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Spadaro D, Lorè A, Amatulli MT, Garibaldi A, Gullino ML. First Report of Penicillium griseofulvum Causing Blue Mold on Stored Apples in Italy (Piedmont). PLANT DISEASE 2011; 95:76. [PMID: 30743679 DOI: 10.1094/pdis-08-10-0568] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In northern Italy, blue mold can occur generally on apples after 3 months of storage under controlled atmospheres. The mold can be caused by Penicillium griseofulvum Dierckx (synonym P. urticae Bainier). During 2008, several postharvest fruit rots were observed on apples (cv. Golden Delicious) after 180 to 240 days of storage at 1°C. Approximately 8% of the fruits showed blue mold. Apples had been cultivated in Aosta (Aosta Valley Region) and Lagnasco (Piedmont Region). Infected fruits showed soft, watery, brown spots enlarging rapidly at 20°C. There was a distinct margin between soft rotted flesh and firm healthy tissues. Under high humidity, masses of blue-green spores formed on the surface of the lesion. Apple fruit excisions from the margin between the healthy and diseased tissues were plated on potato dextrose agar (PDA), pH 5.6. The recovered fungus produced abundant mycelium and conidia, with the colonies attaining a diameter of 2.0 to 2.4 cm after 7 days at 20 ± 2°C on PDA. Colonies were mostly yellow-green, with a yellowish-to-orange brown underside. Conidiophores were mononematous or loosely synnematous, hyaline, with branches strongly divergent. Phialides were cylindrical with a very short neck. Conidia were ellipsoidal, sometimes subglobose, 2.5 to 3.5 × 2.2 to 2.5 μm, hyaline to greenish. Preliminary morphological identification of the fungus (2) was confirmed by PCR using genomic DNA extracted from mycelia of pure cultures. Two sequences, obtained through the amplification of ribosomal region ITS1-5.8S-ITS2 (1), were blast searched in GenBank and showed 99% sequence coverage and 99% similarity to ribosomal sequences of P. griseofulvum. Two sequences were deposited in GenBank with Accession Nos. HQ012498 (a strain from Aosta Valley) and HQ012499 (a strain from the Piedmont Region). Pathogenicity was tested on 20 ripe fruits each of four apple cultivars (Golden Delicious, Red Chief, Granny Smith, and Royal Gala). Fruits were surface sterilized with 1% sodium hypochlorite. Conidial suspensions (30 μl of 105 conidia/ml) of the fungus were placed on artificial wounds generated on the apple surface. Control fruits were treated with sterile water. Seven days after inoculation, the symptoms were reproduced on the four cultivars and P. griseofulvum was reisolated on PDA from the inoculated fruits of all four cultivars. Control fruits were symptomless. An analysis using high-performance liquid chromatography with diode array of the rotting tissues associated with inoculated fruits of all four cultivars (4) confirmed, as in the case of other strains of P. griseofulvum, the production of the mycotoxin patulin (12.1 to 44.4 mg kg-1). Previously, P. griseofulvum was reported on apple in other countries such as the United States (3), Japan, Egypt, and Brazil. To our knowledge, this is the first report of P. griseofulvum on apples during storage in Italy. References: (1) R. Nilsson et al. FEMS Microbiol. Lett. 296:97, 2009. (2) R. A. Samson and J. L. Pitt. Integration of Modern Taxonomic Methods for Penicillium and Aspergillus Classification. Harwood Academic Publishers, Singapore, 2001. (3) P. G. Sanderson and R. A. Spotts. Phytopathology 85:103, 1995. (4) D. Spadaro et al. Food Addit. Contam. B 1:134, 2008.
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Spadaro D, Ciavorella AA, Lopez-Reyes JG, Garibaldi A, Gullino ML. Effect of culture age, protectants, and initial cell concentration on viability of freeze-dried cells of Metschnikowia pulcherrima. Can J Microbiol 2010; 56:809-15. [PMID: 20962903 DOI: 10.1139/w10-068] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of freeze-drying using different lyoprotectants at different concentrations on the viability and biocontrol efficacy of Metschnikowia pulcherrima was evaluated. The effects of initial yeast cell concentration and culture age on viability were also considered. Yeast cells grown for 36 h were more resistant to freeze-drying than were 48 h cells. An initial concentration of 10⁸ cells·mL⁻¹ favoured the highest survival after freeze-drying. When maltose (25%, m/v) was used as protectant, a high cell viability was obtained (64.2%). Cells maintained a high viability after 6 months of storage at 4 °C. The biocontrol efficacy of freeze-dried cells was similar to the activity of fresh cells on 'Gala' apples and was slightly lower on 'Golden Delicious' apples. After optimizing freeze-drying conditions, the viability of M. pulcherrima cells was similar to that obtained in other studies. The results constitute a first step towards the commercial development of M. pulcherrima as a biocontrol agent.
