First Report of Fusarium proliferatum Causing Rot on Garlic and Onion in Argentina

In October 2001 and January 2002, in onion fields (Allium cepa L. cv Valencianita) in the Provinces of San Juan (SJ) and Mendoza (MZ), Argentina, plants were observed with chlorosis, dry leaf tips, and bulbs showing discoloration and rot. During the summer of 2002, a tan rot with white mycelium in rot cavities was also observed in stored garlic bulbs (Allium sativum) in MZ. Four monosporic cultures obtained with a micro punch adapted microscope (three from onion CSJ1, CMZ1, CMZ2 and one from garlic AMZ1) were characterized by morphology on PDA and carnation leaf agar (2). The isolates were deposited in the fungal collection of the Plant Mycosis Laboratory of the Integrated Unit Balcarce. The isolates produced abundant aerial white mycelium and a violet to vinaceous pigmentation. Club-shaped microconidia were abundant, in chains on both mono- and polyphialides. Slender, thin-walled and relatively straight macroconidia were produced only under black light and were mostly 3-septate. Chlamydospores were absent. The isolates were identified as Fusarium proliferatum. Crosses to confirm mating populations and to identify mating types were made in triplicate on carrot agar (3) with standard tester strains D-04853 (MATD-2) and D-04854 (MATD-1) as female parents and the field isolates as male parents. Crosses were examined weekly and were scored positive only if perithecia were seen oozing a cirrhus of ascospores. The identities of these isolates were confirmed as showing positive crosses with standard tester strains of Gibberella intermedia. Pathogenicity tests were conducted with healthy 45-day-old onion seedlings (cv. Valcatorce INTA). The roots of the onion seedlings were soaked in a conidial suspension (5 × 106 conidia/ml) of each isolate (CSJ1, CMZ1, CMZ2) for 2 h; the control was soaked in sterile water (SW). Seedlings were transplanted to pots in a sterile mixture of soil and sand (v/v). Five plants were used for each of 3 replications. The plants were placed in a greenhouse and irrigated with SW. After 3 weeks, symptoms were evaluated. All inoculated plants exhibited symptoms similar to those observed in the bulbs from which the pathogen was isolated and a brown rot appeared on the basal plate of the onion, later becoming dark brown. In garlic, the inoculation consisted of a wound 4.5 mm deep and 2 mm wide in superficially sterilized garlic cloves (cv. Nieve INTA). Inside the cavity, a drop (50 μl) was placed from a suspension of 5 × 106 conidia/ml (AMZ1), then covered with a drop of paraffin. Controls used SW. The garlic cloves were incubated in hermetically sealed trays at 22 ± 3°C in darkness for 3 weeks (1). Garlic showed tan rot and white mycelium in the wound. F. proliferatum was reisolated from inoculated onion seedlings and garlic cloves. The controls did not exhibit symptoms nor were any fungi recovered when tissue was excised from the inoculation points and plated on agar. F. proliferatum was previously reported in Argentina on asparagus (4) with symptoms similar to those of onion and garlic. To our knowledge, this is the first report of F. proliferatum attacking onion and garlic in Argentina. This pathogen has the potential risk of mycotoxin accumulation in contaminated bulbs. References: (1) F. M. Dugan et al. J. Phytopathol. 155:437, 2007. (2) W. Gerlach and H. Nirenberg. The genus Fusarium – A Pictorial Atlas. Mitt. Biol. Bundesanst. Land. Forstwirsch. Berl.-Dahlem, 1982. (3) C. J. R. Klittich and J. F. Leslie. Genetics 118:417, 1988. (4) G. Lori et al. Plant Dis. 82:1405, 1998.

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First report of Colletotrichum siamense causing anthracnose on Erythrina crista-galli in China

Plant Disease ◽

10.1094/pdis-05-20-1080-pdn ◽

2020 ◽

Author(s):

Min Li ◽

Zhaoyin Gao ◽

Xiaoyu Hong ◽

Zhang Shao Gang ◽

Chao Zhao ◽

...

