First Report of Gray Mold of Rhizoma paridis Caused by Botrytis cinerea in China

Rhizoma paridis is a perennial, traditional Chinese medicinal herb. In May 2013, a disease was observed in an approximately 10 ha cultivated field in Enshi, Hubei Province, China. Approximately 80% of plants in the field were affected. Symptoms were visible on the basal leaves of affected plants. Chlorosis followed by necrosis started at the leaf tips and margins and gradually spread inward until the entire leaf was necrotic. Thick, gray mycelium and conidia were visible on both sides surface of leaves under wet, humid conditions. The leading edge of the chlorotic leaves was excised from 20 plant samples surface disinfested with 1% NaOCl solution for 1 min, rinsed in sterile water, air dried, and placed on potato dextrose agar (PDA). Plates were incubated at 22°C in the dark. Mycelia were initially hyaline and white, and became dark gray after 72 h. Mycelia were septate with dark branched conidiophores. Conidia were smooth, hyaline, ovoid, aseptate, and ranged from 8 to 14.5 × 7 to 8.5 μm. Numerous hard, small, irregular, and black sclerotia that were 1 to 3 × 2 to 5 mm were visible on PDA plates after 12 days. The fungus was identified as Botrytis cinerea on the basis of these characters (1). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1 and ITS4 primer and sequenced (GenBank Accession No. KF265499). BLAST analysis of the PCR product showed 99% identity to Botryotinia fuckeliana (perfect stage of B. cinerea) (EF207415.1, EF207414.1). The pathogen was further identified to the species level as B. cinerea using gene sequences from glyceraldehyde-3-phosphate dehydrogenase (G3PDH), heat-shock protein 60 (HSP60), and DNA-dependent RNA polymerase subunit II (RPB2) (2) (KJ638600, KJ638602, and KJ638601). Pathogenicity was tested by spraying the foliage of 40 two-year-old plants with a suspension of 106 conidia per ml of sterile distilled water. Each plant received 30 ml of the inoculum. Ten healthy potted plants were inoculated with sterilized water as control. All plants were covered with plastic bags for 5 days after inoculation to maintain high relative humidity and were placed in a growth chamber at 22°C. The first foliar lesions developed on leaves 7 days after inoculation and were similar to those observed in the field. No symptoms developed on the control plants. B. cinerea was consistently re-isolated from all artificially inoculated plants. The pathogenicity test was completed twice. To our knowledge, this is the first report of gray mold of R. paridis caused by B. cinerea in China. The root of R. paridis is the most commonly used Chinese herbal medicine to treat viper bites. In recent years, cultivation of this herb has increased in China because of its high value. Consequently, the economic importance of this disease is likely to increase with the greater prevalence of this host species. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (2) M. Staats et al. Mol. Biol. Evol. 22:333, 2005.

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First Report of Gray Mold Caused by Botrytis cinerea on Stevia rebaudiana in Italy

Plant Disease ◽

10.1094/pdis-93-3-0318a ◽

2009 ◽

Vol 93 (3) ◽

pp. 318-318

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

P. Pensa ◽

M. L. Gullino

Keyword(s):

