First report of stem rot of rosemary caused by Sclerotinia sclerotiorum in the United States

2004 ◽  
Vol 53 (2) ◽  
pp. 252-252 ◽  
Author(s):  
M. L. Putnam
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
The United States ◽  
Stem Rot ◽  
First Report

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 Sclerotinia sclerotiorum on Campanula carpatica and Schizanthus × wisetonensis in Italy

Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 71-71
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
Ornamental Plants ◽  
Soil Surface ◽  
The United States ◽  
First Report ◽  
Potted Plants ◽  
Initial Symptoms ◽  
Stem Necrosis ◽  
Campanula Carpatica

The production of potted ornamental plants is very important in the Albenga Region of northern Italy, where plants are grown for export to central and northern Europe. During fall 2000 and spring 2001, sudden wilt of tussock bellflower (Campanula carpatica Jacq.) and butterfly flower (Schizanthus × wisetonensis Hort.) was observed on potted plants in a commercial greenhouse. Initial symptoms included stem necrosis at the soil line and yellowing and tan discoloration of the lower leaves. As stem necrosis progressed, infected plants growing in a peat, bark compost, and clay mixture (70-20-10) wilted and died. Necrotic tissues were covered with whitish mycelia that produced dark, spherical (2 to 6 mm diameter) sclerotia. Sclerotinia sclerotiorum was consistently recovered from symptomatic stem pieces of both plants disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with streptomycin sulphate at 100 ppm. Pathogenicity of three isolates obtained from each crop was confirmed by inoculating 45- to 60-day-old C. carpatica and Schizanthus × wisetonensis plants grown in containers (14 cm diameter). Inoculum that consisted of wheat kernels infested with mycelia and sclerotia of each isolate was placed on the soil surface around the base of previously artificially wounded or nonwounded plants. Noninoculated plants served as controls. All plants were maintained outdoors where temperatures ranged between 8 and 15°C. Inoculated plants developed symptoms of leaf yellowing, followed by wilt, within 7 to 10 days, while control plants remained symptomless. White mycelia and sclerotia developed on infected tissues and S. sclerotiorum was reisolated from inoculated plants. To our knowledge, this is the first report of stem blight of C. carpatica and Schizanthus × wisetonensis caused by S. sclerotiorum in Italy. The disease was previously observed on C. carpatica in Great Britain (2) and on Schizanthus sp. in the United States (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) J. Rees. Welsh J. Agric. 1:188, 1925.

scholarly journals First Report of Stem Rot of Stevia Caused by Sclerotinia sclerotiorum in North Carolina

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1433-1433 ◽  
Author(s):  
A. Koehler ◽  
H. Shew
Keyword(s):  
United States ◽  
North Carolina ◽  
Sclerotinia Sclerotiorum ◽  
The United States ◽  
Stem Rot ◽  
Stem Tissue ◽  
Causal Organism ◽  
Broad Institute ◽  
Stem Lesions ◽  
Β Tubulin