Keyword(s):

Leaf Spot ◽

Phylogenetic Analyses ◽

Conidial Suspension ◽

Disease Symptoms ◽

First Report ◽

Brown Center ◽

Detached Leaves ◽

Leaf Tissues ◽

Pathogenicity Tests ◽

White Mycelium

Erythrina crista-galli L. (Fabaceae) is a popular ornamental plant in tropical and subtropical regions of South Asia. In October 2019, anthracnose-like lesions were observed on the leaves of E. crista-galli planted in Haikou, China. 5-30% of leaves were infected. At first, the circular spots of 1-2 mm in diameter were reddish-brown on the leaves, and then enlarged to circular, subcircular or irregular spots with reddish-brown center and surrounded by a diffuse yellow margin. Neighboring spots sometimes coalesced. Under continuously wet or humid conditions, the lesions expanded quickly, and became gray, subcircular or irregular spots covered by grayish-white mycelium and orange-pink conidial masses. Diseased leaves eventually fell off the trees. To identify the pathogen, diseased leaves were sampled from four gardens. Leaf tissues (5×5 mm) were cut from the margins of typical symptomatic lesions, surface-sterilized in 1% sodium hypochlorite for 1 min, plated on potato dextrose agar (PDA) medium, and incubated at 28.0±0.5℃ in the dark. Similar fungal colonies were obtained from all plated tissues after 3 days. The single-conidium colonies of all isolates were white to pale gray and cottony with visible orange conidial masses. Conidia were one-celled, aseptate, hyaline, straight, cylindrical to fusiform with obtuse ends, and ranged from 14.2-18.6 µm (16.4 µm)× 3.8-5.4 µm (4.7 µm) (n=100). After germination, conidia formed single, brown, oval or slightly irregular appressoria ranging from 8.0 to 11.8 μm (9.6 µm), and from 4.8 to 6.0 μm (5.4 µm). Sexual stage was absent. These characteristics of conidia and appressoria were matched with C. siamense belonging to the C. gloeosporioides complex (Prihastuti et al. 2009; Yang et al. 2009; Weir et al. 20012; Hu et al. 2015). To accurately identify the species, DNA was extracted from four purified isolates (JG-1, JG-3-1, SWS-1-3, SWS-2-1) （Fu et al. 2019）. The internal transcribed spacer of rDNA region (ITS), glyceraldehydes-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), actin (ACT) and chitin synthase (CHS) genes were amplified and sequenced. The nucleotide sequences were all deposited in GenBank (ITS: MT229427-MT229430, GAPDH: MT250821-MT250824, CAL: MT258893-MT258896, ACT: MT258897-MT258900 and CHS: MT258901-MT258904). Multi-locus phylogenetic analyses (ITS, GAPDH, CAL, ACT and CHS) (Weir et al. 2012) showed that the four isolates were clustered with C. siamense, which was in accordance with BLAST results. Pathogenicity tests of the four isolates were repeated three times on detached leaves (Ji et al. 2019). The conidial suspension (1×106 conidia/mL) was prepared using the conidia from 10-day-old cultures grown on PDA. Two 20-µL drops of conidial suspension were inoculated on non-wounded young healthy leaves, and each isolate was inoculated on 10 leaves. Two 20-µL drops of sterile water were inoculated on non-wounded young healthy leaves as control. The samples were maintained in containers at a relative humidity of 90± 5 per cent inside and 28℃ with a 12-h photoperiod. Gray, subcircular spots similar to the field disease symptoms were observed on the all inoculated leaves after 7 days, whereas no visible symptoms appeared on the non-inoculated leaves. The pathogen was re-isolated from inoculated leaves thus fulfilling Koch’s postulates. C. gloeosporioides has been previously reported as a pathogen causing leaf spot on Erythrina (E. indica var. picta, E. variegata var. orientalis) in Guam in 1983 and Brazil in 2012. (Russo et al. 1983; Oliveira et al. 2012). To our knowledge, this is the first report of C. siamense causing leaf spot of E. crista-galli in China.

