First Report of Southern Blight Caused by Sclerotium rolfsii on Laurustinus

Laurustinus (Viburnum tinus L.), native to the Mediterranean Region, is an evergreen shrub commonly used as a specimen shrub or small tree or used in border plantings. During August 2003, a blight occurred on 2-year-old-plants of laurustinus growing in pots in a nursery in eastern Sicily (Italy). Disease incidence ranged from 2 to 5% across the field. Symptoms included 3 to 4 cm long lesions and the development of white mycelial strands and brown, 1.0 to 1.8 mm, nearly spherical sclerotia on the crown of plants at the soil line that are typical of Sclerotium rolfsii Sacc. The foliage of infected plants wilted, followed by a sudden collapse of the plant. The fungus was consistently isolated on acidified potato dextrose agar (PDA) (pH 4.5) by plating symptomatic tissues that were surface disinfested (1.2% NaOCl) for 1 min. and rinsed in sterile water. Pathogenicity tests were performed by sprinkling 50 sclerotia, obtained from infected oat kernels (2), on the soil surface around the collar of each of 10 healthy, potted 1-year-old plants of laurustinus. Five of the plants were previously wounded on the crown 1.5 cm above or below the soil line with a sterile needle. Five noninoculated plants served as controls. All plants were maintained at 25 ± 2°C and enclosed for 72 hr in polyethylene bags (90 to 95% relative humidity). Blight symptoms similar to those seen in nursery were observed on inoculated plants 20 to 25 days after inoculation, while no symptoms developed on control plants. Koch's postulates were fulfilled by reisolation of the fungus on acidified PDA from all infected laurustinus plants. S. rolfsii was previously recorded on Prague viburnum (Viburnum × pragense L.) as the causal agent of southern blight (1). To our knowledge, this is the first report of southern blight caused by S. rolfsii on laurustinus. References: (1) A. Hagan. Southern blight on flowers, shrubs, and trees. On-line publication ANR-1157. Alabama A & M, and Auburn University ( www.aces.edu/dept/extcomm/publications/html ). (2) R. Rodriguez-Kabana et al. Plant Dis. Rep. 59:5, 1975.

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First Report of Southern Blight Caused by Sclerotium rolfsii on St.-John's-Wort

Plant Disease ◽

10.1094/pdis.1999.83.7.696c ◽

1999 ◽

Vol 83 (7) ◽

pp. 696-696 ◽

Cited By ~ 2

Author(s):

A. P. Keinath ◽

J. W. Rushing ◽

R. J. Dufault

Keyword(s):

Sclerotium Rolfsii ◽

Soil Surface ◽

The United States ◽

Pathogenicity Test ◽

First Report ◽

Southern Blight ◽

St John’S Wort ◽

St John's Wort ◽

Pathogenicity Tests ◽

Hypericum Perforatum L

Interest in commercial production of common St.-John's-wort (Hypericum perforatum L.), an herb that is dried, processed, and used as an anti-depressant medication, is increasing. In August 1998, St.-John's-wort growing in the field at Charleston, SC, showed blight symptoms. Leaves on prostrate branches turned reddish-yellow, then brown, and then abscised. As the disease progressed, branches and approximately 10% of the plants were killed. Coarse, white mycelia were present on the bases of dead branches. Segments cut from symptomatic branches were disinfested in 0.5% sodium hypochlorite and placed on potato dextrose agar (PDA) at 25°C. Sclerotium rolfsii Sacc. was isolated from one of 12 branches with discolored leaves and six of six dead branches. For pathogenicity tests, sclerotia were harvested from 6-week-old cultures on PDA. Ten-week-old St.-John's-wort plants, growing in potting mix in 10-cm pots, were inoculated by placing four sclerotia on the soil surface 1 to 1.5 cm from the main stem of each plant. Plants were grown in a greenhouse at 90% relative humidity and 25 to 35°C. Single blighted branches were observed on three plants 12 days after inoculation and all plants were blighted 28 days after inoculation. S. rolfsii was recovered from 10 and 9 of 10 plants inoculated with isolates of S. rolfsii from St.-John's-wort and tomato, respectively. All 10 noninoculated plants remained symptomless. The pathogenicity test was repeated and the results were similar. This is the first report of S. rolfsii causing Southern blight on St.-John's-wort in the United States.