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Garibaldi A, Gilardi G, Gullino ML. First Report of Collar and Root Rot Caused by Phytophthora tentaculata on Witloof Chicory (Cichorium intybus) in Italy. PLANT DISEASE 2010; 94:1504. [PMID: 30743403 DOI: 10.1094/pdis-03-10-0206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Witloof chicory (Cichorium intybus L.) is an important crop in Italy where most of the crop is still produced in soil. In September 2009, chicory plants (cv. Pan di Zucchero) grown on a commercial farm in Tarquinia (central Italy) showed symptoms of a previously unknown disease. Symptoms, observed 20 days after transplanting, consisted of stunting, yellowing of leaves, and a crown and root rot. Affected plants turned brown, wilted, and eventually died. At the soil level, dark brown-to-black water-soaked lesions coalesced and often girdled the stem. All of the crown and root system was affected. At this location, the disease was severe and widespread, with 60% of observed plants being affected. A Phytophthora-like organism was consistently isolated on a medium selective for oomycetes (4) after disinfestation of lower stem and root pieces of C. intybus for 1 min in a solution containing 1% NaOCl. Tissue fragments of 1 mm2 were excised from the margins of the root and crown lesions. The pathogen genus was identified as Phytophthora based on morphological and physiological features. Sporangia were produced for identification by growing a pure culture for 15 days on modified V8 juice agar medium (Campbell V8 juice [200 ml], agar [15 g], CaCo3 [0.5 g], and sterile water [800 ml]) under alternating light and dark (12/12 h). Sporangia were pyriform to ovoid, papillate, and measured 33.3 to 59.2 × 18.9 to 30.2 μm (average 39.9 × 25.8 μm). Chlamydospores developed in 28-day-old cultures and measured 21.3 to 30.2 × 19.5 to 29.7 μm (average 24.4 × 23.6 μm). Oogonia were globose and measured 26 to 41 μm (average 32.5 μm). Eighty percent of antheridia were paragynous. Amphyginous antheridia (15 to 20%) were also observed. Oospores were scarcely produced and measured 24 to 32 μm in diameter. The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 851-bp segment showed 100% homology with the sequence of Phytophthora tentaculata. The nucleotide sequence has been assigned GenBank Accession No. GU949536. Pathogenicity of this isolate was confirmed by inoculating C. intybus cv. Pan di Zucchero plants 20 days after transplant. The same isolate was grown for 15 days on a mixture of 70:30 wheat/hemp kernels and then 5 g/liter of the inoculum was mixed into a substrate containing a mixture of blond and black peat (15:85 vol/vol), pH 5.5. Five plants per 2-liter pot were transplanted and four replicates were carried out. Twenty noninoculated plants represented the control treatment. The trial was repeated. Plants were kept in two growth chambers at two temperatures (20 and 25°C). Symptoms similar to those observed in the field developed 7 days after inoculation. Twenty days later, 100 and 40% of the plants were dead at 25 and 20°C, respectively. Control plants remained symptomless. P. tentaculata was consistently reisolated from symptomatic plants. To our knowledge, this is the first report of P. tentaculata on C. intybus in the world ( http://nt.ars-grin.gov/fungaldatabases/index.cfm ). P. tentaculata was recently reported on lavender in Spain (2) and oregano in Italy (3). The economic importance of this disease is relatively low on most commercial farms. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) L. Alvarez et al. Plant Dis. 90:523, 2006. (3) P. Martini et al. Plant Dis. 93:843, 2009. (4) H. Masago et al. Phytopathology 67:425, 1977.
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Garibaldi A, Gullino M. EMERGING SOILBORNE DISEASES OF HORTICULTURAL CROPS AND NEW TRENDS IN THEIR MANAGEMENT. ACTA ACUST UNITED AC 2010. [DOI: 10.17660/actahortic.2010.883.2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Gilardi G, Gullino M, Garibaldi A, Baudino M. EFFECTIVENESS OF FUMIGANTS ALONE AND IN COMBINATION WITH GRAFTING TO CONTROL VERTICILLIUM WILT AND ROOT-KNOT NEMATODES IN EGGPLANT AND TOMATO BROWN ROOT ROT CAUSED BY COLLETOTRICHUM COCCODES. ACTA ACUST UNITED AC 2010. [DOI: 10.17660/actahortic.2010.883.21] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Spadaro D, Patharajan S, Kartikeyan M, Lorè A, Garibaldi A, Gullino ML. Specific PCR primers for the detection of isolates of Aspergillus carbonarius producing ochratoxin A on grapevine. ANN MICROBIOL 2010. [DOI: 10.1007/s13213-010-0131-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Garibaldi A, Bertetti D, Pensa P, Gullino ML. Powdery Mildew Caused by Golovinomyces biocellatus on Spearmint (Mentha spicata) in Italy. PLANT DISEASE 2010; 94:1171. [PMID: 30743697 DOI: 10.1094/pdis-94-9-1171a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spearmint (Mentha spicata) is grown for its aromatic and carminative oil and as an ornamental. During the fall of 2009, 4-month-old plants grown on a commercial farm located near Albenga (northern Italy) showed signs and symptoms of an unknown powdery mildew. The adaxial leaf surfaces were covered with white mycelia and conidia, while the abaxial surfaces were less infected. As the disease progressed, infected leaves turned yellow and wilted. Mycelia were also observed on stems. Conidia were hyaline, elliptical to doliform, borne in short chains (two to three conidia per chain), and measured 35 × 21 μm (30 to 43 × 18 to 26 μm). Conidiophores measured 86 × 11 μm (76 to 97 × 9 to 13 μm) followed by one to three shorter cells, measuring, respectively, 22 × 11 μm (13 to 28 × 9 to 15 μm). Fibrosin bodies were absent. Chasmothecia were not observed in the collected samples. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced (1) (GenBank Accession No. HM053470). The 567-bp amplicon had 100% homology with the sequence of Golovinomyces biocellatus (GenBank Accession No. AB307675). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of healthy M. spicata plants. Three plants were inoculated, while the same number of noninoculated plants served as a control. Plants were maintained at temperatures from 18 to 25°C. Twelve days after inoculation, typical symptoms of powdery mildew developed on inoculated plants. The fungus observed on inoculated plants was morphologically identical to that originally observed. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. G. biocellatus has been reported on Mentha spp. in Australia (3) and the United States (4) and the pathogen is present on other plant genera in Italy. A similar powdery mildew of M. spicata was attributed to Erysiphe orontii in the United States (2). The economic importance of this disease is currently limited in Italy because of the limited planting of this host, but potted aromatic plants represent a steadily increasing crop in Italy. 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) S. T. Koike and G. S. Saenz. Plant Dis. 83:399, 1999. (3) J. R. Liberato and J. H. Cunnington. Australas. Plant Dis. Notes 2:83, 2007. (4) D. B. Marcum et al. Plant Dis. 94:276, 2010.
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Gullino ML, Tinivella F, Garibaldi A, Kemmitt GM, Bacci L, Sheppard B. Mancozeb: Past, Present, and Future. PLANT DISEASE 2010; 94:1076-1087. [PMID: 30743728 DOI: 10.1094/pdis-94-9-1076] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This feature article reviews the broad-spectrum fungicide mancozeb. Introduced in 1962, it still plays a significant role in the world fungicide market. Mancozeb possesses a number of key attributes that have contributed toward its development into a globally important tool in modern chemical-based plant disease management. These attributes are discussed from the perspective of both public and private research.
