First Report of Powdery Mildew on Caragana arborescens and Caragana grandiflora in Alaska caused by Microsphaera (Erysiphe) palczewskii

2005 ◽  
Vol 6 (1) ◽  
pp. 23
Author(s):  
Dean A. Glawe ◽  
Gary A. Laursen
Keyword(s):  
Powdery Mildew ◽  
Causal Agent ◽  
First Report ◽  
Caragana Arborescens ◽  
Ornamental Species

During August 2004, the authors surveyed sites in and near Fairbanks, AK for powdery mildew diseases and found a powdery mildew previously unreported in Alaska on two specimen plants of the introduced ornamental species Caragana arborescens Lam. (Siberian pea tree) and C. grandiflora DC. The causal agent was determined to be Microsphaera palczewskii Jacz. This report provides the first documentation of M palczewskii in AK and includes information on the morphology and taxonomy of this species. Accepted for publication 27 September 2005. Published 17 October 2005.

First Report of Powdery Mildew on Caragana arborescens in Minnesota and North Dakota Caused by Microsphaera (Erysiphe) palczewskii

2006 ◽  
Vol 7 (1) ◽  
pp. 59
Author(s):  
Dean A. Glawe ◽  
Robert W. Stack ◽  
James A. Walla
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
North Dakota ◽  
Rocky Mountains ◽  
Causal Agent ◽  
First Report ◽  
Powdery Mildew Disease ◽  
Caragana Arborescens ◽  
First Time

In North Dakota and Minnesota, the authors encountered a powdery mildew disease of Caragana arborescens Lam. (Siberian pea tree) previously unreported from these states. The causal agent was determined to be Microsphaera palczewskii Jacz. This report documents for the first time the presence of M. palczewskii in North America east of the Rocky Mountains and includes information on the morphology, classification, and distribution of this species. Accepted for publication 4 January 2006. Published 17 January 2006.

First Report of Powdery Mildew of Coreopsis Species Caused by Golovinomyces cichoracearum in the Pacific Northwest

2006 ◽  
Vol 7 (1) ◽  
pp. 57
Author(s):  
Dean A. Glawe ◽  
Gary G. Grove ◽  
Mark Nelson
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Causal Agent ◽  
Diagnostic Features ◽  
First Report ◽  
The Pacific ◽  
Powdery Mildew Disease ◽  
Golovinomyces Cichoracearum

In 2005, the authors encountered a previously unreported powdery mildew disease of Coreopsis verticillata L. (whorled tickseed) ‘Zagreb’ and C. auriculata L. (lobed tickseed) ‘Nana’ in central Washington and determined the causal agent to be Golovinomyces cichoracearum (DC.) VP Gelyuta. This report documents the occurrence of G. cichoracearum on Coreopsis species in the Pacific Northwest, and describes diagnostic features of the disease and causal agent. Accepted for publication 2 March 2006. Published 5 April 2006.

First Report of Powdery Mildew on Dipsacus sylvestris Caused by Sphaerotheca dipsacearum in North America

2006 ◽  
Vol 7 (1) ◽  
pp. 54
Author(s):  
Frank M. Dugan ◽  
Dean A. Glawe
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
Causal Agent ◽  
European Species ◽  
First Report ◽  
Dipsacus Sylvestris ◽  
Noxious Weed

Common teasel (Dipsacus sylvestris) is a European species introduced into North America, and is now widely established and regarded as a noxious weed. In October 2005, a powdery mildew was observed on D. sylvestris in two locations in Pullman, Whitman Co., WA. Examination of diseased material confirmed that the causal agent was S. dipsacearum. This report provides the first documentation of S. dipsacearum on D. sylvestris in North America. Accepted for publication 20 April 2006. Published 7 June 2006.

scholarly journals First Report of Powdery Mildew (Microsphaera palczewskii) on Siberian Pea Tree (Caragana arborescens) in North America

