First Report of Powdery Mildew on Azalea Cv. Mollis (Rhododendron japonicum × R. molle) in Italy

Rhododendron cultivation has a long history in northern Italy, where a wide selection of varieties and hybrids are grown. In summer 2001, a previously unknown powdery mildew was observed on azalea cv. Mollis (Rhododendron japonicum × R. molle) grown in several gardens in the province of Biella. Initial symptoms included chlorotic spots, followed by white fungal mycelia on both leaf surfaces. Eventually, infected leaves turned reddish and dropped prematurely. Fruit were also infected. On infected tissues, dark brown-to-black spherical cleistothecia developed, alone or in groups. The teleomorph was identified by light microscopy examination of cleistothecia. Cleistothecia measured 110 to 140 µm and were dark brown. They contained four to eight stalked or sessile asci that measured 35 to 45 µm × 40 to 55 µm, each containing six to eight ascospores. Ascospores were ellipsoid to ovoid and measured 12 to 18 µm × 20 to 25 µm. Cleistothecial characteristics were consistent with those described for Microsphaera azaleae but were different from those of the recently described species M. digitata reported in Belgium (1). The presence of conidia was rare in the specimens, so the anamorph could not be identified. To our knowledge, this is the first report of M. azaleae in Italy, but three outbreaks of powdery mildew on rhododendron were first reported in the United Kingdom on plants grown in glasshouses in the mid-1950s, 1969 and 1973 (1). Outdoors, powdery mildew was first reported on rhododendron in Europe in 1981. M. azaleae has been identified as the causal agent of rhododendron powdery mildew in the United Kingdom, Germany, and Switzerland (1). In most cases the disease is readily controlled by regular application of fungicides commonly used against powdery mildews of other crops. Reference: (1) A. J. Inman et al. J. Phytopathol. 148:17, 2000.

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First Report of Powdery Mildew Caused by Erysiphe aquilegiae var. aquilegiae on Aquilegia flabellata in Italy

Plant Disease ◽

10.1094/pdis.2004.88.6.681a ◽

2004 ◽

Vol 88 (6) ◽

pp. 681-681

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

United States ◽

Powdery Mildew ◽

The United States ◽

Northern Italy ◽

American Phytopathological Society ◽

First Report ◽

Powdery Mildews ◽

The Family ◽

White Mycelium ◽

The University

Aquilegia flabellata Sieb. and Zucc. (columbine) is a perennial garden species belonging to the family Ranunculaceae. During the summer of 2003, a severe outbreak of a previously unknown powdery mildew was observed in several gardens near Biella (northern Italy). Upper surfaces of leaves were covered with a white mycelium and conidia, and as the disease progressed infected leaves turned yellow and died. Foot cell was cylindric and appressorium lobed. Conidia were hyaline, ellipsoid, and measured 31.2 to 47.5 × 14.4 to 33 μm (average 38.6 × 21.6 μm). Fibrosin bodies were not present. Cleistothecia were globose, brown, had simple appendages, ranged from 82 to 127 (average 105) μm in diameter, and contained one to two asci. Ascocarp appendages measured five to eight times the ascocarp diameter. Asci were cylindrical (ovoidal) and measured 45.3 to 58.2 × 30.4 to 40.2 μm. Ascospores (three to four per ascus) were ellipsoid or cylindrical and measured 28.3 to 31.0 × 14.0 to 15.0 μ;m. On the basis of its morphology, the pathogen was identified as Erysiphe aquilegiae var. aquilegiae (1). Pathogenicity was confirmed by gently pressing diseased leaves onto leaves of five, healthy A. flabellata plants. Five noninoculated plants served as controls. Inoculated and noninoculated plants were maintained in a garden where temperatures ranged between 20 and 30°C. After 10 days, typical powdery mildew symptoms developed on inoculated plants. Noninoculated plants did not show symptoms. To our knowledge, this is the first report of the presence of powdery mildew on Aquilegia flabellata in Italy. E. communis (Wallr.) Link and E. polygoni DC. were reported on several species of Aquilegia in the United States (2), while E. aquilegiae var. aquilegiae was previously observed on A. flabellata in Japan and the former Union of Soviet Socialist Republics (3). Specimens of this disease are available at the DIVAPRA Collection at the University of Torino. References: (1) U. Braun. Nova Hedwigia, 89:700, 1987. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St Paul, MN, 1989. (3) K. Hirata. Host Range and Geographical Distribution of the Powdery Mildews. Faculty of Agriculture, Niigata University, 1966.