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First Report of Southern Blight Caused by Sclerotium rolfsii on Lily in China

Plant Disease ◽

10.1094/pd-91-0109c ◽

2007 ◽

Vol 91 (1) ◽

pp. 109-109 ◽

Cited By ~ 3

Author(s):

X. M. Yang ◽

J. H. Wang ◽

S. P. Qu ◽

L. H. Wang

Keyword(s):

Disease Incidence ◽

Sclerotium Rolfsii ◽

First Report ◽

Southern Blight ◽

Inoculation Trial ◽

Leaf Yellowing ◽

White Mycelium ◽

Bulb Rot ◽

Oriental Lily ◽

Wheat Kernels

Lily (Lilium spp.) is an economically important cut flower cultivated in China. The soilborne fungus, Sclerotium rolfsii, is a major pathogen on many plants. During July 2005, severe basal stem rot and bulb rot symptoms were observed on an oriental lily cultivar (Sorbonne) in some commercial fields in northern Kunming (China). Disease incidence ranged from 20 to 30% across fields. Leaves of infected plants were chlorotic initially. As the disease progressed, stems and bulbs rotted and plants wilted. In the presence of abundant moisture, a white mycelium occurred on infected tissues. White or light-to-dark brown sclerotia (1 to 3 mm in diameter) developed from mycelium. Fungal isolates from infected bulbs grown on potato dextrose agar (PDA) produced white mycelia and 1- to 2-mm diameter dark brown sclerotia. Sclerotia were nearly round with smooth surfaces and distributed over the entire colony. Isolates were identified as S. rolfsii on the basis of mycelial characteristics and color, size, and distribution of sclerotia. Pathogenicity was tested in the greenhouse on oriental lily cv. Sorbonne grown in pots (1 plant per pot, five replicates). Inoculum that consisted of 1 g per pot of wheat kernels infested with mycelium and sclerotia was placed at the base of each inoculated plant. Five noninoculated plants served as controls. The inoculation trial was repeated once. After inoculation, all plants were covered with a polyethylene bag for 72 h and kept at temperatures ranging between 25 and 27°C. Inoculated plants developed symptoms of leaf yellowing within 12 days, soon followed by the appearance of white mycelium and sclerotia, and then eventually wilted. Control plants remained symptomless. S. rolfsii was reisolated from inoculated plants. To our knowledge, this is the first report of southern blight caused by S. rolfsii on lily in China. Infection of lily bulbs by S. rolfsii may cause losses in production fields in China, and the presence of infected bulbs may also interfere with bulb shipment.

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First Report of Southern Blight on Canadian Goldenrod (Solidago canadensis) Caused by Sclerotium rolfsii in China

Plant Disease ◽

10.1094/pdis-94-9-1172b ◽

2010 ◽

Vol 94 (9) ◽

pp. 1172-1172 ◽

Cited By ~ 7

Author(s):

W. Tang ◽

Y. Z. Zhu ◽

H. Q. He ◽

S. Qiang

Keyword(s):

