First Report of Leaf Spot of Wild (Diplotaxis tenuifolia) and Cultivated (Eruca vesicaria) Rocket Caused by Alternaria japonica in Italy

Wild (Diplotaxis tenuifolia) and cultivated (Eruca vesicaria) rocket, popular crops in Italy as well as in many Mediterranean areas, are grown for fresh consumption as well as for dish decoration. During fall and winter of 2010 to 2011, extensive necroses were observed on leaves of D. tenuifolia and E. vesicaria that were grown in commercial greenhouses in Piedmont and Liguria (northern Italy). The disease affected 30 to 40% of 60-day-old plants. First symptoms were usually black-brown lesions, 1 to 30 mm in diameter, which progressively turned black. Lesions usually started on the upper side of older leaves at the leaf margins and tips and developed a yellow halo. Eventually, lesions also affected leaf veins and stems. A fungus was consistently isolated from infected leaves on potato dextrose agar and was grown on water agar (15 g/liter) amended with autoclaved rocket tissues (100 g/liter). After 12 days of growth at 22°C and 12-h dark/12-h light, conidia that were produced were dark brown, obclavate, obpyriform, ovoid or ellipsoid, with beaks. Round conidia without beaks were also present. Conidia showed two to seven (average three to four) transverse and one to three longitudinal septa, and measured 17.7 to 56.2 (average 30.9) × 6.6 to 17.8 (average 10.8) μm. Conidia were produced singly or in short chains (two to three elements) and mostly presented a conical or cylindrical beak, 1.8 to 7.3 (average 3.6) μm, pale light brown to brown. On the basis of its morphological characteristics, the pathogen was identified as an Alternaria sp. (3). DNA was extracted with Terra PCR Direct Polymerase Mix (Clontech, Mountain View, CA) and PCR was carried out with ITS 1/ ITS 4 primer (4). A 553-bp PCR product was sequenced and a BLASTn search (1) confirmed that the sequence corresponded to Alternaria japonica. The nucleotide sequence has been assigned the GenBank Accession No. JP 742643. Pathogenicity tests were performed by spraying leaves of healthy 30-day-old wild and cultivated rocket plants with an aqueous 1 × 105 spore/ml suspension. The inoculum was obtained from cultures of the fungus grown on sterilized host leaves placed on water agar for 20 days in light/dark at 22 ± 1°C. Plants sprayed only with water served as controls. Three pots (four plants per pot) were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained in a glasshouse at 22 ± 1°C. Lesions developed on leaves 7 days after inoculation with the spore suspension, whereas control plants remained healthy. A. japonica was consistently reisolated from these lesions. The pathogenicity test was carried out twice. The presence of A. japonica has been reported on several brassica hosts, such as Brassica napus, B. nigra, B. oleracea, and B. rapa (2). This is, to our knowledge, the first report of A. japonica on wild and cultivated rocket in Italy as well as in Europe. Because of the importance of rocket in many countries, the potential impact of this disease is high. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) J. C. David, IMI Description of Fungi and Bacteria. 144:1432, 2000. (3) E. G. Simmons. Alternaria. An Identification Manual. CBS Biodiversity Series 6, Utrecht, The Netherlands, 2007. (4) T. J. White et al. In: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

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First Report of Leaf Spot of Saponaria officinalis Caused by Alternaria nobilis in Italy

Plant Disease ◽

10.1094/pdis-09-12-0839-pdn ◽

2013 ◽

Vol 97 (3) ◽

pp. 424-424 ◽

Cited By ~ 2

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

A. Poli ◽

M. L. Gullino

Keyword(s):