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Spadaro D, Lorè A, Garibaldi A, Gullino M. Occurrence of ochratoxin A before bottling in DOC and DOCG wines produced in Piedmont (Northern Italy). Food Control 2010. [DOI: 10.1016/j.foodcont.2010.02.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Spadaro D, Garibaldi A, Gullino M. EFFICACY OF BIOCONTROL YEASTS AGAINST PENICILLIUM EXPANSUM AND PATULIN ON DIFFERENT CULTIVARS OF APPLE IN POSTHARVEST. ACTA ACUST UNITED AC 2010. [DOI: 10.17660/actahortic.2010.873.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Garibaldi A, Gilardi G, Gullino ML. First Report of Collar and Root Rot Caused by Pythium ultimum on Coriander in Italy. PLANT DISEASE 2010; 94:1167. [PMID: 30743716 DOI: 10.1094/pdis-94-9-1167b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Coriander, Coriandrum sativum L., is an annual herb in the family Apiaceae. This plant, native to southern Europe, northern Africa, and southeastern Asia, is used in cooking as well as for medicinal uses. The leaves are commonly referred to as cilantro. In October 2009, severe outbreaks of a previously unknown root rot were observed in a commercial field located in the Alessandria Province (northern Italy) on 20-day-old plants belonging to cv. Comune. Five percent of plants were affected, showing stunting and extensive chlorosis starting on external leaves that eventually wilted. Root systems and collars of diseased plants appeared rotted. In advanced stages, young leaves were affected and the plants eventually collapsed and tissues dried out. Tissue fragments of 1 mm2 were excised from the roots of infected plants, dipped in a solution containing 1% sodium hypochlorite, and plated on potato dextrose agar (PDA) and a medium selective for Oomycetes (3). Plates were incubated under constant fluorescent light at 22 ± 1°C for 4 to 5 days. One isolate, grown on V8 medium (vegetable mix, 300 g; agar, 15 g; CaCO3, 1.5g; and distilled water, 1 liter), and observed under a light microscope showed hyphae generally aseptate, ranging from 1.3 to 6.24 μm in diameter, and produced sporangia consisting of complexes of swollen hyphal branches. Oogonia were globose, smooth, and 20.3 to 33.4 (average 25.4) μm in diameter. Antheridia were monoclinous, extending from immediately below oogonium, and measured 10.8 to 17.8 × 7.6 to 12.7 (average 14.4 × 10.4) μm. Oospores were single, globose, aplerotic and thick walled, and 15.8 to 24.2 (average 17.8) μm in diameter. These morphological characters were used to identify the microorganism as a Pythium sp. (3). The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using the primers ITS1/ITS4 (2,4) and sequenced. BLAST analysis (1) of the 874-bp segment showed a 100% homology with the sequence of Pythium ultimum. The nucleotide sequence has been assigned the GenBank Accession No. GU478314. Pathogenicity tests were performed twice on coriander cv. Comune. Plants were grown in 2-liter pots containing a Brill Type 5 substrate (Brill Substrate GmbH & Co. KG, Niedersachsen, Germany) consisting of 15% blond peat, 85% black peat, pH 5.5 to 6, and pasteurized at 80°C for 30 min. The potting mix was infested at a rate of 5 g/liter with wheat and hemp kernels colonized with one strain of P. ultimum. Ten plants (1 plant per pot) were grown in the infested substrate and 10 plants were grown in noninfested substrate. Plants were kept in a growth chamber at 20°C. The first symptoms, consisting of reduced growth and chlorosis, developed within 7 days, while control plants remained healthy. P. ultimum was consistently isolated from the roots. To our knowledge, this is the first report of P. ultimum causing disease of coriander in Italy as well as worldwide. At this time, the economic importance of Pythium rot on coriander in Italy remains unknown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) W. Chen et al. Exp. Mycol.16:22, 1992. (3) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, Boca Raton, FL, 2002. (4) T. J. White et al. Page 38 in: PCR protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.
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Spadaro D, Amatulli MT, Garibaldi A, Gullino ML. First Report of Penicillium glabrum Causing a Postharvest Fruit Rot of Pomegranate (Punica granatum) in the Piedmont Region of Italy. PLANT DISEASE 2010; 94:1066. [PMID: 30743464 DOI: 10.1094/pdis-94-8-1066b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pomegranates (Punica granatum L.) are widely grown in many tropical and subtropical countries, especially in the moderate climate of the Mediterranean Region. In Italy, pomegranates are harvested from September to November. During October and November 2009 in Orbassano (Piedmont Region), postharvest fruit rots were observed on pomegranates (cv. Dente di Cavallo) after 30 days of storage at 5°C. Infected fruits showed soft, brown tissues that later were covered with masses of green mycelium, conidiophores, and hyphae of a fungus. Tissues were excised from the margin between the healthy and diseased tissues on pomegranates and plated on potato dextrose agar amended with 25 μg of streptomycin per liter. The fungus recovered from the tissue produced abundant mycelium and conidia on PDA after 7 days at 20 ± 2°C. Colonies consisting of dense erect conidiophores appeared velvety, gray-green, and the reverse of PDA culture was usually yellow to yellow-orange. Conidiophores were monoverticilliate, consisting of an unbranched stipe, smooth to finely roughened, and germinating in a whorl of 10 to 12 phialides. Phialides were flask shaped and 8 to 12 × 3 to 3.5 μm. Conidia were produced in typical long columns, globose to subglobose, smooth to finely roughened, with walls somewhat echinulate, and ranging from 3 to 3.5 μm in diameter (3). Preliminary morphological identification of the fungus was confirmed by PCR using genomic DNA extracted from the mycelia of pure cultures. One sequence, obtained through the amplification of ribosomal region ITS1-5.8S-ITS2 (4), was blasted in GenBank and showed 100% sequence coverage and 99% similarity to ribosomal sequences of Penicillium glabrum. The sequence was deposited in GenBank (Accession No. GU734815). Pathogenicity was tested on 10 ripe fruits (cv. Dente di Cavallo) surface sterilized with 1% sodium hypochlorite. To make inoculum, 7-day-old PDA cultures of the fungus were flooded with sterile water and scraped with a sterile spatula. Resulting suspensions were filtered through two layers of sterile cotton lint and brought to a final concentration of 105 conidia/ml with sterile distilled water. Conidial suspensions (30 μl) were placed on artificial wounds generated on the fruit surface. Control fruits were treated with sterile water. Ten days after inoculation, P. glabrum was reisolated on PDA from the inoculated fruit. Control fruits were symptomless. Previously, P. glabrum was reported on pomegranate in Greece (1). Other species of Penicillium, including P. expansum, P. implicatum, and P. purpurogenum, also were reported on pomegranate in the United States (2), Slovakia, and India, respectively. To our knowledge, this is the first report of P. glabrum causing a postharvest fruit rot of pomegranate in Italy. References: (1) G. A. Bardas et al. Plant Dis. 93:1347, 2009. (2) A. M. French. California Plant Disease Host Index. Calif. Dep. Food Agric., Sacramento, 1989. (3) R. A. Samson et al. Introduction to Food-Borne Fungi. Centraalbureau voor Schimmelcultures, Baarn, the Netherlands, 1995. (4) T. J. White et al. Page 315: in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.
