First Report of Podosphaera aphanis Causing Powdery Mildew on Wild Blackberry Species (Rubus spp.) in Mexico

Wild blackberry species (Rubus spp. L.; Rosaceae) represents an invaluable source of genes for the generation of new varieties, but also serve as a primary source of disease inoculum. During April of 2020, symptoms of powdery mildew were observed on four populations of wild blackberry species located in the states of Chiapas (16°59'11"N, 92°59'07"W; 16°47'08"N, 92°31'05"W) and Michoacán (19°37'17"N, 100°08'59"W; 19°29'25"N, 101°32'54"W), Mexico. Signs of the pathogen were white powdery masses mainly on the top of new shoots. Symptoms included yellowing, necrosis, and early defoliation of the plants. Hyphae were tin-walled, hyaline, smooth, and 4.0–9.0 mm wide. Appressoria were indistinct -to- nipple-shaped. Conidiophores (n=30, 75–225 × 10.5–13.5 μm) were straight, and unbranched with cylindrical foot cells (n=30, 31.5–158 × 8–13.5 μm), straight, somewhat widening upwards, followed by 1–3 shorter cells. Conidia (n=100; 25.5–38.5 × 9.5–22.5 μm) were catenulate, ellipsoid-ovoid -to- doliiform, containing fibrosin bodies (in 3% KOH). Germ tubes (n=30, 13.5–40.5 × 4.5 μm) emerged laterally, and were unbranched with slightly swollen tips. Chasmothecia were not found. Morphological characters of the fungus in all samples corresponded to the previous descriptions of Podosphaera aphanis by Braun and Cook (2012) and Stevanovi´c et al. (2020). Voucher specimens were deposited in the Department of Agricultural Parasitology Herbarium at the Chapingo Autonomous University under accessions UACH421, UACH423, UACH425, UACH426. To confirm the species identification, the internal transcribed spacer (ITS) of one sample was amplified using the primers ITS5 (White et al. 1990) and P3 (Kusaba and Tsuge, 1995) and sequenced. The sequence was deposited in GenBank (accession number MW988591). A phylogenetic analysis using Bayesian inference and maximum likelihood was performed (Hernández-Restrepo et al. 2018) and included other Podosphaera species (Takamatsu et al. 2010). The sequence from the isolate UACH426 clustered with the strain MUMH1871 of P. aphanis forming a definite clade and remained as a sister taxon of P. pannosa. Pathogenicity was verified through inoculation by gently dusting conidia from one powdery mildew patch onto leaves of five healthy blackberry plants of each specie. The same number of noninoculated plants served as controls. All plants were maintained in a greenhouse at 25–30°C with 75% relative humidity. All inoculated plants developed powdery mildew symptoms after 12 days, whereas no symptoms were observed on noninoculated plants. The fungus recovered from the inoculated plants was morphologically identical to that originally observed on diseased blackberry plants, demonstrating the pathogenicity of the fungus. Based on morphological data and phylogenetic analysis, the fungus was identified as P. aphanis. This fungus has been reported to cause powdery mildew on blackberry plants in Serbia (Stevanovi´c et al. 2020). This is the first report of P. aphanis causing powdery mildew on wild backberry species in Mexico according to Farr and Rossman (2021). The primary source of inoculum of powdery mildew for commercial plantings is wild blackberry plants from noncultivated areas and may warrant control of wild populations.

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First Report of Powdery Mildew Caused by Erysiphe macleayae on Torenia fournieri in China

Plant Disease ◽

10.1094/pdis-03-14-0294-pdn ◽

2014 ◽

Vol 98 (9) ◽

pp. 1277-1277 ◽

Cited By ~ 1

Author(s):

X.-Y. Men ◽

S.-Y. Liu ◽

W.-T. Jiang ◽

Y. Li

Keyword(s):

