scholarly journals First Report of the Teleomorph of an Oidium sp. Causing Powdery Mildew on Flowering Dogwood in South Carolina

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 200-200 ◽  
Author(s):  
M. R. Williamson ◽  
J. H. Blake
Keyword(s):  
South Carolina ◽  
Powdery Mildew ◽  
Morphological Features ◽  
Minor Importance ◽  
Cornus Florida ◽  
First Report ◽  
Flowering Dogwood ◽  
Young Leaves ◽  
First Time ◽  
Leaf Symptoms

Prior to 1994, powdery mildew had rarely been reported on flowering dogwood (Cornus florida) in the southeastern U.S. That year, and every year since, epiphytotics of powdery mildew have occurred. Leaf symptoms include distortion and necrotic areas on young leaves and an increase in red pigmentation surrounding infection sites. Young seedlings may be stunted by this disease and growth of older trees may be slowed (2). In early November, 1996, dogwood (C. florida) trees at 10 locations each in Anderson, Oconee, and Pickens counties in northwestern South Carolina were surveyed for the presence of powdery mildew. Leaves with signs of powdery mildew (white, powdery patches of mycelium, conidiophores, and conidia) were examined with a ×10 hand lens and leaves with cleistothecia were collected and taken back to the laboratory. Numerous leaves from each site were first examined at ×50 on a dissecting microscope to observe gross morphological features of cleistothecia. Then, approximately 10 cleistothecia from each of two sites were examined on a compound microscope at ×100 or higher to make further observations and measurements. Cleistothecial diameter ranged from 75.0 to 92.5 μm (average 81.8 μm). Appendages, which averaged 6 to 11 per cleistothecium, were 110 to 140 μm long (average 125.7 μm) or 1.54 times the cleistothecial diameter. The apices of appendages were dichotomously branched 2 to 3 times and the tips were distinctly re-curved. The stalks were aseptate and hyaline. Cleistothecia contained 3 to 5 asci. Each ascus contained 2 to 6 ascospores measuring 18 to 28 × 13 to 15 μm. Based on these characteristics, the teleomorph was tentatively identified as Microsphaera pulchra. Cleistothecia were found to be slightly smaller and the number of appendages fewer than Braun's lectotype (1), but these differences were judged to be of minor importance. Therefore, we conclude that the teleomorph of the Oidium sp., herein reported on flowering dogwood for the first time in South Carolina, is Microsphaera pulchra References: (1) U. Braun. Nova Hedwigia 89:1, 1987. (2) L. A. Klein et al. Plant Dis. 82:383, 1998.

scholarly journals First Report of Powdery Mildew Caused by Erysiphe pulchra on Cornus florida in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 320-320 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
Powdery Mildew ◽  
Its Region ◽  
The United States ◽  
Deciduous Tree ◽  
Herbarium Specimens ◽  
Pathogenicity Test ◽  
Cornus Florida ◽  
First Report ◽  
Flowering Dogwood ◽  
Young Leaves

Cornus florida L. (Cornaceae), flowering dogwood, is a small deciduous tree whose showy inflorescences, clusters of bright red fruits and red and purple leaves in autumn, make it a much appreciated ornamental. During the summer of 2008, severe outbreaks of a previously unknown powdery mildew were observed in several gardens and nurseries in Piedmont (northern Italy). Young leaves were covered with dense, white mycelia and conidia, especially on the adaxial surface. As the disease progressed, infected leaves turned red. Conidia were hyaline, elliptical, borne singly, and measured 32 to 46 × 15 to 20 (average 38 × 17) μm. Conidiophores measured 68 to 77 × 8 to 9 (average 73 × 8) μm, with a cylindrical foot cell measuring 26 to 37 × 8 to 10 (average 31 × 9) μm, followed by two shorter cells. Fibrosin bodies were absent. No chasmothecia were observed. The ITS region (internal transcribed spacer) of rDNA was amplified using primers ITS4/ITS6 and sequenced. The 627-bp sequence (Accession No. EU FJ436989 in GenBank) has 99% identity with Erysiphe pulchra. As proof of pathogenicity, diseased leaves were pressed against leaves of three healthy 3-year-old plants. Three noninoculated plants served as controls. Inoculated and noninoculated plants were maintained outdoors at 13 to 21°C. After 15 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 C. florida caused by E. pulchra in Italy. Powdery mildew of dogwood, caused by Microsphaera (Erysiphe) pulchra, has been reported in the United States (3) and Japan (1). In Italy, a powdery mildew caused by an Oidium sp. has been reported on C. sanguinea (2). Herbarium specimens of this disease are available at AGROINNOVA Collection, University of Torino, Italy. References: (1) T. Kobayashi. Index of Fungi Inhabiting Woody Plants in Japan. Host, Distribution, and Literature. Zenkoku-Noson-Kyoikai Publishing Co., Ltd., Tokyo, 2007. (2) G. Sicoli et al. Inf. Agrario 56/48:84, 2000. (3) V. L. Smith. Plant Dis. 83:782, 1999.