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Garibaldi A, Gilardi G, Bertetti D, Gullino ML. First Report of Leaf Blight on Woodland Sage Caused by Rhizoctonia solani AG 1 in Italy. PLANT DISEASE 2010; 94:1071. [PMID: 30743475 DOI: 10.1094/pdis-94-8-1071c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Woodland sage (Salvia nemorosa L.; Lamiaceae) is a hardy herbaceous perennial plant that is easy to grow and propagate and is used in parks and grown as potted plants. During the summer of 2009 in a nursery near Torino in northern Italy, a leaf blight was observed on 30-day-old plants of cv. Blau Koenigin grown in pots under shade. Semicircular, water-soaked lesions developed on leaves just above the soil line at the leaf-petiole junction and later along leaf margins. Lesions expanded along the midvein until the entire leaf was destroyed. Blighted leaves turned brown, withered, and clung to the shoots. No symptoms were observed on the roots. Severely infected plants died. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with 25 mg/liter of streptomycin sulfate. A fungus with morphological characters of Rhizoctonia solani (3) was consistently recovered. Ten-day-old mycelium grown on PDA at 22 ± 1°C appeared light brown, rather compact, and with radial growth. Sclerotia were irregular and measured between 0.5 and 2 mm. Pairings were made with tester isolates of AG 1, 2, 3, 4, 5, 6, 7, 11, and AG B1. The only successful anastomosis was with tester isolate AG 1 (ATCC 58946). The hyphal diameter at the point of anastomosis was reduced, the anastomosis point was obvious, and cell death of adjacent cells was observed. Results were consistent with other reports on anastomosis reactions (2). The description of sclerotia of the isolate AG1 was typical for subgroup 1A Type 2 (3). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 688 bp showed a 100% homology with the sequence of R. solani AG-1A and the nucleotide sequence has been assigned (GenBank Accession No. HM044764). For pathogenicity tests, the inoculum of one isolate of R. solani from the nursery was prepared by growing the pathogen on PDA for 7 days. The foliage of 30-day-old potted plants of S. nemorosa cv. Blau Koenigin was artificially inoculated with an aqueous suspension of PDA and mycelium fragments (1 g per mycelium per plant) prepared from cultures with a blender. Plants were covered with plastic bags for 3 days. Plants inoculated with water and PDA fragments alone served as control treatments. Plants were maintained in a glasshouse at 20 to 25°C. The first symptoms, similar to those observed in the nursery, developed 7 days after foliar inoculation. R. solani was consistently reisolated from infected leaves. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. To our knowledge, this is the first report of leaf blight of S. nemorosa caused by R. solani in Italy as well as worldwide. The importance of the disease is still unknown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. Carling. Page 35 in: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. Kluwer Academic Publishers, the Netherlands, 1996. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St Paul, MN, 1991.
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Garibaldi A, Bertetti D, Gullino ML. First Report of Collar and Root Rot Caused by Phytophthora nicotianae on Oriental Paperbush (Edgeworthia papyrifera) in Italy. PLANT DISEASE 2010; 94:917. [PMID: 30743580 DOI: 10.1094/pdis-94-7-0917a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Edgeworthia papyrifera, Oriental paperbush, is a deciduous flowering shrub becoming increasingly popular because of its clove-like perfumed flowers appearing in late winter-early spring. During August of 2009 in a commercial nursery close to Maggiore Lake (Verbano-Cusio-Ossola Province) in northwest Italy, 2-year-old plants of E. papyrifera showed extensive chlorosis and root rot. Twigs wilted and died, dropping leaves in some cases. Most frequently, wilted leaves persisted on stems. At the soil level, dark brown-to-black water-soaked lesions formed and coalesced, girdling the stem. All of the crown and root system was affected. Infected plants died within 14 days of the appearance of symptoms. Disease was widespread and severe, affecting 90 of the 100 plants present. After disinfestation for 1 min in a solution containing 1% NaOCl, rotting root and collar pieces of E. papyrifera consistently produced a Phytophthora-like organism when plated on a medium selective for oomycetes (3). The pathogen was identified morphologically as Phytophthora nicotianae (= P. parasitica) (2). On V8 agar, coenocytic hyphae, 4 to 8 μm in diameter, formed fluffy, aerial colonies and spherical, intercalary chlamydospores, 21.0 to 36.5 (average 26.7) μm in diameter. Colonies grew well at 35°C and stopped growing at 40°C. Sporangia were produced by growing a pure hyphal-tip culture in a diluted, sterilized soil-extract. Sporangia were borne singly, laterally attached to the sporangiophore, were noncaducous, spherical to ovoid, papillate, and measured 28.6 to 55.2 × 22.4 to 45.1 (average 42.4 × 34.6) μm, length/breadth ratio (1.1:1)-1.2:1-(1.3:1). Papillae measured 3.1 to 7.6 (average 4.6) μm. The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified with primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 839-bp segment showed 99% homology with the sequence of P. nicotianae (No. AJ854296). The sequence has been assigned the GenBank No. GU353341. Pathogenicity of isolates Edg.1 and Edg.2 obtained, respectively, from the root and collar of an infected plant was confirmed by inoculating 1-year-old plants of E. papyrifera. Both strains were grown for 15 days on a mixture of 70:30 wheat/hemp kernels, and 4 g/liter of the inoculum was mixed into a substrate containing sphagnum peat moss/pumice/pine bark/clay (50:20:20:10 vol/vol). One plant per 3-liter pot was transplanted into the substrate and constituted the experimental unit. Five plants were used for each test strain and noninoculated control treatment; the trial was repeated once. All plants were kept in a greenhouse at 25 to 28°C. Plants inoculated with Edg.1 and Edg.2 developed chlorosis and root rot 18 and 14 days after the inoculation, respectively, and wilt rapidly followed. Control plants remained symptomless. P. nicotianae was consistently reisolated from inoculated plants. To our knowledge, this is the first report of P. nicotianae on E. papyrifera in Italy as well as worldwide. The current economic importance of the disease is minor due to the limited number of farms that grow this crop in Italy, although spread could increase as the popularity of plantings expand. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phtytopathological Society, St Paul, MN, 1996. (3) H. Masago et al. Phytopathology 67:425, 1977.