Morphological Characteristics ◽

Pathogenicity Test ◽

Academic Press ◽

First Report ◽

Perennial Plant ◽

Plastic Bags ◽

Pcr Product ◽

Pathogenicity Tests ◽

Alternaria Sp ◽

Saponaria Officinalis

Saponaria officinalis (Vize) Simmons (common name bouncingbet) is a low maintenance perennial plant belonging to the Caryophyllaceae family, typically grown in parks and gardens. During the summers of 2011 and 2012, extensive necrosis were observed on leaves of plants grown in private gardens, near Biella (northern Italy). The disease affected 90% of 1- to 2-year-old plants. The first symptoms were usually pale brown lesions 1 to 5 mm in diameter and sometimes coalesced. Lesions were circular to irregular with a dark purple halo, with infected leaves eventually turning chlorotic. The conidia observed on infected leaves were olivaceous brown and obclavate, with a beak. Conidia showed 8 to 15 (average 12) transverse and 4 to 14 (average 11) longitudinal septa, with slight constrictions connected with septa, and were 78.3 to 177.7 (average 135.5) × 19.0 to 34.3 (average 26.5) μm. The beak was 20.0 to 62.2 (average 33.7) μm in length, with 0 to 6 (average 3) transverse septa and no longitudinal septa. The fungus was consistently isolated from infected leaves on potato dextrose agar (PDA). The isolate, grown for 14 days at 20 to 24°C with 10 h of darkness and 14 h of light on sterilized host leaves plated on PDA, produced conidiophores single, unbranched, flexuous, septate with conidia in short chains, similar to those observed on the leaves and previously described. On the basis of its morphological characteristics, the pathogen was identified as Alternaria sp. (3). DNA was extracted using Nucleospin Plant Kit (Macherey Nagel) and PCR carried out using ITS 1/ITS 4 primer (4). A 542-bp PCR product was sequenced and a BLASTn search confirmed that the sequence corresponded to A. dianthi (AY154702), recently renamed A. nobilis (2). The nucleotide sequence has been assigned the GenBank Accession No. JX647848. Pathogenicity tests were performed by spraying leaves of healthy 3-month-old plants of S. officinalis with an aqueous 2 × 105 spore/ml suspension. The inoculum was obtained from cultures of the fungus grown on PDA amended with host leaves for 14 days, in light-dark, at 22 ± 1°C. Plants sprayed only with water served as controls. Four pots (1 plant/pot) were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained in a glasshouse at 21 ± 1 °C. Lesions developed on leaves 9 days after inoculation with the spore suspension, whereas control plants remained healthy. A. nobilis was consistently reisolated from these lesions. The pathogenicity test was carried out twice. The presence of A. dianthi was reported on S. officinalis in Denmark (1) and Turkey. This is, to our knowledge, the first report of A. nobilis on S. officinalis in Italy. The presence and importance of this disease is, at present, limited. References: (1) P. Neergaard. Danish species of Alternaria and Stemphylium. Oxford University Press, 1945. (2) E. G. Simmons. Mycotaxon 82:7, 2002. (3) E. G. Simmons. Alternaria: An Identification Manual. CBS Biodiversity Series 6, Utrecht, The Netherlands, 2007. (4) T. J. White et al. In: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

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First Report of Leaf Spot Caused by Phoma multirostrata on Fuchsia × hybrida in Italy

Plant Disease ◽

10.1094/pdis-94-3-0382a ◽

2010 ◽

Vol 94 (3) ◽

pp. 382-382 ◽

Cited By ~ 4

Author(s):

A. Garibaldi ◽

G. Gilardi ◽

M. L. Gullino

Keyword(s):

Leaf Surface ◽

Morphological Characteristics ◽

Its Region ◽

Northern Italy ◽

Pathogenicity Test ◽

First Report ◽

Plastic Bags ◽

Pathogenicity Tests ◽

Necrotic Spots ◽

Mycelial Suspension

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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First Report of Rhizoctonia solani AG 4 on Lamb's Lettuce in Italy

Plant Disease ◽

10.1094/pd-90-1109c ◽

2006 ◽

Vol 90 (8) ◽

pp. 1109-1109 ◽

Cited By ~ 2

Author(s):

A. Garibaldi ◽

G. Gilardi ◽

M. L. Gullino

Keyword(s):

