scholarly journals First Report of Bleeding Canker Caused by Phytophthora cactorum on Horse Chestnut in Turkey

Plant Disease ◽  
2002 ◽  
Vol 86 (6) ◽  
pp. 697-697 ◽  
Author(s):  
M. Intini ◽  
M. Gurer ◽  
S. Ozturk
Keyword(s):  
The United States ◽  
Potato Dextrose Agar ◽  
Horse Chestnut ◽  
Phytophthora Cactorum ◽  
American Phytopathological Society ◽  
Healthy Horse ◽  
First Report ◽  
Bark Tissue ◽  
Pure Cultures ◽  
First Time

Bleeding canker on horse chestnut (Aesculus sp.), caused by Phytophthora cactorum (Lebert and Cohn) Schröeter previously has been reported from the United States and Europe (1). In August 2000, it was found for the first time in a park in Ankara Province, Turkey. Symptoms included sparse yellowish brown foliage with abnormally small leaves, and dark-stained spots or dark brown necrosis of the bark on the trunk and main branches, with or without a reddish black gummy exudate. P. cactorum was isolated from tissues taken from the margins of necrotic bark. Pure cultures were slightly radiate, fluffy but not dense, and had short aerial hyphae when grown on carrot agar, potato dextrose agar, or V8 agar. Sporangia were ovoid, strongly papillate, and averaged 35.6 μm in length and 26.8 μm in width (range: 24 to 55 μm × 19 to 40 μm). The isolates were homothallic with smooth-walled paragynous oogonia ranging from 23.5 to 34.5 μm in diameter. To satisfy Koch's postulates, mycelium of P. cactorum was placed under the bark of six branches of healthy horse chestnut. Noninoculated wounds served as controls. Four months later a reddish black gummy exudate was observed oozing from the inoculated wounds, and the bark tissue was necrotic for 3 to 4 cm around each infection. P. cactorum was successfully reisolated from the necrotic bark tissue. Control wounds remained healthy. To our knowledge, this is the first report of this disease on horse chestnut in Asia Minor. Reference: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996.

scholarly journals First Report of Albugo tragopogonis on Cultivated Sunflower in North America

Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 559-559
Author(s):  
T. J. Gulya ◽  
F. Viranyi ◽  
J. Appel ◽  
D. Jardine ◽  
H. F. Schwartz ◽  
...  
Keyword(s):  
North America ◽  
Pathogenic Fungi ◽  
The United States ◽  
Adjacent Area ◽  
American Phytopathological Society ◽  
First Report ◽  
White Rust ◽  
Production Area ◽  
Stem Lesions ◽  
First Time

White rust, caused by Albugo tragopogonis (Pers.) S.F. Gray, was observed on a few plants of both oilseed and confection sunflowers (Helianthus annuus L.) in northwestern Kansas (Cheyenne County) in 1992. The disease was observed again from 1993 to1995 in nine counties in western Kansas, with incidence per field ranging up to 35%. White rust was found only on late-planted fields in 1996 and 1997 and was not found at all from 1998 to 2001. White rust was also observed on cultivated and wild sunflower (H. annuus) for the first time in eastern Colorado (Kit Carson and Yuma counties) from 1994 to 1997, but was absent from 1998 to 2001. Leaf pustules on both cultivated and wild sunflowers were similar in appearance. Pustules were convex, chlorotic on the upper side of the leaf, and concave and dull white on the under side of the leaf. Pustules on cultivated sunflower were generally limited to three to six leaves in the middle of the plant and affected 10 to 40% of the leaf area. Sporangial dimensions fell within the reported dimensions for A. tragopogonis (2). In 1997, water-soaked lesions 1 to 2 cm long containing oospores of A. tragopogonia were observed on the lower to middle portions of stems of cultivated sunflower in western Kansas and the adjacent area of Colorado. Stem lesions were observed much less frequently than foliar lesions and only in 1997. Sporangia were not observed in stem lesions, nor were any other fungi isolated from these lesions. To our knowledge, this is the first report of white rust occurring on cultivated sunflower in any production area of North America; the disease has not been observed in the major U.S. sunflower production area of North Dakota, South Dakota, and Minnesota. Foliar white rust lesions generally have little economic impact on sunflower, but the presence of stem lesions is significant because stem lesions may lead to lodging (3). Lodging due to A. tragopogonia was not observed in either Kansas or Colorado. White rust has previously only been reported on wild H. annuus in Wisconsin and on perennial Helianthus spp. in Missouri and Illinois (1). References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN 1989. (2) K. G. Mukeri. Description of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK 1976. (2) P. S. van Wyk et al. Helia 22:83, 1995.