Botrytis Cinerea ◽

Stevia Rebaudiana ◽

Its Region ◽

Morphological Characters ◽

Gray Mold ◽

Fluorescent Light ◽

Pathogenicity Test ◽

Leaf Extracts ◽

First Report ◽

Potted Plants

Stevia rebaudiana (sweetleaf) is a perennial shrub belonging to the Asteraceae family and is widely grown for its sweet leaves. With its extracts having as much as 300 times the sweetness of sugar, this species is used in many countries for the production of sugar substitutes. However, in Italy, as well as in other countries, this species cannot be grown for the use of its leaf extracts. This plant is grown in a few nurseries in the Albenga Region (northern Italy) as potted plants. In February of 2008, 3-month-old plants grown in plastic pots (14-cm diameter) under glasshouse on heated benches started showing symptoms of a previously unknown blight. The temperature in the glasshouse ranged between 16 and 20°C and plants were watered by sprinkle irrigation. Leaves, starting from the basal ones, showed small, brown spots that spread across the entire leaf surface. Subsequently, the crown and stem were infected, and the pathogen developed abundant, soft, gray mycelium on leaves and stems and in the middle of the heads of S. rebaudiana. Flowers were not present when the symptoms appeared. Severely infected leaves dried out and became necrotic. The disease was observed in one nursery in which 5% of the plants were affected. The margins of the lesions were excised from leaves, immersed in a solution containing 1% sodium hypochlorite, and then cultured on potato dextrose agar (PDA) medium. A fungus produced abundant mycelium when incubated under constant fluorescent light at 22 ± 1°C after 10 days. The conidia were smooth, hyaline, ovoid, measuring 15.5 to 8.3 × 11.1 to 7.3 (average 11.6 × 8.6) μm, and were similar to those described for Botrytis cinerea. Conidiophores were slender and branched with enlarged apical cells bearing conidia on short sterigmata. The identity of the fungus was also confirmed by the production of numerous, small, black sclerotia on PDA plates incubated for 20 days at 8 ± 1°C. Sclerotia were dark and irregular with a diameter ranging from 1 to 2 mm. These morphological characters identified the fungus as B. cinerea (2). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 780-bp segment showed a 100% homology with the sequence of Botryotinia fuckeliana (perfect stage of B. cinerea). The nucleotide sequence has been assigned GenBank Accession No. FJ486270. Pathogenicity tests were performed by spraying leaves of six healthy 6-month-old potted S. rebaudiana plants with a 105 conidia/ml suspension. Six plants sprayed with water only served as controls. Plants were covered with plastic bags for 3 days after inoculation to maintain high relative humidity and were placed in a growth chamber at 20 ± 1°C. The first foliar lesions developed on leaves 4 days after inoculation, whereas control plants remained healthy. B. cinerea was consistently reisolated from these lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of B. cinerea on S. rebaudiana in Italy. The disease has been reported in Ukraine (3) and more recently in Japan (4). The economic importance of this disease is at the moment limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (3) J. Takeuch and H. Horie. Annu. Rep. Kanto-Tosan Plant Prot. Soc. 53:87, 2006. (4) V. F. Zubenko et al. Zash. Rast. 18, 1991.

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First Report of Botrytis Blight Caused by Botrytis cinerea on Lavandula stoechas in Italy

Plant Disease ◽

10.1094/pdis-94-3-0380a ◽

2010 ◽

Vol 94 (3) ◽

pp. 380-380 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

P. Pensa ◽

M. L. Gullino

Keyword(s):

Botrytis Cinerea ◽

Its Region ◽

Northern Italy ◽

Fluorescent Light ◽

Pathogenicity Test ◽

Commonwealth Mycological Institute ◽

First Report ◽

Potted Plants ◽

Lavandula Stoechas ◽

Plastic Bags

Lavandula stoechas or French lavender (Labiatae) is a perennial shrub that produces pinkish purple flowers and is endemic to the Mediterranean Region. In the Albenga area (northern Italy), this species is grown as a potted plant. In October 2008, symptoms of a previously unknown blight were observed in a commercial glasshouse in the Savona Province (northern Italy) on 10% of 3-month-old ‘Sugarberry Ruffles’ potted plants. Glasshouse temperatures ranged between 11 and 32°C (average of 21°C) and plants were overhead irrigated. Initially, leaves and stems appeared chlorotic. Subsequently, necrotic lesions developed on infected tissues. After 10 days, fluffy, gray mycelium became apparent on symptomatic tissue, especially on the basal parts of the plants. Severely infected plants eventually died. Tissues were excised from diseased leaves, immersed in an aqueous solution of 1% sodium hypochlorite for 10 s, and then cultured on potato dextrose agar (PDA). A fungus developed abundant mycelium when incubated under constant fluorescent light at 22 ± 1°C. Numerous small sclerotia developed on PDA plates incubated for 20 days at 8 ± 1°C. Sclerotia were dark and irregular and measured 2 to 5 × 1 to 2 mm. Conidia were smooth, gray, unicellular, ovoid, measured 9.4 to 13.6 × 6.2 to 7.9 (average 11.4 × 7.2) μm, and similar to those described for Botrytis cinerea (2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 573-bp segment was 100% similar to the sequence of Botryotinia fuckeliana (perfect stage of B. cinerea). The nucleotide sequence has been assigned GenBank Accession No. GQ375747. Pathogenicity tests were performed by spraying leaves of 9-month-old healthy potted L. stoechas ‘Blue Star’, ‘Madrid Blue’, ‘Madrid Purple’, and ‘Madrid White’ plants with a 7.5 × 104 conidia/ml spore suspension obtained from 7-day-old PDA cultures. Each plant received 5 ml of inoculum. Plants sprayed with water only served as controls. Four plants per treatment and per cultivar were used. Plants were covered with plastic bags for 4 days after inoculation and maintained in a growth chamber at 20 ± 1°C. The first lesions developed on flowers 5 days after inoculation, and 2 days later, lesions developed on leaves and stems. Lesions were similar to those observed in the commercial glasshouse. Control plants remained healthy. B. cinerea was consistently reisolated from these lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of B. cinerea on L. stoechas in Italy as well as worldwide. Botrytis blight previously has been described on L. angustifolia in Japan (4) and Poland (3). In Italy, the economic importance of the disease is currently still limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) L. B. Orlikowski and A. Valjiuskaite. Acta Mycol, 42:193, 2007. (4) J. Takeuch and H. Horie. Annu. Rep. Kanto-Tosan Plant Prot. Soc. 53:87, 2006.