Rhizoctonia Solani ◽

Morphological Characteristics ◽

Northern Italy ◽

Crown Rot ◽

Pathogenicity Test ◽

First Report ◽

Pathogenicity Tests ◽

Hyphal Diameter ◽

Wheat Kernels ◽

Extensive Necrosis

Lamb's lettuce or corn salad (Valerianella olitoria) is increasingly grown in Italy and used primarily in the preparation of mixed processed salad. In the fall of 2005, plants of lamb's lettuce, cv Trophy, exhibiting a basal rot were observed in some commercial greenhouses near Bergamo in northern Italy. The crown of diseased plants showed extensive necrosis, progressing to the basal leaves, with plants eventually dying. The first symptoms, consisting of water-soaked zonate lesions on basal leaves, were observed on 30-day-old plants during the month of October when temperatures ranged between 15 and 22°C. Disease was uniformly distributed in the greenhouses, progressed rapidly in circles, and 50% of the plants were affected. Diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with 100 μg/liter of streptomycin sulfate. A fungus with the morphological characteristics of Rhizoctonia solani was consistently and readily isolated and maintained in pure culture after single-hyphal tipping (3). The five isolates of R. solani, obtained from affected plants successfully anastomosed with tester isolate AG 4, no. RT 31, received from R. Nicoletti of the Istituto Sperimentale per il Tabacco, Scafati, Italy (2). The hyphal diameter at the point of anastomosis was reduced, and cell death of adjacent cells occurred (1). Pairings were also made with AG 1, 2, 3, 5, 7, and 11 with no anastomoses observed between the five isolates and testers. For pathogenicity tests, the inoculum of R. solani (no. Rh. Vale 1) was grown on autoclaved wheat kernels at 25°C for 10 days. Plants of cv. Trophy were grown in 10-liter containers (20 × 50 cm, 15 plants per container) on a steam disinfested substrate (equal volume of peat and sand). Inoculations were made on 20-day-old plants by placing 2 g of infected wheat kernels at each corner of the container with 3 cm as the distance to the nearest plant. Plants inoculated with clean wheat kernels served as controls. Three replicates (containers) were used. Plants were maintained at 25°C in a growth chamber programmed for 12 h of irradiation at a relative humidity of 80%. The first symptoms, consisting of water-soaked lesions on the basal leaves, developed 5 days after inoculation with crown rot and plant kill in 2 weeks. Control plants remained healthy. R. solani was consistently reisolated from infected plants. The pathogenicity test was carried out twice with similar results. This is, to our knowledge, the first report of R. solani on lamb's lettuce in Italy as well as worldwide. The isolates were deposited at the AGROINNOVA fungal collection. The disease continues to spread in other greenhouses in northern Italy. References: (1) D. Carling. Rhizoctonia Species: Pages 37–47 in: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. B. Sneh et al., eds. Kluwer Academic Publishers, the Netherlands, 1996. (2) J. Parmeter et al. Phytopathology, 59:1270, 1969. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St. Paul, MN, 1996.

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First Report of Black Rot Caused by Phomopsis cucurbitae on Cantaloupe (Cucumis melo) in the Piedmont Region of Northern Italy

Plant Disease ◽

10.1094/pdis-06-11-0481 ◽

2011 ◽

Vol 95 (10) ◽

pp. 1317-1317

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

A. Poli ◽

M. L. Gullino

Keyword(s):