scholarly journals First Report of Sclerotinia Stem Rot Caused by Sclerotinia sclerotiorum on Hibiscus trionum in New York

Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 673-673
Author(s):  
J. Strauss ◽  
H. R. Dillard
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
The United States ◽  
Potato Dextrose Agar ◽  
Stem Rot ◽  
Stem Tissue ◽  
Sclerotinia Stem Rot ◽  
American Phytopathological Society ◽  
First Report ◽  
Hibiscus Trionum

Hibiscus trionum L. (Venice mallow) is an annual weed widely distributed in the United States. In September of 2008, Venice mallow plants with bleached stems and necrotic tissues were observed in a commercial field of cabbage (Brassica oleracea L. cv. Moreton) in Geneva, NY. White, cottony mycelium and dark sclerotia were readily found on the stems and in the stem pith. Cabbage plants in direct contact with diseased Venice mallow also displayed signs and symptoms of infection by Sclerotinia sclerotiorum (Lib.) de Bary. Sclerotia from within diseased Venice mallow stems were placed in 9-cm-diameter petri plates on potato dextrose agar amended with 0.1 g/liter each of chloramphenicol and streptomycin (ABPDA) and incubated at room temperature. In addition, diseased stem tissue was surface disinfested for 3 min in 0.525% sodium hypochlorite solution, rinsed for 3 min in sterile distilled water, and placed on ABPDA. After 5 days, hyphae from the colony margin were excised and transferred to potato dextrose agar (PDA) plates. Fungal cultures consisting of white mycelia and medium-sized (~4 mm), black, irregular sclerotia were consistently recovered and identified as S. sclerotiorum based on morphological characteristics (1). Pathogenicity of two isolates (one from a sclerotium and one from stem tissue) was determined by inoculating seven 43-day-old Venice mallow plants growing in greenhouse pots (65 mm in diameter). Mycelia plugs (7 mm in diameter) were excised from 2-day-old PDA cultures of each isolate and placed on the stems at the soil line. Seven control plants were inoculated with noncolonized PDA plugs. All plants were enclosed in plastic bags for 72 h and placed under shade in the greenhouse with temperatures from 20 to 38°C (average 27°C). Symptoms similar to those observed in the affected fields were evident within 2 days after inoculation, while control plants remained symptomless. S. sclerotiorum was successfully recovered from infected plant tissue, fulfilling Koch's postulates. The experiment was repeated with similar results. To our knowledge, this is the first report of Sclerotinia stem rot of Hibiscus trionum caused by S. sclerotiorum (2,3). References: (1) L. Buchwaldt. Sclerotinia White Mold. Page 43 in: Compendium of Brassica Diseases, 1st ed. S. R. Rimmer et al., eds. The American Phytopathological Society, St. Paul, MN, 2007. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, MN, 1989. (3) C. Wehlburg et al. Index of Plant Diseases in Florida. Fla Dep. Agric. Consum. Serv. Bull. 11, 1975.

scholarly journals First Report of Wisteria vein mosaic virus in Wisteria sinensis in the United States of America

2008 ◽  
Vol 9 (1) ◽  
pp. 42 ◽  
Author(s):  
Rayapati A. Naidu ◽  
Gandhi Karthikeyan
Keyword(s):  
United States ◽  
Mosaic Virus ◽  
United States Of America ◽  
The United States ◽  
Home Gardens ◽  
First Report ◽  
Woody Perennial ◽  
Wisteria Sinensis ◽  
First Time ◽  
Wisteria Vein Mosaic Virus

The ornamental Chinese wisteria (Wisteria sinensis) is a woody perennial grown for its flowering habit in home gardens and landscape settings. In this brief, the occurrence of Wisteria vein mosaic virus (WVMV) was reported for the first time in Chinese wisteria in the United States of America. Accepted for publication 18 June 2008. Published 18 August 2008.

