of the areas underlying mycelium. Blades of samaras also bore white mycelium. Chasmothecia were present singly or in groups on the mycelium. Morphology of chasmothecia, including simple and bifid appendages with uncinate to circinate apices, was sufficient to identify the pathogen to the genus Sawadaea (1). Data for nuclear rDNA ITS sequence (546 bp) obtained for a specimen (GenBank Accession No. EU247884) exactly matched sequences for Sawadea tulasnei (GenBank Accession Nos. AB 193363, 478 bp; AB193385, 490 bp; AB193390 and AB193391, 546 bp). This data was 96% similar (528 of 552 nucleotides) to that of another European powdery mildew pathogen, S. bicornis (GenBank Accession No. AB193380), which is also reported to occur on maples in Idaho, Washington, and Wisconsin (2,3). A further survey revealed the same fungus on several additional nearby Norway maples along streets and in yards (including varieties with both darkly colored and variegated leaves), but on these trees very few leaves were affected and usually less than 5% of the upper leaf surfaces bore mycelium. This pathogen was not observed on leaves of either red (A. rubrum) or silver maples (A. saccharinum) examined in the same area. S. tulasnei was previously known in North America only by collections in New York, Ohio, and Montreal, Canada (4), but our observation indicates that the geographic distribution of this pathogen is probably much broader and overlaps with that of S. bicornis. Specimens from Beaver Dam, WI have been deposited in the U.S. National Fungus Collections (BPI 878273). References: (1) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena-Stuttgart, New York, 1995. (2) C. Nischwitz and G. Newcombe. Plant Dis. 87:451, 2003. (3) G. Stanosz et al. Plant Dis. 91:636, 2007. (4) J. Weiland and G. Stanosz. Plant Dis. 90:830, 2006.

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 First record of Euxestonotus error (Hymenoptera: Platygastridae) in the Pacific Northwest, United States of America

2016 ◽  
Vol 148 (5) ◽  
pp. 616-618 ◽  
Author(s):  
E.R. Echegaray ◽  
R.N. Stougaard ◽  
B. Bohannon
Keyword(s):  
United States ◽  
New York ◽  
Pacific Northwest ◽  
United States Of America ◽  
First Record ◽  
The United States ◽  
Sitodiplosis Mosellana ◽  
Wheat Midge ◽  
The Pacific ◽  
Northwestern Montana

AbstractEuxestonotus error (Fitch) (Hymenoptera: Platygastridae) is considered part of the natural enemy complex of the wheat midge Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae). Although previously reported in the United States of America, there is no record for this species outside the state of New York since 1865. A survey conducted in the summer of 2015 revealed that E. error is present in northwestern Montana and is likely playing a role in the suppression of wheat midge populations.

First Report of Powdery Mildew of Lycium chinense (Chinese Matrimony Vine) Caused by Arthrocladiella mougeotii in the Pacific Northwest

2004 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Dean A. Glawe
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
Medicinal Plant ◽  
Pacific Northwest ◽  
Morphological Features ◽  
Lycium Chinense ◽  
First Report ◽  
Landscape Plant ◽  
The Pacific ◽  
Plant Grown

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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