scholarly journals First Report of Pilidiella granati on Pomegranate with Symptoms of Crown Rot in the Prefecture of Xanthi, Greece

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 79-79 ◽  
Author(s):  
T. Thomidis ◽  
E. Exadaktylou
Keyword(s):  
Potato Dextrose Agar ◽  
Crown Rot ◽  
Fruit Rot ◽  
Adhesive Tape ◽  
Petroleum Jelly ◽  
Koch’S Postulates ◽  
First Report ◽  
Agar Plug ◽  
Pilidiella Granati ◽  
Koch's Postulates

In spring 2010, plants of pomegranate (Punica granatum L.) cv. Wonderful with symptoms of crown rot were observed in the Prefecture of Xanthi, Thrace, Greece. Close examination of these plants revealed distinct symptoms of crown rots. Isolations from the lower margins of the necrotic area were made by plating tissues of approximately 3 mm on acidified (2.5 ml of 85% lactic acid per liter of nutrient medium to create a pH = 3.5 after autoclaving) potato dextrose agar. The plates were incubated at 23°C for 5 to 7 days, and consistent colonies with light yellow, leathery mycelia and abundant, black, solitary pycnidia of various sizes were observed. Hyphae were septate and conidia were hyaline, one-celled, and ellipsoid to fusiform (average 10.1 to 20.2 × 3.2 to 4.3 μm). The pathogen was identified as Pilidiella granati Saccardo (synonym Coniella granati (Saccardo) Petrak & Sydow (3)) based on mycelium and spore morphology and ribosomal ITS1-5.8S-ITS2 sequences, which were identical to GenBank No. FN908875. Koch's postulates were completed in the laboratory by inoculating 20 1-year-old plants of pomegranate cv. Wonderful. With a 7-mm-diameter cork borer, a wound was created in the middle of each collar by removing the bark. A 6-mm-diameter agar plug bearing mycelia and spores from a 15-day-old culture of P. granati was inserted into each wound. The wound was covered with petroleum jelly and wrapped with adhesive tape to prevent desiccation. Ten trees were inoculated with sterile potato dextrose agar plugs to serve as controls. All plants were incubated at 25°C for 10 days, at which time necrosis was observed. Koch's postulates were satisfied after reisolating the fungus from inoculated plants that developed symptoms similar to those observed in the field. Control plants produced no symptoms of disease. To our knowledge, this is the first report of P. granati from pomegranate plants with symptoms of crown rots in Greece. The role of predisposing factors such as herbicides and frost damage to infection by P. granati is unknown. This pathogen has been reported to cause fruit rot of pomegranate in Spain (2) and California (1). References: (1) T. J. Michailides et al. (Abstr.) Phytopathology 100(suppl.):S83, 2010. (2) L. Palou et al. New Dis. Rep. Online publication. doi:10.5197/j.2044-0588.2010.022.021, 2010. (3) G T. Tziros and K. Tzavella-Klonari. Plant Pathol. 57:783, 2007.

scholarly journals First Report of Botryosphaeria dothidea Causing Shoot Blight of Kiwifruit (Actinidia deliciosa) in Greece

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1503-1503 ◽  
Author(s):  
T. Thomidis ◽  
E. Exadaktylou
Keyword(s):  
Random Amplified Polymorphic Dna ◽  
Morphological Characteristics ◽  
Fungal Mycelium ◽  
Adhesive Tape ◽  
Petroleum Jelly ◽  
Koch’S Postulates ◽  
First Report ◽  
Agar Plug ◽  
Dna Primers ◽  
Koch's Postulates