Eastern China ◽

Sclerotium Rolfsii ◽

Soil Surface ◽

Pathogenicity Test ◽

Solidago Canadensis ◽

Uniform Size ◽

First Report ◽

Southern Blight ◽

Perennial Plant ◽

Nanjing City

Canadian goldenrod (Solidago canadensis L., Asteraceae) is a rhizomatous perennial plant native to North America that has invaded eastern China and continues to spread northward and westward. It is quite common on field borders, roadsides, and in undeveloped areas, posing a serious threat to native ecosystems and their biodiversity. During the late summers of 2007 and 2008, wilted Canadian goldenrod plants were occasionally found in invasive populations in the suburb of Nanjing city. Wilted plants were transplanted and maintained in a greenhouse at Nanjing Agricultural University. A white mass of fungal hyphae, which grew on the soil surface around the stem of the symptomatic S. canadesis plants and eventually covered the stem, was observed. Initially, the base of the stem became yellow, turned brown, and the light brown discoloration extended up the stem to a height of 3 to 7 cm. The leaves then collapsed, starting from the top until the entire plant wilted. The fungus produced numerous, small, roundish sclerotia of uniform size (0.7 to 2.0 mm in diameter), which were white at first and then became brown to dark brown. The fungus grew into the stems and downward into the rhizome area, but no sclerotia were detected inside the stem or root. Diseased tissue with sclerotia was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with 100 mg/liter of streptomycin sulfate. On the basis of sclerotia morphology and the presence of clamp connections at hyphal septa, the fungus was identified as Sclerotium rolfsii. Pathogenicity of the isolate was confirmed by inoculating 1-year-old S. canadensis plants (average 1.5 m high) grown in pots. The inoculum consisted of cottonseed hulls infested with mycelium and sclerotia of the pathogen and was placed on the soil surface around the base of each unwounded plant. Noninoculated plants served as controls. The pathogenicity test was conducted twice. After inoculation, the plants were maintained at high humidity and 30°C for 3 days and then transferred to a greenhouse. All inoculated plants developed symptoms of southern blight. Inoculated plants developed symptoms of wilting 5 to 7 days after inoculation and were completely wilted within 15 to 20 days. Symptoms of wilting were soon followed by the appearance of white-to-light brown sclerotia on the collar region. Control plants remained symptomless and Sclerotium rolfsii was reisolated from inoculated plants. To our knowledge, this is the first report of southern blight of Canadian goldenrod caused by Sclerotium rolfsii in China.

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First Report of Athelia rolfsii Causing Southern Blight on Sarcandra glabra in China

Plant Disease ◽

10.1094/pdis-12-20-2555-pdn ◽

2021 ◽

Author(s):

Ling Lei ◽

Yan-Yun Hong ◽

Tu-Yong Yi ◽

Xiaoying Nie ◽

Shengeng Xiao

Keyword(s):