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First Report of Botrytis Blight Caused by Botrytis cinerea on Chamelaucium uncinatum in Italy

Plant Disease ◽

10.1094/pdis-93-9-0968b ◽

2009 ◽

Vol 93 (9) ◽

pp. 968-968 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

F. Tinivella ◽

M. L. Gullino

Keyword(s):

Botrytis Cinerea ◽

Its Region ◽

Northern Italy ◽

Fluorescent Light ◽

Pathogenicity Test ◽

Commonwealth Mycological Institute ◽

First Report ◽

Potted Plants ◽

Plastic Bags ◽

Chamelaucium Uncinatum

Chamelaucium uncinatum (wax flower), an evergreen shrub belonging to the Myrtaceae family, is suitable for growing in containers. In the Albenga area (northern Italy), this species is grown as a potted plant. In April 2009, symptoms of a previously unknown blight were observed in a commercial glasshouse in the Savona Province (northern Italy) on 80% of 500 potted plants of cv. Snow Flake. Glasshouse temperatures ranged between 16 and 22°C and plants were drip irrigated. Initially, leaves and calyces appeared chlorotic. Subsequently, necrotic lesions developed on flower stalks and occasionally the corollas. After 10 days, soft, gray mycelium became apparent on symptomatic tissue, especially on the foliage. Severely infected leaves and flowers eventually became completely necrotic and abscised. Tissues were excised from diseased leaves, immersed in a solution containing 1% sodium hypochlorite for 10 s, and then cultured on potato dextrose agar (PDA) medium. A fungus developed abundant mycelium when incubated under constant fluorescent light at 23 ± 1°C. Numerous, small sclerotia also developed on PDA plates incubated for 20 days at 8 ± 1°C. Sclerotia were dark, spheroid, and measured 0.5 to 1.8 × 0.5 to 1.5 (average 1.2 × 1.0) mm. Conidia were smooth, gray, unicellular, ovoid, measured 8.5 to 11.1 × 7.1 to 8.6 (average 9.7 × 7.8) μm, and similar to those described for Botrytis cinerea (2). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 495-bp segment showed 100% similarity with the sequence of Botryotinia fuckeliana (perfect stage of B. cinerea). The nucleotide sequence has been assigned the GenBank Accession No. GQ149477. Pathogenicity tests were performed by spraying leaves of healthy potted C. uncinatum with a spore suspension (2 × 104 conidia/ml) obtained from PDA cultures of the pathogen. Each plant received 30 ml of the inoculum. Plants sprayed with water only served as controls. Three plants per treatment were used. Plants were covered with plastic bags for 5 days after inoculation and maintained in a growth chamber at 20 ± 1°C. The first foliar lesions developed on leaves 7 days after inoculation and were similar to those observed in the commercial glasshouse, whereas control plants remained healthy. B. cinerea was consistently reisolated from these lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of B. cinerea on C. uncinatum in Italy as well as in Europe. The disease has been reported in California (3) and more recently in South Africa (4). In Italy, the economic importance of the disease is currently still limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) A. M. French. California Plant Disease Host Index. Calif. Dep. Food Agric., Sacramento, 1989. (4) L. Swart and S. Coertze. Plant Dis. 86:440, 2002.

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First Report of Gray Mold Caused by Botrytis cinerea on Greenhouse-Grown Zucchini in Korea

Plant Disease ◽

10.1094/pdis-01-13-0005-pdn ◽

2013 ◽

Vol 97 (8) ◽

pp. 1116-1116 ◽

Cited By ~ 1

Author(s):

W. Cheon ◽

Y. H. Jeon

Keyword(s):

