Differences in resistance of wild Lactuca species to natural infection of lettuce powdery mildew (Erysiphe cichoracearum)

Euphytica ◽  
1985 ◽  
Vol 34 (2) ◽  
pp. 521-523 ◽  
Author(s):  
A. Lebeda
Keyword(s):  
Powdery Mildew ◽  
Natural Infection ◽  
Erysiphe Cichoracearum ◽  
Lactuca Species ◽  
Lettuce Powdery Mildew

scholarly journals First Report of Powdery Mildew, Caused by Erysiphe cichoracearum, on Coneflowers

Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 694-694 ◽  
Author(s):  
P. L. Sholberg ◽  
J. H. Ginns ◽  
T. S. C. Li
Keyword(s):  
Powdery Mildew ◽  
Ornamental Plants ◽  
Echinacea Purpurea ◽  
The United States ◽  
Plant Diseases ◽  
Conidial Suspension ◽  
Decay Fungi ◽  
Erysiphe Cichoracearum ◽  
Epidermal Surface ◽  
Medicinal Properties

Purple coneflowers (Echinacea purpurea) are grown in North America and Europe for their medicinal properties and as ornamental plants. In September 1997 and again in 1998, a previously undescribed disease was noticed on fully grown coneflower plants in Summerland and Oliver, British Columbia. Mycelia were observed on stems, foliage, and flowers, and distinct dark red to black, round (approximately 5 mm in diameter) lesions were observed on the flower petals. The disease appeared similar to powdery mildews that have been reported on numerous genera of the Asteraceae. Samples of the diseased tissue were examined and the salient features of the fungus on two specimens were determined: cleistothecia infrequent, subglobose or flattened on the side next to the leaf surface, 121 to 209 μm in diameter; epidermal (surface) cells 20 μm in diameter; appendages hyphoid, 5 μm in diameter, up to 200 μm long; asci, 10 to 19 in each cleistothecium, broadly ellipsoid, 47 to 85 × 28 to 37 μm with a short stalk, about 8 to 13 μm long and 8 μm in diameter; ascospores, immature, two per ascus, ellipsoid to broadly ellipsoid, 17 to 25 × 11 to 13 μm, thin walled, hyaline, and smooth; conidia oblong with sides slightly convex and apices truncate, 27 to 40 × 14 to 20 μm, walls hyaline, thin, smooth. Based on the occurrence of asci that contained two ascospores and the hyphoid appendages on the cleistothecia we concluded that the fungus was Erysiphe cichoracearum DC. Damage due to this disease was minimal in 1997 and 1998 because it developed very late in the growing season and occurred sporadically within the plantings. In order to complete Koch's postulates, Echinacea purpurea plants grown in the greenhouse were inoculated with a conidial suspension (105 to 106 conidia per ml) from field-infected plants. Powdery mildew first appeared 3 months later, eventually infecting leaves and stems of 12 of 49 inoculated plants. It was distinctly white and in discrete patches on leaves, compared with coalescing dark brown areas on the stems. Microscopic examination of the conidia confirmed that they were E. cichoracearum. Although powdery mildew caused by E. cichoracearum has been widely reported on lettuce, safflower, and other cultivated and wild Compositae, we found no reference to it on Echinacea spp. in Canada (1,2), the U.S. (3), or elsewhere in the world (4). The specimens have been deposited in the National Mycological Herbarium of Canada (DAOM) with accession numbers 225933 and 225934 for Oliver and Summerland, B.C., respectively. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) I. L. Conners. 1967. An annotated index of plant diseases in Canada and fungi recorded on plants in Alaska, Canada, and Greenland. Canada Dept. of Agric. Pub. 1251. (3) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN. (4) J. Ginns. 1986. Compendium of plant disease and decay fungi in Canada, 1960-1980. Agriculture Canada Pub. 1813.

scholarly journals First Report of Erysiphe cichoracearum Infecting Hedera canariensis var. azorica in Italy