Disease Incidence ◽

Market Price ◽

Hunan Province ◽

Molecular Characteristics ◽

Post Inoculation ◽

First Report ◽

Southern Blight ◽

Athelia Rolfsii ◽

Pathogenicity Tests ◽

Artificial Cultivation

Sarcandra glabra, belonging to the family Chloranthaceae, is a Chinese medicinal plant. The whole dry plant can be used as a medicine; it is rich in bioactive phytochemicals that possess anti-bacterial, anti-inflammatory, anti-oxidant, and anti-tumor properties (Xie et al. 2020). The current market price of S. glabra is around US$5/kg, and the annual demand is 3 500 000~4 000 000 kg in China (Pan et al. 2007). To meet consumer demand for safe and high-quality herbal products, the artificial cultivation of S. glabra has been vigorously promoted. In 2020, it was observed that a plant disease affected S. glabra growth in Hunan province. The disease symptoms included constriction at the base of the stem, with decay and a white mycelium covering. The plants finally died with a disease incidence ranging from 15% to 20%. Using our previously published methods (Yi et al. 2019), one fungal isolate was isolated from the cultured symptomatic stem tissue on potato dextrose agar (PDA) medium and was named as Kb. The isolate was subsequently transferred into 70% glycerol for preservation. The Kb colony varied in color from white to light yellow. The septate hyphae grew rapidly on PDA medium, at approximately 25 mm/day, at 28 °C. On the fifth day, rhizomorphs were formed at the edge and on the center of the PDA plate. On the sixth day, sclerotia developed into a rapeseed shape (d = 1.2~2.3 mm) with a smooth surface, and with white, yellow, or chestnut brown coloring. Morphologically, Kb was similar to Sclerotium rolfsii (Sun et al. 2020). Vigorously growing aerial hyphae were selected for molecular identification. The internal transcribed spacers (ITS) were amplified using the primer pairs ITS1/ITS4 (Glass et al. 1995). BLAST searches against Genbank indicated that Kb’s ITS sequence shared 97% similarity with that of Athelia rolfsii (MN696630.1). Based on morphological and molecular characteristics, Kb was identified as A. rolfsii. The sequence was deposited in GenBank (MW288292). Pathogenicity tests were carried out using the following procedures. Three healthy S. glabra seedlings were inoculated at the stem base with a PDA plug (5 mm in diameter) covered with 5-day-old fungal mycelium cultured at 28 °C, while the remaining three seedlings were inoculated with distilled water only, as the control. Plants were incubated in a greenhouse at 28 °C. At 7 days post inoculation, the inoculated sites infected with the putative pathogen displayed identical constrictions as previously observed in the field. In contrast, the controls remained symptomless. The pathogen was reisolated from these infected seedlings, and its culture showed the same morphological and molecular traits as the original isolates. No pathogens were isolated from the control plants. Pathogenicity tests were repeated three times. Koch’s postulates were fulfilled. Although S. rolfsii has been previously reported to cause Southern Blight on mung bean crops in China (Sun et al. 2020), this is the first report on A. rolfsii causing similar symptoms of Southern Blight on S. glabra in Hunan Province, China. Identification of the pathogens causing each disease is important for the development of effective disease management strategies and for extensive artificial cultivation.

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First Report of Southern Blight of Iresine herbstii Caused by Sclerotium rolfsii in Taiwan

Plant Disease ◽

10.1094/pdis-04-12-0372-pdn ◽

2012 ◽

Vol 96 (11) ◽

pp. 1692-1692

Author(s):

C. H. Fu ◽

Y. P. Huang ◽

F. Y. Lin

Keyword(s):

Sclerotium Rolfsii ◽

Soil Surface ◽

Herbaceous Plant ◽

First Report ◽

Southern Blight ◽

Potted Plants ◽

Agar Plug ◽

Initial Symptoms ◽

Pure Cultures ◽

Causal Fungus

Widely cultivated commercially, Iresine herbstii Hook is a potted herbaceous plant popular for its foliage, which varies from a dark red to brownish maroon. In the summer of 2010, a sudden wilt of I. herbstii plants was observed at a recreational farm in Taipei City in northern Taiwan. The initial symptoms were water-soaked lesions that became soft and then rotted. Necrotic areas on the stems were covered with fans of white mycelium as well as abundant spherical, brown sclerotia. A fungus was isolated from both infected tissue and sclerotia and maintained on potato dextrose agar (PDA) plates incubated at 25°C without light. Colonies were white and cottony, often forming mycelial fans. Pure cultures were prepared by transferring single hyphal tips to PDA. Sclerotia formed after 7 days. Sclerotia were initially white becoming dark brown with age and were 0.8 to 1 mm in diameter at maturity. These are typical features of Sclerotium rolfsii. Koch's postulates were performed by inoculating five healthy, potted I. herbstii plants with 10 fresh sclerotia placed on the soil surface around the base of each plant. In a second test, five healthy potted plants were inoculated with a single 10-mm-diameter mycelial agar plug placed at the stem base of each plant. Five noninoculated plants served as controls. All plants were incubated in a growth chamber at 25 to 35°C. Basal stem rot and wilt developed within 4 days on plants inoculated with sclerotia or mycelial plugs. All plants were dead by 7 days after inoculation whereas the controls remained healthy. The fungus was reisolated from the symptomatic tissue and produced sclerotia and mycelium consistent with S. rolfsii. To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) rDNA region of the causal fungus was amplified using the primers ITS4 and ITS5 (3) and sequenced. The resulting sequence of 687 bp was uploaded in NCBI (Accession No. JN543691.1). The sequence was 98% similar to sequences of Athelia rolfsii (anamoprh S. rolfsii). This disease has been observed on many species of plants (1, 2). To our knowledge, this is the first report of I. herbstii caused by S. rolfsii in Taiwan or any other part of the world. References: (1) T. T. Chang. Bull. Taiwan For. Res. Inst. 9:191, 1994. (2) Y. N. Wang et al. J. Exp. For. Nat. Taiwan Univ. 20:45, 2006. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