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Garibaldi A, Bertetti D, Amatulli MT, Gullino ML. First Report of Leaf Spot of Orange Coneflower (Rudbeckia fulgida) Caused by a Phoma sp. in Italy. PLANT DISEASE 2010; 94:788. [PMID: 30754322 DOI: 10.1094/pdis-94-6-0788a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Rudbeckia fulgida (orange coneflower) is an herbaceous species (Asteraceae) grown in full sun in flower beds and borders in gardens. In the summer of 2009, a previously unknown leaf spot was observed on R. fulgida plants in three private gardens located near Biella (northern Italy). Leaves of infected plants showed extensive and irregular, dark brown, necrotic lesions that were slightly sunken with a well-defined border. Lesions initially ranged from 0.5 to 3 mm in diameter and eventually coalesced to cover the entire leaf, which curled without falling. At a later stage, stems were also affected, causing death of the plant. The disease affected 90% of plants. Dark brown pycnidia, 68 to 195 × 60 to 165 (average 135 × 117) μm in diameter, containing hyaline (light gray in mass), and ellipsoid, nonseptate conidia measuring 4.0 to 7.0 × 2.4 to 3.5 (average 5.4 × 3.0) μm were observed on symptomatic tissue. On the basis of these morphological characteristics, the fungus was related to the genus Phoma. Diseased tissue was excised from the margin of lesions, immersed in a solution containing 1% sodium hypochlorite for 2 to 3 s, rinsed in sterile distilled water, and then cultured on potato dextrose agar (PDA) medium. Fungal colonies initially produced a white mycelium that became greenish gray when incubated at temperatures ranging between 22 and 25°C under alternating daylight and darkness (13 h of light and 11 h of dark). After 14 days of incubation, unicellular, cylindrical or truncated cone-shaped, light brown chlamydospores measuring 6 to 12 μm in diameter developed in long chains. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 498-bp segment showed 100% homology with a sequence of a Phoma sp. (EF585395). The nucleotide sequence of our isolate was assigned GenBank Accession No. GU573979. Pathogenicity tests were performed by placing 100 ml of a water homogenate of mycelium (1 × 105 mycelial fragments/ml) obtained from 15-day-old PDA cultures of the fungus on leaves of three healthy 4-month-old potted R. fulgida plants. Three plants inoculated with a homogenate of PDA served as controls. Plants were maintained in a greenhouse, in a high humidity chamber for 7 days after inoculation, at temperatures ranging from 18 to 22°C and under high relative humidity conditions (70 to 90%). The first foliar lesions developed on leaves 7 days after inoculation, and after 10 to 12 days, 80% of leaves were severely infected. Control plants remained healthy. The organism reisolated on PDA from leaf lesions was identical in morphology to the isolate used for inoculation. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of a Phoma sp. on R. fulgida in Italy. Mycosphaerella ligulicola was reported on Rudbeckia sp. (2), while M. rudbeckiae and Phoma exigua have been reported on R. hirta (3). Currently, the economic importance of this disease is limited, but may become a more significant problem if the cultivation of this species increases. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) C. G. C. Chesters and J. P. Blakeman. Ann. Appl. Biol. 60:385, 1967. (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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Garibaldi A, Bertetti D, Amatulli MT, Gullino ML. First Report of Postharvest Fruit Rot in Persimmon Caused by Phacidiopycnis washingtonensis in Italy. PLANT DISEASE 2010; 94:788. [PMID: 30754321 DOI: 10.1094/pdis-94-6-0788b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Persimmon (Diospyros kaki L.) is widely grown in Italy, the leading producer in Europe. In the fall of 2009, a previously unknown rot was observed on 3% of fruit stored at temperatures between 5 and 15°C in Torino Province (northern Italy). The decayed area was elliptical, firm, and appeared light brown to dark olive-green. It was surrounded by a soft margin. The internal decayed area appeared rotten, brown, and surrounded by bleached tissue. On the decayed tissue, black pycnidia that were partially immersed and up to 0.5 mm in diameter were observed. Light gray conidia produced in the pycnidia were unicellular, ovoid or lacriform, and measured 3.9 to 6.7 × 2.3 to 3.5 (average 5.0 × 2.9) μm. Fragments (approximately 2 mm) were taken from the margin of the internal diseased tissues, cultured on potato dextrose agar (PDA), and incubated at temperatures between 23 and 26°C under alternating light and darkness. Colonies of the fungus initially appeared ash colored and then turned to dark greenish gray. After 14 days of growth, pycnidia and conidia similar to those described on fruit were produced. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 502-bp segment showed a 100% similarity with the sequence of Phacidiopycnis washingtonensis Xiao & J.D. Rogers (GenBank Accession No. AY608648). The nucleotide sequence has been assigned the GenBank Accession No. GU949537. Pathogenicity tests were performed by inoculating three persimmon fruits after surface disinfesting in 1% sodium hypochlorite and wounding. Mycelial disks (10 mm in diameter), obtained from PDA cultures of one strain were placed on wounds. Three control fruits were inoculated with plain PDA. Fruits were incubated at 10 ± 1°C. The first symptoms developed 6 days after the artificial inoculation. After 15 days, the rot was very evident and P. washingtonensis was consistently reisolated. Noninoculated fruit remained healthy. The pathogenicity test was performed twice. Since P. washingtonensis was first identified in the United States on decayed apples (2), 'Fuji', 'Gala', 'Golden Delicious', 'Granny Smith', 'Red Chief', and 'Stark Delicious', apple fruits also were artificially inoculated with a conidial suspension (1 × 106 CFU/ml) of the pathogen obtained from PDA cultures. For each cultivar, three surface-disinfested fruit were wounded and inoculated, while three others served as mock-inoculated (sterile water) controls. Fruits were stored at temperatures ranging from 10 to 15°C. First symptoms appeared after 7 days on all the inoculated apples. After 14 days, rot was evident on all fruit inoculated with the fungus, and P. washingtonensis was consistently reisolated. Controls remained symptomless. To our knowledge, this is the first report of the presence of P. washingtonensis on persimmon in Italy, as well as worldwide. The occurrence of postharvest fruit rot on apple caused by P. washingtonensis was recently described in the United States (3). In Italy, the economic importance of the disease on persimmon fruit is currently limited, although the pathogen could represent a risk for apple. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) Y. K. Kim and C. L. Xiao. Plant Dis. 90:1376, 2006. (3) C. L. Xiao et al. Mycologia 97:473, 2005.