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First Report of Gray Leaf Spot on St. Augustinegrass in Italy

Plant Disease ◽

10.1094/pdis.2003.87.12.1536a ◽

2003 ◽

Vol 87 (12) ◽

pp. 1536-1536 ◽

Cited By ~ 1

Author(s):

G. Polizzi ◽

I. Castello ◽

A. M. Picco ◽

D. Rodino

Keyword(s):

Leaf Spot ◽

Magnaporthe Grisea ◽

Fungal Spore ◽

Gray Leaf Spot ◽

Blast Disease ◽

Leaf Spot Disease ◽

High Humidity ◽

Conidial Suspension ◽

First Report ◽

Pathogenicity Tests

St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) is used for lawns in southern Italy because it is much more resistant to biotic and abiotic adversities than other turfgrass species. Because few seeds are viable, this species is established by vegetative propagation. A new disease was noticed during the spring of 2002 and 2003 on cuttings of St. Augustinegrass growing in three greenhouses in eastern Sicily. The disease affected leaves and culms and caused a progressive drying of the plants. The infection was first seen on leaves as gray, necrotic spots that enlarged in high-humidity conditions to form oval, and later, spindle-shaped lesions. In association with the lesions, it was possible to observe fungal spore development and sunken areas with blue-gray centers and slightly irregular, brown margins with yellow halos. Spots were concentrated without specific arrangement along longitudinal veins and the midrib and at the base, tip, and margins of the leaf blade. Symptoms on the culms consisted of brown-to-black blotches that sometimes extended throughout the internodes. From these infected tissues, 20 explants taken from leaves and culms were cut, washed with sterile water, and placed on 1.5% water agar (WA). Later, conidia and conidiophores were obtained from colonies with a sterile glass needle and placed on 4% WA. From these plates, two monoconidial isolates were obtained and transferred to rice meal medium (1). The colonies were identified as Pyricularia grisea Cooke (Sacc.), anamorphic state of Magnaporthe grisea (Hebert) Yeagashi & Udagawa, the cause of rice blast disease and gray leaf spot disease of turfgrasses. The conidia were pyriform to obclavate, narrowed toward the tip, rounded at the base, 2-septate, 21 to 31 μm × 6 to 10 μm (average 25.7 ×8.2 μm). Pathogenicity tests were performed by inoculating leaves and culms of six St. Augustinegrass plants with a conidial suspension of the fungus (1.5 ×105 conidia per ml). The same number of noninoculated plants was used as controls. All plants were incubated in a moist chamber with high humidity at 25°C. After 6 days, all inoculated plants showed typical symptoms of the disease. Koch's postulates were fulfilled by isolating P. grisea from inoculated plants. Gray leaf spot caused by P. grisea has been a chronic problem on St. Augustinegrass since it was first reported in 1957 (2). To our knowledge, this is the first report of P. grisea on St. Augustinegrass in Italy. While it does not appear to be an important disease in the field at this time in Sicily, it could cause losses in greenhouses where vegetative material is propagated for field planting. A preliminary molecular analysis has shown a clear distinction between the tested strain and other strains isolated from rice seeds and plants in northern Italy. References: (1) E. Roumen et al. Eur. J. Plant Pathol. 103:363, 1997. (2) L. P. Tredway et al. Plant Dis. 87:435, 2003.

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First Report of Anthracnose of Onion Caused by Colletotrichum coccodes in Ohio

Plant Disease ◽

10.1094/pdis-01-14-0032-pdn ◽

2014 ◽

Vol 98 (9) ◽

pp. 1271-1271 ◽

Cited By ~ 2

Author(s):

F. Baysal-Gurel ◽

N. Subedi ◽

D. P. Mamiro ◽

S. A. Miller

Keyword(s):