Plant Disease ◽  
2003 ◽  
Vol 87 (4) ◽  
pp. 451-451 ◽  
Author(s):  
C. Nischwitz ◽  
G. Newcombe
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
First Report ◽  
Powdery Mildews ◽  
Leaf Surfaces ◽  
Mean Diameter ◽  
Caragana Arborescens ◽  
The Mean ◽  
Northern United States ◽  
The U.S

Caragana arborescens Lam. is an exotic ornamental that can also be somewhat invasive. In July 2002, powdery mildew was observed on C. arborescens along the Idaho-Washington border in Moscow and Pullman, respectively. Leaves were colonized as soon as they emerged, and entire plants were affected. The fungus covered both leaf surfaces, but cleistothecia were more abundant on abaxial surfaces. The mean diameter of the cleistothecia was 91 (± 9.8) μm. Short-stalked asci averaged 67 (± 7.1) μm × 37 (± 5.2) μm, and the ascospores were 21 (± 2.0) μm × 13 (± 0.8) μm. There are records of four species of Microsphaera on C. arborescens in Europe and Asia. The measurements fit the description of Microsphaera palczewskii Jacz. (1), and the identification was confirmed by comparison with specimens of this fungus on C. arborescens from Sweden (U.S. National Fungus Collections: BPI 749057 and 749058). Specimens of M. grossulariae (Wallr. ex Fr.) Lev. on Ribes divaricatum Dougl. from California (BPI 558266) were also examined, but the cleistothecial appendages were distinctly different from those of the Idaho specimens. To our knowledge, this is the first reported occurrence in North America of powdery mildew on C. arborescens and the first report of M. palczewskii. The latter may have been introduced recently into North America because there are areas in southern Canada and the northern United States in which C. arborescens is unaffected by powdery mildew. Interestingly, it is only in recent decades that M. palczewskii has spread from Asia into Europe (2). Now, host and parasite have been reunited in North America as well. Specimens have been deposited in the U.S. National Fungus Collections (BPI). References: (1) U. Braun. A monograph of the Erysiphales (powdery mildews) J. Cramer, Berlin-Stuttgarg, 1987. (2) S. Huhtinen et al. Karstenia 41:31, 2001.

scholarly journals Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

2017 ◽  
Vol 57 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Nujoud Alimad ◽  
Walid Naffaa ◽  
Fawaz Azmeh
Keyword(s):  
Powdery Mildew ◽  
Winter Season ◽  
Causal Agent ◽  
Bud Break ◽  
Erysiphe Necator ◽  
First Report ◽  
Primary Inoculum ◽  
Grapevine Powdery Mildew ◽  
Histopathological Studies ◽  
Grapevine Buds

AbstractThe main aims of this study were to determine the overwintering form and the primary inoculum ofErysiphe necator,the causal agent of grapevine powdery mildew in southern Syria. Eleven vineyards located at five different geographical sites were visited every week from March to November in 2014 and 2015. The results of field and histopathological studies showed thatE. necatorsurvived as mycelium in dormant grapevine buds during the winter season. The first flag shoots were observed shortly after bud break in spring. The number of flag shoots varied greatly according to vineyards, cultivars and years, being present on 27.4 to 61.9% of the grapevines in 2014, and on 5.2 to 40% of the grapevines in 2015. The percentage of flag shoots on the same grapevine also varied according to the year, cultivar and location. It was between 4.3 to 9.4% in 2014, and 2.1 to 3.6% in 2015. The disease was observed only on Balady and Black cultivars. Conidia were released from the second week of May to early September. The first conidia were trapped around mid-May, and the first secondary symptoms were observed on leaves from mid-May to early June according to the site. Chasmothecia were observed on leaves in 45.5% of the studied vineyards. The first observation of chasmothecia on leaves was in July, and their numbers varied greatly between vineyards and years. Chasmothecia were not detected on bark, nor were ascospores trapped at the beginning of the season. These results confirmed that the ascospores did not have any role in the initiation of spring infection. To the best of our knowledge, this is the first report of the overwintering form ofE. necatorin Syria.