Powdery Mildew ◽

Morphological Characteristics ◽

Its Region ◽

Chelidonium Majus ◽

Torenia Fournieri ◽

Chinese Medicinal Herb ◽

First Report ◽

Advanced Stages ◽

Voucher Specimens ◽

Germ Tubes

Torenia fournieri (Linderniaceae) is a common ornamental plant in China. It is also an important Chinese medicinal herb for its heart clearing and toxin removal properties. In October 2013, severe powdery mildew infections were observed on T. fournieri in Baihuayuan Garden (125.35°E, 43.88°N), China. Voucher specimens were deposited in the Herbarium of Mycology of Jilin Agricultural University under the accession number HMJAU02176. Whitish colonies covered the surface of leaves, petioles, sepals, and stems. The infected leaves became yellow and necrotic by advanced stages of the infection. Chasmothecia with a diameter between 63.5 and 95 μm were present singly or in groups, and bore dark brown mycelioid. The appendages were 0.5 to 4 times as long as the chasmothecial diameter, brown at the base and paler toward the apex. Asci were 2 to 6 per chasmothecium, short-stalked or sessile, 50 to 62 × 30 to 50.5 μm, and 2- to 4-spored. Ascospores were pale brown, oval to ellipsoid, 27 to 43 × 13 to 17 μm. Hyphae were flexuous to straight, branched, and septate. Appressoria were well-developed, lobed, and solitary or in opposite pairs. Conidiophores were unbranched, cylindrical, and 94 to 185 × 9 to 15 μm. Foot-cells were straight, cylindrical, 19 to 40 μm long, and followed by 1 to 3 cells shorter or nearly equal to the foot-cell. Conidia were singly produced, cylindrical or oval, 34 to 44 × 16 to 20 μm, and without distinct fibrosin bodies. Lobed germ tubes were produced at the tip of conidia. The morphological characteristics of sexual and asexual structures were consistent with Erysiphe macleayae (1,2). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of the pathogen was amplified with the primers ITS1/ITS4 and sequenced (3). The resulting 574-bp sequence (KJ600796) showed 100% similarity with E. macleayae (KF856294) and Oidium sp. isolated from Chelidonium majus (HQ286645 to 46) and one base different from M. microcarpa (JQ681217). Koch's postulate was completed by gently pressing a diseased leaf onto three young excised leaves of asymptomatic seedlings. Three non-inoculated leaves were used as controls. Inoculated leaves were incubated in separate petri dishes in a greenhouse at 20 to 25°C. Symptoms developed 5 days after inoculation, whereas the control leaves remained symptomless (voucher specimens HMJAU02176I). The morphology of the fungus on the inoculated leaves was identical to that observed on the originally diseased leaves. Powdery mildew on T. fournieri has only been reported as Golovinomyces sp. in Hungary (4). To our knowledge, this is the first report of powdery mildew caused by E. macleayae on T. fournieri worldwide. Infection of Torenia by E. macleayae, a common powdery mildew on various hosts of the Papaveraceae, is very unusual and unexpected. It demonstrates a wider host range of this species beyond the limits of the Papaveraceae. References: (1) U. Braun and R. T. A. Cook. Taxonomic manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series 11. CBS, Utrecht, the Netherlands, 2012. (2) M. J. Park et al. Plant Dis. 96:1376, 2012. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) P. Vági et al. Eur. J. Plant Pathol. 117:89, 2007.

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First Report of Powdery Mildew Caused by Erysiphe heraclei on Dill in Korea

Plant Disease ◽

10.1094/pdis-02-12-0118-pdn ◽

2012 ◽

Vol 96 (6) ◽

pp. 907-907 ◽

Cited By ~ 1

Author(s):

S. E. Cho ◽

J. H. Park ◽

J. Y. Kim ◽

H. D. Shin

Keyword(s):