Stevia (Stevia rebaundiana Bertoni) is an emerging perennial crop in the United States. The crop is grown for 3 to 5 years with two harvests per growing season. Stevia contains numerous glycosides that are used as a natural noncaloric sweetener, and in 2008 was approved by the USDA as a sugar substitute. In commercial plantings of second-year stevia in North Carolina, diseased plants were observed in April and May of 2013. Diseased plants were observed in several counties in the state in fields that had been planted primarily in a corn-soybean rotation prior to stevia planting. Symptoms included wilting, chlorotic leaves, necrotic leaves at the base of the stem, bleached stem lesions, and dead plants. Symptomatic plants often also had tufts of white hyphae present on stems and large, irregularly shaped 2- to 8-mm black sclerotia frequently were present on the base of the stem. Isolations from infected stem tissue were made on potato dextrose agar amended with 50 μg/ml of streptomycin sulfate and penicillin G. Based on hyphal and sclerotial characteristics, isolates were tentatively identified as Sclerotinia sclerotiorum (Lib.) de Bary (4). Koch's postulates were confirmed on 10-week-old Stevia plants cv. G3 grown in the greenhouse in 10-cm-diameter pots containing a sterile 1:1:1 sand, loam, media mix. Oat grains infested with one isolate obtained from diseased field plants served as the inoculum. Oats were sterilized on three consecutive days, inoculated with colonized agar plugs of S. sclerotiorum, and then incubated at room temperature until they were thoroughly colonized. Three infested oat grains were buried 1 cm deep approximately 2 cm from the base of the plant in each of the six test pots and plants were observed over a 3-week period for symptoms. Symptoms developed on all plants within 5 days of inoculation. Leaves began to wilt, then turned chlorotic and necrotic, with stem lesions and sclerotia present at the base of the plant. Isolations were taken from infected stem tissue and pure cultures were prepared for molecular identification. Uninoculated control plants did not develop symptoms. Pathogen identification was confirmed using universal primers ITS 4,5 and β-tubulin (2,3). Mycelium from the cultured greenhouse stem isolations were grown in potato dextrose broth. Mycelium samples were aspirated and lyophilized prior to DNA extraction. Extracted DNA was amplified through PCR with ITS and β-tubulin primers and sent for sequencing. Sequences were aligned using CLC Workbench. Sequences from ITS45 had 100% identity to S. sclerotiorum GenBank Accession No. KF859933.1, confirming S. sclerotiorum as the causal organism. The β-tubulin sequence was compared against the Broad Institute S. sclerotiorum whole genome shotgun sequence and was confirmed to have 100% identity to the beta tubulin chain (5). This is the first report of S. sclerotiorum on stevia in the United States. Chang et al. (2) reported a stem rot of stevia in Canada and confirmed S. sclerotiorum as the causal organism. References: (1) K. Chang et al. Plant Dis. 81:311, 1997. (2) J. Freeman et al. Eur. J. Plant Pathol. 108:877, 2002. (3) N. L. Glass and G. C. Donaldson. Appl. Environ. Microbiol. 61:1323, 1995. (4) J. E. M. Mordue and P. Holliday. CMI No. 513, 1976. (5) Sclerotinia sclerotiorum Sequencing Project, Broad Institute of Harvard and MIT. Online: http://www.broadinstitute.org/ , accessed July 16, 2014.

scholarly journals Occurrence of Stem Rot on Canola Caused by Sclerotinia sclerotiorum in Argentina

Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 530-530 ◽  
Author(s):  
S. Gaetán ◽  
M. Madia
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
Buenos Aires ◽  
Disease Incidence ◽  
Fungal Growth ◽  
Ground Level ◽  
The United States ◽  
Stem Rot ◽  
Buenos Aires Province ◽  
Rot Disease