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First Report of Southern Blight of Okra (Abelmoschus esculentus) Caused by Sclerotium rolfsii in Côte d'Ivoire

Plant Disease ◽

10.1094/pdis-06-10-0449 ◽

2010 ◽

Vol 94 (11) ◽

pp. 1379-1379 ◽

Cited By ~ 2

Author(s):

D. Koné ◽

D. Mohamed ◽

S. Soro ◽

B. A. Bolou Bi ◽

Y. J. Kouadio ◽

...

Keyword(s):

Cote D'ivoire ◽

Côte D’Ivoire ◽

Disease Incidence ◽

Sclerotium Rolfsii ◽

Abelmoschus Esculentus ◽

Cote D’Ivoire ◽

First Report ◽

Southern Blight ◽

Côte D'ivoire ◽

Field Samples

Southern blight caused by Sclerotium rolfsii Sacc. was observed on okra (Abelmoschus esculentus) cv. Clemson Spineless in January 2010 during a survey of vegetable fields in Rubbino, Côte d'Ivoire, which is one of the most important areas for vegetable production. Plants exhibited symptoms of a dark brown lesion on the stems near the soil line. Upper roots became light to dark brown, the lower leaves wilted, turned yellow, and a white mat of fungal mycelium developed on the stem lesion. Numerous, white, spherical sclerotia formed on the infected stem and on soil surfaces around the infected plants. Sclerotia (0.5 to 1.2 mm in diameter) later turned tan to dark brown and the entire plant wilted. Eleven fields, with a total of approximately 26 ha surveyed, were affected and disease incidence reached approximately 15% in the fields. Sclerotia were collected and the fungus cultured on acidified potato dextrose agar (PDA) plates. The fungus grew rapidly on PDA and the hyphae at the edge of the colonies were large straight cells with one or more clamp connections at each septum. Secondary and tertiary hyphae were slender and lacked clamp connections. Whitish sclerotia were observed on the mycelial mats 5 to 7 days after incubation, which later turned tan to brown when mature. The fungus was identified as S. rolfsii based on the characteristics of mycelia and sclerotia (1). Sclerotia produced on PDA were used to inoculate okra seedlings under greenhouse conditions at rates of 10, 20, and 30 sclerotia per plant. Sclerotia were placed just under the soil surface around the root of 4-week-old seedlings of okra cv. Clemson Spineless. Symptoms identical to those on field samples developed on all inoculated plants. S. rolfsii was reisolated from diseased plants and the identity was confirmed. S. rolfsii has previously been reported as causing disease in Côte d'Ivoire (2). To our knowledge, this is the first report of southern blight caused by S. rolfsii on okra in this country. Okra is an important vegetable crop in Côte d'Ivoire and therefore the occurrence of southern blight and susceptibility of okra cultivars to this disease needs to be taken into account in okra production. References: (1) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996. (2) R. Resplandy et al. Ann. Epiphyt. 1:1, 1954.