In the spring of 2010, in commercial orchards located in the Prefecture of Pieria in northern Greece, wilted shoots of kiwifruit cv. Hayward were observed. Blighted shoots took on a distinct dark color. Isolations from the lower margins of the cankers were made by plating sodium-hypochlorite-treated shoot tissue sections of approximately 3 mm on acidified (2.5 ml of 85% lactic acid per liter of nutrient medium to create a pH = 3.5 after autoclaving) potato dextrose agar. Plates were incubated at 23°C for 5 days, and a fast-growing, mouse-gray colored fungus was consistently isolated from diseased stems. Identification of the pathogen was based on morphological characteristics and confirmed by using the four random amplified polymorphic DNA primers (K19 [CAC AGG CGG A], K20 [GTG TCG CGA G], R13 [GGA CGA CAA G], and R15 [GGA CAA CGA G], suggested by Ma et al. (2). This fungus formed darkly pigmented pycnidia (170 × 155 μm), while the conidia observed in these bodies were one-celled, hyaline, ellipsoidal to fusoid with distinctly truncate bases, and measured 10.9 to 21.55 × 3.25 to 10.10 μm. The pycnidia exuded conidia in white tendrils. Koch's postulates were completed in the laboratory by inoculating 20 segments (6 cm long and 1.5 to 2 cm in diameter) of 1-year-old woody shoots of kiwifruit cv. Hayward. Using a cork borer, a 7-mm-diameter wound was created in the middle of each shoot segment by removing the bark and a 6-mm-diameter agar plug bearing mycelia from a 15-day-old culture of B. dothidea was inserted into the wound. The wound was covered with petroleum jelly and wrapped with adhesive tape to prevent desiccation. Ten control segments were similarly wounded and inoculated with an agar disk without fungal mycelium. All inoculated and noninoculated shoot segments were incubated at 25°C in moist chambers, after which the resulting necrosis was recorded. Koch's postulates were satisfied after reisolating the fungus from inoculated shoots that developed symptoms similar to those observed on shoots collected from orchards. Although B. dothidea has been previously reported to cause dieback on kiwifruit in Japan (1), to our knowledge, this is the first report of the occurrence of B. dothidea on kiwifruit in Greece. This pathogen can cause a high level of shoot blights in diseased plants and presents a significant threat to the commercial kiwifruit production in Greece. References: (1) M. Kinugawa and T. Sato. Ann. Phytopathol. Soc. Jpn. 69:373, 2003. (2) Z. Ma et al. Phytopathology 91:665, 2001.

Red Crown Rot of Hop in Oregon Caused by Phomopsis tuberivora

2013 ◽  
Vol 14 (1) ◽  
pp. 52
Author(s):  
David H. Gent ◽  
George Mueller-Warrant ◽  
Joanna L. Woods ◽  
Melodie L. Putnam ◽  
Megan C. Twomey
Keyword(s):  
Crown Rot ◽  
Management Implications ◽  
Koch’S Postulates ◽  
First Report ◽  
Red Crown Rot ◽  
Weak Growth ◽  
Koch's Postulates

During July 2007, symptoms including weak growth and death of plants of cultivar Fuggle were reported by a hop grower in Marion Co., OR. Phomopsis tuberivora H.T. Güssow & W.R. Foster 1932 was consistently recovered from affected plants. Koch's postulates were fulfilled with three isolates of the fungus, establishing the pathogen and the disease red crown rot as the cause of the damage. This is the first report of red crown rot on hop in Oregon, which may have important management implications for affected hop yards and farms. Accepted for publication 19 March 2013. Published 24 June 2013.

scholarly journals First Report of Aspergillus niger Causing Postharvest Fruit Rot of Cherry in the Prefectures of Imathia and Pella, Northern Greece

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 458-458 ◽  
Author(s):  
T. Thomidis ◽  
E. Exadaktylou
Keyword(s):  
Aspergillus Niger ◽  
Fungal Spores ◽  
Morphological Characteristics ◽  
Fruit Rot ◽  
Northern Greece ◽  
Centraalbureau Voor ◽  
Koch’S Postulates ◽  
First Report ◽  
Postharvest Rot ◽  
Koch's Postulates