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

Plant Disease ◽

10.1094/pdis.2003.87.4.451b ◽

2003 ◽

Vol 87 (4) ◽

pp. 451-451 ◽

Cited By ~ 1

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.

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First Report of Powdery Mildew Caused by Oidium Subgenus Pseudoidium on Lonicera caprifolium in Italy

Plant Disease ◽

10.1094/pdis.2004.88.9.1045b ◽

2004 ◽

Vol 88 (9) ◽

pp. 1045-1045

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

Powdery Mildew ◽

Growing Season ◽

Northern Italy ◽

First Report ◽

Leaf Surfaces ◽

Voucher Specimens ◽

Inoculation Procedure ◽

White Mycelium ◽

The University

Honeysuckle (Lonicera caprifolium L., family Caprifoliaceae) is a climbing shrub used in gardens to cover walls and supports. During the summer of 2003, severe outbreaks of a previously unknown powdery mildew were observed on this species in some gardens near Biella (northern Italy). The first symptoms included extensive chlorosis on leaves, followed by the appearance of white mycelium on the adaxial and abaxial leaf surfaces. As the disease progressed, infected leaves turned yellow and died. Conidia were hyaline, ellipsoidal, and measured 27.6 to 43.2 × 12.2 to 21.6 μm (average 35.7 × 17.6 μm). Foot cells were cylindric and appressoria lobed. Fibrosin bodies were not present. Cleistothecia were not observed during the growing season. The pathogen was identified as Oidium subgenus Pseudoidium (2). The inoculation procedure involved gently pressing diseased leaves onto leaves of healthy L. caprifolium plants. Three plants of L. caprifolium were used as replicates. Noninoculated plants served as control. Inoculated and noninoculated plants were maintained in a garden at temperatures ranging from 15 to 25°C. After 10 days, typical symptoms of powdery mildew developed on inoculated plants. Noninoculated plants did not show symptoms. To our knowledge, this is the first report of powdery mildew on L. caprifolium in Italy. The presence of powdery mildew on different species of Lonicera has been reported in several countries, particularly, Microsphaera miurae U. Braun on L. morowii A. Gray in Germany (1), M. lonicerae (DC.) Winter on L. peryclimenum L. in England (3), and M. lonicerae-ramosissimae on L. ramosissima Fr. & Sav. in Japan (4). The conidia of M. lonicerae are smaller than those of the Oidium sp. reported on L. caprifolium. Voucher specimens are available at DIVAPRA Collection at the University of Torino. References: (1) U. Braun. Mycotaxon 16:417, 1983. (2) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (3) J. Robbins. Cecidology 15:15, 2000. (4) S. Tanda. Mycoscience 41:155, 2000.

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First Report of Oidium longipes as the Causal Agent of Petunia Powdery Mildew in the United Kingdom

Plant Disease ◽

10.1094/pdis-09-10-0680 ◽

2011 ◽

Vol 95 (3) ◽

pp. 361-361 ◽

Cited By ~ 1

Author(s):

L. Kiss ◽

Z. Bereczky

Keyword(s):