Leaf Tissue ◽

Its Region ◽

The United States ◽

Tween 20 ◽

Colletotrichum Coccodes ◽

Academic Press ◽

Conidial Suspension ◽

First Report ◽

Allium Cepa L ◽

Total Dna

Dry bulb onion (Allium cepa L. cvs. Pulsar, Bradley, and Livingston) plants with symptoms of anthracnose were observed in three commercial fields totaling 76.5 ha in Huron Co., Ohio, in July 2013. Symptoms were oval leaf lesions and yellowing, curling, twisting, chlorosis, and death of leaves. Nearly half of the plants in a 32.8-ha field of the cv. Pulsar were symptomatic. Concentric rings of acervuli with salmon-colored conidial masses were observed in the lesions. Conidia were straight with tapered ends and 16 to 23 × 3 to 6 μm (2). Colletotrichum coccodes (Wallr.) S. Hughes was regularly isolated from infected plants (2). Culturing diseased leaf tissue on potato dextrose agar (PDA) amended with 30 ppm rifampicin and 100 ppm ampicillin at room temperature yielded white aerial mycelia and salmon-colored conidial masses in acervuli. Numerous spherical, black microsclerotia were produced on the surface of colonies after 10 to 14 days. To confirm pathogen identity, total DNA was extracted directly from a 7-day-old culture of isolate SAM30-13 grown on PDA, using the Wizard SV Genomic DNA Purification System (Promega, Madison, WI) following the manufacturer's instructions. The ribosomal DNA internal transcribed spacer (ITS) region was amplified by PCR using the primer pair ITS1 and ITS4 (2), and sequenced. The sequence, deposited in GenBank (KF894404), was 99% identical to that of a C. coccodes isolate from Michigan (JQ682644) (1). Ten onion seedlings cv. Ebenezer White at the two- to three-leaf stage of growth were spray-inoculated with a conidial suspension (1 × 105 conidia/ml containing 0.01% Tween 20, with 10 ml applied/plant). Plants were maintained in a greenhouse (21 to 23°C) until symptoms appeared. Control plants were sprayed with sterilized water containing 0.01% Tween 20, and maintained in the same environment. After 30 days, sunken, oval lesions each with a salmon-colored center developed on the inoculated plants, and microscopic examination revealed the same pathogen morphology as the original isolates. C. coccodes was re-isolated consistently from leaf lesions. All non-inoculated control plants remained disease-free, and C. coccodes was not re-isolated from leaves of control plants. C. coccodes was reported infecting onions in the United States for the first time in Michigan in 2012 (1). This is the first report of anthracnose of onion caused by C. coccodes in Ohio. Unusually wet, warm conditions in Ohio in 2013 likely contributed to the outbreak of this disease. Timely fungicide applications will be necessary to manage this disease in affected areas. References: (1) A. K. Lees and A. J. Hilton. Plant Pathol. 52:3. 2003. (2) L. M. Rodriguez-Salamanca et al. Plant Dis. 96:769. 2012. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

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First Report of Brown Rot Caused by Monilinia fructicola Affecting Peach Orchards in Slovenia

Plant Disease ◽

10.1094/pdis-94-9-1166a ◽

2010 ◽

Vol 94 (9) ◽

pp. 1166-1166 ◽

Cited By ~ 15

Author(s):

A. Munda ◽

M. Viršček Marn

Keyword(s):