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.

Development ofErysiphe pulchra, the causal agent of powdery mildew, on leaf disks of susceptible and resistant flowering dogwood (Cornus florida)

2006 ◽  
Vol 28 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Y. H. Li ◽  
M. T. Windham ◽  
R. N. Trigiano ◽  
D. C. Fare ◽  
J. M. Spiers ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Causal Agent ◽  
Cornus Florida ◽  
Flowering Dogwood ◽  
Leaf Disks

First Report of Powdery Mildew of Mahonia aquifolium Caused by Microsphaera berberidis (Erysiphe berberidis) in North America

2003 ◽  
Vol 4 (1) ◽  
pp. 41
Author(s):  
Dean A. Glawe
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
First Report ◽  
Mahonia Aquifolium ◽  
First Time ◽  
Grown Plant

Mahonia aquifolium is a widely-grown plant in the coastal Pacific Northwest. This report documents for the first time a powdery mildew on M. aquifolium in North America caused by a fungus fitting the description of Microsphaera berberidis. Accepted for publication 14 January 2003. Published 6 February 2003.

scholarly journals ‘Appalachian Joy’ is a Supernumerary, White-bracted Cultivar of Flowering Dogwood (Cornus florida) Resistant to Powdery Mildew (Erysiphe pulchra)

HortScience ◽  
2016 ◽  
Vol 51 (5) ◽  
pp. 592-594 ◽  
Author(s):  
Robert N. Trigiano ◽  
Alan S. Windham ◽  
Mark T. Windham ◽  
Phillip A. Wadl
Keyword(s):  
Powdery Mildew ◽  
Cornus Florida ◽  
Flowering Dogwood

scholarly journals First Report of Powdery Mildew of Platanus occidentalis Caused by Erysiphe platani in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 843-843 ◽  
Author(s):  
Y. J. La ◽  
S. E. Cho ◽  
H. D. Shin
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
Its Region ◽  
The United States ◽  
Control Measures ◽  
Base Substitution ◽  
Width Ratio ◽  
First Report ◽  
Platanus Occidentalis ◽  
Young Leaves

Platanus occidentalis L., called American sycamore or American plane, is native to North America. The trees are commonly planted throughout the world on the sides of roads and in parks. In June 2012, diseased leaves exhibiting signs of powdery mildew from a park in Daegu City of Korea were sent to Plant Clinic of Seoul National University for diagnosis. Our observations in Daegu City during September and October 2012 showed that nearly 99% of the approximately 1,000 trees surveyed were infected with a powdery mildew. Voucher specimens (n = 6) were deposited at the Korea University Herbarium (KUS). Symptoms were characterized by chlorosis, distortion, or cupping of young leaves. White superficial colonies developed amphigenously on leaves. Hyphae were flexuous to straight, branched, septate, 4 to 7 μm wide, and had lobed appressoria. Conidiophores were 120 to 350 × 5 to 7.5 μm and produced conidia singly. Foot-cells of conidiophores were straight, cylindric, and 115 to 200 μm long. Conidia were hyaline, ellipsoid-ovoid, measured 33 to 47.5 × 17.5 to 29 μm with a length/width ratio of 1.5 to 2.0, lacked distinct fibrosin bodies, and showed reticulate wrinkling of the outer walls. Germ tubes were produced on the subterminal position of conidia. No chasmothecia were observed. The structures and measurements were compatible with those of the anamorphic state of Erysiphe platani (Howe) U. Braun & S. Takam. (1). To confirm the identification, the complete internal transcribed spacer (ITS) region of the rDNA from isolate KUS-F26959 was amplified with nested PCR and sequenced. The resulting sequence of 625 bp was deposited in GenBank (Accession No. JX997805). A GenBank BLAST search of this sequence showed only one base substitution with the four sequences (JQ365940 to JQ365943) of E. platani on Platanus spp. Pathogenicity was confirmed through inoculation tests by gently pressing diseased leaves onto young leaves of three 2-year-old disease-free seedlings. Three non-inoculated plants were used as control. Plants were maintained in a greenhouse at 24 to 30°C. Inoculated leaves developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was morphologically identical to that observed on the original diseased leaves, fulfilling Koch's postulates. Since E. platani first was recorded in the United States in 1874, it has been regarded as endemic in North America. From the second half of the 20th century, introduction and expansion of the range of this fungus to South America, South Africa, Australia and New Zealand, Europe, and Asia have been reported (1,2). To our knowledge, this is the first report of E. platani infections of P. occidentalis in Korea. This species was recorded on P.× hispanica from Japan in 1999 (4) and on P. orientalis from China in 2006 (3), suggesting invasive spread of the sycamore powdery mildew in East Asia. Since American sycamores are widely planted in Korea, control measures should be made to prevent further spread of the disease. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved October 22, 2012. (3) C. Liang et al. Plant Pathol. 57:375, 2008. (4) S, Tanda. J. Agric. Sci., Tokyo Univ. Agric. 43:253, 1999.