Powdery Mildew ◽

Sequence Similarity ◽

Signs And Symptoms ◽

Its Region ◽

Anethum Graveolens ◽

First Report ◽

The Family ◽

Causal Fungus ◽

Voucher Specimens ◽

Germ Tubes

Dill (Anethum graveolens L.) is a scented herb belonging to the family Apiaceae. The plant has a long and ancient history in many countries as a culinary and medicinal herb. In October 2008, plants showing typical symptoms of powdery mildew disease were found in polythene tunnels in Icheon, Korea. Symptoms first appeared as thin white colonies, which subsequently showed abundant growth on the leaves and stems. Most diseased plantings were unmarketable and shriveled without being harvested. The damage caused by powdery mildew infections on dill has reappeared every year, with confirmation of the causal agent made again in 2011. Voucher specimens were deposited in the Korea University Herbarium (KUS). Hyphae were septate, branched, and 4 to 7 μm wide. Appressoria on the mycelium were multilobed or moderately lobed. Conidiophores were unbranched, cylindrical, 80 to 140 × 8 to 10 μm, straight or slightly flexuous in foot cells, and produced conidia singly, followed by two to three cells. Conidia were oblong elliptical to oblong, 28 to 50 × 14 to 18 μm, lacked fibrosin bodies, and produced germ tubes on the subterminal position, with angular/rectangular wrinkling of the outer walls. Primary conidia were apically conical, basally subtruncate, and generally smaller than the secondary conidia. No chasmothecia were found but the above characteristics are consistent with Erysiphe heraclei DC. (1). To confirm the identity of the causal fungus, the complete internal transcribed spacer (ITS) region of rDNA from isolate KUS-F26425 was amplified with primers ITS5 and P3 as described by Takamatsu et al. (3) and directly sequenced. The resulting 630-bp sequence was deposited in GenBank (Accession No. JQ517297). Comparison with the sequences available in the GenBank database revealed that the isolate showed >99% sequence similarity with those of E. heraclei from Pleurospermum camtschaticum (GU173850) and Daucus carota (EU371725). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of five healthy potted dill plants. Five noninoculated plants served as controls. Plants were maintained in a greenhouse at 22 ± 2°C. Inoculated plants developed signs and symptoms after 7 days, whereas the control plants remained healthy. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants. Powdery mildew caused by E. heraclei on dill has been known worldwide where the plant is cultivated (2). In East Asia, however, dill powdery mildew was known only from Taiwan (4). To our knowledge, this is the first report of powdery mildew infections by E. heraclei on dill in Korea. Since cultivation of dill was only recently started on a commercial scale in Korea, powdery mildew infections pose a serious threat to safe production of this herb, especially in organic farming where chemical control would be prohibited. References: (1) U. Braun. Beih. Nova Hedw. 89:1, 1987. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ January 28, 2012. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) J. G. Tsay. Trans. Mycol. Soc. Repub. China 5:1, 1990.

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Taxonomy of the genus Commelina Plum. ex L. (Commelinaceae) in Nepal

Botanica Orientalis Journal of Plant Science ◽

10.3126/botor.v6i0.2907 ◽

2010 ◽

Vol 6 ◽

pp. 25-31 ◽

Cited By ~ 1

Author(s):

Jyoti P Gajurel ◽

Krishna K Shrestha

Keyword(s):

Key Words ◽

Taxonomic Status ◽

Morphological Characters ◽

Species Level ◽

Morphological Data ◽

Plant Science ◽

The World ◽

Voucher Specimens ◽

Key Words Anatomy ◽

Anatomical Characters

About 170 species of Commelina are known from tropical and subtropical regions of the world. Nepal contributes 6 species of Commelina to the world flora. In the present work, taxonomy of all the six species of Commelina reported from Nepal (C. benghalensis, C. caroliniana, C. diffusa, C. maculata, C. paludosa and C. suffruticosa) was studied. Voucher specimens were collected from Central and Eastern Nepal, covering 14 districts. Morphological characters were studied from these collections. Palynological and anatomical characters were also used to see if they are taxonomically important to delimit the taxa within Commelina. Morphological characters seemed promising to delimit the taxa within Commelina. The key identifying characters at species level are modification in root, form of spathe, structure of leaves and seeds, shape of stomata and pollen. Palynological and anatomical characters were also useful, to some extent, in separating some species, but were not significant as compared to morphological data. Some specimens, close to C. benghalensis and C. caroliniana, showed very different characters. Thus further study is needed to confirm their taxonomic status. Key-words: anatomy; flora; morphological characters; palynology; voucher specimens.DOI: 10.3126/botor.v6i0.2907 Botanica Orientalis - Journal of Plant Science (2009) 6: 25-31

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Characterisation of the Australian Nacophorini using adult morphology, and phylogeny of the Geometridae based on morphological characters

Zootaxa ◽

10.11646/zootaxa.1736.1.1 ◽

2008 ◽

Vol 1736 (1) ◽

pp. 1 ◽

Cited By ~ 9

Author(s):