scholarly journals First Report of Choke Disease Caused by Epichloë typhina on Orchardgrass (Dactylis glomerata) in China

Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 673-673 ◽  
Author(s):  
C. J. Li ◽  
Z. F. Wang ◽  
N. Chen ◽  
Z. B. Nan
Keyword(s):  
Dactylis Glomerata ◽  
The United States ◽  
Leaf Sheath ◽  
Climatic Conditions ◽  
Disease Spread ◽  
Willamette Valley ◽  
First Report ◽  
Epichloë Typhina ◽  
Pure Cultures ◽  
Choke Disease

Orchardgrass or cocksfoot (Dactylis glomerata L.) has been widely cultivated as a forage crop in many provinces of China (1). It is also a native perennial forage grass, which grows at the edge of forests, shrubs, and mountainous grasslands in Xinjiang and Sichuan (2). In September of 2007, signs of choke disease on orchardgrass were observed in a native grassland under birch woodland near Altai City, Xinjiang, China. Stromata, which formed on culms of diseased grass, enclosing the inflorescence and leaf sheath, were 4.5 to 5.5 mm long, smooth or wrinkled, white and later becoming yellowish or yellow, tuberculate, dry, and covered with perithecia. Inflorescences surrounded by fungal stromata were choked and failed to mature, thus restricting seed production. Pure cultures were obtained by directly scraping stromata from the surface and incubating it on antibiotic potato dextrose agar (PDA). The colonies were cottony, white on the upper surface, and white to yellow on the reverse. The growth rate was 13 to 21 mm per week at 25°C on PDA. Conidia were hyaline, lunate to reniform, and measured 4.1 ± 0.5 × 2.2 ± 0.5 μm. They accumulated in small globose heads at the tips of conidiogenous cells and were produced singly on conidiophores of 13 to 33 μm long and 2.7 to 4.1 μm wide at the base. Internal transcribed spacer (ITS) sequence by BLAST search had 99% similarity with an Epichloë typhina isolate of orchardgrass in Spain (GenBank Accession No. AM262420.1). Cultural characteristics, microscopic examination, and phylogenetic analysis showed that this choke disease on D. glomerata was caused by the fungus E. typhina (Pers.) Tul. & C. Tul. as described by White (4). To our knowledge, this is the first report of E. typhina causing choke disease on orchardgrass in China. The pathogen has been identified in France, England, Germany, Sweden, Switzerland, and the United States (3,4) with the same symptoms as those reported here. In 1997, choke disease was found in 70% of the fields in the Willamette Valley of Oregon, with disease incidences ranging from 0.05 to 28%. It was predicted to increase and spread under the prevailing climatic conditions (3). This new disease report is to provide observational and diagnostic information to help with recognition and prevention of disease spread in orchardgrass cultivation regions of China. References: (1) X. R. Chao et al. Shandong Agric. Sci. 1:7, 2005. (2) S. X. Jia, ed. China Forage Plant Flora. China Agriculture Press, Beijing, 1987. (3) W. F. Pfender and S. C. Alderman. Plant Dis. 83:754, 1999. (4) J. W. White. Mycologia 85:444, 1993.

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

Plant Disease ◽  
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.

scholarly journals First Report of Sclerotinia sclerotiorum on Common Ragweed (Ambrosia artemisiifolia) in Europe

Plant Disease ◽  
1999 ◽  
Vol 83 (3) ◽  
pp. 302-302 ◽  
Author(s):  
Gy. Bohár ◽  
L. Kiss
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Aerial Mycelium ◽  
The United States ◽  
Ambrosia Artemisiifolia ◽  
American Phytopathological Society ◽  
Common Ragweed ◽  
First Report ◽  
Sclerotinia Rot ◽  
Stem Lesions ◽  
Test Plants