Canola (Brassica napus) was introduced as an alternative crop for wheat in Argentina. During 2003, typical symptoms of stem rot disease were observed on canola plants in two commercial fields located at Bragado, in northern Buenos Aires Province in Argentina. Average disease incidence across four canola cultivars was 21% (range = 13 to 29%). Symptoms included chlorosis and wilting of foliage and necrosis of basal stems. The disease appeared singly or in patches consisting of 4- to 5-month-old plants. The first visible symptom noticed was chlorosis and wilting of the foliage beginning from the basal leaves. Infection of the main stem at ground level typically was followed by a grayish white discoloration that progressed above the soil line to the apex. In advanced stages of the disease, stems and branches became bleached and eventually died. Black and irregularly shaped sclerotia (average size 5.5 × 2.8 mm) inside necrotic stem tissue were the typical signs of the pathogen. From September to October 2003, four samples consisting of six affected plants per sample were arbitrarily collected from two commercial fields located at Bragado. Sclerotia were taken from diseased stems, dipped in 70% ethanol, surface sterilized with 1% sodium hypochlorite for 1 min, and rinsed in sterile water. Each sclerotium was blotted dry on sterile Whatman's filter paper and placed on potato dextrose agar. Plates were incubated in the dark at 25°C for 2 to 3 days, followed by incubation under 12-h NUV light/12-h dark for 6 to 8 days. Six resulting colonies were identified as Sclerotinia sclerotiorum (Lib.) de Bary on the basis of taxonomic characteristics of the plant pathogenic species of Sclerotinia (3). Koch's postulates for three fungal isolates from infected plants were carried out on 6-week-old canola plants (cvs. Eclipse, Impulse, Master, and Mistral) by placing a colonized agar disk into wounds made in the basal stem region with a sterile scalpel. Pathogenicity tests, which included five inoculated and three control plants potted in a sterilized soil mix (soil/sand, 3:1), were conducted in a greenhouse at 23 to 26°C and 75% relative humidity with no supplemental light. Characteristic symptoms identical to the original observations developed within 12 days after inoculation on 100% of the inoculated plants for three isolates. Symptoms included wilted foliage, collapsed plants, and plant death. White mycelium and sclerotia developed on infected tissues, and the pathogen was successfully reisolated from symptomatic plants in all instances. Control plants, which were treated similarly except that the agar disk did not contain fungal growth, remained healthy. The experiment was repeated, and the results were identical to the first inoculations. Canola stem rot disease incited by S. sclerotiorum was first reported in Argentina during 1995 at experimental field plots in Buenos Aires. S. sclerotiorum, which has been reported to cause disease in canola in Canada (2) and the United States (1,4), currently represents a serious problem to the main canola cultivars grown in Argentina. To our knowledge, this is the first report of the occurrence of S. sclerotiorum causing a high incidence of stem rot in commercial crops of canola in Argentina. 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) L. B. Jamaux et al. Plant Pathol. 44:22, 1995. (3) L. M. Kohn. Phytopathology 69:881, 1979. (4) D. V. Phillips et al. Phytopathology 92:785, 2002.

scholarly journals First Report of Basal Stem Rot of Apple Cactus (Cereus peruvianus monstruosus) Caused by Fusarium oxysporum in Italy

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 877-877
Author(s):  
A. Garibaldi ◽  
P. Pensa ◽  
D. Bertetti ◽  
A. Poli ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Fusarium Oxysporum ◽  
The United States ◽  
Stem Rot ◽  
Fluorescent Light ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Single Spore ◽  
Basal Stem Rot ◽  
First Report

