scholarly journals First Report of Pepper Powdery Mildew Caused by Leveillula taurica in Oklahoma

Plant Disease ◽  
1999 ◽  
Vol 83 (11) ◽  
pp. 1072-1072 ◽  
Author(s):  
J. P. Damicone ◽  
A. J. Sutherland
Keyword(s):  
Powdery Mildew ◽  
Capsicum Annuum ◽  
First Report ◽  
Leveillula Taurica ◽  
Leaf Surfaces ◽  
Leaf Drop ◽  
Bell Peppers ◽  
Potential Impact ◽  
Powdery Mildew Pathogen ◽  
Field Production

During April 1999, bell peppers (Capsicum annuum L.) from a commercial hydroponics greenhouse in Oklahoma County, OK, were severely affected by powdery mildew caused by Leveillula taurica (Lév.) Arnaud (anamorph Oidiopsis taurica (Lév.) Salmon). Defoliation levels (50 to 75%) were similar for cvs. Valencia, Lavender Islander, Sweet Chocolate, Aladdin, Purple Beauty, Golden Summer, Chocolate Beauty, Early Sunsation, Fat N'Sassy, Lilac, Sweet Rainbow Mix, and Ivory. Fruit from infected plants were small and unmarketable. Newly infected leaves exhibited light powdery colonies that were visible on abaxial leaf surfaces. On older leaves, abaxial leaf surfaces were completely covered by powdery mildew. Severely infected leaves developed chlorotic and necrotic patches on adaxial leaf surfaces prior to leaf drop. L. taurica was identified by the presence of endophytic mycelia, often-branched conidiophores, and dimorphic conidia borne singly or in short chains (1). In 50 measurements of each type, pyriform conidia averaged 67.8 ± 5.3 × 17.9 ± 2.2 μm and cylindrical conidia averaged 62.7 ± 6.2 × 15.7 ± 2.0 μm. Although conidia were slightly longer and narrower than those reported for isolates of L. taurica from pepper in California (2), dimensions were within the range reported for the species (1). The teleomorph of this powdery mildew pathogen was not observed. Peppers were grown from seed on the site. The source of L. taurica for the outbreak and the potential impact of powdery mildew on field production of peppers are unknown. Tomatoes in another hydroponics greenhouse within 100 m were not affected. This is the first report of L. taurica in Oklahoma. References: (1) H. J. Boesewinkel. Bot. Rev. 46:167, 1980. (2) J. C. Correll et al. Plant Dis. 71:248, 1987.

scholarly journals First Report of Powdery Mildew in Chilhuacle Chili (Capsicum annuum) Caused by Leveillula taurica in Southern Mexico

Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2325-2325 ◽  
Author(s):  
V. García-Gaytán ◽  
S. García-Morales ◽  
H. V. Silva-Rojas ◽  
L. I. Trejo-Téllez ◽  
F. C. Gómez-Merino
Keyword(s):  
Powdery Mildew ◽  
Capsicum Annuum ◽  
Southern Mexico ◽  
First Report ◽  
Leveillula Taurica

scholarly journals First report of Leveillula taurica causing powdery mildew on cucumber in Mexico

2018 ◽  
Vol 100 (2) ◽  
pp. 353-353
Author(s):  
Hugo Beltrán-Peña ◽  
Alma Rosa Solano-Báez ◽  
Miguel Ángel Apodaca-Sánchez ◽  
Moisés Camacho-Tapia ◽  
Rubén Félix-Gastélum ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
First Report ◽  
Leveillula Taurica

First Report of Powdery Mildew Caused by Leveillula taurica of Field-Grown Sweet Pepper in the Pacific Northwest

2010 ◽  
Vol 11 (1) ◽  
pp. 45 ◽  
Author(s):  
Dean A. Glawe ◽  
Tess Barlow ◽  
Jordan E. Eggers ◽  
Philip B. Hamm
Keyword(s):  
Powdery Mildew ◽  
Economic Impact ◽  
Pacific Northwest ◽  
Sweet Pepper ◽  
Disease Outbreak ◽  
First Report ◽  
Leveillula Taurica ◽  
The Pacific