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 198-198
Author(s):  
C. Nali
Keyword(s):  
New York ◽  
Powdery Mildew ◽  
Citrullus Lanatus ◽  
Ornamental Plants ◽  
Morphological Characteristics ◽  
Hedera Helix ◽  
Cucumis Sativus L ◽  
First Report ◽  
Erysiphe Cichoracearum ◽  
English Ivy

A powdery mildew disease of variegated ivy (Hedera canariensis L. var. azorica) was observed on the Tyrrhenian coast in Tuscany (Italy) in spring 1998. Symptoms began as small, nearly circular reddish spots that later enlarged and coalesced. The hyaline mycelium produced abundant, ellipsoid conidia in long chains that ranged from 20 to 40 μm in length and from 12 to 25 μm in width. Cleistothecia were globose (100 to 120 μm diameter), dark brown (when mature) with a basal ring of mycelioid appendages, and contained several (up to 20) ovate asci, each generally containing two ascospores. Ascospores were hyaline, one-celled, ellipsoid (20 to 35 μm in length and 10 to 20 μm in width). The morphological characteristics of this fungus were those given for Erysiphe cichoracearum DC. Infection also was found on English ivy (Hedera helix L.). It is reported that this species is, occasionally, subject to powdery mildew caused by E. cichoracearum (1). Conidia from infected leaves were shaken onto leaves of melon (Cucumis melo L.), cucumber (Cucumis sativus L.), watermelon (Citrullus lanatus [Thunb.] Matsum. & Nakai), lettuce (Lactuca sativa L.), tomato (Lycopersicon esculentum Mill.), tobacco (Nicotiana tabacum L.) and variegated and English ivy. After 7 days, the disease was observed on cucumber, melon, watermelon, tobacco, and variegated ivy. Examination confirmed that test plants were infected with E. cichoracearum. This is the first report of E. cichoracearum on variegated ivy in Italy. Reference: (1) P. P. Pirone. 1970. Diseases and Pests of Ornamental Plants. The Ronald Press, New York.

scholarly journals Response of Pisum sativum germplasm resistant to Erysiphe pisi to inoculation with Erysiphe baeumleri, a new pathogen of pea

2010 ◽  
Vol 41 (No. 3) ◽  
pp. 95-103 ◽  
Author(s):  
M. Ondřej ◽  
R. Dostálová ◽  
L. Odstrčilová
Keyword(s):  
Powdery Mildew ◽  
Pisum Sativum ◽  
Natural Infection ◽  
Erysiphe Pisi ◽  
Field Screening ◽  
Susceptible Control ◽  
High Level ◽  
Screening Trials

Cultivars, homozygous sources and lines of pea (<I>Pisum sativum</I> L.) resistant to <I>Erysiphe pisi</I> had recently been attacked by another powdery mildew species, <I>Erysiphe</I> <I>baeumleri,</I> in the field and in glasshouse conditions. Inoculation with <I>E. baeumleri</I> was carried out in the glasshouse to evaluate the level of resistance of 16 pea genotypes. Susceptible pea lines produced abundant conidia and cleistocarps on petioles and leaves. Only the genotype Tudor (Cebeco 4119) was found to be completely resistant to <I>E. baeumleri</I>. Nineteen pea genotypes (with gene <I>er-1</I>) were tested to natural infection by <I>E. baeumleri</I> in field screening trials. Only few of them demonstrated a high level of resistance (Fallon, AC Melfort and Joel). Consort R, SGL 2024, SGL 1977 and Franklin were very susceptible to <I>E. baeumleri</I>. Cleistocarps with 1–4× dichotomously branching apices of appendages were formed only on susceptible and very susceptible plants of genotypes SGL 444/2185, Consort R, SGL 2024, SGL 1977, LU 390-R2, Lifter, Highlight, Cebeco 1171 and Carneval R in the field and glasshouse. Susceptible control genotypes without gene <I>er-1</I> (Komet, Adept and Gotik) were attacked in the trials by <I>E.&nbsp;pisi</I> only.