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Lopez-Reyes JG, Spadaro D, Gullino ML, Garibaldi A. Efficacy of plant essential oils on postharvest control of rot caused by fungi on four cultivars of applesin vivo. FLAVOUR FRAG J 2010. [DOI: 10.1002/ffj.1989] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Garibaldi A, Bertetti D, Pellegrino C, Gullino ML. First Report of Leaf Spot of Milky Bellflower (Campanula lactiflora) Caused by a Phoma sp. in Italy. PLANT DISEASE 2010; 94:638. [PMID: 30754443 DOI: 10.1094/pdis-94-5-0638a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Campanula lactiflora (milky bellflower), a perennial herbaceous plant in the Campanulaceae, is used in park and gardens and sometimes cultivated for cut flower production. In June 2008, a previously unknown leaf spot was observed on C. lactiflora 'New Hybrids' plants from an experimental nursery located near Carmagnola (Torino, northern Italy). Leaves of infected plants showed extensive and irregular, dark brown, necrotic lesions that were slightly sunken with well-defined borders. Lesions initially ranged from 0.5 to 3 mm, eventually coalesced, and covered the entire leaf. Black pycnidia (107 to 116 μm in diameter) containing hyaline, ellipsoid, nonseptate conidia measuring 3.7 to 4.7 × 1.2 to 2.0 (average 4.3 × 1.6) μm were observed. On the basis of these morphological characteristics, the fungal causal agent of the disease could be related to the genus Phoma. In some cases, the basal leaves turned completely necrotic and the plant died. The disease affected 50% of plants. Diseased tissue was excised, immersed in a solution containing 1% sodium hypochlorite for 2 to 3 s, rinsed in water, and then cultured on potato dextrose agar (PDA) medium. A fungus developed that produced a greenish gray mycelium with a white border when incubated under 12 h/day of fluorescent light at 22 to 25°C. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 459-bp segment showed a 100% similarity with the sequence of a Didymella sp. (synonym Mycosphaerella), anamorphic stage of Phoma spp. The nucleotide sequence has been assigned GenBank Accession No. GU128503. Pathogenicity tests were performed by placing 8-mm-diameter mycelial disks removed from PDA cultures of the fungus isolated from infected plants on leaves of healthy potted 4-month-old C. lactiflora 'New Hybrids' plants. Eight disks were placed on each plant. Plants inoculated with PDA alone served as controls. Six plants per treatment were used. Plants were covered with plastic bags for 4 days after inoculation and maintained in a growth chamber with daily average temperatures ranging between 23 and 24°C. The first foliar lesions developed on leaves 5 days after inoculation, and after 8 days, 80% of leaves were severely infected. Control plants remained healthy. A Didymella sp. was consistently reisolated from leaf lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of a Didymella sp. on C. lactiflora in Italy. Mycosphaerella campanulae and M. minor were reported on C. americana and C. lasiocarpa in the United States (2). The economic importance of the disease currently is limited, but could become a more significant problem in the future if the cultivation of this species becomes more widespread. 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. The American Phytopathological Society, St. Paul, MN, 1989.
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Garibaldi A, Gilardi G, Gullino ML. First Report of Leaf Spot Caused by Phoma multirostrata on Fuchsia × hybrida in Italy. PLANT DISEASE 2010; 94:382. [PMID: 30754229 DOI: 10.1094/pdis-94-3-0382a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Fuchsia × hybrida (Onagraceae) is widely used in gardens and very much appreciated as a potted plant. During the summer of 2008, a severe foliar disease was observed on 1- to 2-year-old plants in several gardens located near Biella (northern Italy). Small necrotic spots were observed on the upper and lower sides of infected leaves. Spots enlarged to form round areas of 2 to 12 mm in diameter and were well defined by a brown-purple margin at temperatures between 15 and 25°C. Severely infected leaves wilted and abscised as disease progressed. The disease occurred on 100% of the plants and at least 30% of the leaf surface was affected. Stems and flowers were not affected by the disease. A fungus was consistently isolated from infected leaves on potato dextrose agar amended with 25 mg/liter of streptomycin. The fungus was grown on leaf extract agar, including 30 g of autoclaved fuchsia leaves per liter, and maintained at 22°C (12-h light, 12-h dark). After 30 days, black pycnidia 150 to 450 μm in diameter developed, releasing abundant hyaline, elliptical, nonseptate conidia measuring 5.6 to 14.3 (10.3) × 1.9 to 5.6 (3.5) μm. On the basis of these morphological characteristics, the fungus was identified as a Phoma sp. (2). The internal transcribed spacer (ITS) region of rDNA of the isolate coded FuHy1 was amplified using primers ITS4/ITS6 (3) and sequenced. BLAST analysis (1) of the 488-bp segment obtained showed an E-value of 0.0 with Phoma multirostrata. The nucleotide sequence has been assigned GenBank Accession No. GU220539. Pathogenicity tests were performed by spraying leaves of healthy 6-month-old potted Fuchsia × hybrida plants with a spore and mycelial suspension (1 × 106 spores or mycelial fragments per milliliter). Noninoculated plants sprayed with water served as controls. Five plants were used for each treatment. Plants were covered with plastic bags for 5 days after inoculation and kept under greenhouse conditions at 20 to 24°C. Symptoms previously described developed on leaves 12 days after inoculation, whereas control plants remained healthy. The fungus was consistently reisolated from the lesions of the inoculated plants. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of P. multirostrata on fuchsia in Italy as well as worldwide. The importance of the disease is still limited in Italy. References: (1) S. F. Altschud et al. Nucleic Acids Res. 25:3389, 1997. (2) G. H. Boerema and G. J. Bollen. Persoonia 8:111, 1975. (3) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997.