During the summer of 2010, 20% of 7,000 4-month-old plants of apple cactus (Cereus peruvianus monstruosus) showed symptoms of a basal stem rot in a commercial nursery located in Liguria (northern Italy). Affected plants showed yellow orange-to-pale brown color from the crown level to the stem apex and a water-soaked rot was observed on the stem starting from the base. Brown discoloration was observed in the vascular system. Eventually stems bent, plants collapsed and died, and affected tissues dried out. A Fusarium sp. was consistently and readily isolated from symptomatic tissue on Komada selective medium. Isolates were purified and subcultured on potato dextrose agar (PDA). Single-spore cultures on PDA, Spezieller Nährstoffarmer agar (SNA) (3), and carnation leaf-piece agar (CLA) (2) were incubated at 26 ± 1°C (12-h fluorescent light, 12-h dark). On PDA, cultures produced a thick growth of white-to-pink mycelium and pale pink pigments in the agar. On SNA, cultures produced short monophialides with unicellular, ovoid-elliptical microconidia measuring 4.3 to 8.2 × 2.3 to 3.8 (average 6.0 × 2.8) μm. Chlamydospores were abundant, single or paired, terminal and intercalary, rough walled, and 6 to 8 μm in diameter. On CLA, cultures produced orange sporodochia with macroconidia that were 3 to 4 septate, nearly straight with a foot-shaped basal cell and a short apical cell, and measured 31.1 to 51.5 × 4.4 to 3.5 (average 43.2 × 3.8) μm. Such characteristics are typical of Fusarium oxysporum (3). Amplification of the ITS (internal transcribed spacer) of the rDNA using primers ITS1/ITS4 (4) yielded a 498-bp band. Sequencing and BLASTn analysis of this band showed an E-value of 0.0 with F. oxysporum. The nucleotide sequence has been assigned GenBank Accession No. JF422071. To confirm pathogenicity, five 6-month-old healthy plants of C. peruvianus monstruosus were inoculated by dipping roots in a conidial suspension (2.4 × 106 CFU/ml) of F. oxysporum isolated from affected plants. Inoculum was obtained from pure cultures of three single-spore isolates grown for 10 days on casein hydrolysate liquid medium. Roots were not wounded before the inoculation. Plants were transplanted into pots filled with steam-sterilized substrate (sphagnum peat/perlite/pine bark/clay 50:20:20:10). Five noninoculated plants served as a control. Plants were placed in a climatic chamber at 25 ± 1°C (12-h fluorescent light, 12 h-dark). Basal stem rot and vascular discoloration in the crown and stem developed within 30 days on each inoculated plant. Noninoculated plants remained healthy. F. oxysporum was consistently isolated from symptomatic plants. The pathogenicity test was conducted twice. F. oxysporum has been reported on Cereus spp. in the United States (1). To our knowledge, this is the first report of F. oxysporum on C. peruvianus monstruosus in Italy as well as in Europe. Currently, this disease is present in a few nurseries in Liguria. 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) N. L. Fisher et al. Phytopathology 72:151, 1982. (3) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell, Ames, IA, 2006. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

scholarly journals First Report of White Mold Caused by Sclerotinia sclerotiorum on Persian Buttercup (Ranunculus asiaticus) in Italy

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1151-1151 ◽  
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
Soil Surface ◽  
The United States ◽  
First Report ◽  
Inoculation Trial ◽  
Initial Symptoms ◽  
Leaf Yellowing ◽  
Ranunculus Asiaticus ◽  
Stem Necrosis

Persian buttercup (Ranunculus asiaticus L.) is grown in the Albenga Region of northern Italy for cut flower production and exportation to central and northern Europe. During the winter of 2003, sudden wilt was observed in commercial plantings of R. asiaticus. Initial symptoms included stem necrosis at the soil level and yellowing and tan discoloration of leaves. As stem necrosis progressed, infected plants wilted and died. Wilt occurred within a few days on young plants and was characterized by the presence of soft and watery tissues. Necrotic tissues became covered with whitish mycelium that produced dark, spherical sclerotia (1 to 4 mm in diameter). Sclerotinia sclerotiorum (Lib.) de Bary (1) was consistently recovered from infected stem pieces of R. asiaticus that were disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm of streptomycin sulfate. Pathogenicity of three isolates obtained from infected plants of persian buttercup was confirmed by inoculating 30-day-old plants grown in containers. Inoculum that consisted of wheat kernels infested with mycelium and sclerotia of each isolate was placed on the soil surface around the base of each of five plants. Noninoculated plants served as controls. The inoculation trial was repeated once. All plants were kept at temperatures ranging between 8 and 22°C and watered as needed. Inoculated plants developed symptoms of leaf yellowing followed by wilt within 15 days, while control plants remained symptomless. White mycelium and sclerotia developed on infected tissues, and S. sclerotiorum was reisolated from inoculated plants. S. sclerotiorum has been previously reported on R. asiaticus in the United States (2) and Japan (3). To our knowledge, this is the first report of wilt of R. asiaticus caused by S. sclerotiorum in Italy and Europe. References: (1) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 1949. (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) T. Urushibara et al. Annu. Rep. Kanto-Tosan Plant Prot. Serv. 46:61, 1999.