In August 2009, a grower reported a disease affecting nearly all plants in a drip-irrigated field of sweet pepper cv. Excalibur in Umatilla Co., OR. The fungus was determined to be Leveillula taurica (Lév.) G. Arnaud, previously unreported from this host in Oregon or from field-grown peppers in the Pacific Northwest. This report documents the taxonomic determination of this species and provides information about the disease outbreak, including economic impact. Accepted for publication 18 May 2010. Published 8 July 2010.

scholarly journals A Short-Read Genome Assembly Resource for Leveillula taurica Causing Powdery Mildew Disease of Sweet Pepper (Capsicum annuum)

2020 ◽  
Vol 33 (6) ◽  
pp. 782-786
Author(s):  
Stefan Kusch ◽  
Márk Z. Németh ◽  
Niloofar Vaghefi ◽  
Heba M. M. Ibrahim ◽  
Ralph Panstruga ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Capsicum Annuum ◽  
Genome Assembly ◽  
Reference Genome ◽  
Gc Content ◽  
Sweet Pepper ◽  
Mesophyll Cells ◽  
Short Read ◽  
Leveillula Taurica ◽  
Reference Genome Assembly

Powdery mildew of sweet pepper (Capsicum annuum) is an economically important disease. It is caused by Leveillula taurica, an obligate biotrophic ascomycete with a partly endophytic mycelium and haustoria, i.e., feeding structures formed in the mesophyll cells of infected host plant tissues. The molecular basis of its pathogenesis is largely unknown because genomic resources only exist for epiphytically growing powdery mildew fungi with haustoria formed exclusively in epidermal cells of their plant hosts. Here, we present the first reference genome assembly for an isolate of L. taurica isolated from sweet pepper in Hungary. The short read–based assembly consists of 23,599 contigs with a total length of 187.2 Mbp; the scaffold N50 is 13,899 kbp and N90 is 3,522 kbp; and the average GC content is 39.2%. We detected at least 92,881 transposable elements covering 55.5 Mbp (30.4%). BRAKER predicted 19,751 protein-coding gene models in this assembly. Our reference genome assembly of L. taurica is the first resource to study the molecular pathogenesis and evolution of a powdery mildew fungus with a partly endophytic lifestyle.

First report of Leveillula taurica causing powdery mildew on Tropaeolum majus in Taiwan

2021 ◽  
Author(s):  
Yi-Ting Xiao ◽  
Hiran A. Ariyawansa ◽  
Chao-Jen Wang ◽  
Tung-Chin Huang ◽  
Yuan-Min Shen
Keyword(s):  
Powdery Mildew ◽  
First Report ◽  
Leveillula Taurica ◽  
Tropaeolum Majus

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

Plant Disease ◽  
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.

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

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 329-329
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
United Kingdom ◽  
Powdery Mildew ◽  
Northern Italy ◽  
First Report ◽  
The United Kingdom ◽  
Powdery Mildews ◽  
Initial Symptoms ◽  
Leaf Surfaces ◽  
Microscopy Examination ◽  
Selection Of

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.

scholarly journals First Report of Podosphaera xanthii Causing Powdery Mildew on Mungbean (Vigna radiata) in Taiwan

Plant Disease ◽  
2021 ◽  
Author(s):  
Zong-ming Sheu ◽  
Ming-hsueh Chiu ◽  
Lawrence Kenyon
Keyword(s):  
Powdery Mildew ◽  
Vigna Radiata ◽  
Morphological Characteristics ◽  
Resistance Breeding ◽  
Its Region ◽  
Infected Leaf ◽  
Pathogenicity Test ◽  
Causal Organism ◽  
First Report ◽  
Powdery Mildew Pathogen