United Kingdom ◽

Powdery Mildew ◽

Its Region ◽

Its Sequences ◽

Nuclear Ribosomal Dna ◽

Herbarium Specimens ◽

First Report ◽

The United Kingdom ◽

The Uk ◽

Solanaceous Plants

In autumn 2009, during a survey of powdery mildews of solanaceous plants in the United Kingdom, petunia (Petunia × hybrida) plants showing typical symptoms of powdery mildew infections were repeatedly collected in East Malling, Rochester, and Sandringham, UK. Leaves, stems, and petals of the collected plants, grown as outdoor ornamentals, were covered by dense, sporulating, white mycelium. Conidia were ellipsoid-cylindrical, measured 20 to 30 × 10 to 15 μm, and were produced in chains. Germ tubes arose from the ends of conidia and terminated in simple, unlobed apices. Some of the conidiophores were extremely long, up to 250 μm, because the second or third cell, or sometimes the foot cell, was up to 105 to 170 μm long. Other conidiophores were shorter, with no exceptionally long cells, but all of them exhibited a few characteristics in common: their width increased from base to top, sometimes enlarging considerably at a particular point of the foot cell, and basal septa were usually located 7 to 30 μm from the point of branching. Hyphal appressoria were nipple shaped. The teleomorph stage was not found. On the basis of these characteristics, the fungus was identified as Oidium longipes, a recently described (4) and little known pathogen of petunia and other solanaceous plants (1,3). To support the identification of this fungus, DNA was extracted from conidia collected with sterile brushes from single leaves collected in Sandringham, East Malling, and Rochester with a Qiagen DNeasy Plant Kit (Qiagen, Hilden, Germany), and the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA was amplified and determined as described in Jankovics et al. (2). The three identical ITS sequences, deposited in GenBank under Accession Nos. HM156495, HM156496, and HM156497, were identical to several ITS sequences of O. longipes, such as AF250777, EU327324, and EU327325. This has also supported that the disease was caused by this species. Herbarium specimens were deposited under the Accession Nos. HAL 2373F, HAL 2374F, and HAL 2375F at the Herbarium of Martin Luther University, Halle, Germany. To our knowledge, this is the first report of O. longipes in the UK. References: (1) A. Bolay. Cryptogam. Helv. 20:1, 2005. (2) T. Jankovics et al. Phytopathology 98:529, 2008. (3) L. Kiss et al. Plant Disease 92:818, 2008. (4) M. E. Noordeloos and W. M. Loerakker. Persoonia 14:51, 1989.

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First Report of Powdery Mildew on Dollar-plant (Crassula ovata) Caused by an Oidium sp.

Plant Disease ◽

10.1094/pdis.1999.83.2.199c ◽

1999 ◽

Vol 83 (2) ◽

pp. 199-199 ◽

Cited By ~ 2

Author(s):

L. Kiss

Keyword(s):

Powdery Mildew ◽

The United States ◽

Diseased Plant ◽

Powdery Mildew Fungus ◽

History Museum ◽

First Report ◽

Powdery Mildews ◽

Leaf Surfaces ◽

Hungarian Natural History Museum ◽

Germ Tubes

Dollar-plant (Crassula ovata) is a perennial, succulent ornamental grown worldwide. In 1998, powdery mildew colonies were observed on the adaxial leaf surfaces of a 4-year-old specimen maintained outdoors. Symptoms included necrosis of the infected tissues and defoliation 2 months after the appearance of the first colonies. Conidia were produced in chains on unbranched conidiophores. Hyphal appressoria were lobed to multi-lobed, mostly opposite or spread. Conidia were ellipsoid to cylindrical, measured 34 to 48 μm × 17 to 26 μm, and contained no fibrosin bodies. On water agar, conidia produced a single germ tube from the end of the conidium. Germ tubes were either very short with lobed appressoria, or were two to three times longer than conidia, and terminated in lobed or unlobed appressoria. Cleistothecia were not produced. The pathogen was identified as an Oidium sp. belonging to the genus Erysiphe sect. Galeopsidis (1). To confirm pathogenicity, small, potted C. ovata plants were placed near the diseased plant in the laboratory. After 2 weeks, powdery mildew appeared on the small plants, and the pathogen was morphologically identical to the original fungus. This is the first report of a powdery mildew fungus on C. ovata, and it is different from both species of the Erysiphaceae identified on other Crassula spp. (1,2). Infected C. ovata leaves were deposited at the Department of Botany of the Hungarian Natural History Museum in Budapest under the accession number BP 91732. References: (1) U. Braun. 1995. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena. (2) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.

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First Report of Powdery Mildew Caused by Golovinomyces orontii on Corn-Salad in the United States

Plant Disease ◽

10.1094/pd-89-0686c ◽

2005 ◽

Vol 89 (6) ◽

pp. 686-686 ◽

Cited By ~ 1

Author(s):

S. T. Koike ◽

G. S. Saenz

Keyword(s):

