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

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.

Download Full-text

First Report of Southern Blight on Silverbush (Convolvulus cneorum) Caused by Sclerotium rolfsii in Italy

Plant Disease ◽

10.1094/pdis-94-1-0131a ◽

2010 ◽

Vol 94 (1) ◽

pp. 131-131 ◽

Cited By ~ 3

Author(s):

G. Polizzi ◽

D. Aiello ◽

V. Guarnaccia ◽

G. Parlavecchio ◽

A. Vitale

Keyword(s):

Sclerotium Rolfsii ◽

Ground Level ◽

Limiting Factor ◽

First Report ◽

Southern Blight ◽

The World ◽

Perennial Shrub ◽

Stem Lesions ◽

The Masses ◽

Tropical Climates

The genus Convolvulus has more than 200 species that are encountered in temperate to tropical climates all around the world. Convolvulus cneorum L., also known as silverbush, is a perennial shrub native to southern Europe (Sicily and Croatia) with dense, silver foliage and masses of large, circular, white flowers. During July of 2009, a widespread blight was observed on approximately 10% of 12,000 4-month-old potted silverbush plants. The plants were obtained from cuttings and produced by a commercial nursery in eastern Sicily, Italy. Symptomatic plants initially had sunken, tan lesions at the ground level that developed into typical southern blight. Circular and crescent-shaped patches were observed on the masses of weeds on the surface of the containers where silverbush were grown. At the soil line, white mycelia and small (1 to 2 mm in diameter), brown, spherical sclerotia with internally differentiated rind, cortex, and medulla characteristic of Sclerotium rolfsii Sacc. were observed. Crown and stem lesions were surface disinfested (1% NaOCl) for 1 min, rinsed in sterile water, and placed on potato dextrose agar. Isolation consistently yielded colonies of Sclerotium rolfsii (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough) with typical sclerotia produced within 6 to 7 days (2). Pathogenicity tests were performed on 20 plants by placing 10 sclerotia obtained from 10-days-old cultures in the soil below the crown portion on each of 5-month-old healthy cuttings of silverbush. The same number of plants served as noninoculated controls. All plants were maintained in a growth chamber at 25 ± 1°C and enclosed for 7 days in polyethylene bags. Plants were then moved to a greenhouse where temperatures ranged from 24 to 28°C. Symptoms of southern blight developed after 7 to 20 days on all inoculated plants. Control plants remained symptomless. S. rolfsii was reisolated from symptomatic plants. S. rolfsii was reported for the first time in Sicily in 2004 in an ornamental nursery (1). To our knowledge, this is the first report in the world of S. rolfsii on silverbush and it is the first outbreak of southern blight on Convolvulus species. The high susceptibility of silverbush to the pathogen could be a limiting factor for the cultivation in nursery of this indigenous wildflower plant. References: (1) G. Polizzi et al. Plant Dis. 88:310, 2004. (2) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996.

Download Full-text

First report of southern blight of mung bean caused by Sclerotium rolfsii in China

Crop Protection ◽

10.1016/j.cropro.2019.105055 ◽

2020 ◽

Vol 130 ◽

pp. 105055 ◽

Cited By ~ 3

Author(s):

Suli Sun ◽

Feifei Sun ◽

Dong Deng ◽

Xu Zhu ◽

Canxing Duan ◽

...

Keyword(s):

Mung Bean ◽

Sclerotium Rolfsii ◽

First Report ◽

Southern Blight

Download Full-text

First Report of Southern Blight Caused by Sclerotium rolfsii on Hemp (Cannabis sativa) in Sicily and Southern Italy

Plant Disease ◽

10.1094/pdis-91-5-0636a ◽

2007 ◽

Vol 91 (5) ◽

pp. 636-636 ◽

Cited By ~ 7

Author(s):

A. Pane ◽

S. L. Cosentino ◽

V. Copani ◽

S. O. Cacciola

Keyword(s):

Southern Italy ◽

Cannabis Sativa ◽

Natural Fiber ◽

Irrigation System ◽

Sclerotium Rolfsii ◽

Herbaceous Plant ◽

European Union Policy ◽

Susceptible Host ◽

First Report ◽

Southern Blight

Hemp (Cannabis sativa L.), family Cannabaceae, is an annual herbaceous plant that is 1.5 to 4.0 m tall and native to the Caucasus Region, northern India, and Iran. It is cultivated in warm to temperate regions worldwide for its fiber, oil, and psychoactive substances. In Europe, commercial plantings have decreased from 52,872 ha in 1989 to 18,716 ha in 2005. Recently however, cultivation of hemp as a natural fiber species has been encouraged by European Union policy (2). During the summer of 2003, patches of dead plants were observed in test plots of 12 monoecious and dioecious hemp cultivars (Beniko, Epsylon 68, Felina 34, Ferimon, Fedora 17, Futura 75, Bialobrzeskie, Dioica 88, Fibranova, Tiborszallasi, Lovrin, and Carmagnola) in an experimental field near Catania (eastern Sicily) previously planted to artichoke (Cynara scolymus L.). Plots were irrigated with a drip irrigation system. Symptoms were first detected in July with day/night temperatures between 35 and 26°C. Infected plants showed a dark brown-to-tan discoloration of the stem near the soil line. As disease progressed, the rot extended down to the crown and taproot, foliage became yellow, and the entire plant eventually collapsed. An extensive white, cottony mycelium and numerous spherical tan-to-dark brown sclerotia (0.5 to 4.0 mm in diameter) developed externally on infected tissues and soil. As much as 60% of the plants were affected in a single plot. Monoecious cultivars that had been planted earlier escaped the disease. Isolations from diseased tissues were performed by plating symptomatic tissues previously disinfected for 1 min in 1% NaOCl and rinsed in sterile water on acidified potato dextrose agar (pH 4.5). Isolations consistently yielded a fungus whose characters corresponded to Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough). Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 120-day-old hemp plants grown in individual pots. Twenty plants for each of the above listed cultivars (10 plants for each isolate) were inoculated by applying toothpick tips (5 mm) colonized by S. rolfsii to the lower part of the stem. Ten noninoculated plants served as controls. Plants were kept in a greenhouse with temperatures between 26 and 32°C and 95% relative humidity. High soil moisture was maintained with frequent watering. All inoculated plants showed blight and basal stem rot after 2 weeks, irrespective of the cultivar. By the third week, plants began to dry up and mycelium and sclerotia developed on the crown. Noninoculated controls remained symptomless. S. rolfsii was reisolated from inoculated plants. Although S. rolfsii has been reported on hemp in India since the 1930s (3), to our knowledge, this is the first report of southern blight caused by this fungus on C. sativa in Sicily and southern Italy. Residues of artichoke, a very susceptible host of S. rolfsii (1), might have been the source of inoculum for this outbreak on hemp. Most likely, high summer temperatures and overirrigation exacerbated the disease severity. References: (1) C. Cariddi and R. Lops. La Difesa delle Piante 19(1):27, 1996. (2) S. L. Cosentino et al. Agroindustria 2:137, 2003. (3) G. P. Hector. Ann. Rep. Dep. Agric. Bengal 35, 1931.

Download Full-text

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.

Download Full-text