CATHERINE J. YOUNG

Keyword(s):

Phylogenetic Analysis ◽

Majority Rule ◽

Morphological Character ◽

Morphological Characters ◽

Data Sources ◽

Morphological Data ◽

Bootstrap Support ◽

Consensus Tree ◽

Molecular Analyses ◽

Character Set

The Australian Nacophorini and related taxa are described using a matrix of 116 adult morphological characters. Adults of 72 species are illustrated using photographs and electron micrographs. Subsets of the characters are used to conduct a phylogenetic analysis based on cladistic principles. The adult morphological character set was augmented with 17 characters from eggs and 27 from larvae. The resulting phylogeny is poorly resolved but provides support for many of the relationships recovered by previous molecular analyses of the group, including basal derivations for characters of Larentiinae and Sterrhinae relative to those of the rest of Geometridae, and the monophyly of the Geometrinae + Oenochrominae s. str. Combining 28S D2 datawith morphological data produced a matrix of 60 taxa and 590 characters. The majority rule consensus tree produced by the combined morphological and 28S D2 data is almost identical to the majority rule consensus tree produced by the 28S D2 data alone, except that bootstrap support is lower for most nodes. Common clades obtained from the molecular and morphological trees are described in terms of morphological data. On this basis a concept of the Australian Nacophorini includes Lithinini and Australian Archiearinae. Two robust groups within the tribe also are delimited using characters from all data sources. Comparsions are made between the Nearctic and Neotropical Nacophorini on the basis of shared morphological characters. Australian Boarmiini are defined by synapomorphies.

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First Report of Powdery Mildew Caused by Sphaerotheca fusca on Tomatillo in California

Plant Disease ◽

10.1094/pdis.1998.82.6.711c ◽

1998 ◽

Vol 82 (6) ◽

pp. 711-711 ◽

Cited By ~ 1

Author(s):

S. T. Koike ◽

R. F. Smith

Keyword(s):

Powdery Mildew ◽

Fungal Growth ◽

Premature Senescence ◽

First Report ◽

Powdery Mildew Disease ◽

Salinas Valley ◽

Germ Tubes ◽

Husk Tomato ◽

Sphaerotheca Fusca ◽

Commercial Field

Tomatillo or husk tomato (Physalis ixocarpa Brot.) is an annual Solanaceous bush grown for its fruit, which are harvested when the fruit fill the enlarged calyx and are used primarily in Hispanic cooking. In the summer of 1997, commercial field-grown tomatillo in the Salinas Valley (Monterey County) was severely affected by a powdery mildew disease. Fungal growth was found on leaves, petioles, and calyces and resulted in twisting, desiccation, and premature senescence of the tissues. The mycelium was white to gray, ectophytic, amphigenous, and effuse. Mycelial appressoria were indistinct. Conidiophore foot cells were straight, cylindric, measured 36.1 to 61.1 µm (mean 47.0) × 11.1 to 13.9 µm (mean 11.7), and were followed by 1 to 3 shorter cells. Doliform conidia were formed in chains and measured 25.0 to 50.0 µm (mean 32.5) × 11.1 to 22.2 µm (mean 17.7). The length-to-width ratios of conidia generally were less than 2.0, and fibrosin bodies were present. Germ tubes usually were laterally inserted, lacked conspicuous appressoria, and were of the pannosa-type. Cleistothecia were not observed. Based on these characters, the fungus was identified as Sphaerotheca fusca (Fr.) Blumer, Beitr. Krypt.-Fl. Schweiz (1). Pathogenicity was confirmed by gently pressing infected leaves onto leaves of potted tomatillo. Inoculated plants were kept in a chamber at 100% humidity for 48 h, and then maintained in a greenhouse. Powdery mildew developed on inoculated plants after 12 to 14 days, while uninoculated plants did not develop disease. The experiment was conducted a second time and the results were the same. This is the first report of a powdery mildew disease of tomatillo in California. Reference: (1) U. Braun. Nova Hedwigia 89:1, 1987.

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First Report of Powdery Mildew Caused by Leveillula taurica on Cynanchum kashgaricum in China

Plant Disease ◽

10.1094/pdis-11-11-0947-pdn ◽

2012 ◽

Vol 96 (9) ◽

pp. 1373-1373

Author(s):

G. He ◽

B. Xu ◽

J. G. Song ◽

L. L. Zhang ◽

Z. Y. Zhao ◽

...