New York ◽

Botrytis Cinerea ◽

Severe Disease ◽

Morphological Characteristics ◽

Its Region ◽

Gray Mold ◽

Greenhouse Production ◽

First Report ◽

Plastic Bags ◽

Diseased Fruit

In the winter of 2011, greenhouse-grown zucchini (Cucurbita pepo) in Andong City, Korea, showed severe disease symptoms on fruits and dying leaves of zucchini plants that resembled gray mold disease with about 20% yield loss. Symptoms included extensive growth of mycelia and gray conidia on stem and fruit lesions. Lesions expanded rapidly under cool, humid conditions. As the disease progressed, leaves, stems, and fruits became necrotic and were covered by an abundant, soft, gray, sporulating mycelium. Diseased fruit tissue was excised and surface sterilized by immersion in 2% NaOCl for 1 min, placed on PDA (potato dextrose agar), and incubated at 22°C. Fungal colonies were initially white and became gray to brown after 72 h. Analysis of light micrographs showed the presence of elliptical conidia on PDA that was 7.5 to 16.0 μm long and 5 to 10.5 μm wide. In culture, a few, black, small and large irregular sclerotia were produced. Microsclerotia were round, spherical or irregular in shape, and ranged from 1.0 to 3.3 and 1.2 to 3.4 mm (width and length). Conidiophores were slender and branched with enlarged apical cells bearing smooth, ash-colored conidia. These morphological characteristics identified the fungus as Botrytis cinerea (1). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1 (forward) and ITS4 (reverse) primer set (ITS1: 5′-TCCGTAGGTGAACCTGCGG-3′, ITS4: 5′-TCCTCCGCTTATTGATATGC-3′) and sequenced (2). BLAST analysis of the PCR product showed that the sequence had 100% identity with the nucleotide sequences for B. cinerea. Pathogenicity tests were performed by placing mycelium fragments (1 cm2) of PDA cultures on zucchini fruits. Controls were treated with PDA alone. Five replicates for the inoculated and control plants were used. All fruits were covered with plastic bags and incubated in a growth chamber to maintain 90 to 100% relative humidity at 22°C. Typical symptoms appeared 2 to 6 days after inoculation. The inoculated plants developed typical gray mold symptoms with gray sporulating lesions, while controls remained healthy with no lesions. B. cinerea reisolated from the inoculated tissues was morphologically identical to the original isolates. In a cold outside (below 0°C), wet greenhouse, plants are likely to be exposed to resident Botrytis populations and if the gray mold disease occurs, it can spread on zucchini plants very fast, in 2 days to a week inside a 100 m2 greenhouse. Therefore, gray mold disease could have a significant impact on greenhouse production of zucchini. To our knowledge, this is the first report of B. cinerea causing gray mold of greenhouse-grown zucchini in Korea. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (2) T. J. White et al. PCR Protocols. Academic Press, Inc., New York, 1990.

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First Report of Botrytis Blight Caused by Botrytis cinerea on Gaura lindheimeri in Italy

Plant Disease ◽

10.1094/pdis-93-1-0107c ◽

2009 ◽

Vol 93 (1) ◽

pp. 107-107

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

P. Pensa ◽

M. L. Gullino

Keyword(s):

Botrytis Cinerea ◽

Leaf Tissue ◽

Fluorescent Light ◽

Pathogenicity Test ◽

First Report ◽

Perennial Plant ◽

Potted Plants ◽

Plastic Bags ◽

Pathogenicity Tests ◽

Basal Portion

Gaura lindheimeri (wand flower) is a perennial plant belonging to the Onagraceae family that is used for perennial borders in xeric and mesic landscapes. It produces flowers floating above the plant like small, dancing butterflies. This plant is becoming popular in the Albenga Region (northern Italy) where white and rose varieties are grown as potted plants. In January of 2008, 5-month-old ‘Whirling Butterflies’ plants grown in plastic pots (14 cm in diameter) in the open field started showing symptoms of a previously unknown blight. When the disease developed, temperatures ranged between 3 and 17°C (average 9°C) and average relative humidity was 64%. Small, brown spots appeared on the basal portion of leaves first, eventually spreading to cover entire leaves. Subsequently, the pathogen developed abundant, soft gray mycelium on affected leaf tissue. Severely infected leaves eventually became completely rotten and desiccated. Sixty percent of plants were affected by the disease. Tissues were excised from diseased leaves, immersed in a solution containing 1% sodium hypochlorite for 10 s, and then cultured on potato dextrose agar (PDA) medium. The fungus produced abundant mycelium on PDA medium when incubated under constant fluorescent light at 22 ± 1°C. The conidia were smooth, hyaline, globoid, measuring 11.8 to 9.4 × 8.3 to 6.6 (average 10.7 × 7.4) μm, and are similar to those described for Botrytis cinerea. The identity of the pathogen was also confirmed by the production of numerous sclerotia on PDA plates incubated for 20 days at 8 ± 1°C. Sclerotia were dark, irregular, and measured 3 to 4 × 2 to 3 mm. The fungus was identified as B. cinerea on the basis of these characters (1). Pathogenicity tests were performed by spraying leaves of healthy, potted 8-month-old G. lindheimeri ‘Whirling Butterflies’ plants with a 105 conidia/ml suspension. Plants sprayed with water only served as controls. Five plants per treatment were used. Plants were covered with plastic bags for 6 days after inoculation and maintained in a growth chamber at 20 ± 1°C. The first foliar lesions developed on leaves 5 days after inoculation, whereas control plants remained healthy. B. cinerea was consistently reisolated from these lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of B. cinerea on G. lindheimeri in Italy. The economic importance of this disease will increase with the increased cultivation of this species. Reference: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972.