First Report of Podosphaera alpina f. alpina on Tolmiea menziesii in Washington State and British Columbia

2009 ◽  
Vol 10 (1) ◽  
pp. 42
Author(s):  
Lydia S. Putnicki ◽  
Dean A. Glawe
Keyword(s):  
British Columbia ◽  
Powdery Mildew ◽  
Washington State ◽  
Causal Agent ◽  
Understory Species ◽  
First Report

Tolmiea menziesii (Pursh) Torr. & A. Gray (Saxifragaceae, piggyback plant) is an understory species typically sold as an ornamental houseplant. We recently made several collections of T. menzii in Washington and British Columbia with powdery mildew symptoms and determined the causal agent to be Podosphaera alpina f. alpina (U. Braun) U. Braun & S. Takam. This is the first report of this fungus on T. menziesii in Washington and British Columbia. Accepted for publication 5 June 2009. Published 10 August 2009.

scholarly journals First Report of Powdery Mildew Caused by Golovinomyces orontii (Erysiphe orontii) on Lamium galeobdolon in Italy

Plant Disease ◽  
2007 ◽  
Vol 91 (5) ◽  
pp. 635-635 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
D. Minerdi ◽  
M. L. Gullino
Keyword(s):  
Powdery Mildew ◽  
Ground Cover ◽  
Herbarium Specimens ◽  
Pathogenicity Test ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Golovinomyces Orontii ◽  
Powdery Mildews ◽  
Blastn Analysis ◽  
Ornamental Species

Lamium galeobdolon L. (Labiatae) is a common ornamental species that grows in shade areas and often used as a ground cover in gardens. During the summer of 2006, severe outbreaks of a previously unknown powdery mildew were observed on all Lamium spp. plants in some gardens near Biella (northern Italy). Both surfaces of the leaves of affected plants were covered with dense, white mycelia and conidia. As the disease progressed, infected leaves turned yellow and died. Mycelia and conidia also were observed on stems and flowers. Conidia were hyaline, ellipsoid, borne in short chains (with a maximum of five conidia per chain), and measured 29 to 37 × 16 to 20 μm (average 33 × 18 μm). Conidiophores, 91 to 104 μm (average 96 μm) long, showed the foot cell measuring 28 to 49 × 9 to 11 μm (average 38 × 10 μm), followed by three shorter cells measuring 14 to 26 × 9 to 15 μm (average 21 × 11 μm). Fibrosin bodies were absent. Chasmothecia were not observed in the collected samples. The internal transcribed spacer region (ITS) of rDNA was amplified using the primers ITS4/ITS6 (4) and sequenced. BLASTn analysis (1) of the 436 bp obtained showed an E-value of 0.0 with Golovinomyces orontii (Erysiphe orontii.) (3). The nucleotide sequence has been assigned GenBank Accession No. EF 121871. Inoculations were made by gently pressing diseased leaves onto leaves of five healthy L. galeobdolon plants. Five noninoculated plants served as controls. Inoculated and noninoculated plants were maintained in a greenhouse at temperatures between 15 and 28°C. After 10 days, typical powdery mildew colonies developed on inoculated plants. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of powdery mildew on L. galeobdolon caused by G. orontii in Italy. Blumer (2) was able to reproduce powdery mildew symptoms on L. galeobdolon using populations from cucumber, while Braun (3) reported L. galeobdolon as a possible host of E. orontii. Herbarium specimens of this disease are available at AGROINNOVA Collection, University of Torino, Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) S. Blumer. Ber. Schweiz. Bot. Ges. 62:384, 1952. (3) U. Braun. A Monograph of the Erysiphaceae (Powdery Mildews). Cramer, Berlin, GDR, 1987. (4) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997.

scholarly journals First Report of Powdery Mildew of Pumpkin Caused by Golovinomyces cichoracearum in Neelum Valley, Azad Kashmir