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First Report of Forsythia Shoot Blight Caused by Phytophthora nicotianae in Connecticut

Plant Disease ◽

10.1094/pdis-03-14-0297-pdn ◽

2014 ◽

Vol 98 (9) ◽

pp. 1278-1278

Author(s):

J. A. LaMondia ◽

D. W. Li ◽

A. M. Madeiras ◽

R. L. Wick

Keyword(s):

Disease Incidence ◽

Morphological Characteristics ◽

Aerial Mycelium ◽

Phytophthora Nicotianae ◽

First Report ◽

Sterile Needle ◽

Shoot Blight ◽

Pathogenicity Tests ◽

Half Strength ◽

Internal Necrosis

Blighting of Forsythia × intermedia ‘Showoff’ was first observed affecting several hundred plants in a commercial nursery in Connecticut in September 2012. Symptoms included wilting, leaf and stem blight, and dieback progressing to plant death. A Phytophthora sp. was isolated from symptomatic tissues on half-strength potato dextrose agar (½PDA). Colonies were white and cottony on ½PDA, reaching 9 mm in 15 days at 25°C, but colorless and inconspicuous on pimaricin, ampicillin, rifampicin, pentachloronitrobenzene agar (PARP) with sparse and limited aerial mycelium, reaching 60 mm in 15 days at 25°C. The characteristics of the pathogen were observed and measured from a 3-month-old colony on ½PDA. Sporangia were abundant, various in shape, ovoid, ellipsoid to pyriform or limoniform, occasionally gourd shaped or irregular; (17.9) 27.2 to 41.4 (47.3) × (12.6) 19.1 to 30.5 (36.7) μm (n = 30), length/breadth ratio 1.4 ± 0.2, papillate and noncaducous. Papillae measured 2.9 ± 0.8 × 3.4 ± 0.8 μm (n = 10). Chlamydospores were present, 23.4 ± 3.1 × 22 ± 3.3 μm (n = 10). Oogonia and oospores were not observed. Arachnoid mycelia were present. These morphological characteristics are consistent with Phytophthora nicotianae Breda de Haan (1). The identity of the pathogen was confirmed as P. nicotianae by BLAST analysis of ITS, Cox II, and beta tubulin gene sequences (99% match for the three sequences, E value = 0). Pathogenicity tests were conducted four times on healthy liners of Forsythia × intermedia ‘Showoff’ grown in 10-cm-diameter pots. Leaves and stems were wounded by pricking with a sterile needle and six plants were inoculated with 0.25 cm2 plugs of the pathogen growing on ½PDA placed on three leaves and in three stem nodes and covered with Parafilm. Controls consisted of an equal number of plants wounded and inoculated with ½PDA alone. All plants were placed inside high humidity chambers for 24 h and then transferred to a greenhouse for up to 1 month. Typical symptoms developed within 1 week of inoculation and the pathogen was re-isolated from diseased tissue. Disease incidence was nearly 100% of inoculated leaves and stems and not observed in control plants without the pathogen. Three replicate 6-week-old broadleaf tobacco ‘C9’ plants were each inoculated with tobacco or forsythia isolates of P. nicotianae or sterile media alone, by wounding stems and placing colonized 0.25 cm2 ½PDA plugs into wounds and covering with Parafilm. After 1 week, stems were split and the length of internal necrosis in the stem measured. Disease resulted from inoculation with both the tobacco and forsythia isolates and stem necrosis averaged 43 and 23 mm for tobacco or forsythia isolates, respectively. No necrosis was observed in the pathogen-free controls. P. nicotianae has been reported from the basal stem and roots of F. viridissima in Italy (2) and from shoots of Forsythia × intermedia in Virginia (3). To our knowledge, this is the first report of P. nicotianae causing shoot blight on Forsythia in the northeastern United States. References: (1) J. van. Breda de Haan. Mededeelingenuit's Lands Plantentuin Batavia. 15:57, 1896. (2) S. O. Cacciola et al. Plant Dis. 78:525, 1994. (3) C. X. Hong et al. Plant Dis. 89:430, 2005.