United States ◽

Powdery Mildew ◽

Mycelial Growth ◽

Leaf Growth ◽

The United States ◽

First Report ◽

Powdery Mildews ◽

Leaf Surfaces ◽

Germ Tubes ◽

Symptoms And Signs

Corn-salad or lamb's lettuce (Valerianella locusta) is a specialty leafy green, annual vegetable that is grown commercially in California for use in salads. During the summer (June through August) of 2004, field plantings in coastal California (Monterey County) showed symptoms and signs of a powdery mildew. White, ectophytic mycelia and conidia were present on leaves and petioles. Extensively colonized leaves were slightly twisted and later developed a tan necrosis. Mycelial growth was spread out, flat, sometimes dense, and colonized both sides of the leaf. Growth was more extensive on the upper leaf surfaces. Hyphae were 5 to 7.5 μm wide with nipple-shaped appressoria. Conidiophores were straight and had foot cells that were simple, mostly curved, measured 50 to 65 × 10 to 12.5 μm, and followed by two to three cells of equal size. Conidia developed in short chains. Conidia were cylindric to doliform, measured 27.5 to 32.5 × 15 to 17.5 μm, and lacked fibrosin bodies. Conidial length-to-width ratios were usually less than or equal to 2.0. Conidia germinated at the ends (cichoracearum-type) and had germ tube lengths that ranged from short to 1.0 to 1.5 times the length of the conidium; germ tubes had swollen tips. Cleistothecia were not observed. On the basis of these characteristics, the fungus is identified as Golovinomyces (Erysiphe) orontii(Cast.) Heluta (1). To demonstrate pathogenicity, heavily colonized corn-salad leaves from commercial plantings were collected and gently pressed onto leaves of potted corn-salad plants. Plants were then maintained in a greenhouse (22 to 24°C). After 8 to 10 days, symptoms and signs of powdery mildew developed on the foliage of inoculated plants, and the pathogen morphology matched that of the originally observed pathogen. Noninoculated control plants did not develop powdery mildew. To our knowledge, this is the first report of powdery mildew of corn-salad caused by G. orontii in the United States. This corn-salad disease has been reported from a number of countries in Europe (2). Because the presence of powdery mildew on the harvested foliage made the leaves unmarketable, part of the crop could not be sold. References: (1) U. Braun. Nova Hedwigia 89:1, 1987. (2) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena, Germany, 1995.

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First Report of Erysiphe sedi on Sedum spectabile in North America

Plant Disease ◽

10.1094/pdis.2001.85.11.1207b ◽

2001 ◽

Vol 85 (11) ◽

pp. 1207-1207 ◽

Cited By ~ 3

Author(s):

L. Kiss ◽

Margery L. Daughtrey

Keyword(s):

New York ◽

North America ◽

Powdery Mildew ◽

Market Value ◽

First Report ◽

Potted Plants ◽

Powdery Mildews ◽

Leaf Surfaces ◽

Detached Leaves ◽

Leaf Tissues

Since 1997, powdery mildew infections have been repeatedly observed on Sedum spectabile plants, cv. Autumn Joy, grown as ornamentals in commercial greenhouses in New York. Circular patches of gray mycelia appeared and spread on upper and occasionally on lower leaf surfaces followed by necrosis of the leaf tissues and defoliation. The new disease reduced the market value of the infected ornamentals and required chemical control. The pathogen produced conidia singly on 2- to 3-celled conidiophores occurring on the ectophytic hyphae. Conidia were subcylindrical, measured 27 to 36 μm × 13 to 17 μm, and contained no fibrosin bodies. Germinating conidia produced a short germ tube, 5 to 30 μm, terminating in a lobed appressorium. Hyphal appressoria were lobed to multi-lobed, opposite or spread along the hyphae. Cleistothecia were not found. Based on conidial characteristics, the pathogen was identified as Erysiphe sedi Braun. To confirm pathogenicity, potted healthy S. spectabile plants were placed near infected plants in the greenhouse. In addition, detached S. spectabile leaves were inoculated with the pathogen by touching them to powdery mildew colonies and then placed in plates filled with one layer of polystyrene balls floated in water. Plates were covered and kept in the laboratory. Uninfected potted plants kept in another greenhouse and noninoculated detached leaves served as controls. After 1 week, powdery mildew appeared on all infected plants and leaves exposed to or inoculated with the pathogen. The pathogen was morphologically identical to the original fungus. No symptoms were observed on the controls. E. sedi is a common Asiatic powdery mildew species infecting many crassulaceous plants (1,2) and was introduced to Eastern Europe from Asia (2). To our knowledge, this is the first report of E. sedi in North America. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fisher Verlag, Jena, 1995.

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Further Support of Conspecificity of Oak and Mango Powdery Mildew and First Report of Erysiphe quercicola and Erysiphe alphitoides on Mango in Mainland Europe

Plant Disease ◽

10.1094/pdis-01-17-0116-re ◽

2017 ◽

Vol 101 (7) ◽

pp. 1086-1093 ◽

Cited By ~ 8

Author(s):

Marie-Laure Desprez-Loustau ◽

Marie Massot ◽

Nicolas Feau ◽

Tania Fort ◽

Antonio de Vicente ◽

...