In June 2011, symptoms of postharvest rot were observed on approximately 3% of all cherries collected from commercial orchards of cultivars Lapen and Ferrovia in the prefectures of Imathia and Pella (northern Greece). Fruit were harvested in a timely manner to avoid overripeness. No wounds or other predisposing injuries were observed on the infected fruits. Lesions enlarged rapidly and separated easily from healthy tissue when pressure was applied. Infected tissues were pale and water soaked and the associated fungal spores were dark and powdery and easily liberated when mature. The fungus grew rapidly and produced black colonies on acidified potato dextrose agar (2.5 ml of 85% lactic acid per liter of nutrient medium) after 5 days at 24°C. Identification of the pathogen was based on morphological characteristics (1). The conidial head was radiate, vesicles were nearly spherical and covered with metulae and phialides (biseriate). Conidia were globose (3 to 5 μm in diameter) and usually very rough with irregular ridges, bars, and verrucae. Koch's postulates were completed in the laboratory by inoculating mature cherry fruits (cv. Lapen). The fruits were surface sterilized by dipping in 10% chloride bleach solution, allowed to dry in a laminar flow hood, and wounded with a sharp glass rod that was 2 mm in diameter. A 40-μl drop of a suspension containing 20,000 conidia per ml of water was placed on each wound. There were 20 inoculated and 20 control fruits (similarly wounded and inoculated with a 40-μl drop of sterile distilled water) in a randomized design and incubated at 24 to 26°C for 6 days. Koch's postulates were satisfied after reisolating the fungus from inoculated fruit that developed symptoms similar to those observed on fruit collected from orchards. Control fruits did not show any symptom of the disease. To our knowledge, this is the first report of the occurrence of Aspergillus niger as the causal agent of postharvest rots of cherries in Greece. Postharvest fruit rots caused by A. niger have been reported in cherry orchards of other countries around the world (2). Because this disease causes postharvest rots of cherry fruits, measures may need to be implemented to manage the pathogen. References: (1) M. A. Klich. Page 12 in: Identification of Common Aspergillus Species. Centraalbureau Voor Schimmelcultures, Utrecht, the Netherlands, 2002. (2) A. Valiuskaite et al. Phytopathol. Pol. 35:197, 2005.

scholarly journals First report of Fusarium petroliphilum causing fruit rot of spaghetti squash in California

Plant Disease ◽  
2021 ◽  
Author(s):  
Albre Brown ◽  
Marinell C Soriano ◽  
Suzanne Rooney-Latham ◽  
Cheryl L. Blomquist
Keyword(s):  
Cucurbita Pepo ◽  
Fruit Size ◽  
Elongation Factor ◽  
Fruit Rot ◽  
Post Inoculation ◽  
Koch’S Postulates ◽  
First Report ◽  
Light Yellow ◽  
Fusarium Petroliphilum ◽  
Koch's Postulates

