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

Plant Disease ◽  
2007 ◽  
Vol 91 (5) ◽  
pp. 636-636 ◽  
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.

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

Plant Disease ◽  
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.

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

Plant Disease ◽  
2020 ◽  
Vol 104 (2) ◽  
pp. 585
Author(s):  
Qiaohuan Chen ◽  
Jinxin Li ◽  
Yuhuan Miao ◽  
Hongyang Wang ◽  
Le Chen ◽  
...  
Keyword(s):  
Sclerotium Rolfsii ◽  
Chrysanthemum Morifolium ◽  
First Report ◽  
Southern Blight

scholarly journals First Report of Southern Blight Caused by Sclerotium rolfsii in Industrial Hemp in Southern Virginia

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1563-1563
Author(s):  
B. S. Amaradasa ◽  
A. Turner ◽  
S. Lowman ◽  
C. Mei
Keyword(s):  
Sclerotium Rolfsii ◽  
First Report ◽  
Southern Blight ◽  
Industrial Hemp

scholarly journals First Report of Leaf Spot of Houttuynia cordata Caused by Alternaria alternata in China

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 359-359
Author(s):  
L. Zheng ◽  
R. Lv ◽  
Q. Li ◽  
J. Huang ◽  
Y. Wang ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Southern China ◽  
Sclerotium Rolfsii ◽  
Tween 20 ◽  
Herbaceous Plant ◽  
Houttuynia Cordata ◽  
First Report ◽  
Perennial Herbaceous Plant ◽  
Pathogenicity Tests

Houttuynia cordata is a perennial herbaceous plant (family Saururaceae) that is native to southern China, Japan, Korea, and Southeast Asia where it grows well in moist to wet soils. It is commonly used as a Chinese herbal medicine and as a vegetable. In North America and Europe it is also used as an ornamental. From September 2007 to November 2009, symptoms of leaf spot were found on H. cordata leaves in Dangyang County, Hubei, China, with the crop area affected estimated to be over 600 ha per year. Rhizome yield was reduced by 20% on average, with up to 70% yield losses in some fields during the autumn growing season. Lesions were initially small, brown, and oval or circular that developed into dark spots and sometimes formed target spots with white centers. These spots enlarged and overlapped, extending until the leaves withered entirely usually within 2 months. A fungus was consistently recovered from symptomatic leaf samples collected in October 2008 or 2009 with an average 90% isolation rate from ~60 leaf pieces that were surface sterilized with 0.1% mercuric chloride solution. Three isolates, HCDY-2, HCDY-3, and HCDY-4, were used to further evaluate characteristics of the pathogen. On potato dextrose agar, all cultures initially developed white colonies and the centers turned gray or brown after 4 days of incubation. Conidiophores were single or fasciculate, straight or knee curved, gray-brown with regular septa, and 42 to 61 × 4 to 5 μm. Conidia were obclavate or ovate, brown, and 26 to 38 × 12 to 20 μm with three to five transverse and one to three longitudinal or oblique septa. The tops of some conidia developed into secondary conidiophores, which were cylindrical, beige, and 5 to 17 × 3 to 5 μm. The pathogen was identified as Alternaria alternata based on descriptions in Simmons (3). Genomic DNA of HCDY-2 was extracted, and the rDNA-internal transcribed spacer sequence showed 99.6% identity to A. alternata (GenBank No. AY513941). Pathogenicity tests were performed with the three isolates by spraying conidial suspensions (1 × 106 conidia/ml) containing 0.1% Tween 20 onto upper and lower surfaces of leaves of 40-day-old 15-cm high plants. There were 20 leaves from five replicate plants for each isolate. Control plants were treated with sterilized water containing 0.1% Tween 20 only. All plants were incubated with a 16-h photoperiod at 25°C and 90% relative humidity in an artificial climate chamber. Five days after inoculation, typical brown spots were observed on all inoculated leaves but no symptoms were seen on water-treated control plants. Koch's postulates were fulfilled by reisolation of A. alternata from diseased leaves. The pathogenicity tests were carried out twice. A survey of the literature revealed only a few fungal diseases associated with H. cordata (1,2,4), including Phyllosticta houttuyniae, Pseudocercospora houttuyniae, Rhizoctonia solani, and Sclerotium rolfsii. Although A. alternata is a cosmopolitan plant pathogen, it has not been reported on any species in the four genera in Saururaceae (Anemopsis, Gymnotheca, Houttuynia, and Saururus) (3). To our knowledge, this is the first report of A. alternata infecting H. cordata worldwide. References: (1) Y. L. Guo and W. X. Zhao. Acta Mycol. Sin. 8:118, 1989. (2) K. Sawada. Spec. Publ. Taiwan Univ. 8:138, 1959. (3) E. G. Simmons. Alternaria: An Identification Manual. The American Phytopathological Society, St. Paul, MN, 2007. (4) Y. Wu et al. J. Changjiang Vegetables (In Chinese) 2:19, 2007.