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First Report of Southern Blight of Ruellia brittoniana Caused by Sclerotium rolfsii in Louisiana

Plant Disease ◽

10.1094/pdis.2004.88.7.770a ◽

2004 ◽

Vol 88 (7) ◽

pp. 770-770

Author(s):

G. E. Holcomb

Keyword(s):

Root Rot ◽

High Speed ◽

Sclerotium Rolfsii ◽

Stem Rot ◽

Basal Stem Rot ◽

First Report ◽

Southern Blight ◽

Agar Plug ◽

Leaf Yellowing ◽

Pathogenicity Tests

Ruellia brittoniana, Mexican petunia, is an herbaceous flowering perennial grown in hardiness zones 8 to 10 in the southern and western United States. Popular dwarf forms with flower colors of white, pink, and blue are used as ground covers and borders. In April of 2003, root and stem rot that caused plant death was observed on cv. Katie (dwarf form, pink flowers) at a wholesale nursery in southern Louisiana. Plants were growing in a vermiculite and sand mix. The grower had purchased the plants from an out-of-state source, and approximately one-half of 1,440 plants were dead or dying. Symptoms included wilt, basal stem rot, and root rot. Peripheral roots were covered with a white mycelial layer that contained white sclerotial initials and small, brown sclerotia. Fungal isolates from infected roots grown on potato dextrose agar (PDA) produced white mycelia and 1- to 2-mm-diameter dark brown sclerotia. Sclerotia were nearly round with smooth surfaces and distributed over the entire colony. Isolates were identified as Sclerotium rolfsii on the basis of mycelial characteristics and color, size, and distribution of sclerotia. Two-month-old seedlings (6 to 10 cm high) of R. brittoniana, from seed of cv. Katie, were used in pathogenicity tests. Inoculum was grown in 10-cm-diameter plastic, culture dishes on PDA medium. Blended inoculum was prepared from a single 1-week-old culture that was composed of mycelia and sclerotia and blended 4 to 6 s at high speed in 100 ml of distilled water. In test one, 5 ml of inoculum was placed at the base of each inoculated plant. In test two, a single 5-mm-diameter agar plug with mycelium plus four sclerotia was placed beside plant stems near soil line. In test three, 5 ml of blended inoculum was dripped on exposed roots after plants were removed from pots. In test four, exposed plant roots were dipped in the blended inoculum. Each test contained 10 inoculated plants, and 10 noninoculated plants served as controls. All plants were placed in a dew chamber maintained at 28°C for 2 days and then returned to a greenhouse to observe development of symptoms and signs of disease. In tests one and two, basal stem rot and wilt developed on inoculated plants after 2 days and after 5 to 8 days all were dead. Inoculated plants from tests three and four were alive 4 months after inoculation, but were showing symptoms including leaf yellowing and drop, moderate to severe root rot, and some plants had begun to show white mycelia and white sclerotial initials on peripheral roots by January 2004. All noninoculated plants remained healthy and S. rolfsii was reisolated from infected plants in each test. To my knowledge, this is the first report of S. rolfsii causing disease on R. brittoniana.

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First Report of Petiole Rot of Pulmonaria longifolia Caused by Sclerotium rolfsii var. delphinii

Plant Disease ◽

10.1094/pdis.2003.87.3.313b ◽

2003 ◽

Vol 87 (3) ◽

pp. 313-313 ◽

Cited By ~ 1

Author(s):

B. A. Edmunds ◽

M. L. Gleason

Keyword(s):