Spaghetti squash (Cucurbita pepo L. subsp. pepo) is a yellow-skinned squash that forms translucent spaghetti-like strands when cooked. California leads the nation in total squash production, the majority of which is grown in the San Joaquin Valley. In October of 2019, severe fruit rot of C. pepo L. subsp. Pepo (C. pepo) was observed in fruit harvested from seven cultivated fields in San Joaquin County, California. Infected fields incurred up to 30% postharvest losses. At harvest, fruit appeared healthy. After ten days in a shaded storage shed, scattered buff to tan ringed lesions extending into the flesh of infected fruits were observed. Lesions had visible sporodochia at the center that were variable in size and continued to expand in storage. Tissue (∼1 mm3) from the lesion margins of symptomatic fruit (n=8) was surface sterilized in 75 % ethanol for 1 min then 0.6% sodium hypochlorite for a minute, and aseptically transferred to half strength acidified potato dextrose agar (0.5 APDA) and incubated at 22–25 °C. Fungal colonies which grew from the pieces were light yellow, with mycelium that was flat and mucoid. Sporodochial conidia were falcate and robust with 3 to 5 septa and measured from 44.2 to 51.6 × 4.6 to 5.9 μm (average 46.3 × 5.2 μm). Aerial conidia were profuse, borne on short monophialides, ovoid to reniform, and measured 5.1 to 12.6 μm × 3.2 to 5.6 μm (average 4.2 × 6.1 μm). DNA extracted from two isolates, was amplified with primers ITS1/ITS4, and EF1-728F/EF1-986R using PCR, to obtain sequences from the internal transcribed spacer (ITS) (White 1990), and elongation factor 1α (EF1α) (Carbone et al. 1999) genetic regions. Sequences from both isolates were identical. Sequences from isolate MVAP50001827, GenBank nos. MZ081401 (ITS) and MZ102267 (EF-1α) matched 100% to sequences of representative isolates of Fusarium petroliphilum (Q.T. Chen & X.H. Fu; Short et al., 2013, MB 802539) from Cucurbita species, MF535516 (ITS) and MF580776 (EF-1α) respectively (González, V. et al. 2018). To fulfill Koch’s postulates, conidia were harvested from a culture of isolate MVAP50001827 and grown for 7 days on 0.5 APDA at room temperature (22–25 °C). A 3-cc syringe with a 25-gauge needle was used to wound and inject 200 μl of 1 × 106 conidia ml–1 into three equally spaced points 1 mm deep into the rind of C. pepo fruit (n=4). C. pepo fruit (n=4) serving as negative controls were treated similarly with 200 μl of sterile deionized water. Fruit was incubated in a growth chamber at 27 °C under 12-h diurnal cycle lighting conditions. Ten days post inoculation, lesions densely covered with white sporodochia had expanded to 7 cm diameter and 5 cm deep on average (average fruit size 31×11 cm). Twenty days post inoculation, severe fruit rot was observed. F. petroliphilum did not grow from the controls, and was successfully reisolated from the symptomatic inoculated fruits, completing Koch’s postulates. Seeds inside the inoculated fruits were completely colonized and covered in conidia. Twenty-five seeds from the source seed lot was tested for F. petroliphilum by surface sterilizing and plating onto 0.5 APDA. No F. petroliphilum grew from tested seed. Postharvest fungal diseases can affect profitability of winter squash, which is often held in storage, and sold when market prices are optimal. To our knowledge, this is the first report of Fusarium petroliphilum infecting spaghetti squash (Cucurbita pepo L. subsp. pepo) in California.

scholarly journals First Report of Phomopsis amygdali Causing Fruit Rot on Peaches in Greece

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1551-1551 ◽  
Author(s):  
T. J. Michailides ◽  
T. Thomidis
Keyword(s):  
Prunus Persica ◽  
Morphological Characteristics ◽  
Fruit Rot ◽  
Peach Fruit ◽  
Koch’S Postulates ◽  
Canker Disease ◽  
First Report ◽  
Immature Fruit ◽  
Diseased Fruit ◽  
Koch's Postulates

In the summer of 2005, the fungus Phomopsis amygdali (Del.) Tuset & Portilla was frequently isolated from decayed peaches (Prunus persica cv. Andross) grown in the province of Imathia, Greece. Fruit infected by P. amygdali developed gray-to-brown decay lesions with white mycelium forming on the surface of lesions. Identification of the pathogen was based on morphological characteristics. Dark-pigmented pycnidia (flask-shaped, conidia-bearing fruiting bodies) were produced over the surface of potato dextrose agar. The pycnidia exuded conidia in white tendrils 7 days later. Koch's postulates were completed in the laboratory by inoculating mature and immature cv. Andross peach fruits with an isolate of P. amygdali isolated from decayed cv. Andross peaches. Thirty peach fruit were surface sterilized by dipping them into 0.1% chlorine solution and allowing them to dry in a laminar flow hood. The peach fruit were wounded with a 2-mm diameter glass rod and a 40-μl drop of 5 × 105 conidia of P. amygdali per milliliter suspension was applied to the wound. Thirty control fruits were similarly wounded and inoculated with a 40-μl drop of sterile water. All inoculated and noninoculated fruit were incubated at 24 to 26°C for 7 days. Koch's postulates were satisfied when the same fungus was reisolated from 100% of inoculated mature and immature fruit that developed symptoms similar to diseased fruit collected from orchards. Although P. amygdali has been previously reported as a causal agent of canker disease (2) and fruit rots of peaches (1) in other countries, to our knowledge, this is the first report of the occurrence of P. amygdali causing a fruit rot of peaches in Greece. References: (1) Y. Ko and S. Sun. Plant Pathol. Bull. 12:212, 2003. (2) E. I. Zehr, Constriction canker. Page 31 in: Compendium of Stone Fruit Diseases. J. M. Ogawa et al., eds. The American Phytopathological Society, St. Paul, MN, 1995.