Prunus Persica ◽

Brown Rot ◽

Fruit Rot ◽

Morphological Identification ◽

Monilinia Fructicola ◽

Conidial Suspension ◽

Stone Fruits ◽

The European Union ◽

First Report ◽

Representative Isolate

Monilinia fructicola, the causal agent of brown rot, is a destructive fungal pathogen that affects mainly stone fruits (Prunoideae). It causes fruit rot, blossom wilt, twig blight, and canker formation and is common in North and South America, Australia, and New Zealand. M. fructicola is listed as a quarantine pathogen in the European Union and was absent from this region until 2001 when it was detected in France. In August 2009, mature peaches (Prunus persica cv. Royal Glory) with brown rot were found in a 5-year-old orchard in Goriška, western Slovenia. Symptoms included fruit lesions and mummified fruits. Lesions were brown, round, rapidly extending, and covered with abundant gray-to-buff conidial tufts. The pathogen was isolated in pure culture and identified based on morphological and molecular characters. Colonies on potato dextrose agar (PDA) incubated at 25°C in darkness had an average daily growth rate of 7.7 mm. They were initially colorless and later they were light gray with black stromatal plates and dense, hazel sporogenous mycelium. Colony margins were even. Sporulation was abundant and usually developed in distinct concentric zones. Limoniform conidia, produced in branched chains, measured 10.1 to 17.7 μm (mean = 12.1 μm) × 6.2 to 8.6 μm (mean = 7.3 μm) on PDA. Germinating conidia produced single germ tubes whose mean length ranged from 251 to 415 μm. Microconidia were abundant, globose, and 3 μm in diameter. Morphological characters resembled those described for M. fructicola (1). Morphological identification was confirmed by amplifying genomic DNA of isolates with M. fructicola species-specific primers (2–4). Sequence of the internal transcribed spacer (ITS) region (spanning ITS1 and ITS 2 plus 5.8 rDNA) of a representative isolate was generated using primers ITS1 and ITS4 and deposited in GenBank (Accession No. GU967379). BLAST analysis of the 516-bp PCR product revealed 100% identity with several sequences deposited for M. fructicola in NCBI GenBank. Pathogenicity was tested by inoculating five mature surface-sterilized peaches with 10 μl of a conidial suspension (104 conidia ml–1) obtained from one representative isolate. Sterile distilled water was used as a control. Peaches were wounded prior to inoculation. After 5 days of incubation at room temperature and 100% relative humidity, typical brown rot symptoms developed around the inoculation point, while controls showed no symptoms. M. fructicola was reisolated from lesion margins. Peach and nectarine orchards in a 5-km radius from the outbreak site were surveyed in September 2009 and M. fructicola was confirmed on mummified fruits from seven orchards. The pathogen was not detected in orchards from other regions of the country, where only the two endemic species M. laxa and M. fructigena were present. To our knowledge, this is the first report of M. fructicola associated with brown rot of stone fruits in Slovenia. References: (1) L. R. Batra. Page 106 in: World Species of Monilinia (Fungi): Their Ecology, Biosystematics and Control. J. Cramer, Berlin, 1991. (2) M.-J. Côté et al. Plant Dis. 88:1219, 2004. (3) K. J. D. Hughes et al. EPPO Bull. 30:507, 2000. (4) R. Ioos and P. Frey. Eur. J. Plant Pathol. 106:373, 2000.

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First report of Trichoderma afroharzianum causing seed rot on maize in Italy

Plant Disease ◽

10.1094/pdis-12-21-2697-pdn ◽

2022 ◽

Author(s):

Martina Sanna ◽

Massimo Pugliese ◽

Maria Lodovica GULLINO ◽

Monica Mezzalama

Keyword(s):