Sclerotium Rolfsii ◽

Soil Surface ◽

Potato Dextrose Agar ◽

Pathogenicity Test ◽

First Report ◽

Plastic Bags ◽

Affected Tissue ◽

Pathogenicity Tests ◽

The Media ◽

Herbaceous Perennial

Sclerotium rolfsii var. delphinii was isolated from the bases of discolored petioles on wilted, yellow leaves of Pulmonaria longifolia (cultivar unknown), an herbaceous perennial growing in a landscape planting in Ames, IA. White mycelia and brick red, 2- to 3-mm-diameter sclerotia were found on affected tissue and nearby soil. The isolates were identified as S. rolfsii var. delphinii based on the formation of dark red, irregularly shaped, >2.0-mm-diameter sclerotia on potato dextrose agar (PDA) around the edge of the culture (1,2). Pathogenicity tests were conducted by inoculating 5-month-old P. longifolia cv. E. B. Anderson growing in 20-cm-diameter pots in a greenhouse at 25 to 30°C. Inoculum was produced by transferring plugs from a 1-week-old culture of the S. rolfsii var. delphinii isolate on PDA to autoclaved carrot disks. After 2 days of incubation, a mycelium-infested carrot disk was placed on the soil surface at the base of each plant. Six plants were inoculated and six plants served as uninoculated controls. All plants were enclosed in plastic bags to maintain high humidity. The pathogenicity test was repeated once. All inoculated plants developed characteristic symptoms within 10 days, whereas all control plants remained symptomless. Sclerotia developed on infected tissue and the media surface, and S. rolfsii var. delphinii was reisolated on PDA from symptomatic petioles. To our knowledge, this is the first report of petiole rot of P. longifolia caused by S. rolfsii var. delphinii. References: (1) Z. K. Punja. Annu. Rev. Phytopathol. 23:97, 1985. (2) Z. K. Punja and A. Damiani. Mycologia 88(5):694, 1996.

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First Report of Southern blight Incited by Sclerotium rolfsii on Dichondra repens in Italy

Plant Disease ◽

10.1094/pd-89-0203b ◽

2005 ◽

Vol 89 (2) ◽

pp. 203-203 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

A. Minuto ◽

M. L. Gullino

Keyword(s):

Sclerotium Rolfsii ◽

Soil Surface ◽

The United States ◽

First Report ◽

Southern Blight ◽

Inoculation Trial ◽

Leaf Yellowing ◽

White Mycelium ◽

Wheat Kernels ◽

Reddish Brown Color

Kidney weed (Dichondra repens) is increasingly used for low maintenance turf in Italy, particularly for gardens and parks in areas characterized by mild climate. During September 2003, on the D. repens turf of a private garden located near Imperia (northern Italy), yellow, circular areas as much as 60 cm in diameter appeared with the grass becoming chlorotic and thin. A ring of the patch at its periphery exhibited a reddish brown color and eventually died. An area of green grass remained in the center of the patch. Rings of dead grass enlarged rapidly during hot, humid weather. In the presence of abundant moisture, a white mycelium occurred on the dying grass at the periphery of the ring. White or light-to-dark brown sclerotia (1 to 3 mm in diameter) developed from mycelium on the dead grass. The diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with 100 mg/l of streptomycin sulphate. Sclerotium rolfsii was consistently isolated from infected plants. Pathogenicity of three isolates obtained from infected plants was confirmed by inoculating healthy D. repens turf (1 m2 plots and three replicates). Inoculum that consisted of wheat kernels infested with mycelium and sclerotia of each isolate was placed on the soil surface. Noninoculated plots served as controls. The inoculation trial was repeated once. Turf was covered with a plastic film for 7 days, kept at temperatures ranging between 22 and 25°C, and watered as needed. Inoculated plants developed symptoms of leaf yellowing within 11 days, soon followed by the appearance of white mycelium and sclerotia, and then eventually wilted. Control plants remained symptomless. Sclerotium rolfsii was re-isolated from inoculated plants. To our knowledge, this is the first report of S. rolfsii on D. repens in Italy. This disease has been reported on kidney weed in several countries such as the United States (3), Brazil (1), and India (2). References: (1) M. Menezes and J. A. A. Lima. Fitossanidade 1:18, 1974. (2) K. Ranganathan and N. Shanmugam. Indian Phytopathol, 27:113, 1974. (3) J. D. Smith et al. Fungal Diseases of Amenity Turf Grasses. E & F.N. Spon, London, 1989.

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