Cucumis Melo ◽

Morphological Characteristics ◽

Its Region ◽

Northern Italy ◽

Pathogenicity Test ◽

First Report ◽

Sterile Needle ◽

Pathogenicity Tests ◽

Cucumis Melo L ◽

Piedmont Region

Cucumis melo L., belonging to the Cucurbitaceae family, is cultivated on more than 23,000 ha in Italy. Cantaloupe (C. melo L. var. cantalupensis Naudin) is the most popular variety. In summer 2010, a previously unknown rot was observed on fruits produced in Italy and marketed in the Piedmont Region of northern Italy. Early symptoms on fruit consisted of irregular, brown, soft, sunken lesions up to 10 cm in diameter. No surface mold was visible and pycnidia were not present. Internally, the decay is adjacent to the sunken area of the fruit's surface and is soft, water soaked, spongy, with a nearly circular margin, and easily separated from healthy tissues. Fragments (approximately 3 mm3) were taken from the margin of the internal diseased tissues, cultured on potato dextrose agar (PDA), and incubated at 24 ± 1°C, (16 h of light and 8 h of darkness). Fungal colonies initially appeared coarse, at first whitish then buff brown, and produced dark pycnidia 0.5 mm in diameter, which exuded numerous conidia belonging to two types. Type A conidia were hyaline, unicellular, ellipsoidal to fusiform, sometimes slightly constricted in the middle, and measured 5.6 to 10.3 × 1.7 to 2.6 (average 8.0 × 2.1) μm. Type B conidia were hyaline, long, slender, curved, and measured 17.1 to 26.6 × 0.7 to 1.4 (average 22.0 × 1.0) μm. Sclerotia were not produced. The morphological characteristics of the fungus corresponded to those of the genus Phomopsis (1). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis of the 543-bp segment showed a 99% similarity with the sequence of a Phomopsis sp. (GenBank Accession No. HM999947). The nucleotide sequence has been assigned the GenBank Accession No. JN032733. Both Phomopsis cucurbitae and P. sclerotioides are pathogenic to Cucurbitaceae, however P. cucurbitae is identifiable by the production of B conidia and the absence of sclerotia. Therefore, P. cucurbitae has been considered the causal agent of the disease. Pathogenicity tests were performed by inoculating three wounded cantaloupe fruits after surface disinfesting in 1% sodium hypochlorite. Six wounds per fruit, 1 cm deep, were made with a sterile needle. Mycelial disks (10 mm in diameter), obtained from PDA cultures of one strain, were placed on each wound. Three control fruits were inoculated with PDA. Fruits were incubated at 16 ± 1°C in the dark. The first symptoms developed 4 days after the artificial inoculation. Two days later, the rot developed at all inoculation points and the pathogen was consistently reisolated. Noninoculated fruit remained healthy. The pathogenicity test was performed twice with similar results. P. cucurbitae has been reported on melon in many countries (2,3). To our knowledge, this is the first report of the disease in Italy. Currently, the relevance of the disease in the country is not yet well known. However, attention must be paid considering that the pathogen can be transmitted through seeds. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (2) L. Beraha and M. J. O'Brien. Phytopathol. Z. 94:199, 1979. (3) E. Punithalingam and P. Holliday. Phomopsis cucurbitae. IMI Descriptions of Fungi and Bacteria. 47, Sheet 469, 1975.

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First Report of a Leaf Spot Caused by Alternaria compacta on Hydrangea anomala subsp. petiolaris in Italy

Plant Disease ◽

10.1094/pdis-92-1-0173c ◽

2008 ◽

Vol 92 (1) ◽

pp. 173-173 ◽

Cited By ~ 2

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

Morphological Characteristics ◽

The United States ◽

Plant Diseases ◽

Spore Suspension ◽

Pathogenicity Test ◽

Aesthetic Quality ◽

First Report ◽

Plastic Bags ◽

Alternaria Sp ◽

The Aesthetic

Hydrangea anomala subsp. petiolaris (synonym H. petiolaris and H. scandens), also known as climbing hydrangea, is cultivated as an ornamental for landscaping in parks and gardens. This species, belonging to the Hydrangeaceae and native to the woodlands of Japan and coastal China, is widely appreciated for its abundant, creamy white flowers with a sweet aroma, particularly in shade gardens. During the summer of 2006, extensive necroses were observed on leaves and young stems of 3-year-old plants grown outdoors in several gardens of Piedmont of northern Italy. In many cases, on the upper side of the leaves, necrotic spots (4 to 10 mm in diameter) turned progressively black. Lesions often coalesced, generating larger (2 to 6 cm in diameter) necrotic areas. Necroses initially developed mainly at leaf margins and near petioles, and severely affected plants were defoliated. Infected plants rarely died, but the presence of lesions reduced the aesthetic quality and subsequently the commercial value. The disease occurred on 50 of 100 plants. A fungus was consistently isolated from infected leaves on potato dextrose agar (PDA) and identified on the basis of its morphological characteristics as an Alternaria sp. Conidia were dark gray, multicellular, clavate to pear shaped, measuring 23 to 54 × 10 to 13 μm (average 38 × 12 μm), with five longitudinal crosswalls and a relatively short apical beak. DNA was extracted with a Nucleospin Plant Kit (Macherey Nagel, Brockville, ON, Canada) and PCR was carried out with ITS 6/ITS 4 primer (2). A 557-bp PCR product was sequenced, and a BLASTn search (1) confirmed that the sequence corresponded to Alternaria compacta (99% homology). The nucleotide sequence has been assigned GenBank Accession No. EU 128529. Pathogenicity tests were performed by spraying leaves of healthy 1-year-old potted H. anomala plants with an aqueous 105 CFU/ml spore suspension. The inoculum was obtained from cultures of the fungus grown on sterilized host leaves placed on PDA for 20 days in light/dark at 23 ± 1°C. Plants sprayed only with water served as controls. Five plants were used for each treatment. Plants were covered with plastic bags for 3 days after inoculation and maintained between 12 and 22°C. Lesions developed on leaves 8 days after inoculation with the spore suspension, whereas control plants remained healthy. A. compacta was consistently reisolated from these lesions. The pathogenicity test was repeated twice. The presence of an Alternaria sp. on H. macrophylla was reported in the United States (3), whereas A. hortensiae was observed in Spain on H. hortensis. Recently, A. alternata belonging to the alternata group was reported on H. macrophylla in Italy (4). This is, to our knowledge, the first report of A. compacta on H anomala subsp. petiolaris in Italy. References: (1) S. F. Altschud et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (3) M. L. Daughtrey et al. Page 9 in: Compendium of Flowering Potted Plant Diseases. American Phytopathological Society. St. Paul, MN, 1995. (4) A. Garibaldi et al. Plant Dis. 91:767, 2007.