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 906-906
Author(s):  
I. Mukhtar ◽  
R. Khurram ◽  
A. Hannan ◽  
Z. Hayat
Keyword(s):  
Powdery Mildew ◽  
Infected Plant ◽  
Causal Agent ◽  
Morphological Observation ◽  
Fungal Culture ◽  
Voucher Specimen ◽  
First Report ◽  
Golovinomyces Cichoracearum ◽  
Azad Kashmir ◽  
Basal Septum

During July 2011, a severe powdery mildew outbreak was recorded in pumpkin (Cucurbita moschata Duch.) fields in economically poor areas in the Neelum Valley (Leswa, Mir Pura, Jura, Kundal Shahi, and Bela). Disease symptoms included grayish white circular to irregular patches consisting of epiphytic mycelia and conidia on both surfaces of the leaves of infected vines. Fungal mycelia and conidiophores were also visible in white powdery patches on the main stems, leaves, and petioles of affected plants. Leaves became necrotic with age. Powdery mildew symptoms were more severe on pumpkin vines located in the shade, and severely affected vines collapsed. A voucher specimen (IR00027) has been deposited in First Fungal Culture Bank of the Pakistan (FCBP), Institute of Agriculture Sciences, University of the Punjab, Lahore, Pakistan. For morphological observation, a clear tape strip was used to remove fungal tissue from infected leaves. The tape was mounted on microscope slides with water and examined with a light microscope (2). Conidiophores were unbranched, cylindrical, erect and arose singly on hyphal cells, 110 to 200 × 6 to 12 μm, composed of a foot cell and three to eight barrel-shaped conidia formed in chains with a sinuate edge, followed with a basal septum at the branching point or slightly displaced from the mycelium. Foot cells were 50 to 80 × 6 to 12 μm, and slightly swollen with constriction at the base. Conidia were cylindrical to doliiform, 30 to 50 × 14 to 20 μm and produced in chains. The length/breadth ratio of the conidia was 1.8 to 2.6. Fibrosin bodies were absent in both conidiophores and conidia. No cleistothecia were observed. Identification of the causal agent as Golovinomyces cichoracearum (DC.) V.P. Heluta (synonym Erysiphe cichoracearum) was based on morphology (1). Pathogenicity was determined using field-infected plant leaves transported to a greenhouse. Fresh conidia of field isolates of G. cichoracearum were transferred by a sterile brush from the affected leaves to fully expanded four to five healthy leaves of three 40-day-old vines. For the control, three vines were stroked with a clean sterile brush and control plants were placed 100 m away from the inoculated plants. For disease development 20°C and 80% relative humidity was maintained in the greenhouse. A plastic sheet was placed around each vine for a week and removed later. Inoculated vines developed visible white spots of powdery mildew on the leaves after 10 days in the greenhouse, whereas control plants remained asymptomatic. Fungal colony and conidial morphology on the leaves of inoculated plants were as described above. Previously, G. cichoracearum has been reported on other cucurbits (3) in the plains of Pakistan. To our knowledge, this is the first report of occurrence of G. cichoracearum as a causal agent of powdery mildew on pumpkin in Neelum Valley, Azad Kashmir. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) J. C. Correll et al. Plant Dis. 71:248, 1987. (3) A. Wahid et al. Pak. J. Agric. Res. 9:209, 1988.

scholarly journals First Report of Erysiphe sp. as a Causal Agent of Powdery Mildew on Punica granatum in Italy

Plant Disease ◽  
2016 ◽  
Vol 100 (9) ◽  
pp. 1949
Author(s):  
S. Pollastro ◽  
D. Gerin ◽  
S. Marullo ◽  
R. M. De Miccolis Angelini ◽  
F. Faretra
Keyword(s):  
Powdery Mildew ◽  
Punica Granatum ◽  
Causal Agent ◽  
First Report
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