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First Report of Leaf Spot Caused by Botrytis cinerea on Cardamine hupingshanensis in China

Plant Disease ◽

10.1094/pdis-04-21-0698-pdn ◽

2021 ◽

Author(s):

Jun Guo ◽

Jin Chen ◽

Zhao Hu ◽

Jie Zhong ◽

Jun Zi Zhu

Keyword(s):

Botrytis Cinerea ◽

Morphological Characteristics ◽

Gray Mold ◽

Hunan Province ◽

Conidial Suspension ◽

Heat Shock Protein 60 ◽

Basal Cells ◽

Single Spore ◽

Internal Transcribed Spacer Region ◽

First Report

Cardamine hupingshanensis is a selenium (Se) and cadmium (Cd) hyperaccumulator plant distributed in wetlands along the Wuling Mountains of China (Zhou et al. 2018). In March of 2020, a disease with symptoms similar to gray mold was observed on leaves of C. hupingshanensis in a nursery located in Changsha, Hunan Province, China. Almost 40% of the C. hupingshanensis (200 plants) were infected. Initially, small spots were scattered across the leaf surface or margin. As disease progressed, small spots enlarged to dark brown lesions, with green-gray, conidia containing mold layer under humid conditions. Small leaf pieces were cut from the lesion margins and were sterilized with 70% ethanol for 10 s, 2% NaOCl for 2 min, rinsed with sterilized distilled water for three times, and then placed on potato dextrose agar (PDA) medium at 22°C in the dark. Seven similar colonies were consistently isolated from seven samples and further purified by single-spore isolation. Strains cultured on PDA were initially white, forming gray-white aerial mycelia, then turned gray and produced sclerotia after incubation for 2 weeks, which were brown to blackish, irregular, 0.8 to 3.0 × 1.2 to 3.5 mm (n=50). Conidia were unicellular, globose or oval, colourless, 7.5 to 12.0 × 5.5 to 8.3 μm (n=50). Conidiophores arose singly or in group, straight or flexuous, septate, brownish to light brown, with enlarged basal cells, 12.5 to 22.1 × 120.7 to 310.3 μm. Based on their morphological characteristics in culture, the isolates were putatively identified as Botrytis cinerea (Ellis 1971). Genomic DNA of four representative isolates, HNSMJ-1 to HNSMJ-4, were extracted by CTAB method. The internal transcribed spacer region (ITS), glyceraldehyde-3-phosphate dehydrogenase gene (G3PDH), heat-shock protein 60 gene (HSP60), ATP-dependent RNA helicaseDBP7 gene (MS547) and DNA-dependent RNA polymerase subunit II gene (RPB2) were amplified and sequenced using the primers described previously (Aktaruzzaman et al. 2018) (MW820311, MW831620, MW831628, MW831623 and MW831629 for HNSMJ-1; MW314722, MW316616, MW316617, MW316618 and MW316619 for HNSMJ-2; MW820519, MW831621, MW831627, MW831624 and MW831631 for HNSMJ-3; MW820601, MW831622, MW831626, MW831625 and MW831630 for HNSMJ-4). BLAST searches showed 99.43 to 99.90% identity to the corresponding sequences of B. cinerea strains, such as HJ-5 (MF426032.1, MN448500.1, MK791187.1, MH727700.1 and KX867998.1). A combined phylogenetic tree using the ITS, G3PDH, HSP60 and RPB2 sequences was constructed by neighbor-joining method in MEGA 6. It revealed that HNSMJ-1 to HNSMJ-4 clustered in the B. cinerea clade. Pathogenicity tests were performed on healthy pot-grown C. hupingshanensis plants. Leaves were surface-sterilized and sprayed with conidial suspension (106 conidia/ mL), with sterile water served as controls. All plants were kept in growth chamber with 85% humidity at 25℃ following a 16 h day-8 h night cycle. The experiment was repeated twice, with each three replications. After 4 to 7 days, symptoms similar to those observed in the field developed on the inoculated leaves, whereas controls remained healthy. The pathogen was reisolated from symptomatic tissues and identified using molecular methods, confirming Koch’s postulates. B. cinerea has already been reported from China on C. lyrate (Zhang 2006), a different species of C. hupingshanensis. To the best of our knowledge, this is the first report of B. cinerea causing gray mold on C. hupingshanensis in China and worldwide. Based on the widespread damage in the nursery, appropriate control strategies should be adopted. This study provides a basis for studying the epidemic and management of the disease.