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First Report of Leaf Spot Caused by a Phoma sp. on Clematis × jackmanii in Italy

Plant Disease ◽

10.1094/pdis-91-10-1363c ◽

2007 ◽

Vol 91 (10) ◽

pp. 1363-1363 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

Morphological Characteristics ◽

The United States ◽

Northern Italy ◽

Pathogenicity Test ◽

Internal Transcribed Spacer Region ◽

Flower Production ◽

Plastic Bags ◽

Pathogenicity Tests ◽

Necrotic Spots ◽

Mycelial Suspension

The genus Clematis, belonging to the Ranunculaceae family, is widely used in gardens and is very much appreciated for its climbing attitude as well as rich flower production. In the fall of 2006, in a private garden located near Biella (northern Italy), a severe foliar disease was observed on 2-year-old plants of Clematis × jackmanii. Small necrotic spots were observed on the upper and lower sides of infected leaves. At temperatures of 15 to 25°C, spots enlarged to form round areas that were 2 to 7 cm in diameter and well defined by a brown margin. Severely infected leaves wilted without abscising. The disease occurred on 100% of the plants of the C. × jackmanii hybrid in one garden. Stems and flowers were not affected by the disease. From infected leaves, a fungus was consistently isolated on potato dextrose agar (PDA) amended with 25 mg/liter of streptomycin. The fungus was grown on PDA and maintained at 22°C (12-h light, 12-h dark). After 10 days, black pycnidia 132 to 340 μm in diameter developed, releasing abundant hyaline, elliptical, nonseptate, conidia measuring 5.1 to 8.3 (6.8) × 1.6 to 3.4 (2.7) μm. On the basis of its morphological characteristics, the fungus was identified as a Phoma sp. (2). The internal transcribed spacer region of rDNA was amplified using primers ITS4/ITS6 (1,3), sequenced (GenBank Accession No. EF566917), and identified as a Phoma sp. Pathogenicity tests were performed by spraying leaves of healthy 1-year-old potted C. × jackmanii (cvs. Superba, Mrs N. Thomson, and Vagebond) plants with a spore and mycelial suspension (4 × 105 spores or mycelial fragments per ml). Noninoculated plants served as controls. Five plants per cultivar were used for each treatment. Plants were covered with plastic bags for 3 days after inoculation and kept in a growth chamber at 18 to 20°C. Symptoms previously described developed on leaves of all tested cultivars 10 days after inoculation, while control plants remained healthy. On the infected leaves, pycnidia and conidia with the same dimensions and characteristics as previously described were observed. The fungus was consistently reisolated from the lesions of the inoculated plants. The pathogenicity test was carried out twice. The presence of Ascochyta clematidina, then renamed as Phoma clematidina, on Clematis species has been reported in the United States (4) and subsequently in the Netherlands, Britain, and New Zealand. 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. (4) W. O. Gloyer. J. Agric. Res. 4:331, 1915.