Rna Polymerase Ii ◽

Elongation Factor ◽

Aerial Mycelium ◽

Light Cycle ◽

Conidial Suspension ◽

Ear Rot ◽

Trichoderma Spp ◽

Trichoderma Species ◽

First Report ◽

Pathogenicity Tests

Maize (Zea mays L.) is a cereal crop of great economic importance in Italy; production is currently of 60,602,320 t, covering 588,597 ha (ISTAT 2021). Trichoderma species are widespread filamentous fungi in soil, well known and studied as biological control agents (Vinale et al., 2008). Seeds of a yellow grain hybrid (class FAO 700, 132 days) were collected in September 2020 from an experimental field located in Carmagnola (TO, Italy: GPS: 44°53'11.0"N 7°40'60.0"E) and tested with blotter test (Warham et al., 1996) to assess their phytosanitary condition. Over the 400 seeds tested, more than 50% showed rotting and development of green mycelium typical of the genus Trichoderma. Due to the high and unexpected percentage of decaying kernels, ten colonies were identified by morphological and molecular methods. Single conidia colonies of one Trichoderma (T5.1) strain were cultured on Potato Dextrose Agar (PDA) for pathogenicity tests, and on PDA and Synthetic Nutrient-Poor Agar (SNA) for morphological and molecular identification. The colonies grown on PDA and SNA showed green, abundant, cottony, and radiating aerial mycelium, and yellow pigmentation on the reverse. Colony radius after 72 h at 30°C was of 60-65 mm on PDA and of 50-55 mm on SNA. The isolates produced one cell conidia 2.8 - 3.8 µm long and 2.1 - 3.6 µm wide (n=50) on SNA. Conidiophores and phialides were lageniform to ampulliform and measured 4.5 – 9.7 µm long and 1.6 – 3.6 µm wide (n=50); the base measure 1.5 – 2.9 µm wide and the supporting cell 1.4 – 2.8 µm wide (n=50). The identity of one single-conidia strain was confirmed by sequence comparison of the internal transcribed spacer (ITS), the translation elongation factor-1α (tef-1α), and RNA polymerase II subunit (rpb2) gene fragments (Oskiera et al., 2015). BLASTn searches of GenBank using ITS (OL691534) the partial tef-1α (OL743117) and rpb2 (OL743116) sequences of the representative isolate T5.1, revealed 100% identity for rpb2 to T. afroharzianum TRS835 (KP009149) and 100% identity for tef-1α to T. afroharzianum Z19 (KR911897). Pathogenicity tests were carried out by suspending conidia from a 14-days old culture on PDA in sterile H2O to 1×106 CFU/ml. Twenty-five seeds were sown in pots filled with a steamed mix of white peat and perlite, 80:20 v/v, and maintained at 23°C under a seasonal day/night light cycle. Twenty primary ears were inoculated, by injection into the silk channel, with 1 ml of a conidial suspension of strain T5.1 seven days after silk channel emergence (BBCH 65) (Pfordt et al., 2020). Ears were removed four weeks after inoculation and disease severity, reaching up to 75% of the kernels of the twenty cobs, was assessed visually according to the EPPO guidelines (EPPO, 2015). Five control cobs, inoculated with 1 ml of sterile distilled water were healthy. T. afroharzianum was reisolated from kernels showing a green mold developing on their surface and identified by resequencing of tef-1α gene. T. afroharzianum has been already reported on maize in Germany and France as causal agent of ear rot of maize (Pfordt et al. 2020). Although several species of Trichoderma are known to be beneficial microorganisms, our results support other findings that report Trichoderma spp. causing ear rot on maize in tropical and subtropical areas of the world (Munkvold and White, 2016). The potential production of mycotoxins and the losses that can be caused by the pathogen during post-harvest need to be explored. To our knowledge this is the first report of T. afroharzianum as a pathogen of maize in Italy.

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First Report of Stem Blight on Perilla (Perilla frutescens) Caused by Corynespora cassiicola in Korea

Plant Disease ◽

10.1094/pdis-93-5-0550a ◽

2009 ◽

Vol 93 (5) ◽

pp. 550-550 ◽

Cited By ~ 2

Author(s):

H. B. Lee ◽

C. J. Kim ◽

H. Y. Mun

Keyword(s):