Common ragweed (Ambrosia artemisiifolia L.) is reported as a host of Sclerotinia sclerotiorum (Lib.) de Bary in North America (2,4), but not in Europe. A Hungarian survey of fungal diseases of ragweed in 1994 did not find sclerotinia rot of common ragweed (A. artemisiifolia var. elatior (L.) Descourt.) (1). In autumn 1998, mature ragweed plants, 1 to 1.5 m tall, were collected from the borders of four sunflower (Helianthus annuus L.) fields in which sclerotinia rot of sunflower was frequently observed during the season, and also from six other roadside sites in Hungary. Ragweed plants exhibiting symptoms characteristic of sclerotinia rot, i.e., wilting foliage and light brown, dry lesions on the stems, were found only near two sunflower fields. Black, round to irregular or oblong sclerotia were also observed on the infected ragweed plants both externally on the stem lesions and internally, in the pith cavity. Sclerotia measured up to 5 mm in diameter and were 5 to 14 mm long. After isolation on potato dextrose agar, the pathogen produced abundant aerial mycelium and large sclerotia characteristic of S. sclerotiorum. To confirm pathogenicity, potted seedlings and mature plants of ragweed were inoculated in the greenhouse with autoclaved wheat grains colonized with mycelia of S. sclerotiorum placed 0.5 to 1 cm from the collar of the test plants. Seedlings were killed in 2 to 3 days while mature plants wilted after 5 to 6 days. In a field test, six mature plants were inoculated by attaching mycelial disks to their stems with Parafilm. These plants wilted 12 to 14 days after inoculation. The pathogen was reisolated from all diseased plants. This is the first report of S. sclerotiorum on common ragweed in Europe. Nonsclerotial mutants of the fungus (3) are being produced to be tested as potential biocontrol agents of common ragweed, which has become not only the most widespread, but also the most important allergenic plant species in Hungary since the early 1990s. References: (1) Gy. Bohár and L. Vajna. Nōvényvédelem 32:527, 1996. (2) G. J. Boland and R. Hall. Can. J. Plant Pathol. 16:93, 1994. (3) G. J. Boland and E. A. Smith. Phytopathology 81:766, 1991.(4) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.

scholarly journals First Report of Powdery Mildew, Caused by an Oidium sp., on Poinsettia in California

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 128-128 ◽  
Author(s):  
S. T. Koike ◽  
G. S. Saenz
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Pacific Northwest ◽  
The United States ◽  
Euphorbia Pulcherrima ◽  
American Phytopathological Society ◽  
First Report ◽  
The Pacific ◽  
Uninoculated Control ◽  
Alternative Identification

In December 1996 and January 1997, powdery mildew was observed on potted poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) plants in Monterey County, CA. Mycelia were observed on stems, petioles, mature and immature leaves, and bracts. Severely diseased leaves became twisted and bent and senesced prematurely. The white mycelia were conspicuous, epiphytic, and amphigenous; hyphae measured 4.6 to 6.9 μm in diameter. Growth initially was in patches but eventually became effused. Appressoria were slightly lobed to lobed and sometimes opposite. Conidiophore foot cells were cylindrical, sometimes bent at the base, and slightly flexuous to flexuous. Foot cells measured 30.0 to 46.2 μm × 5.8 to 6.9 μm and were followed by one to two shorter cells. Conidia were cylindrical to slightly doliform and measured 25.4 to 32.3 μm × 11.6 to 18.5 μm. The length-to-width ratios of conidia generally were greater than 2.0. Conidia were produced singly, placing the fungus in the Pseudoidium-type powdery mildew group. Conidia germinated at the ends, and no fibrosin bodies were observed. Cleistothecia were not found. The fungus was identified as an Oidium species. Pathogenicity was demonstrated by gently pressing infected leaves having abundant sporulation onto leaves of potted poinsettia plants (cvs. Freedom Red, Peter Star Marble, and Nutcracker White), incubating the plants in a moist chamber for 48 h, and then maintaining plants in a greenhouse. After 12 to 14 days, powdery mildew colonies developed on the inoculated plants, and the pathogen was morphologically identical to the original isolates. Uninoculated control plants did not develop powdery mildew. This is the first report of powdery mildew on poinsettia in California. This fungus appears similar to Microsphaera euphorbiae but has longer, slightly flexuous foot cells that do not match the description for M. euphorbiae (1,2). An alternative identification would be Erysiphe euphorbiae; however, there are no available mitosporic descriptions for morphological comparisons (1,2). In the United States, powdery mildew of poinsettia previously has been reported in various states in the Pacific Northwest, Midwest, and Northeast. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.