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First Report of Leaf Spot and Root Rot Caused by Phoma betae on Beta vulgaris subsp. vulgaris (Garden Beet Group) in Italy

Plant Disease ◽

10.1094/pdis-91-11-1515c ◽

2007 ◽

Vol 91 (11) ◽

pp. 1515-1515 ◽

Cited By ~ 7

Author(s):

A. Garibaldi ◽

G. Gilardi ◽

D. Bertetti ◽

M. L. Gullino

Keyword(s):

Beta Vulgaris ◽

Morphological Characteristics ◽

Its Region ◽

Pathogenicity Test ◽

Vegetable Crops ◽

Plastic Bags ◽

Blastn Analysis ◽

Commercial Farms ◽

Pathogenicity Tests ◽

Phoma Betae

In the winter of 2007 in Piedmont (northern Italy), symptoms of a previously unknown disease were observed on beet (Beta vulgaris L. subsp. vulgaris) (garden beet group) grown under a tunnel on several commercial farms near Cuneo. First symptoms appeared on 1-month-old plants, occurring as brown, round-to-oval spots as much as 2 cm in diameter with dark concentric rings near the perimeter. Small, dark pycnidia were present throughout the spots in concentric rings. Generally, older, lower leaves were affected more than the younger ones. Ten to fifteen percent of the plants were affected. Symptoms on the roots began near the crown as small, dark, sunken spots that became soft and water soaked. Eventually, spots on the roots turned dark brown to black and black lines separated diseased and healthy tissues. Older infected tissues were black, dry, shrunken, and spongy. Pycnidia were not observed on affected roots. From infected leaves and roots, a fungus was consistently isolated on potato dextrose agar (PDA) amended with 25 mg/l of streptomycin. The fungus was grown on PDA and maintained at 22°C (12 h of light, 12 h of dark). After 10 days, black pycnidia (130 to 328 [204] μm in diameter) developed, releasing abundant hyaline, elliptical, nonseptate conidia measuring 3.9 to 6.7 (5.1) × 2.4 to 5.9 (3.6) μm. On the basis of its morphological characteristics, the fungus was identified as a Phoma sp. (1). The internal transcribed spacer (ITS) region was amplified using primers ITS4/ITS6 (2) and sequenced. BLASTn analysis of the 557 bp obtained showed an E-value of 0.0 with Phoma betae. The nucleotide sequence has been assigned GenBank Accession No. EU003450. Pathogenicity tests were performed by spraying leaves of healthy 20-day-old potted B. vulgaris plants with a spore and mycelial suspension (1 × 106 spores or mycelial fragments per ml). Noninoculated plants sprayed only with water served as controls. Fifteen plants (three per pot) were used for each treatment. Plants were covered with plastic bags for 5 days after inoculation and kept in a growth chamber at 20°C. Symptoms previously described developed on leaves of all inoculated plants 5 days after inoculation, while control plants remained healthy. Later, pycnidia and conidia, with the same dimensions and characteristics previously described, were observed on the infected leaves. The fungus was consistently reisolated from the lesions of the inoculated plants. The pathogenicity test was carried out twice. P. betae on B. vulgaris var. cycla has been reported in Canada (3) as well as in other countries. The same pathogen was reported in Italy on sugar beet (2). References: (1) G. H. Boerema and G. J. Bollen. Persoonia 8:111, 1975. (2) A. Canova. Inf. Fitopatol. 16:207, 1966. (3) D. E L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (4) J. R. Howard et al. Diseases of Vegetable Crops in Canada. Canadian Phytopathological Society, 1994.

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First Report of Typhula Blight on Agrostis stolonifera and Poa annua in Italy

Plant Disease ◽

10.1094/pdis.2003.87.7.875c ◽

2003 ◽

Vol 87 (7) ◽

pp. 875-875 ◽

Cited By ~ 1

Author(s):

P. Titone ◽

M. Mocioni ◽

A. Garibaldi ◽

M. L. Gullino

Keyword(s):