Keyword(s):

Powdery Mildew ◽

Morphological Characters ◽

Taklimakan Desert ◽

Its Sequence ◽

Endangered Plant ◽

Voucher Specimen ◽

First Report ◽

Leveillula Taurica ◽

The Family ◽

In The Wild

Cynanchum kashgaricum Liou f., belonging to the family Apocynaceae, is an endemic herbaceous perennial and extremely endangered plant species, only found in the wild in desert regions of Xinjiang, China (3), and is valuable for sand stabilization. In August 2010, a previously unknown and widespread powdery mildew disease was observed on C. kashgaricum growing in the Taklimakan Desert in Xinjiang, China. Disease symptoms included the appearance of a white mycelial coating on the upper surfaces of leaves, while the corresponding abaxial surfaces of infected leaves became chlorotic. As the disease progressed, the infected leaves turned yellow and necrotic. In this survey, the incidence of affected C. kashgaricum plants was 60%. On the basis of microscopic examination, the morphology of the fungus can be described as follows: the primary conidia of the fungus were lanceolate or clavate, with a pointed apex and rounded base, measuring 40.4 to 82.5 × 11.1 to 24.6 μm, with an irregular surface covered by warts; the secondary conidia varied in shape from subcylindrical to cylindrical, with rounded ends, and had lateral borders that were parallel to each other with rounded or truncate bases, measuring 40.5 to 73.5 × 11.2 to 23.9 μm. The ascomata were nearly gregarious and globe-shaped, of dust-colored appearance, and 113 to 267 μm in diameter; they were immersed in dense mycelial tomentum with numerous asci (usually 10 to 18 per ascoma). Numerous, well-developed appendages were present on the lower half of the ascomata; these appendages were irregularly branched and their length was 0.15 to 0.3 times the diameter of the ascomata. The asci were stalked, long or wide ellipsoidal in shape, and 93 to 140 × 27.6 to 52.9 μm. The asci usually contained two ellipsoidal ascospores 24.5 to 49.5 × 18.3 to 29.5 μm. On the basis of morphologic characteristics, the fungus was identified as Leveillula taurica (2). A voucher specimen of the fungus under the identifier HMTU09021 was deposited in the Mycological Herbarium of Tarim University (HMTU). To verify the identity of the fungus, the internal transcribed spacer (ITS) rDNA was amplified and sequenced, and the sequences were deposited as GenBank Accession No. JN861731. Comparison with sequences in the GenBank database revealed that the ITS sequence showed 100% homology with the sequence of L. taurica on Capsicum annuum (Accession No. GQ167201) and Lepidium latifolium (Accession No. AB044349). Thus, the pathogen was identified as L. taurica on the basis of the anamorphic and teleomorphic morphological characters and the ITS sequence. To our knowledge, while L. taurica infection in plants of the family Apocynaceae has been reported around the world (1), in east Asia only a single report of C. glaucum infection in this genus has occurred, in Afghanistan (1). This is the first report of L. taurica infection of C. kashgaricum. Outbreaks of this powdery mildew could not only threaten growth of the endangered plant but also accelerate local ecological deterioration. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi, 2nd ed. Japan Scientific Societies Press, Tokyo, Japan, 1986. (2) U. Braun. A Monograph of the Erysiphales (Powdery Mildews). Nova Hedwigia Beiheft 89:1, 1987. (3) F. Ying et al. Acta Bot. Boreali-Occidentalia Sin. 23:263, 2003.

