First Report on Pink Rot of Sunflower (Helianthus annuus) Caused by Trichothecium roseum in Korea

Widespread infection of charcoal rot was observed in a commercial sunflower field in Minnesota in September 2009. Based on morphology, isolates were identified as F. sporotrichioides and F. acuminatum. Koch's postulates demonstrated pathogencity of both species. To our knowledge, this is the first report of F. sporotrichoides and F. acuminatum causing disease on Helianthus annuus L. in the United States. Accepted for publication 23 August 2010. Published 15 September 2010.

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First Detailed Report of Trichothecium roseum Causing Post-harvest Pink Rot of Avocado in Israel

Plant Disease ◽

10.1094/pdis-08-15-0914-pdn ◽

2016 ◽

Vol 100 (4) ◽

pp. 856-856 ◽

Cited By ~ 1

Author(s):

G. Sharma ◽

M. Maymon ◽

S. Freeman

Keyword(s):

Detailed Report ◽

Post Harvest ◽

Pink Rot ◽

Trichothecium Roseum

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First Report of Trichothecium roseum Causing Trunk Disease of Acer buergerianum in China

Plant Disease ◽

10.1094/pdis-05-15-0595-pdn ◽

2015 ◽

Vol 99 (12) ◽

pp. 1864-1864 ◽

Cited By ~ 1

Author(s):

Q. Tang ◽

L. Fang ◽

Y. J. Liu

Keyword(s):

First Report ◽

Trichothecium Roseum ◽

Trunk Disease

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First Report of Trichothecium roseum Causing Trunk Disease of Ginkgo biloba in China

Plant Disease ◽

10.1094/pdis-09-15-1051-pdn ◽

2016 ◽

Vol 100 (6) ◽

pp. 1234

Author(s):

Y. P. Li ◽

L. H. Zhang ◽

Q. Tang ◽

Y. J. Liu

Keyword(s):

Ginkgo Biloba ◽

First Report ◽

Trichothecium Roseum ◽

Trunk Disease

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First Report of Stem Rot and Wilt of Sunflower Caused by Sclerotinia minor in Spain

Plant Disease ◽

10.1094/pdis.2002.86.6.697d ◽

2002 ◽

Vol 86 (6) ◽

pp. 697-697

Author(s):

M. L. Molinero-Ruiz ◽

J. M. Melero-Vara

Keyword(s):

Helianthus Annuus ◽

Root Rot ◽

Mycelial Growth ◽

Disease Incidence ◽

Potato Dextrose Agar ◽

Stem Rot ◽

Sclerotinia Minor ◽

Stem Base ◽

First Report ◽

White Mycelium

In 2001, sunflower (Helianthus annuus L.) plants with symptoms of stem and root rot and wilt were observed in Soria, Spain. Light brown, water-soaked lesions developed on the collar of infected plants and extended along the stem, affecting the pith and causing early and sudden wilt. White mycelium and sclerotia (0.5 to 2 mm long) formed in the pith of stems. The sclerotia were disinfested in NaClO (10% vol/vol) for 1 min, transferred to potato dextrose agar (PDA), and incubated at 20°C. The fungus consistently obtained was identified as Sclerotinia minor Jagger (1). Pathogenicity was confirmed in a greenhouse experiment (15 to 25°C, 13 h light). Seven-week-old plants of six genotypes of sunflower (‘Peredovik’, HA89, HA821, HA61, RHA274, and HA337) were inoculated by placing one PDA disk with active mycelial growth adjacent to each basal stem just below the soil line and covering it with peat/sand/silt (2:2:1, vol/vol). Six plants of each genotype were inoculated without wounding, and another six were inoculated immediately after stem base wounding with a scalpel; six wounded and uninoculated plants were used as controls. First symptoms (wilting) appeared 4 days after inoculation in all genotypes. Two weeks after inoculation, the percentage of dead plants ranged from 33 to 92% (depending on cultivar), white mycelium was observed at the base of affected plants, and sclerotia were present in the pith of diseased plants. There was no effect of plant wounding on disease incidence or severity, and the fungus was reisolated from inoculated plants. To our knowledge, this is the first report of S. minor in Spain. Reference: (1) L. M. Kohn. Mycotaxon IX 2:365, 1979.