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First Report of Web Blight on Oregano (Origanum vulgare L.) Caused by Rhizoctonia solani AG-1-IB in Italy

Plant Disease ◽

10.1094/pdis-02-13-0138-pdn ◽

2013 ◽

Vol 97 (8) ◽

pp. 1119-1119 ◽

Cited By ~ 2

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

P. Pensa ◽

A. Poli ◽

M. L. Gullino

Keyword(s):

Rhizoctonia Solani ◽

Its Region ◽

Morphological Characters ◽

Anastomosis Group ◽

Morphological Identification ◽

Pathogenicity Test ◽

Origanum Vulgare ◽

First Report ◽

Plastic Bags ◽

Hyphal Diameter

Origanum vulgare L., common name oregano, family Labiatae, is grown for its aromatic and medicinal properties and as ornamental. In the fall of 2012, a blight was observed in a farm located near Albenga (northern Italy) on 6% of 30,000 50-day-old plants, grown in trays in a peat/perlite mix. Semicircular, water soaked lesions appeared on leaves and stems, starting from the basal ones. As the disease progressed, blighted leaves turned brown, withered, clung to the shoots, and matted on the surrounding foliage. Eventually, infected plants died. Leaf and stem fragments taken from the margin of the diseased tissues belonging to 10 plants were disinfected for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA). A fungus with the morphological characters of Rhizoctonia solani was consistently recovered. Three isolates of R. solani obtained from affected plants were successfully anastomosed with R. solani isolate AG 1 (ATCC 58946). Three pairings were made for each tester strain. The hyphal diameter at the point of anastomosis was reduced, the anastomosis point was obvious, and death of adjacent cells was observed. Results were consistent with other reports on anastomosis reactions (2). Isolates from oregano were paired with R. solani isolates AG 2, 3, 4, 6, 7, or 11 and examined microscopically. Anastomosis was not observed in any of the pairings. Tests were conducted twice. Mycelium of 10-day-old isolates from oregano appeared reddish brown, coarse, and radiate. Numerous dark brown sclerotia, 0.3 to 1.0 mm diameter (average 0.7) developed within 10 days after transfer of mycelia to PDA in 90 mm diameter petri dishes at 21 to 24°C. The descriptions of mycelium and sclerotia were typical for subgroup IB Type 1 (4). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 and sequenced. BLASTn analysis (1) of the 538 bp showed a 99% homology with the sequence of R. solani FJ746937, confirming the morphological identification of the species. The nucleotide sequence has been assigned the GenBank Accession KC493638. For pathogenicity tests, one of the isolates assigned to the anastomosis group AG-1-IB was tested by placing 9 mm diameter mycelial disks removed from PDA 10-day-old cultures of the fungus on leaves of 90-day-old oregano plants (n = 35). Thirty-five plants inoculated with non-inoculated PDA disks served as controls. Plants were covered with plastic bags and maintained in a growth chamber at 25 ± 1°C with 12 h light/dark. The first symptoms, similar to those observed in the farm, developed 3 days after inoculation. Nine days after the artificial inoculation, 50% of plants were dead. About 10 colonies of R. solani were reisolated from infected leaves of inoculated plants. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. Symptoms caused by R. solani have been recently observed on O. vulgare in Greece (3). This is, to our knowledge, the first report of blight of O. vulgare caused by R. solani in Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res., 25:3389, 1997. (2) D. E. Carling. Grouping in Rhizoctonia solani by hyphal anastomosis reactions. In: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease control. Kluwer Academic Publishers, The Netherlands, pp. 37-47, 1996. (3) C. D. Holevas et al. Benaki Phytopathol. Inst., Kiphissia, Athens, 19:1-96, 2000. (4) R. T. Sherwood. Phytopathology 59:1924, 1969.