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Phylogenetic Signal and Bias in Paleontology

Systematic Biology ◽

10.1093/sysbio/syab072 ◽

2021 ◽

Author(s):

Robert J Asher ◽

Martin R Smith

Keyword(s):

Phylogenetic Analysis ◽

Phylogenetic Signal ◽

Morphological Characters ◽

Tree Of Life ◽

Morphological Data ◽

Phylogenetic Resolution ◽

Phylogeny Estimation ◽

Better Than

Abstract An unprecedented amount of evidence now illuminates the phylogeny of living mammals and birds on the Tree of Life. We use this tree to measure phylogenetic value of data typically used in paleontology (bones and teeth) from six datasets derived from five published studies. We ask three interrelated questions: 1) Can these data adequately reconstruct known parts of the Tree of Life? 2) Is accuracy generally similar for studies using morphology, or do some morphological datasets perform better than others? 3) Does the loss of non-fossilizable data cause taxa to occur in misleadingly basal positions? Adding morphology to DNA datasets usually increases congruence of resulting topologies to the well corroborated tree, but this varies among morphological datasets. Extant taxa with a high proportion of missing morphological characters can greatly reduce phylogenetic resolution when analyzed together with fossils. Attempts to ameliorate this by deleting extant taxa missing morphology are prone to decreased accuracy due to long-branch artefacts. We find no evidence that fossilization causes extinct taxa to incorrectly appear at or near topologically basal branches. Morphology comprises the evidence held in common by living taxa and fossils, and phylogenetic analysis of fossils greatly benefits from inclusion of molecular and morphological data sampled for living taxa, whatever methods are used for phylogeny estimation.

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First Report of Powdery Mildew Caused by Podosphaera xanthii on Calendula officinalis in Italy

Plant Disease ◽

10.1094/pdis-92-1-0174c ◽

2008 ◽

Vol 92 (1) ◽

pp. 174-174 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

G. Gilardi ◽

M. L. Gullino

Keyword(s):

Powdery Mildew ◽

Its Region ◽

Pathogenicity Test ◽

Podosphaera Xanthii ◽

Calendula Officinalis ◽

First Report ◽

Potted Plants ◽

Blastn Analysis ◽

Voucher Specimens ◽

Pot Marigold

Calendula officinalis L. (Asteraceae) (pot marigold or English marigold) is an ornamental species grown in gardens and as potted plants for the production of cut flower. It was also used in ancient Greek, Roman, Arabic, and Indian cultures as a medicinal herb as well as a dye for fabrics, foods, and cosmetics. During the summer of 2007, severe outbreaks of a previously unknown powdery mildew were observed on plants in several gardens near Biella (northern Italy). Both surfaces of leaves of infected 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 flower calyxes. Conidia were hyaline, ellipsoid, born in short chains (four to six conidia per chain), and measured 27.0 to 32.1 (31.4) × 12.9 to 18.4 (18.2) μm. Conidiophores measured 49 to 77.3 (67.2) × 8 to 13.3 (10.8) μm and showed a foot cell measuring 44 to 59 (51.9) × 9.3 to 12.6 (11.3) μm followed by one shorter cell measuring 15.6 to 18.9 (17.6) × 10.4 to 13.6 (12.2) μm. Fibrosin bodies were present. Chasmothecia were spherical, amber colored, with a diameter of 89 to 100 (94.5) μm. Each chasmothecium contained one ascus with eight ascospores. On the basis of its morphology, the causal agent was determined to be a Podosphaera sp. (2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 588 bp showed a 100% homology with the sequence of Podosphaera xanthii (2). The nucleotide sequence has been assigned GenBank Accession No. EU100973. Pathogenicity was confirmed through inoculations by gently pressing diseased leaves onto leaves of healthy C. officinalis plants. Five plants were inoculated. Five noninoculated plants served as control. Plants were maintained in a greenhouse at temperatures ranging from 20 to 26°C. Eleven days after inoculation, typical symptoms of powdery mildew 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 powdery mildew on C. officinalis in Italy. C. officinalis was previously described as a host to Sphaerotheca fuliginea (synonym S. fusca) in Great Britain (4) as well as in Romania (3). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (3) E. Eliade. Rev. Appl. Mycol. 39:710, 1960. (4) F. J. Moore. Rev. Appl. Mycol. 32:380, 1953.