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

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 109-109 ◽  
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.

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

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 131-131 ◽  
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.

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

2020 ◽  
Vol 130 ◽  
pp. 105055 ◽  
Author(s):  
Suli Sun ◽  
Feifei Sun ◽  
Dong Deng ◽  
Xu Zhu ◽  
Canxing Duan ◽  
...  
Keyword(s):  
Mung Bean ◽  
Sclerotium Rolfsii ◽  
First Report ◽  
Southern Blight

scholarly journals First Report of Diaporthe phaseolorum Causing Stem Canker of Hemp (Cannabis sativa)

Plant Disease ◽  
2021 ◽  
Author(s):  
Marcus Vinicius Marin ◽  
Nan-Yi Wang ◽  
Jacqueline Coburn ◽  
Johan Desaeger ◽  
Natalia A. Peres
Keyword(s):  
Cannabis Sativa ◽  
Phylogenetic Analyses ◽  
Stem Canker ◽  
Tween 20 ◽  
Future Research ◽  
Herbaceous Plant ◽  
Pathogenicity Test ◽  
Single Spore ◽  
Isolation Medium ◽  
First Report

Hemp is an annual herbaceous plant that is used for its fiber and oil in a variety of commercial and industrial products. In Florida, it is currently being explored as a new specialty crop. During a field trial from October to January 2019 in Wimauma, FL, a stem canker was observed on up to 60% of three-month-old plants of 'Eletta Campana', 'Carmagnola Selezionata', and 'Tygra'. Symptoms started on the main stems with light-to-dark brown lesions of different sizes and shapes. Over time, the lesions coalesced into large necrotic areas and bore pycnidia. Isolations were made from diseased stem tissues on General Isolation medium (Amiri et al. 2018) after surface disinfestation (Marin et al. 2020). The plates were placed in a growth chamber at 25°C under a 12/12 photoperiod. A fungus with white, floccose, aerial mycelium and pycnidia producing alpha and beta conidia was consistently isolated. Three single spore isolates were chosen for identification and pathogenicity tests. Pycnidia on PDA were globose to irregular and ranged from 170 to 250 μm long (210 ± 2.5, n = 50) and 140 to 220 μm wide (180 ± 2.7, n = 50). The alpha conidia were unicellular, hyaline, ellipsoidal to fusiform and ranged from 5.3 to 7.7 μm long (6.5 ± 1.6, n = 50) and 1.5 to 4.6 μm wide (2.8 ± 1.8, n = 50). The beta conidia were hyaline, elongated, filiform, straight or curved and ranged from 10.2 to 17.7 μm long (16.1 ± 2.2, n = 50) and 0.5 to 1.8 μm wide (0.8 ± 0.2, n = 50). Perithecia were not observed. Based on morphological features, the fungus was similar to anamorphs of Diaporthe spp. (Santos et al. 2011; Udayanga et al. 2015). DNA from the same three isolates was extracted using the FastDNA kit, and the ribosomal internal transcribed spacer (ITS), β-tubulin (TUB), and calmodulin (CAL) regions were amplified following Udayanga et al. (2014), and Sanger sequenced by Genewiz. Sequences were deposited in GenBank (accession no. MT497039 to MT497047 for ITS, TUB, and CAL). BLASTn searches revealed isolates 20-58, 20-59, and 20-60 were 96.34% identical to the epitype isolate D. phaseolorum AR4203 for ITS (KJ590738.1, 527 bp out of 547 bp), 100% for TUB (KJ610893.1, 459 bp out of 459 bp), and 100% for CAL (KJ612135.1, 522 bp out of 522 bp) (Udayanga et al. 2015). Their identity was confirmed by phylogenetic analyses using maximum likelihood and Bayesian inference methods. To complete Koch’s postulates, pycnidia of the same three isolates were harvested and crushed in 2 mL Eppendorf tubes containing 0.01% Tween 20. Conidia suspensions were adjusted to 106 spores/mL. Three 5-week-old potted plants of 'Eletta Campana' and 'Carmagnola Selezionata' per isolate were inoculated using a 1 mL syringe with a needle by injecting 200 µL of the suspension into the stem. Plants were placed inside clear plastic bags for 48 h and maintained in the greenhouse. Control plants were injected with sterile deionized water and kept under the same conditions. The pathogenicity test was repeated once. Four weeks after inoculation, inoculated plants developed stem cankers from which the same pathogen was isolated, whereas controls remained healthy. To our knowledge, this is the first report of D. phaseolorum causing stem canker on hemp. This pathogen has been reported causing canker on sunflower and Phaseolus spp. (Gomzhina and Gannibal 2018; Udayanga et al. 2015; Vrandecic et al. 2009). This discovery may help shape future research into disease epidemiology and management for a crop in which very limited disease information is available at the moment.

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