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Garibaldi A, Bertetti D, Pensa P, Gullino ML. First Report of Botrytis Blight Caused by Botrytis cinerea on Lavandula stoechas in Italy. PLANT DISEASE 2010; 94:380. [PMID: 30754237 DOI: 10.1094/pdis-94-3-0380a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
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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Spadaro D, Ciavorella A, Dianpeng Z, Garibaldi A, Gullino ML. Effect of culture media and pH on the biomass production and biocontrol efficacy of aMetschnikowia pulcherrimastrain to be used as a biofungicide for postharvest disease control. Can J Microbiol 2010; 56:128-37. [DOI: 10.1139/w09-117] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Few strains of Metschnikowia pulcherrima (Pitt) M.W. Miller are under development for control of postharvest pathogens on fruit. A substrate was developed to optimize the biomass production of M. pulcherrima strain BIO126. Different complex nutrient sources, with or without pH control, were tested. Growth in yeast extract provided at concentrations ≥30 g·L–1yielded the highest biomass. The addition of two carbon sources, d-mannitol and l-sorbose, at 5 g·L–1each, significantly improved yeast growth. The greatest amount of yeast growth occurred when pH values of the medium ranged from 5.0 to 7.5. A combination of yeast extract, d-mannitol, and l-sorbose (YEMS), probably with diauxic utilization, showed a synergistic effect, widening the exponential phase (maximum specific growth rate of 0.45 h–1) and increasing the final cell number (1.5 × 109cells·mL–1) and dry biomass (6.0 g·L–1) in well-controlled batch fermentation. In efficacy trials on ‘Golden Delicious’ apples, M. pulcherrima grown in YEMS effectively reduced incidence and severity of Botrytis cinerea (51.1% and 70.8%, respectively) and Penicillium expansum (41.7% and 14.0%, respectively). Also on ‘Gala’ apples, the best reduction of grey and blue mould incidence was obtained with cells grown in YEMS (58.1% and 50.5%, respectively).
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Pugliese M, Gullino ML, Garibaldi A. Efficacy of microorganisms selected from compost to control soil-borne pathogens. COMMUNICATIONS IN AGRICULTURAL AND APPLIED BIOLOGICAL SCIENCES 2010; 75:665-669. [PMID: 21534476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Suppression of soil-borne plant pathogens with compost has been widely studied. Compost has been found to be suppressive against several soil-borne pathogens in various cropping systems. However, an increase of some diseases due to compost usage has also been observed, since compost is a product that varies considerably in chemical, physical and biotic composition, and, consequently, also in ability to suppress soil borne diseases. New opportunities in disease management can be obtained by the selection of antagonists from suppressive composts. The objective of the present work was to isolate microorganisms from a suppressive compost and to test them for their activity against soil-borne pathogens. A compost from green wastes, organic domestic wastes and urban sludge's that showed a good suppressive activity in previous trials was used as source of microorganisms. Serial diluted suspensions of compost samples were plated on five different media: selective for Fusarium sp., selective for Trichoderma sp., selective for oomycetes, potato dextrose agar (PDA) for isolation of fungi, lysogeny broth (LB) for isolation of bacteria. In total, 101 colonies were isolated from plates and tested under laboratory conditions on tomato seedlings growing on perlite medium in Petri plates infected with Fusarium oxysporum f.sp. radicis-lycopersici and compared to a commercial antagonist (Streptomyces griserovidis, Mycostop, Bioplanet). Among them, 28 showed a significant disease reduction and were assessed under greenhouse condition on three pathosystems: Fusarium oxysporum f.sp. basilica/basil, Phytophthora nicotianae/tomato and Rhizoctonia solani/bean. Fusarium spp. selected from compost generally showed a good disease control against Fusarium wilts, while only bacteria significantly controlled P. nicotianae on tomato under greenhouse conditions. None of the microorganisms was able to control the three soil-borne pathogens together, in particular Rhizoctonia solani. Results confirmed the good suppressive activity of the compost under study against soil-borne pathogens. The selection of antagonists from compost is a promising strategy for the development of new biological control agents against soil-borne pathogens.
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Garibaldi A, Bertetti D, Pensa P, Gullino ML. First Report of Verticillium Wilt Caused by Verticillium dahliae on Figmarigold in Italy. PLANT DISEASE 2010; 94:129. [PMID: 30754404 DOI: 10.1094/pdis-94-1-0129b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Lampranthus spp. N.B. Brown (figmarigold) belongs to the Aizoaceae family and is grown as a ground cover in gardens or as a potted plant. In January 2009, severe outbreaks of a previously unknown wilt were observed at a commercial farm in Liguria (northern Italy) where 7-month-old potted plants were grown outdoors in a mix of peat/clay/pumice at pH 6.5. In cultivars with pink flowers, 12% of plants were affected, while only a few cultivars with red flowers were diseased. Initial symptoms were yellowing of external leaves and brown or black streaks in the vascular tissue of roots, crown, and leaves. Subsequently, infected tissues wilted and stopped growing, stems and leaves appeared desiccated, and infected plants died. Stems of 10 pink-flowered plants were severed with a knife, cut ends sealed with wax, and surfaces disinfected with 1% sodium hypochlorite. Cross-sections (1 mm long) through symptomatic vascular tissue were plated onto potato dextrose agar. After 10 days at 22°C, 90% of the stems tested positive for Verticillium. Irregular, dark microsclerotia, 22 to 128 × 13 to 66 (average 51 × 29) μm, developed in hyaline hyphae after 10 days of growth at 22 ± 1°C (12-h photoperiod). Hyaline, elliptical, single-celled conidia, 2.9 to 4.8 × 1.3 to 2.4 (average 4.1 × 1.7) μm, developed on verticillate conidiophores. On the basis of these morphological characteristics, the fungus was identified as V. dahliae (3). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 (2) and sequenced. BLASTn analysis (1) of the 476-bp segment showed a 100% homology with the sequence of V. dahliae. The nucleotide sequence has been assigned GenBank Accession No. GQ 149479. Pathogenicity tests were performed twice using five 40-day-old plants of a pink-flower cultivar of a Lampranthus sp. grown in 1-liter pots containing a 50:20:20:10 mix of peat moss/pumice/pine bark cortex/clay. The substrate was infested with a conidial suspension (1.0 × 107/ml) of one isolate of V. dahliae recovered from infected plants. Inoculum (50 ml) were added to each pot, drenching the top of the soil. Noninoculated plants served as controls. Plants (five per treatment) were maintained in a glasshouse at daily average temperatures between 20 and 26°C and at 50 to 70% relative humidity. The first wilt symptoms and a vascular discoloration in the roots, crown, and veins developed 30 days after inoculation. V. dahliae was consistently reisolated. Noninoculated plants remained healthy. In a second test, the susceptibility of purple-, white-, yellow-, red-, and orange-flowered cultivars was tested. Ten rooted cuttings of each cultivar were inoculated as described above. The severity of Verticillium wilt was evaluated and each cultivar was classified as resistant, partially resistant, average susceptible, susceptible, or highly susceptible. All tested cultivars were susceptible or highly susceptible to Verticillium. Only the purple cultivar showed an average susceptibility. To our knowledge, this is the first report of Verticillium wilt on Lampranthus spp. in Italy as well as worldwide. Today, the economic importance of Verticillium wilt on figmarigold in Italy is still limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) M. A. Innis et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (3) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002.