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First Report of Diaporthe gulyae Causing Phomopsis Stem Canker of Sunflower (Helianthus annuus) in Argentina

Plant Disease ◽

10.1094/pdis-10-18-1907-pdn ◽

2019 ◽

Vol 103 (7) ◽

pp. 1769-1769

Author(s):

M. F. Mancebo ◽

M. E. Bazzalo ◽

R. J. Reid ◽

B. Kontz ◽

F. M. Mathew

Keyword(s):

Helianthus Annuus ◽

Stem Canker ◽

First Report

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A Post-Harvest Pink Rot of Pepper Caused by Trichothecium roseum in China

Plant Disease ◽

10.1094/pdis-02-16-0246-pdn ◽

2016 ◽

Vol 100 (10) ◽

pp. 2164-2164 ◽

Cited By ~ 1

Author(s):

S. H. Lin ◽

J. H. Wang ◽

A. B. Wu

Keyword(s):

Post Harvest ◽

Pink Rot ◽

Trichothecium Roseum

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First Report of Phomopsis Stem Canker of Sunflower (Helianthus annuus) Caused by Diaporthe gulyae in Canada

Plant Disease ◽

10.1094/pdis-08-14-0858-pdn ◽

2015 ◽

Vol 99 (1) ◽

pp. 160-160 ◽

Cited By ~ 7

Author(s):

F. M. Mathew ◽

K. Y. Rashid ◽

T. J. Gulya ◽

S. G. Markell

Keyword(s):

Helianthus Annuus ◽

Disease Severity ◽

Its Region ◽

Stem Canker ◽

Stem Length ◽

Lesion Length ◽

First Report ◽

Leaf Petiole ◽

Mycelial Plug ◽

Blastn Analysis

During September 2012, Phomopsis stem canker was observed on sunflowers (Helianthus annuus L.) in a production field during seed filling with an average incidence of 15% in Morden, Manitoba (approximately 49°11′N and 98°09′W). The infected plants had elongated, brown-black lesions surrounding the leaf petiole, with numerous pycnidia, pith damage, and mid-stem lodging. Twenty sunflower plants were randomly sampled from the field. Isolations were made from the margins of the necrotic stems lesions by plating small pieces (5 mm) on potato dextrose agar (PDA) amended with 0.02% streptomycin sulfate. Plates were incubated at 25°C for 14 days under a 12-h photoperiod, and hyphal tips of white to grey colonies were transferred to PDA. Five isolates producing black pycnidia (occasionally with ostiolate beaks) and alpha conidia were tentatively identified as a Diaporthe sp. Alpha conidia were ellipsoidal, hyaline, and 6.5 to 8.5 × 2.5 to 3.5 μm. DNA was extracted from the mycelium of five isolates, and the ITS region was amplified and sequenced using primers ITS5 and ITS4 (4). BLASTn analysis of the 600-bp fragment (GenBank Accession Nos. KM391960 to KM391964) showed that the best match was Phomopsis sp. AJY-2011a strain T12505G (Diaporthe gulyae R.G. Shivas, S.M. Thompson & A.J. Young [3], Accession No. JF431299) from H. annuus with identities = 540/540 (100%) and gaps = 0/540 (0%). The five D. gulyae isolates were tested for pathogenicity on a sunflower confection inbred cv. HA 288 using the stem-wound method (2). Four-week-old sunflower plants (10 plants per isolate) were inoculated by wounding the stems on the second internode with a micropipette tip and placing a Diaporthe-infested mycelial plug on the wound. All plugs were attached to the wound with Parafilm. The pots were placed on the greenhouse benches at 25°C under a 16-h light/dark cycle. At 3 days after inoculation, dark brown lesions were observed on the stems extending upward from the inoculation site. Stem and leaves wilted, causing plant death 14 days after inoculation. Disease severity was calculated as a percentage of stem lesion (lesion length/stem length × 100%) at 14 days after inoculation. Significant differences (P ≤ 0.05) in disease severity were observed among D. gulyae isolates, which ranged from 34.9 to 100.0% (n = 5). Ten control plants similarly treated with sterile PDA plugs did not display symptoms. To complete Koch's postulates, D. gulyae was re-isolated from the inoculated stems, and the pathogen's identity was confirmed via sequencing of the ITS regions using primers ITS5 and ITS4 (4). The pathogen was not isolated from the control plants. D. gulyae was first reported as a pathogen on H. annuus in Australia and United States in 2011 (1,3). The pathogen was determined to be as or more aggressive than the other causal agents of Phomopsis stem canker (2,3), and its identification in both countries was circumstantially associated with increased incidence and yield loss in commercial production fields (1,3). In Canada, Phomopsis stem canker has been observed in sunflower fields over the last 10 years at low incidences, especially in years with above-normal temperatures during the sunflower growing season; however, the causal agent was not confirmed. To the best of our knowledge, this is the first report of D. gulyae causing Phomopsis stem canker on sunflowers in Canada. Since there is currently no known resistance to D. gulyae in sunflower, this newly discovered pathogen may become a threat to sunflower production in Canada. References: (1) F. Mathew et al. Phytopathology 101:S115, 2011. (2) F. Mathew et al. Phytopathology 103:S2.91, 2013. (3) S. M. Thompson et al. Persoonia 27:80, 2011. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