Control of Fusarium wilt of muskmelon and other effects of benomyl soil drenches

1970 ◽  
Vol 16 (7) ◽  
pp. 615-620 ◽  
Author(s):  
R. N. Wensley ◽  
C. M. Huang
Keyword(s):  
Powdery Mildew ◽  
Fusarium Wilt ◽  
Active Material ◽  
Fruit Production ◽  
Early Growth ◽  
Single Application ◽  
Erysiphe Cichoracearum ◽  
Low Levels ◽  
Pot Culture

The application of benomyl (Benlate),* methyl 1-(butyl-carbamoyl)-2-benzimidazole-carbamate, to infested soils controlled populations of the wilt Fusarium (F. oxysporum f. melonis), reduced wilt losses to low levels, and permitted a harvest to be taken. Powdery mildew (Erysiphe cichoracearum) was also inhibited. In pot culture the compound was effective in single or split applications of 0.08 g active material and in a single application of 0.16 g or 4 applications of 0.04 g each per 1000 g soil. At the above rates Benlate prevented increases in populations of the pathogen in soil planted with susceptible melons. In the field, three applications of 0.64 g each/0.09 m2 (11.49 kg/ha), or one application of either 1.28 g (7.66 kg/ha), or 2.56 g (15.32 kg/ha) controlled wilt. Treatments that controlled wilt also retarded early growth and delayed the onset of fruiting. Recovery was made, however, followed by a prolonged period of growth and fruit production.

scholarly journals Powdery Mildew Caused by Golovinomyces cichoracearum on Paris Daisy (Argyranthemum frutescens) in Italy

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1135-1135
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
S. Frati ◽  
A. Minuto ◽  
M. L. Gullino
Keyword(s):  
Powdery Mildew ◽  
Its Region ◽  
Pathogenicity Test ◽  
Potted Plants ◽  
Erysiphe Cichoracearum ◽  
Golovinomyces Cichoracearum ◽  
Blastn Analysis ◽  
Voucher Specimens ◽  
White Mycelium ◽  
The Impact

Paris daisy (Argyranthemum frutescens), also known as Marguerite daisy, is an economically important crop in the Riviera Ligure (northern Italy) where approximately 18 million potted plants per year are produced for export. During the fall and winter of 2007, Paris daisy ‘Bright Carmen’ plants, started in a greenhouse and growing outside in a commercial nursery at Albenga, showed a previously unknown powdery mildew. Young stems, particularly in the interior portions of the plant, were covered with a white mycelium. As the disease progressed, leaves became covered with the mycelium, resulting in smaller, chlorotic leaves. Conidia were hyaline, cylindrical, borne in chains (two to three conidia per chain) and measured 30 × 12 μm (20 to 34 × 10 to 15 μm). Conidia were generated by conidiophores represented by a foot cell measuring 55 to 101 × 11 to 12 μm followed by two shorter cells measuring 19 to 29 × 11 to 14 and 24 to 33 × 12 to 14 μm. 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 441 bp showed a 100% homology with the sequence of Golovinomyces cichoracearum (= Erysiphe cichoracearum) (3). The nucleotide sequence has been assigned GenBank Accession No. EU486992. Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of healthy Paris daisy plants of cvs. Blazer Rose, Bright Carmine, Cherry Harmony, Crowned Rose, Fulvia, Sole Mio, Stella 2000, Summit Pink, and Sun Light. Three plants per cultivar were inoculated, while the same number served as noninoculated controls. The pathogenicity test was carried out twice. Plants were maintained in a greenhouse at temperatures ranging from 15 to 21°C. Fifteen days after inoculation, typical symptoms of powdery mildew developed on inoculated plants of all cultivars, with the exception of Stella 2000. The fungus observed on inoculated plants was morphologically identical to that originally observed. Noninoculated plants did not show symptoms. To our knowledge, this is the first report of powdery mildew on A. frutescens in Italy. G. cichoracearum has been reported on Chrysanthemum frutescens in Switzerland (2). The economic impact of this disease is limited but can easily increase because of the intensive cultivation of this crop. The availability of resistant or partially resistant cultivars will help reduce the impact of this new disease. 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) A. Bolay, Cryptogam. Helv. 20:1, 2005. (3) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000.

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