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First Report of Powdery Mildew Caused by Podosphaera xanthii on Calendula officinalis in Italy

Plant Disease ◽

10.1094/pdis-92-1-0174c ◽

2008 ◽

Vol 92 (1) ◽

pp. 174-174 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

G. Gilardi ◽

M. L. Gullino

Keyword(s):

Powdery Mildew ◽

Its Region ◽

Pathogenicity Test ◽

Podosphaera Xanthii ◽

Calendula Officinalis ◽

First Report ◽

Potted Plants ◽

Blastn Analysis ◽

Voucher Specimens ◽

Pot Marigold

Calendula officinalis L. (Asteraceae) (pot marigold or English marigold) is an ornamental species grown in gardens and as potted plants for the production of cut flower. It was also used in ancient Greek, Roman, Arabic, and Indian cultures as a medicinal herb as well as a dye for fabrics, foods, and cosmetics. During the summer of 2007, severe outbreaks of a previously unknown powdery mildew were observed on plants in several gardens near Biella (northern Italy). Both surfaces of leaves of infected plants were covered with dense, white mycelia and conidia. As the disease progressed, infected leaves turned yellow and died. Mycelia and conidia also were observed on stems and flower calyxes. Conidia were hyaline, ellipsoid, born in short chains (four to six conidia per chain), and measured 27.0 to 32.1 (31.4) × 12.9 to 18.4 (18.2) μm. Conidiophores measured 49 to 77.3 (67.2) × 8 to 13.3 (10.8) μm and showed a foot cell measuring 44 to 59 (51.9) × 9.3 to 12.6 (11.3) μm followed by one shorter cell measuring 15.6 to 18.9 (17.6) × 10.4 to 13.6 (12.2) μm. Fibrosin bodies were present. Chasmothecia were spherical, amber colored, with a diameter of 89 to 100 (94.5) μm. Each chasmothecium contained one ascus with eight ascospores. On the basis of its morphology, the causal agent was determined to be a Podosphaera sp. (2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 588 bp showed a 100% homology with the sequence of Podosphaera xanthii (2). The nucleotide sequence has been assigned GenBank Accession No. EU100973. Pathogenicity was confirmed through inoculations by gently pressing diseased leaves onto leaves of healthy C. officinalis plants. Five plants were inoculated. Five noninoculated plants served as control. Plants were maintained in a greenhouse at temperatures ranging from 20 to 26°C. Eleven days after inoculation, typical symptoms of powdery mildew developed on inoculated plants. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. To our knowledge, this is the first report of powdery mildew on C. officinalis in Italy. C. officinalis was previously described as a host to Sphaerotheca fuliginea (synonym S. fusca) in Great Britain (4) as well as in Romania (3). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (3) E. Eliade. Rev. Appl. Mycol. 39:710, 1960. (4) F. J. Moore. Rev. Appl. Mycol. 32:380, 1953.

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First Report of Botrytis Blight Caused by Botrytis cinerea on Platycodon grandiflorum in Italy

Plant Disease ◽

10.1094/pdis-93-9-0969b ◽

2009 ◽

Vol 93 (9) ◽

pp. 969-969

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

United States ◽

Botrytis Cinerea ◽

Its Region ◽

The United States ◽

Fluorescent Light ◽

Pathogenicity Test ◽

Commonwealth Mycological Institute ◽

Platycodon Grandiflorum ◽

First Report ◽

Bedding Plant

Platycodon grandiflorum (balloon flower), a perennial plant belonging to the Campanulaceae family, is widely grown as a bedding plant in temperate gardens. This species is characterized by the ability to bloom profusely throughout the summer into early fall and for its white to blue and pink flowers. In September 2008, symptoms of a previously unknown blight were observed in six gardens located in the Biella Province of northern Italy. When the disease developed, temperatures ranged between 15 and 22°C with frequent rains (149.8 mm of rainfall registered in September 2008 by the meteorological station of Oropa, located in the same area in which the disease appeared). Initially, leaves and petioles appeared chlorotic. Subsequently, lesions developed on the stems and flowers were sometimes affected. In each garden examined, approximately 50% of the plants were affected by the disease. A soft, gray mycelium was observed on symptomatic tissues, especially the stems. Severely infected leaves and stems eventually became completely rotted and later desiccated. Diseased tissue was excised from affected leaves, immersed in a solution containing 1% sodium hypochlorite for 10 s, and then cultured on potato dextrose agar (PDA) medium. A fungus developed that produced abundant mycelium on PDA medium when incubated under constant fluorescent light at 22 ± 1°C. Numerous sclerotia were produced on PDA plates incubated for 20 days at 8 ± 1°C. Sclerotia were dark, irregular, and measured 1 to 3.5 × 0.9 to 2.5 (average 2.1 × 1.5) mm. Conidia were smooth, ash colored, unicellular, ovoid, and measured 11 to 19 × 7 to 13 (average 15 × 11) μm. These morphological features were typical of those described for Botrytis cinerea (2). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 539-bp segment showed 100% similarity with the sequence of Botryotinia fuckeliana (perfect stage of B. cinerea). The nucleotide sequence has been assigned the GenBank Accession No. GQ149480. Pathogenicity tests were performed by placing 1-cm2 fragments removed from PDA cultures of B. cinerea isolated from balloon flower on leaves of healthy potted P. grandiflorum plants (4-month-old). Five fragments were placed on each plant. Plants inoculated with PDA alone served as controls. Ten plants per treatment were used. Plants were covered with plastic bags for 5 days after inoculation and maintained in a greenhouse at temperatures between 18 and 23°C. The first foliar lesions developed on leaves 3 days after inoculation, and after 5 days, 80% of the leaves were severely infected. As the infection progressed after the inoculation, the stems also became infected. Control plants remained healthy. B. cinerea was consistently reisolated from leaf and stem lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of B. cinerea on P. grandiflorum in Italy, as well as in Europe. Blight on balloon flower attributed to Botrytis spp. was previously reported in the United States (3). References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989.