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First Report of Diaporthe phaseolorum on Sunflower (Helianthus annuus) in Croatia

Plant Disease ◽

10.1094/pdis-93-10-1074c ◽

2009 ◽

Vol 93 (10) ◽

pp. 1074-1074 ◽

Cited By ~ 2

Author(s):

K. Vrandecic ◽

J. Cosic ◽

D. Jurkovic ◽

T. Duvnjak ◽

L. Riccioni

Keyword(s):

New York ◽

Helianthus Annuus ◽

Morphological Characteristics ◽

Aerial Mycelium ◽

Petri Dish ◽

Aluminum Foil ◽

Pathogenic Fungi ◽

Fungal Species ◽

Universal Primers ◽

First Report

Sunflower (Helianthus annuus L.) is a crop that is grown worldwide for the production of edible oil. In Croatia, it has considerable economic significance. From 2004 to 2007, sunflower stems showed light-to-dark brown lesions of different sizes and shapes. The lesions were observed for the presence of pycnidia in affected areas. Isolations from infected tissue on potato dextrose agar (PDA) yielded in two fungal species. One, which was isolated in most cases, was the well known sunflower pathogen Diaporthe helianthi Munt. Cvet. Morphological characteristics, stromata pattern, formation of alpha and beta conidia, and ascostromata characteristic of the other isolated fungus matched the description of D. phaseolorum (Cooke & Ellis) Sacc. (2). D. phaseolorum frequency was 5%. On PDA, the fungus formed white, floccose, aerial mycelium that filled a petri dish (9 cm) in 6 days. D. phaseolorum produces conidiomata in black stromatic structures, which consist of pycnidia with alpha and beta conidia. The alpha conidia were unicellular, hyaline, ellipsoidal to fusiform, and 5.6 to 10.0 × 1.9 to 4.8 μm. The beta conidia were hyaline, elongated, filiform, straight, curved at one or both ends, and 11.7 to 27.6 × 0.7 to 2.0 μm. After 50 days, perithecia were formed. Asci were clavate and 27.64 to 40.1 × 5.70 to 8.2 μm. Eight ascospores formed within asci. Ascospores were two-celled, elliptic, hyaline, and slightly constricted at the septa, and 8.93 to 13.5 × 2.1 to 4.0 μm. Amplification and sequencing of the internal transcribed spacer (ITS) rDNA region were performed with ITS4 and ITS5 universal primers (3) on two isolates (Su9 and Su10) and data were deposited in GenBank (Accession Nos. GQ149763 and GQ149764). Comparison of sequences available in GenBank revealed that the ITS sequence was identical to D. phaseolorum found on Stokesia laevis Hill (Greene) (U11323/U11373) and identical to the strain CBS 116020 isolated from Aster exilis Elliot. (AY745018). On the basis of the obtained results of morphological characteristics and molecular approaches, the pathogen was identified as D. phaseolorum. Pathogenicity evaluation consisted of artificial infections on field-grown sunflower plants at the full button stage as described by Bertrand and Tourvielle (1). A leaf test was done by placing a mycelial plug of 5 × 5 mm from a cork borer of two isolates (Su9 and Su10) on the tip of the main vein. The inoculation site was covered with moistened, cotton wool and wrapped in aluminum foil to prevent the inoculum from drying out. Ten plants of each of the four replications were inoculated. Control plants were inoculated with pure PDA plugs. Lesions of 12 to 40 mm long were observed on the sunflower leaf 10 days after inoculation. Control plants did not develop symptoms. The pathogen was reisolated from the infected plants. To our knowledge, this is the first report of the finding of D. phaseolorum on sunflower in Croatia and we have no literature data about the occurrence of this fungus on sunflower in the world. References: (1) F. Bertrand and D. Tourvielle. Inf. Tech. CETIOM 98:12,1972. (2) E. Punithalingma and P. Holliday. No. 336 in: Descriptions of Pathogenic Fungi and Bacteria. CMI/CAB, Kew, Surrey, England, 1972. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, Inc., New York, 1990.