scholarly journals First Report of Azalea Petal Blight Caused by Pestalotiopsis guepini in Argentina

Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 100-100 ◽  
Author(s):  
M. C. Rivera ◽  
E. R. Wright
Keyword(s):  
Buenos Aires ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
Commonwealth Mycological Institute ◽  
Conidial Suspension ◽  
Koch’S Postulates ◽  
First Report ◽  
Pure Cultures ◽  
Pathogenicity Testing ◽  
Koch's Postulates

The most important azalea (Rhododendron spp.) growing area in Argentina is located in the outskirts of Buenos Aires. A disease of the azalea flower was detected during surveys conducted during September 1998. Irregular brown spots were uniformly distributed on petals and resulted in a flower blight that did not lead to abscission of petals. Pieces of infected petals were surface-sterilized for 1 min in 2% NaOCl, plated on potato dextrose agar, and incubated at 24 ± 2°C. Pure cultures were identified as Pestalotiopsis guepini (Desmaz.) Steyaert (synamorph P. guepini Desmaz.) based on morphological characteristics (1,2). Inoculation for pathogenicity testing was carried out by spraying a conidial suspension (1 × 106 conidia per ml) on plants with previously punctured petals. Inoculated plants with unwounded flowers, as well as noninoculated controls, were included. Plants were incubated in moist chambers at 24°C. Symptoms appeared on all punctured flowers within 4 to 5 days. Petals were blighted by 9 days after inoculation and were covered with black acervuli by 12 days after inoculation. Unwounded and noninoculated controls remained symptomless. The pathogen was reisolated from inoculated flowers, completing Koch's postulates. Pathogenicity of P. guepini on azalea leaves in Argentina was reported in 1991. This is the first report of P. guepini causing disease on azalea flowers in Argentina. References: (1) J. E. M. Mordue. CMI Descr. Pathog. Fungi Bact. No. 320, 1971. (2) B. C. Sutton. 1980. The Coelomycetes. Commonwealth Mycological Institute, Kew, England.

scholarly journals First Report of Neofusicoccum mediterraneum and N. australe Causing Decay in Vitis vinifera in Castilla y León, Spain

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 876-876 ◽  
Author(s):  
M. T. Martin ◽  
L. Martin ◽  
M. J. Cuesta
Keyword(s):  
Elongation Factor ◽  
Morphological Characteristics ◽  
Genetic Identity ◽  
Malt Extract ◽  
Koch’S Postulates ◽  
First Report ◽  
Castilla Y Leon ◽  
Agar Plug ◽  
Koch's Postulates ◽  
Β Tubulin