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Troisi M, Bertetti D, Garibaldi A, Gullino ML. First Report of Powdery Mildew Caused by Golovinomyces cichoracearum on Gerbera (Gerbera jamesonii) in Italy. PLANT DISEASE 2010; 94:130. [PMID: 30754421 DOI: 10.1094/pdis-94-1-0130c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Gerbera (Gerbera jamesonii) is one of the top 10 economically important flower crops in Europe as well as the United States. The acreage devoted to this crop continues to increase especially for use in landscape typologies. Abundant flowering from spring until autumn allows the use of this plant to decorate gardens, terraces, and borders. During the summer of 2009, an outbreak of a previously unknown powdery mildew was observed on potted gerbera 'Mini Yellow' growing in a private garden in Turin (northern Italy). Adaxial leaf surfaces were covered with white mycelium and conidia, and as the disease progressed, infected leaves turned yellow and died. Conidia were hyaline, ellipsoid, borne in chains (three conidia per chain), and measured 16 to 45 × 10 to 30 μm. Conidiophores measured 109 to 117 × 11 to 13 μm and had a foot cell measuring 72 to 80 × 11 to 12 μm followed by two shorter cells measuring 19 to 29 × 11 to 14 and 20 to 32 × 12 to 14 μm. Fibrosin bodies were absent and chasmothecia were not observed in the collected samples. On the basis of its morphology, the pathogen was identified as Golovinomyces cichoracearum. The internal transcribed spacer (ITS) region of rDNA was amplified with primers ITS1/ITS4 and sequenced. BLASTn analysis of the 548-bp fragment showed an E-value of 0.0 and a percentage homology of 99% with G. cichoracearum isolated from Coreopsis leavenworthii (Accession No. DQ871605) confirming diagnosis inferred by morphological analysis. The nucleotide sequence has been assigned GenBank Accession No. GQ870342. Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of three healthy potted plants of Gerbera 'Mini Yellow'. Three noninoculated plants served as the control. Plants were maintained in a greenhouse at temperatures ranging between 20 and 30°C. Inoculated plants developed signs and symptoms after 8 days, whereas control plants remained healthy. The fungus present on inoculated plants was morphologically identical to that originally observed on diseased plants. To our knowledge, this is the first report of the presence of powdery mildew caused by G. cichoracearum on gerbera in Italy. Specimens are available at the Agroinnova Collection at the University of Torino. Gerbera is also susceptible to different powdery mildews. Powdery mildew of Gerbera jamesonii caused by Sphaerotheca fusca was reported in Italy (4). G. cichoracearum on Gerbera jamesonii was reported in North America (2), Argentina (3), and Switzerland (1). References: (1) A. Bolay. Cryptogam. Helv. 20:1, 2005. (2) M. Daughtrey et al. Page 39 in: Compendium of Flowering Potted Plant Diseases. The American Phytopathological Society, St Paul, MN, 1995. (3) R. Delhey et al. Schlechtendalia 10:79, 2003. (4) F. Zaccaria et al. Ann. Fac. Agrar. Univ. Stud. di Napoli Federico II 34:44, 2000.
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Garibaldi A, Bertetti D, Pensa P, Gullino ML. First Report of Sclerotinia Blight Caused by Sclerotinia sclerotiorum on Petunia × hybrida in Italy. PLANT DISEASE 2009; 93:1353. [PMID: 30759528 DOI: 10.1094/pdis-93-12-1353a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Petunia × hybrida (Solanaceae) includes several hybrids that are grown as ornamental plants and are very much appreciated for their long-lasting flowering period. During the spring of 2009, extensive wilting was observed on 2-month-old potted plants of Petunia × hybrida cv. Sanguna Lilac Vein grown in a commercial glasshouse near Albenga (northern Italy). First symptoms included stem necrosis and darkening and withering of leaves. Wilt occurred a few days after the appearance of the first symptoms. Infected plants were characterized by the presence of soft, watery tissues. In the presence of high relative humidity, lesions became covered with a whitish mycelium and irregular, dark gray sclerotia (3.0 to 6.5 × 2.0 to 5.0 mm, average 4.8 × 3.3 mm) were produced on the mycelium. Diseased tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (3) was consistently recovered from infected stem pieces. Sclerotia produced on PDA measured 2.0 to 6.0 × 1.5 to 5.0 mm (average 3.9 × 3.1) mm. The internal transcribed spacer (ITS) region of rDNA was amplified with primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 548-bp segment showed a 100% homology with the sequence of S. sclerotiorum. The nucleotide sequence has been assigned GenBank Accession No. GQ375746. Pathogenicity of one isolate obtained from sclerotia of infected plants was confirmed by inoculating three 90-day-old plants belonging to cv. Sanguna Lilac Vein transplanted in 22-cm-diameter pots in a glasshouse in a sphagnum peat/pomix/pine bark/clay (50:20:20:10) mix. Inoculum that consisted of 2 g/liter of substrate of wheat kernels infested with mycelium and sclerotia was placed in the soil and around the base of each plant. Three noninoculated plants served as controls. Plants were maintained in greenhouse at temperatures ranging between 22 and 26°C and relative humidity >90%. The inoculation trial was carried out twice. All inoculated plants developed leaf yellowing by 20 days after soil infestation. White, cottony mycelium and dark sclerotia developed on stems and at the base of all inoculated plants. Eventually, infected plants wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. To our knowledge, this is the first report of S. sclerotiorum on Petunia × hybrida in Italy. The disease has been previously reported on Petunia × hybrida in Bermuda (2) and the United States (4). References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) R. M. Brien. N.Z. J. Sci. Tech., A, 24, 62, 1942. (3) N. F. Buchwald. Kongl. Veterisk Landb. Aarssk. 75, 1949. (4) 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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