Perilla Frutescens ◽

Morphological Data ◽

Conidial Suspension ◽

Corynespora Cassiicola ◽

Cucumis Sativus L ◽

First Report ◽

Potted Plants ◽

Rdna Sequences ◽

Pathogenicity Tests ◽

Stem Lesions

Perilla or kkaennip (Perilla frutescens (L.) Britton), an annual herb of the mint family, Lamiaceae, is used in salads and kimchi and for wrapping sliced raw fish. In September 2007, a disease occurred on greenhouse-produced perilla (cv. Manchu) in Gwangyang and Jeonnam provinces, Korea. Symptoms included leaf blight and irregularly shaped stem lesions approximately 1 to 3 cm long. Plants eventually died. In some greenhouses, 10 to 30%, and occasionally as much as 70%, of the plants were affected. Isolations on potato dextrose agar yielded a fungus with single conidiophores (439 to 656 [average 524] μm long × 6.2 to 11.6 [average 9.2] μm wide) with three to eight septa. Conidia were fusiform, obclavate to subcylindrical, straight or curved, and 30.4 to 180.1 (average 98.2) μm long × 6.7 to 18.1 (average 10.5) μm wide with 5 to 16 (commonly 13) distosepta. On the basis of morphological data and ITS rDNA sequences, the fungus was identified as Corynespora cassiicola (Berk. & Curt.) Wei. (1,2). Sequences of one isolate, EML-COR1, were more than 99% identical to sequences of C. cassiicola ATCC64204 (GenBank Accession No. AY238606) and C. cassiicola (GenBank Accession No. EF490450). In pathogenicity tests, the stems and leaves of two 2-month-old wounded and nonwounded potted plants (cv. Manchu) were sprayed until runoff with a conidial suspension of 5 × 104 conidia per ml. The plants were maintained for 48 h in a humid chamber and then moved to a greenhouse. Symptoms similar to those observed in the commercial greenhouse developed on wounded stems within 10 days. On nonwounded plants, symptoms developed 3 to 4 weeks after inoculation. C. cassiicola was reisolated from these lesions. Control plants (sprayed with distilled water) remained symptomless. The experiment was repeated with similar results. Although C. cassiicola causes blight of cucumber (Cucumis sativus L.), sesame (Sesamum indicum L.), and other crops, to our knowledge, this is the first report of C. cassiicola on perilla. References: (1) M. B. Ellis. Page 372 in: Dematiaceous Hyphomycetes. 1971. (2) J. L. D. Silva et al. Plant Pathol. 55:580, 2006.

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First Report of Postharvest Fruit Rot in Persimmon Caused by Phacidiopycnis washingtonensis in Italy

Plant Disease ◽

10.1094/pdis-94-6-0788b ◽

2010 ◽

Vol 94 (6) ◽

pp. 788-788 ◽

Cited By ~ 2

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

M. T. Amatulli ◽

M. L. Gullino

Keyword(s):

United States ◽

Its Region ◽

The United States ◽

Fruit Rot ◽

Diospyros Kaki ◽

Pathogenicity Test ◽

Conidial Suspension ◽

First Report ◽

Pathogenicity Tests ◽

Phacidiopycnis Washingtonensis

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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First Report of Fusarium proliferatum Causing Fruit Rot of Grapes (Vitis vinifera) in Pakistan

International Journal of Phytopathology ◽

10.33687/phytopath.007.02.2589 ◽

2018 ◽

Vol 7 (2) ◽

pp. 85-88 ◽

Cited By ~ 1

Author(s):

Salman Ghuffar ◽

Gulshan Irshad ◽

Fengyan Zhai ◽

Asif Aziz ◽

Hafiz M. Asadullah M. Asadullah ◽

...

Keyword(s):