Mungbean (Vigna radiata L.) is routinely grown in the experimental fields at the headquarters of the World Vegetable Center (23°6'30.88"N, 120°17'51.31"E) for breeding, research and germplasm multiplication. In a spring 2016 mungbean trial, about 50% of the plants were affected with powdery mildew. The white, powdery-like patches first appeared on the upper leaf surfaces, and soon developed to grey patches on both sides of the leaves. Purple to brown discoloration appeared on the underside of the infected leaf. Microscopy examination revealed that the causal organism was not Erysiphe polygoni, which had previously been documented as the powdery mildew pathogen on mungbean in Taiwan (Hartman et al. 1993). The fungus produced typical structures of the powdery mildew Euoidium, anamorph of the genus Podosphaera. The mycelium consisted of septate, flexuous hyphae with indistinct appressoria. The erect conidiophores arising from superficial hyphae varied from straight or slightly curved to curled. Three to ten conidia were borne in long chains with crenate edges. Foot-cells were straight, cylindrical and measured 30 to 52 µm long. Conidia were hyaline, ellipsoid-ovoid to barrel-shaped, with fibrosin bodies, and measured 27 to 33 (mean = 30.4) × 15 to 20 (mean = 16.6) µm. Germ tubes were clavate and occasionally forked, and were produced from the lateral sites of the conidia. No chasmothecia were found in the samples. The morphological characteristics were consistent with P. xanthii (Castagne) U. Braun & Shishkoff (Braun & Cook 2012). To confirm the identity, the internal transcribed spacer (ITS) region of rDNA and partialβ-tubulin gene (TUB2) for the isolate MG3 were amplified with the primers ITS4/ITS5 (White et al. 1990) and BtuF5/BtuR7a (Ellingham et al. 2019), respectively. BLASTn analysis revealed the ITS sequence (MN833717) was 100% identical to many records of P. xanthii whereas the TUB2 sequence (MW363957) was 100% identical to a record of P. fusca (syn. P. xanthii; KC333362) in NCBI GenBank. A pathogenicity test was conducted by dusting conidia from an infected leaf onto six healthy four-week-old mungbean plants (cv ‘Tainan No. 3’). Another three plants were not inoculated and were used as control. All the plants were maintained in a greenhouse at 25 to 28°C. All inoculated plants developed powdery mildew symptoms after 10 days, whereas the control plants remained symptomless. To our knowledge, this is the first report of P. xanthii causing disease on mungbean in Taiwan. P. xanthii also has been reported on mungbean in Thailand (Meeboon et al. 2016), while other records referring to E. polygoni infecting Vigna spp. are from Brazil and Fiji (Farr & Rossman 2020). Although both P. xanthii and E. polygoni have now been reported as causing powdery mildew on mungbean in Taiwan, which species predominates or is more important remains unclear. A comprehensive survey with accurate species identification is required to develop effective management of the disease, particularly for resistance breeding.

scholarly journals Fungicide evaluation for control of powdery mildew, Leveillula taurica (Lev.) Arn., of peppers in Puerto Rico

1969 ◽  
Vol 75 (2) ◽  
pp. 119-123
Author(s):  
José A. Negrón ◽  
Rocío Rodríguez ◽  
Lucas Avilés
Keyword(s):  
Puerto Rico ◽  
Powdery Mildew ◽  
Capsicum Annuum ◽  
Disease Incidence ◽  
Causal Agent ◽  
Field Conditions ◽  
Copper Hydroxide ◽  
Leveillula Taurica

The effectiveness of benomyl, chlorothalonil, copper hydroxide, dinocap, sulfur and triadimefon for the control of the fungus Leveillula taurica, causal agent of the powdery mildew of peppers (Capsicum annuum), was evaluated under field conditions. Results from two experiments indicate that weekly applications of benomyl and triadimefon reduced disease incidence and increased pepper yield. In the first experiment, plots treated with triadimefon (0.35 L/ha) and benomyl (0.55 kg/ha) produced 20.2 and 17.2 kg fruit/plot, respectively, whereas the nontreated plots yielded 13,9 kg/plot. A similar trend but with higher yields was obtained in the second experiment. Treatments with triadimefon (0.70 L/ha) and benomyl (0.55 kg/ha) produced 41.0 and 41.3 kg of fruit/plot, respectively, as compared with the control treatments which yielded 29.0 kg/plot.

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.

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