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First Report of Powdery Mildew Caused by Podosphaera aphanis var. aphanis on Potentilla fruticosa in Italy

Plant Disease ◽

10.1094/pd-89-1362c ◽

2005 ◽

Vol 89 (12) ◽

pp. 1362-1362

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

United States ◽

Powdery Mildew ◽

The United States ◽

Pathogenicity Test ◽

First Report ◽

Potentilla Fruticosa ◽

Erysiphe Polygoni ◽

Voucher Specimens ◽

White Mycelium ◽

Sphaerotheca Macularis

Potentilla fruticosa L. (bush cinquefoil), belonging to the family Rosaceae, is an ornamental plant used in parks and gardens. During the spring and summer of 2005, severe outbreaks of a previously unknown powdery mildew were observed in several private gardens located near Biella (northern Italy). The adaxial and abaxial surfaces of leaves as well as the stems were covered with white mycelium. Buds and flowers also were affected. As disease progressed, infected leaves turned yellow and dehisced. Conidia formed in chains and were hyaline, ovoid, and measured 24.0 to 36.0 × 15.8 to 24.0 μm (average 30.1 × 20.0 μm). Fibrosin bodies were present. Chasmothecia were numerous, sphaerical, amber colored, and diameters ranged from 84.0 to 98.4 μm (average 90.4 μm). Each chasmothecium contained one ascus with eight ascospores. Ascospores measured 26.5 to 27.2 × 13.2 to 15.6 μm (average 26.8 × 14.0 μm). On the basis of its morphology, the causal agent was determined to be Podosphaera aphanis (Wallr.) U. Braun & S. Takamatsu var. aphanis U. Braun (1). Pathogenicity was confirmed through inoculations by gently pressing diseased leaves onto leaves of healthy P. fruticosa plants. Three plants were inoculated. Three noninoculated plants served as a control. Plants were maintained at temperatures ranging from 12 to 23°C. Ten days after inoculation, typical symptoms of powdery mildew 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 powdery mildew on P. fruticosa in Italy. Erysiphe polygoni D.C. and Sphaerotheca macularis (Wallr.:Fr.) Lind were observed in the United States on P. fruticosa (2), while in Japan, the presence of S. aphanis var aphanis was reported (3). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000 (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) S. Tanda et al. J. Agric. Sci. 39:258, 1995.

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First Report of Powdery Mildew Caused by Golovinomyces cichoracearum on English Daisy (Bellis perennis) in Italy

Plant Disease ◽

10.1094/pdis-92-3-0484a ◽

2008 ◽

Vol 92 (3) ◽

pp. 484-484 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

A. Minuto ◽

M. L. Gullino

Keyword(s):

Powdery Mildew ◽

Its Region ◽

Northern Italy ◽

Flowering Plant ◽

Pathogenicity Test ◽

First Report ◽

Golovinomyces Cichoracearum ◽

Blastn Analysis ◽

Commercial Farms ◽

Voucher Specimens

Bellis perennis (English daisy) is a flowering plant belonging to the Asteraceae and is increasingly grown as a potted plant in Liguria (northern Italy). In February 2007, severe outbreaks of a previously unknown powdery mildew were observed on plants in commercial farms at Albenga (northern Italy). Both surfaces of leaves of affected plants were covered with white mycelia and conidia. As the disease progressed, infected leaves turned yellow. Mycelia and conidia also were observed on stems and flower calyxes. Conidia were hyaline, ellipsoid, borne in chains (as many as three conidia per chain), and measured 27.7 × 16.9 (15.0 to 45.0 × 10.0 to 30.0) μm. Conidiophores measured 114.0 × 12.0 (109.0 to 117.0 × 11.0 to 13.0) μm and showed a foot cell measuring 78.0 × 11.0 (72.0 to 80.0 × 11.0 to 12.0) μm followed by two shorter cells. Fibrosin bodies were absent. Chasmothecia were not observed in the collected samples. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 415 bp obtained showed an E-value of 7e–155 with Golovinomyces cichoracearum (3). The nucleotide sequence has been assigned the GenBank Accession No. AB077627.1 Pathogenicity was confirmed through inoculations by gently pressing diseased leaves onto leaves of healthy B. perennis plants. Twenty plants were inoculated. Fifteen noninoculated plants served as a control. Plants were maintained in a greenhouse at temperatures ranging from 10 to 30°C. Seven days after inoculation, typical symptoms of powdery mildew developed on inoculated plants. The fungus observed on inoculated plants was morphologically identical to that originally observed. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. To our knowledge, this is the first report of powdery mildew on B. perennis in Italy. The disease was already reported in other European countries (2). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) U. Braun The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena, Germany, 1995. (3) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000.

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