During a survey for grapevine decline, five young grapevines (cvs. Tempranillo and Viura) with low vigor and reduced foliage were collected (June and August 2009). Fungal isolations were performed from vascular and brown wood. Small pieces of brown wood were placed onto malt extract agar supplemented with 0.25 g/liter of chloramphenicol and incubated at 25°C in darkness. Five resulting colonies were transferred to potato dextrose agar (PDA). Isolates were characterized by abundant, gray, aerial mycelium that reached a radius of 45 mm after 4 days. Pycnidia induced on water agar with pine needles and UV light contained conidia that were hyaline, smooth, thin walled, fusiform, (20-) 22 to 26 (-28) × (5.5-) 6 (-6.5) μm, with granular cytoplasm. On the basis of morphological characteristics Neofusicoccum mediterraneum was suspected (1). Single-conidial cultures were generated from each isolate. DNA analyses were described in Martin and Cobos (2). Sequences of the internal transcribed spacer (ITS) region confirmed the identification and revealed 99% genetic identity with N. mediterraneum (GenBank Accession No EU040221). A sequence of the ITS fragment was deposited with Accession No. JF437919. Partial sequences of β-tubulin and 1-α elongation factor genes were amplified and deposited in the GenBank with Accession Nos. JF437921 and JF437923, showing 100 and 99% similarity to Accession Nos. GU292786 and GU251350, respectively. Pathogenicity tests were conducted with two isolates. The inoculations were carried out on a fresh wound on which an agar plug was applied; on 110R-rootstock woods of 12 young vines with N. mediterraneum and 12 other control plants were treated with agar only. Grapevines were maintained in a greenhouse at 20 to 25°C. After 4 months, N. mediterraneum was reisolated from vascular and brown tissues in 92% of inoculated plants, fulfilling Koch's postulates. Control plants were asymptomatic and N. mediterraneum was not recovered. With the same methodology, isolate Y264-21-1 reached a radius of 43 mm after 4 days at 25°C on PDA, presented colonies becoming olivaceous with a moderately dense mycelia, mat in center, and aerial around. Conidia were hyaline, fusiform, base subtruncate (19-) 23 to 26 (-31) × 5 to 6 (7.5) μm, unicellular, and smooth with granular contents. Based on these descriptions, N. australe was suspected (3). ITS sequence comparison revealed 99% genetic identity with N. australe (Accession No. FJ150697), a sequence of the fragment was deposited with Accession No. JF437920. Partial sequences of β-tubulin and 1α-elongation factor were deposited in the GenBank (Accession Nos. JF437922 and JF437924) showing 100 and 99% similarity to Accession Nos. AY615149 and GU251352, respectively. Koch's postulates were completed as described above. After 4 months, N. australe was reisolated from internal brown lesions in 92% of inoculated plants. Control plants were asymptomatic and N. australe was not recovered. The streaking length average from inoculation point for N. mediterraneum was 42 ± 22 mm and 53 ± 7 mm for N. australe. To our knowledge this is the first report of N. mediterraneum and N. australe in Castilla y León (Spain). References: (1) P. W. Crous et al. Fungal Planet 19:2, 2007. (2) M. T. Martin and R. Cobos. Phytopathol. Mediterr. 46:18, 2007. (3) B. Slippers et al. Mycologia 96:1030, 2004.

First Report of Crown Rot Caused by Phytophthora tropicalis on Gloxinia in North Carolina

2010 ◽  
Vol 11 (1) ◽  
pp. 47 ◽  
Author(s):  
Heather A. Olson ◽  
D. Michael Benson
Keyword(s):  
North Carolina ◽  
Its Rdna ◽  
Crown Rot ◽  
Successful Completion ◽  
Koch’S Postulates ◽  
First Report ◽  
Koch's Postulates

In 2007, wilting and crown rot were observed on recently transplanted gloxinias (a popular ornamental houseplant) in a commercial greenhouse in North Carolina. The pathogen was identified as Phytophthora tropicalis based on morphology and sequencing of the ITS rDNA region. Pathogenicity of the isolates to gloxinia was confirmed by successful completion of Koch's postulates. To our knowledge, this is the first report of Phytophthora tropicalis on gloxinia. Accepted for publication 2 June 2010. Published 8 July 2010.