scholarly journals First Report of Seedling Blight Caused by Sclerotium rolfsii on Wheat in Oklahoma

Plant Disease ◽  
2006 ◽  
Vol 90 (5) ◽  
pp. 686-686 ◽  
Author(s):  
V. Choppakatla ◽  
R. M. Hunger ◽  
H. A. Melouk
Keyword(s):  
Filter Paper ◽  
Sclerotium Rolfsii ◽  
Significant Risk ◽  
Triticum Aestivum L ◽  
The United States ◽  
Damping Off ◽  
Wheat Seedlings ◽  
First Report ◽  
Significant Difference ◽  
Pure Cultures

Wheat (Triticum aestivum L.) is an important crop in Oklahoma and throughout the Central Plains of the United States. The soilborne fungus, Sclerotium rolfsii, is a major pathogen on peanut (Arachis hypogaea L.) but is not known to cause major damage on wheat. During September of 1998, damping-off and rotting of young wheat seedlings were observed in breeder plots in Payne County, OK. The occurrence of symptoms was sporadic with an estimated stand reduction of 10 to 15%. Symptomatic plants were collected from the field and brought to the laboratory. Sclerotia-like bodies from the symptomatic plants were surface disinfested in aqueous 1% NaOCl for 2 min and allowed to germinate at 25 ± 2°C on sterile filter paper moistened with a 1% aqueous solution of methanol. Aerial mycelia from germinating sclerotia were transferred to potato dextrose agar amended with 100 ppm of streptomycin (SPDA) to obtain pure cultures. Pure cultures had coarse, white mycelium distinctive of S. rolfsii and produced very small (0.05 to 0.1 mm), abundant, round, brown sclerotia on the surface of the medium after 15 days of incubation. Pathogenicity was tested on three hard red winter wheat cultivars commonly grown in Oklahoma (Jagger, 2137, and 2174). Four plants of each cultivar were inoculated at the two-leaf stage (Feekes' scale stage 1) by placing a 0.5-cm agar disk removed from a 3-day-old culture onto a 1-cm diameter filter paper that was then pressed to the base of the shoot. Noninoculated plants were used as a control. After inoculation, pots were covered with polyethylene sheets to maintain 95 to 100% relative humidity and incubated at 25 ± 2°C in the greenhouse. Lesions were initially superficial, yellowish, and water soaked. Lesions expanded and resulted in damping-off of seedlings. Noninoculated plants were free of disease and remained healthy. No significant difference (P ≤ 0.05) in disease severity was observed among the cultivars. To fulfill Koch's postulates, the fungus was reisolated onto SPDA where it had the same characteristics as the initial culture. To our knowledge, this is the first report of S. rolfsii on wheat in Oklahoma. Even though S. rolfsii is not expected to pose a significant risk to wheat production, infection of wheat may enhance survival of S. rolfsii and facilitate infection and losses in a following peanut crop. This is especially important in certain areas of Oklahoma where a wheat-peanut rotation is occasionally practiced.

scholarly journals First Report of Leaf Spot Caused by Phyllosticta yuccae on Yucca filamentosa in Brazil

Plant Disease ◽  
2013 ◽  
Vol 97 (9) ◽  
pp. 1257-1257 ◽  
Author(s):  
A. D. A. Silva ◽  
D. B. Pinho ◽  
B. T. Hora Junior ◽  
O. L. Pereira
Keyword(s):  
Leaf Spot ◽  
Its Region ◽  
The United States ◽  
Leaf Spot Disease ◽  
Infected Leaf ◽  
Single Spore ◽  
First Report ◽  
Leaf Spots ◽  
Slime Layer ◽  
Pure Cultures