scholarly journals First Report of Stem Rot on Cereus peruvianus monstruosus Caused by Bipolaris cactivora (Petr.) Alcorn in Italy

Plant Disease ◽  
2014 ◽  
Vol 98 (1) ◽  
pp. 159-159 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
P. Pensa ◽  
A. Poli ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Morphological Characteristics ◽  
Its Region ◽  
The United States ◽  
Stem Rot ◽  
Pathogenicity Test ◽  
First Report ◽  
Plastic Bags ◽  
Blastn Analysis ◽  
Dark Green

Cereus peruvianus monstruosus, known as “monster cactus,” family Cactaceae, is grown as a potted plant. In the winter of 2013, a stem rot was observed on a farm located near Ventimiglia (northern Italy) on 80% of 4,000 9-month-old plants grown in trays in a peat substrate. Symptoms consisted of a rapid rot of the upper portion of the stem. Affected stems at first showed yellowish spots that became brown irregular necrotic lesions with well-defined margins. The tissues below the affected areas were blackened and dry but became soft in the presence of high relative humidity. Fungal sporulation on rotted tissues consisted of caespitose, non-branched, septate conidiophores, olivaceous to brown at the base, paler above, measuring 89.0 to 196.9 × 6.2 to 8.7 (average 124.8 × 7.0) μm. Single conidia were borne on terminal cells. At maturity, conidia with 2 to 5 (average 3) septa were brownish-olivaceous, varying in shape from obclavate, fusiform, ellipsoid or sometimes furcate, and measuring 23.4 to 48.6 × 8.0 to 12.6 (average 38.8 × 10.3) μm. Symptomatic tissues were immersed in 1% sodium hypochlorite for 2 to 3 s and rinsed in sterile distilled water, then fragments excised from the margin of internal lesions were cultured on potato dextrose agar (PDA) medium amended with 25 mg/l of streptomycin sulfate and incubated at 20 to 23°C under alternating daylight and darkness (10 h light, 14 h dark). A fungus that was consistently isolated was subcultured on PDA. At maturity, dark green floccose colonies comprised of light brown septate hyphae, 4.2 to 8.1 (average 5.6) μm in width, produced non-branched, pale to dark brown, septate conidiophores, measuring 99.6 to 176.1 × 4.5 to 6.5 (average 146.7 × 5.4) μm. The conidia produced on PDA were similar to those observed on infected tissues and measured 20.6 to 40.7 × 7.5 to 11.4 (average 32.0 × 9.7) μm, with 1 to 3 septa (average 2). On the basis of the morphological characteristics, the fungus was identified as Bipolaris cactivora (Petr.) Alcorn [Syn.: Drechslera cactivora (Petr.) M. B. Ellis] (4). The internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA) was amplified for one isolate using ITS1/ITS4 primers and sequenced (GenBank Accession No. KF041822). BLASTn analysis (1) of the 557-bp segment showed a 99% similarity with the ITS sequence of Bipolaris cactivora HM598679. For pathogenicity tests, 8 mm diameter mycelial disks removed from 15-day-old PDA cultures of the fungus were placed at the wounded stem apexes of three 7-month-old healthy plants (three disks per plant). Three plants inoculated with non-inoculated PDA disks served as controls. Plants were covered with plastic bags and maintained in a growth chamber at 23 ± 1°C with 12 h light/dark. By 8 days after inoculation, all the inoculated stems were rotted and 10 colonies of B. cactivora were re-isolated from infected tissues. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. Several hosts are listed for B. cactivora including C. peruvianus, and the pathogen has been reported in the United States (2) and in South Korea (3). To our knowledge, this is the first report of B. cactivora on C. peruvianus monstruosus in Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. APS Press, St Paul, MN, 1989. (3) I. H. Hyun et al. Res. Plant Dis. 7:56, 2001. (4) A. Sivanesan. Mycopathologia 111:125, 1990.

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