Agrostis Stolonifera ◽

Northern Italy ◽

Potato Dextrose Agar ◽

Poa Annua ◽

Golf Course ◽

Pathogenicity Test ◽

Potato Dextrose Broth ◽

First Report ◽

Pathogenicity Tests ◽

Typhula Incarnata

During January 2002, Agrostis stolonifera and Poa annua turfgrasses on a golf course in Avigliana (northern Italy) exhibited 10- to 45-cm-diameter circular patches when the snow melted from the greens, tees, and fairways. Many patches coalesced to form large areas of strawcolored blighted turfgrass. At the patch margin, infected plants were covered with white-to-gray mycelium. Plants within patches were matted and appeared slimy with mycelium and sclerotia that were light pink, irregularly shaped, and less than 5 mm in diameter. Isolation from infected leaves on potato dextrose agar, supplemented with 100 mg/l of streptomycin sulfate, consistently yielded a fungus with mycelial, sclerotia, and cultural characteristics of Typhula incarnata (1). Pathogenicity tests were performed by spraying a suspension of mycelium and sclerotia, prepared by chopping mycelium and sclerotia produced in potato dextrose broth, onto 8-week-old A. stolonifera plants grown in plastic trays (45 × 30 cm). Trays were maintained at 0°C for 8 weeks in the dark. Blight symptoms developed on inoculated plants after 6 weeks. Non-inoculated plants remained healthy. The pathogen was reisolated from inoculated plants, and the pathogenicity test was repeated once. Typhula blight incited by T. incarnata was reported in Scandinavian countries and in several European countries including Holland, Germany, Austria, and Switzerland (1). To our knowledge, this is the first report of Typhula blight on turfgrass in Italy. Reference: (1) J. D. Smith et al. 1989. Fungal Diseases of Amenity Turf Grasses. E & FN Spong Ltd, London.

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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 Rust Caused by Pucciniastrum circaeae on Fuchsia × hybrida in Italy

Plant Disease ◽

10.1094/pdis-11-11-0976-pdn ◽

2012 ◽

Vol 96 (4) ◽

pp. 588-588 ◽

Cited By ~ 1

Author(s):

A. Garibaldi ◽

G. Gilardi ◽

G. Ortu ◽

M. L. Gullino

Keyword(s):

Phylogenetic Trees ◽

Aqueous Suspension ◽

Morphological Characteristics ◽

Pcr Amplification ◽

Signs And Symptoms ◽

The United States ◽

Pathogenicity Test ◽

First Report ◽

Potted Plants ◽

Plastic Bags

Fuchsia is a genus of flowering plants that is native to South America and New Zealand and belongs to the family Onagraceae. In September 2011, 2-year-old potted plants of Fuchsia × hybrida, cv. Citation, in a garden located near Biella (northern Italy) showed signs and symptoms of a previously unknown disease. Typically, infected plants showed leaf chlorosis followed by the appearance of necrosis on the adaxial leaf surfaces, while the abaxial surfaces showed orange uredinia irregularly distributed. As the disease progressed, infected leaves turned yellow and wilted. Affected plants showed a progressive phylloptosis and also flowering was negatively affected. Urediniospores were globose, yellow to orange, and measured 14.6 to 25.9 (average 19.6) μm. Teliospores were not observed. Morphological characteristics of the fungus corresponded to those of the genus Pucciniastrum. DNA extraction and PCR amplification were carried out with Terra PCR Direct Polymerase Mix (Clontech, Saint Germain-en-Laye, France) and primers ITS1/ITS4 (4). A 700-bp PCR product was sequenced and a BLASTn search (1) confirmed that the sequence corresponded with a 96% identity to Pucciniastrum circaeae. The nucleotide sequence has been assigned the GenBank Accession No. JQ029688. Pathogenicity tests were performed by spraying leaves of healthy 1-year-old potted Fuchsia × hybrida plants with an aqueous suspension of 1 × 103 urediniospores ml–1. The inoculum was obtained from infected leaves. Plants sprayed only with water served as controls. Three plants were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained outdoors at temperatures ranging between 18 and 25°C. Lesions developed on leaves 20 days after inoculation with the urediniospore suspension, showing the same symptoms as the original plants, whereas control plants remained healthy. The organism that was recovered from the lesions after inoculation was the same as the one obtained from the diseased plants. The pathogenicity test was carried out twice with similar results. The presence of P. fuchsiae, later identified as P. epilobii, was repeatedly reported in the United States (3). P. epilobii and P. circaeae have closely related hosts and morphologically similar urediniospores. These species were reported to form a single group in molecular phylogenetic trees (2). This is, to our knowledge, the first report of P. circaeae on Fuchsia × hybrida in Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) Y. M. Liang et al. Mycoscience 47:137, 2006. (3) L. B. Loring and L. F. Roth. Plant Dis. Rep. 48:99, 1964. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

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