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First Report of Gray Mold on Amorphophallus muelleri Caused by Botrytis cinerea in China

Plant Disease ◽

10.1094/pdis-08-13-0855-pdn ◽

2014 ◽

Vol 98 (5) ◽

pp. 692-692 ◽

Cited By ~ 2

Author(s):

L. Yu ◽

J. R. Zhao ◽

S. G. Xu ◽

Y. Su ◽

D. Gao ◽

...

Keyword(s):

Botrytis Cinerea ◽

Its Region ◽

Gray Mold ◽

Gelling Agent ◽

Commonwealth Mycological Institute ◽

Distilled Water ◽

First Report ◽

Calla Lily ◽

Specialty Crop ◽

Important Cash Crop

Amorphophallus muelleri is a perennial tuberous plant in the family Araceae. The name konjac is commonly used for the species of genus Amorphophallus that produce a polysaccharide, glucomannan. The latter, called konjac glucomannan, is extracted from the tubers of these species. Glucomannan is an excellent gelling agent used in food, pharmaceutical and chemical industry, a specialty crop grown as a source of glucomannan for industrial use. It is an important cash crop and thus contributes to poverty alleviation in southwest China. Its planting area is about 150 million mu (10 million ha). In July 2012, symptoms of an unknown blight were observed on 5 to 10% of A. muelleri flowers and seeds being grown for commercial seed production. Greenhouses temperatures ranged from 20 to 34°C (avg. 26°C). A light grey mycelium was observed on symptomatic tissues, especially flowers. Severely infected flowers and stems eventually rotted, then dried out. Diseased tissue was excised from affected flowers and surfaces and disinfected with 1% sodium hypochlorite, followed by 70% alcohol. The tissue was then rinsed in sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 26°C. Mycelial growth on PDA was initially whitish and turned gray with age. Dark appearing conidiophores bore botryose heads of hyaline, ellipsoid, unicellular conidia, grey in mass, measuring 7.2 (6.2 to 9.5) × 5.3 (4.5 to 6.0) μm. Black, irregular sclerotia formed at random in the culture. These morphological features were typical of those described for Botrytis cinerea (2). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced (1). BLAST analysis of a 557-bp segment had a 99% similarity with the sequence of Botryotinia fuckeliana (anamorph = B. cinerea). The representative nucleotide sequence has been assigned the GenBank Accession No. KC999986. On the basis of morphological and molecular results, the fungus isolated from diseased konjac flowers and flower tissue was confirmed to be B. cinerea. Pathogenicity tests: Inoculum was prepared from 7-day-old cultures on PDA. Six flowering A. muelleri in 1-liter pots were spray inoculated with a 1.0 × 106 conidia/ml suspension from 7-day-old PDA cultures. As a control, six healthy plants were sprayed with sterile distilled water. Each plant was covered with a transparent polyethylene bag for 3 days and maintained in a greenhouse at temperatures between 20 and 26°C. After 8 days, small, round to irregular brown spots developed on both flowers and stems, which finally blighted. Water-treated plants remained symptomless. Koch's postulates were fulfilled when the pathogen was re-isolated from the diseased organs. Blight on common calla lily (calla lily and Amorphophallus are in the same family, different genera) flower attributed to B. cinerea was previously reported in Argentina (3). To our knowledge, this is the first report of the presence of B. cinerea on A. muelleri in China. References: (1) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) M. C. Rivera and S. E. Lopez. Plant Dis. 90:970, 2006.

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