First Report of Powdery Mildew of Hypericum perforatum (St. John's-wort) Caused by an Anamorphic Microsphaera Species in the Pacific Northwest

2004 ◽  
Vol 5 (1) ◽  
pp. 20 ◽  
Author(s):  
Dean A. Glawe
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Hypericum Perforatum ◽  
Growing Season ◽  
Morphological Features ◽  
King County ◽  
First Report ◽  
St John’S Wort ◽  
St John's Wort ◽  
The Pacific

St. John's-wort has been valued as a medicinal herb for centuries. During the 2002 growing season a specimen plant with powdery mildew symptoms was observed in a demonstration garden in Kenmore, King County, WA. This report provides information on symptoms of the disease, morphological features useful in characterizing the causal agent, and taxonomic aspects of the fungus. Accepted for publication 30 June 2004. Published 07 July 2004.

Identification of Races of Colletotrichum orbiculare on Muskmelon in South Carolina

2015 ◽  
Vol 16 (2) ◽  
pp. 88-89 ◽  
Author(s):  
Anthony P. Keinath
Keyword(s):  
South Carolina ◽  
Colletotrichum Orbiculare ◽  
First Report ◽  
Differential Cultivars ◽  
First Time

Anthracnose caused by the fungus Colletotrichum orbiculare was observed on commercial cantaloupe grown in South Carolina for the first time in decades. Isolates from leaves were inoculated onto standard differential cultivars, and races 1, 2, and 2B were identified. This is the first report of C. orbiculare race 2B from South Carolina. Accepted for publication 27 March 2015. Published 1 May 2015.

scholarly journals Evaluation of Biological Agents for Control of Macrophomina Root Rot and Powdery Mildew in Flowering Dogwood (Cornus florida L.)

HortScience ◽  
2018 ◽  
Vol 53 (10) ◽  
pp. 1461-1466
Author(s):  
Margaret T. Mmbaga ◽  
Lucas M. Mackasmiel ◽  
Frank A. Mrema
Keyword(s):  
Powdery Mildew ◽  
Plant Growth ◽  
Root Rot ◽  
Plant Root ◽  
Macrophomina Phaseolina ◽  
Stem Length ◽  
Growth Enhancement ◽  
Cornus Florida ◽  
Bacterial Isolates ◽  
Flowering Dogwood

Six biological control agents (BCAs) (two bacteria, two fungi, and two yeasts) that were previously shown to be effective against powdery mildew (Erysiphe pulchra) were tested for efficacy against Macrophomina phaseolina root rot on flowering dogwood (Cornus florida) in the greenhouse. Two of the bacterial isolates, Stenotrophomonas sp. (B17A) and Serratia sp. (B17B), were effective in controlling both macrophomina root rot and powdery mildew, similar to fungicide control thiophanate methyl, when roots were drenched with the six BCAs individually. In addition, the two bacterial BCAs improved plant growth with respect to stem diameter, stem length, dry weight, and green foliage compared with fungicide-treated plants or nontreated controls grown in sterile soil. These results confirm previous results in which B17A and B17B suppressed powdery mildew and also promoted plant growth in flowering dogwood. Although macrophomina root rot has been previously reported as a potential problem in flowering dogwood, especially in field conditions, simultaneous infection with macrophomina root rot and powdery mildew has not been previously reported. This study confirmed that M. phaseolina infection was characterized by stubby roots and black root lesions, and plants infected with both powdery mildew and macrophomina root rot had smaller root mass compared with fungicide-treated plants. Neither of the two pathogens killed their host plants, but compounded infections significantly reduced the plant root system and plant growth. The efficacy of the two bacterial isolates in controlling both powdery mildew and macrophomina root rot suggests their potential utilization in controlling both diseases in dogwood nursery production and in other plants that are hosts to both powdery mildew and macrophomina root rot. Plant growth promoted by the two BCAs may be attributed to powdery mildew and macrophomina root rot control, but comparisons between fungicide-treated plants and control plants not inoculated with BCAs or root rot pathogen suggested that the two BCAs may play a role as bio-stimulants in growth enhancement. These results also suggest that the two biocontrol agents are not phytotoxic to dogwood.

First Report of Powdery Mildew of Akebia quinata Caused by Microsphaera akebiae (Erysiphe akebiae) in North America

2004 ◽  
Vol 5 (1) ◽  
pp. 24
Author(s):  
Dean A. Glawe ◽  
Jenny R. Glass
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
First Report ◽  
Western Washington ◽  
First Time

Akebia quinata (chocolate-vine, five-leaf akebia) is grown as a perennial ornamental vine in North America. Five collections were made from A. quinata plants in western Washington with symptoms of powdery mildew caused by Microsphaera akebiae Sawada. This report documents the presence of this fungus in North America for the first time, describes and illustrates this fungus and the disease it causes, and reviews the taxonomy and identification of the fungus. Accepted for publication 24 February 2004. Published 16 March 2004.

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