Yucca filamentosa L. (Agavaceae), commonly known as Adam's needle, is known in Brazil as “agulha-de-adão.” It is an ornamental garden plant with medicinal properties (4). In 2010, 100% of Y. filamentosa seedlings and plants were observed with a severe leaf spot disease in two ornamental nurseries located in the municipality of Viçosa, Minas Gerais, Brazil. Initially, lesions were dark brown, elliptical, and scattered, and later became grayish at the center with a reddish brown margin, irregular and coalescent. Infected leaf samples were deposited in the herbarium at the Universidade Federal de Viçosa (Accession Nos. VIC32054 and VIC32055). A fungus was isolated from the leaf spots and single-spore pure cultures were obtained on potato dextrose agar (PDA). The sporulating single-spore cultures were deposited at the Coleção de Culturas de Fungos Fitopatogênicos “Prof. Maria Menezes” (CMM 1843 and CMM 1844). On the leaf, the fungus produced pycnidial conidiomata that were scattered or gregarious, usually epiphyllous, immersed, dark brown, unilocular, subglobose, and 95 to 158 × 108 to 175 μm, with a minute, subcircular ostiole. Conidiogenous cells were blastic, hyaline, conoidal, or short cylindrical. Conidia were aseptate, hyaline, smooth walled, coarsely granular, broadly ellipsoidal to subglobose or obovate, usually broadly rounded at both ends, occasionally truncate at the base or indented slightly at the apex, and 7.5 to 13.5 × 6 to 10 μm. Conidia were also surrounded by a slime layer, usually with a hyaline, flexuous, narrowly conoidal or cylindrical, mucilaginous apical appendage that was 10 to 16 μm long. Spermatia were hyaline, dumbbell shaped to cylindrical, both ends bluntly rounded, and 3 to 5 × 1 to 1.5 μm. These characteristics matched well with the description of Phyllosticta yuccae Bissett (1). To confirm this identification, DNA was extracted using a Wizard Genomic DNA Purification Kit and amplified using primers ITS1 and ITS4 (2) for the ITS region (GenBank Accession Nos. JX227945 and JX227946) and EF1-F and EF2-R (3) for the TEF-1α (JX227947 and JX227948). The sequencing was performed by Macrogen, South Korea. The ITS sequence matched sequence No. JN692541, P. yuccae, with 100% identity. To confirm Koch's postulates, four leaves of Y. filamentosa (five plants) were inoculated with 6-mm-diameter plugs from a 7-day-old culture growing on PDA. The leaves were covered with plastic sack and plants were maintained at 25°C. In a similar manner, fungus-free PDA plugs were placed on five control plants. Symptoms were consistently similar to those initially observed in the nurseries and all plants developed leaf spots by 15 days after inoculation. P. yuccae was successfully reisolated from the symptomatic tissue and control plants remained symptomless. P. yuccae has been previously reported in Canada, the Dominican Republic, Guatemala, Iran, and the United States of America. To our knowledge, this is the first report of P. yuccae causing disease in Y. filamentosa in Brazil and it may become a serious problem for the nurseries, due to the severity of the disease and the lack of chemical products to control this pathogen. References: (1) J. Bissett. Can. J. Bot. 64:1720, 1986. (2) M. A. Innis et al. PCR Protocols: A guide to methods and applications. Academic Press, 1990. (3) Jacobs et al. Mycol. Res. 108:411, 2004. (4) H. Lorenzi and H. M. Souza. Plantas Ornamentais no Brasil. Instituto Plantarum, 2001.

Metabolites of Cercospora arachidicola. The first report of long-chain fatty aldehydes from a fungus

1985 ◽  
Vol 31 (2) ◽  
pp. 129-133 ◽  
Author(s):  
A. Stoessl
Keyword(s):  
Potato Dextrose Agar ◽  
Cercospora Arachidicola ◽  
First Report ◽  
Analytical Procedures ◽  
Fatty Aldehydes ◽  
First Time ◽  
Long Chain

Long-chain fatty aldehydes are reported for the first time as fungal products. They were isolated from potato dextrose agar cultures of Cercospora arachidicola as mixtures that were found by analytical procedures to consist predominantly of penta-and heptadecanal and heptadec-8-enal. Small to trace amounts of tetra-, hexa-, and nonadecanal, tetra- and pentadec-2-, and pentadec-6-enal, and heptadec-8,11 -dienal were also present, together with a mono- and a di-unsaturated C16 aldehyde. Brassicasterol was also isolated.

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