Keyword(s):

Powdery Mildew ◽

Host Range ◽

Molecular Mechanisms ◽

Single Copy ◽

Broad Host Range ◽

First Report ◽

Erysiphe Quercicola ◽

Powdery Mildews ◽

Mango Leaves ◽

Practical Implications

Mango leaves and inflorescences infected by powdery mildew in southern Spain were analyzed using multigene sequencing (ITS + 4 single-copy coding genes) to identify the causal agent. Erysiphe quercicola was detected in 97% out of 140 samples, collected in six different orchards in the Malaga region. Among these, a small proportion also yielded E. alphitoides (8% of all samples) and E. alphitoides was found alone in 3% of samples. A phylogenetic approach was completed by cross inoculations between oak and mango, which led to typical symptoms, supporting the conspecificity of oak and mango powdery mildews. To our knowledge, this is the first report of E. quercicola and E. alphitoides causing powdery mildew on mango trees in mainland Spain, and thus mainland Europe, based on unequivocal phylogenetic and biological evidence. Our study thus confirmed the broad host range of both E. quercicola and E. alphitoides. These results have practical implications in terms of the demonstrated ability for host range expansion in powdery mildews. They also open interesting prospects to the elucidation of molecular mechanisms underlying the ability to infect single versus multiple and unrelated host plants since these two closely related powdery mildew species belong to a small clade with both generalist and specialist powdery mildews.

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First Report of Powdery Mildew on Euryops pectinatus in Italy

Plant Disease ◽

10.1094/pdis.2002.86.8.920b ◽

2002 ◽

Vol 86 (8) ◽

pp. 920-920

Author(s):

A. Garibaldi ◽

A. Minuto ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

Powdery Mildew ◽

Leaf Surface ◽

Northern Italy ◽

Growth Chamber ◽

Growth Reduction ◽

First Report ◽

Similar Disease ◽

Commercial Farms ◽

White Mycelium ◽

Sphaerotheca Fusca

Euryops pectinatus is grown in Italy for landscape use in parks and gardens. In 2001, severe outbreaks of a previously unknown powdery mildew were observed in commercial farms located in Albenga (northern Italy). All green parts (leaves, stems, and petioles) became covered with a white mycelium. Infections were particularly severe on the upper leaf surface. With progress of the disease, infected leaves turned yellow and died. The presence of powdery mildew infections on leaves and stems only rarely was linked to growth reduction. Conidia were hyaline, cylindric to slightly doliform, did not show fibrosin bodies, borne in chains, and measured 24 to 41 × 12 to 20 μm. Cleistothecia were not observed. The pathogen was identified as Oidium sp. subgen. Fibroidium (1). Pathogenicity was confirmed by gently pressing diseased leaves on leaves of healthy E. pectinatus plants. Inoculated plants were maintained in a growth chamber at 20 to 24°C. After 12 to 14 days, powdery mildew symptoms developed. A similar disease of E. pectinatus was observed in 1999 in California and identified as being caused by Podosphaera (Sphaerotheca) fusca (2). It is possible that the powdery mildew observed in Italy belongs to the same species, also considering that recently the two genera, Podosphaera and Sphaerotheca, have been unified in the genus Podosphaera (1). References: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (2) G. S. Saenz et al. Plant Dis. 84:1048, 2000.

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United Kingdom : Good Ideas from Successful Cities : Municipal Leadership on Immigrant Integration

10.32920/17082353.v1 ◽

2021 ◽

Author(s):

Kim Turner

Keyword(s):

United Kingdom ◽

Immigrant Integration ◽

Comparative Perspective ◽

The United Kingdom ◽

The Us ◽

Selection Of

Our main report, Good Ideas from Successful Cities: Municipal Leadership in Immigrant Integration, explores these themes through a selection of nearly 40 profiles of municipal practice and policies from cities across Canada, the US, Europe and Australasia. In this companion report, United Kingdom: Good Ideas from Successful Cities, we present an additional snapshot of municipal leadership and excellence in immigrant integration from cities in the United Kingdom. Each of these five city profiles includes a selection of related international city practices to encourage comparative perspective and enriched learning

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