First Report of Pathogenicity of Fusarium sporotrichioides and Fusarium acuminatum on Sunflowers in the United States

2010 ◽  
Vol 11 (1) ◽  
pp. 42 ◽  
Author(s):  
F. Mathew ◽  
B. Kirkeide ◽  
T. Gulya ◽  
S. Markell
Keyword(s):  
United States ◽  
Helianthus Annuus ◽  
The United States ◽  
Fusarium Sporotrichioides ◽  
Charcoal Rot ◽  
Koch’S Postulates ◽  
First Report ◽  
Fusarium Acuminatum ◽  
Helianthus Annuus L ◽  
Koch's Postulates

Widespread infection of charcoal rot was observed in a commercial sunflower field in Minnesota in September 2009. Based on morphology, isolates were identified as F. sporotrichioides and F. acuminatum. Koch's postulates demonstrated pathogencity of both species. To our knowledge, this is the first report of F. sporotrichoides and F. acuminatum causing disease on Helianthus annuus L. in the United States. Accepted for publication 23 August 2010. Published 15 September 2010.

scholarly journals First Report of Stemphylium botryosum Causing Leaf Blight of Kiwi in the Province Imathia, Northern Greece

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 650-650 ◽  
Author(s):  
T. Thomidis ◽  
T. J. Michailides
Keyword(s):  
Apical Cell ◽  
Morphological Characteristics ◽  
Leaf Blight ◽  
Width Ratio ◽  
Northern Greece ◽  
Cell Width ◽  
Koch’S Postulates ◽  
First Report ◽  
Stemphylium Botryosum ◽  
Koch's Postulates

In Greece, kiwi (Actinidia deliciosa) is mostly found in the northern part of the country where approximately 440,000 ha are grown. In the summer of 2006, a Stemphylium sp. was frequently isolated from leaves of kiwi (cv. Hayward) grown in the province of Imathia. Symptomatic leaves were covered with irregular, necrotic, brown areas. Lesions had a distinct margin that, in some cases, covered a wide part of the diseased leaves. Intense symptoms were frequently observed and associated with defoliation. This Stemphylium sp. was consistently isolated from diseased leaves onto potato dextrose agar (PDA) after surface sterilization with 0.1% chlorine solution. On the basis of morphological characteristics of mycelia, dimensions (length 20 to 29 μm and width 14 to 21 μm) and mean length/width ratio (1.42 μm) of conidia, and width and apical cell width of condiophores, the fungus was identified as Stemphylium botryosum (Wallr.) (2,3) Koch's postulates were completed in the laboratory by inoculating leaves of kiwi (cv. Hayward) with an isolate of S. botryosum originated from a symptomatic leaf of a Hayward kiwi. Twenty leaves were surface sterilized by dipping them into 0.1% chlorine solution for 2 to 3 min, washing in sterile distilled water, and allowing them to dry in a laminar flow hood. A leaf was then placed into a petri plate containing a wet, sterilized paper towel. Inoculation was made by transferring a 5-mm-diameter mycelial disc from the margins of a 7-day-old culture onto the center of each leaf surface. Petri plates were closed and incubated at 25°C with 12 h of light for 6 days. Koch's postulates were satisfied when the same S. botryosum was reisolated from 100% of inoculated leaves that developed symptoms similar to those observed in the vineyards. Leaves inoculated with a PDA plug alone (with no S. botryosum) did not develop any symptoms. Previously, Alternaria alternata was reported as the causal agent of a leaf spot pathogen of kiwi (1,4). To our knowledge, this is the first report of the occurrence of S. botryosum causing leaf blight of kiwi in Greece and worldwide. This pathogen can cause a high level of defoliation in diseased plants. References: (1) L. Corazza et al. Plant Dis. 83:487, 1999. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Mycology Institute. London, England, 1971. (3) E. G. Simmons. Mycologia 61:1, 1969. (4) C. Tsahouridou and C. C. Thanassoulopoulos. Plant Dis. 84:371, 2000

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