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First Report of Puccinia xanthii on Sunflower in North America

Plant Disease ◽

10.1094/pdis.2002.86.5.564a ◽

2002 ◽

Vol 86 (5) ◽

pp. 564-564 ◽

Cited By ~ 3

Author(s):

T. J. Gulya ◽

L. D. Charlet

Keyword(s):

South Africa ◽

North America ◽

Helianthus Annuus ◽

Leaf Surface ◽

Rust Fungi ◽

First Report ◽

Abaxial Leaf Surface ◽

University Of Arizona ◽

Plant Pathol ◽

Size And Morphology

Puccinia xanthii Schwein., commonly known as cocklebur rust, is circumglobal on species of Xanthium and Ambrosia. This microcyclic rust has only been observed on oilseed sunflower (Helianthus annuus L.) in Australia (1) and on ornamental sunflowers in South Africa (4). In September 1999, large (4 to 10 mm), raised, chlorotic pustules were observed on the adaxial leaf surface of oilseed sunflower plants (Dekalb 3790) near Hettinger, ND. Telia were associated with the pustules on the abaxial leaf surface. No cocklebur (X. strumarium L.) plants were found in the field, but rust-infected cocklebur plants were collected several kilometers away. Approximately 10% of sunflower plants in the field were affected, and generally only one or two pustules were observed on one or two leaves per plant. In contrast, numerous leaves of cockleur plants were infected with 12 or more pustules. Teliospores from sunflower were brown, two-celled, and averaged 49 × 17 μm, with a distinctly thicker wall at the spore apex and a persistent pedicel averaging 40 μm long. Teliospores from cocklebur were morphologically similar to those from sunflower and averaged 46 × 16 μm. Size and morphology of teliospores from both hosts fit the description of P. xanthii (2). P. xanthii can be distinguished easily from the ubiquitous P. helianthi Schwein. because the latter has smaller telia (1 to 2 mm diameter) and produces wider teliospores (21 to 30 μm diameter). P. xanthii was not found in surveys of 20 other sunflower fields in southwestern North Dakota nor in 45 fields in eastern ND in 1999, nor was P. xanthii found in this or any other sunflower field in 2000 or 2001. To our knowledge, this is the first report of P. xanthii on cultivated or wild sunflower in North America. The relatively few pustules observed on oilseed sunflower agree with the observation that oilseed sunflowers are much less susceptible to P. xanthii (3) than Xanthium spp. References: (1) J. L. Alcorn and J. K. Kochman. Austral. Plant Pathol. Soc. Newsl. 5:33, 1976. (2) G. B. Cummins. Rust Fungi on Legumes and Composites in North America. University of Arizona Press, Tucson, 1978. (3) J. B. Morin et al. Can. J. Bot. 71:959, 1993. (4) Z. A. Pretorius et al. Plant Dis. 84:924, 2000.

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