Vitis Vinifera ◽

Negative Control ◽

Fusarium Proliferatum ◽

Fruit Rot ◽

Pathogenicity Test ◽

Distilled Water ◽

Conidial Suspension ◽

Fruit Crop ◽

First Report ◽

Thin Walled

Grapes (Vitis vinifera) are the important fruit crop in Pakistan, mostly cultivated for edible purpose. In September 2016, unusual fruit rot symptoms were observed 3-5 days after harvesting on grapes cv. Kishmishi in post-harvest packing houses in Jehlum district (32°56'22.3"N 73°43'31.4"E) of Punjab province. To determine the disease incidence, a total of 10 boxes of grapes from 5 different locations were selected randomly. Each box contained average 12 bunches and 30 bunches out of 120 inspected bunches displayed typical symptoms of the disease. The initial Symptoms were small, round, water-soaked lesions that rapidly developed into soft, white to light pink mycelium near the centre of infected fruits (Figure 1). A total of 186 symptomatic berries were surface sterilized with 1% sodium hypochlorite, rinsed three times with sterile distilled water and dried by placing on filter paper for 45 sec. Sterilized tissues (approximately 4 mm3) were excised and incubated on potato dextrose agar (PDA) medium at 25 ± 4°C. One week after incubation, colonies with abundant aerial mycelium were initially white, cottony and turned to violet and dark purple with age (Figure 2). A total of 25 isolates were examined morphologically. Macroconidia were slender, thin-walled, 3 to 5 septate, curved apical cell, with 20.9 to 45.2 × 3.2 to 7.1 μm and Microconidia were thin-walled, aseptate, club-shaped with 4.5 to 11.2 × 2.3 to 4.1 μm (Figure 3). These characteristics best fit for the description of Fusarium proliferatum (Leslie and Summerell, 2006). Portions of the internal transcribed spacer (ITS) region were sequenced (White et al., 1990). Sequences of two isolates Fus 07 and Fus 09 (GenBank Accessions; MH444366 and MH464139) showed 100% identity to the corresponding gene sequences of Fusarium proliferatum (GenBank Accessions; MH368119, MF033172 and KU939071) (Figure 4). Pathogenicity test was performed by inoculation with 50-μl conidial suspension (1 × 106conidia/ml) of two isolates onto three non-wounded and four wounded asymptomatic grapes berries. Sterile distilled water was used for a negative control (Figure 5). The experiment was conducted twice and berries were incubated at 25 ± 2°C in sterile moisture chambers (Ghuffar et al., 2018). White to light pink mycelium in appearance with the original symptoms were observed on both wounded and non-wounded inoculated berries after 3 days, whereas no symptoms were observed on the negative control. The morphology of the fungus that was re-isolated from each of the inoculated berries was identical to that of the original cultures. Fusarium proliferatum, one of the destructive species, causes diseases like foot-rot of corn (Farr et al., 1990), root rot of soybean (Díaz Arias et al., 2011), bakanae of rice (Zainudin et al., 2008), wilt of date palm (Khudhair et al., 2014), tomato wilt (Chehri, 2016) and tomato fruit rot (Murad et al., 2016). To our knowledge, this is the first report of Fusarium proliferatum causing fruit rot of grapes in Pakistan, where the disease poses a significant threat to the sustainability of this major fruit crop.

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First Report of Colletotrichum acutatum on Strawberry in Northwestern Argentina

Plant Disease ◽

10.1094/pdis.2000.84.6.706b ◽

2000 ◽

Vol 84 (6) ◽

pp. 706-706 ◽

Cited By ~ 5

Author(s):

C. J. Ramallo ◽

L. D. Ploper ◽

M. Ontivero ◽

M. P. Filippone ◽

A. Castagnaro ◽

...

Keyword(s):

Colletotrichum Acutatum ◽

Conidial Suspension ◽

Disease Symptoms ◽

Northwestern Argentina ◽

First Report ◽

Surface Control ◽

Detached Leaves ◽

Strawberry Anthracnose ◽

Pathogenicity Tests ◽

Necrotic Spots

Isolates were obtained from strawberry tissue with anthracnose symptoms from several locations near Tucumán, Argentina. Isolates were characterized using several criteria. Isolates produced fusiform conidia, tapered to a point at both ends, and averaged 13.5 × 4.9 μm. On potato dextrose agar, colonies produced a white cottony mycelial colony that turned orange in older cultures. Compared with Colletotrichum fragariae, the new isolates produced fewer appressoria. Pathogenicity tests were conducted on detached leaves and plants in the greenhouse and field. Detached immature leaves of cvs. Chandler, Fern, and Sweet Charlie were inoculated with a 20-μl droplet of an aqueous conidial suspension (106 conidia per ml) placed on the adaxial surface. Control leaves were inoculated with sterile distilled water. Leaves were maintained under white light (2,000 lux, 12 h/day) at 26°C, and 100% relative humidity. Necrotic spots were visible 4 days after inoculation. Greenhouse and field plants were spray-inoculated and covered for 48 h. Disease symptoms were mainly observed on petioles and runners 9 days after inoculation. No lesions were observed on control detached leaves or plants. Koch's postulates were confirmed in all cases. Based on morphological and cultural characteristics, isolates were identified as C. acutatum Simmonds (1). This is the first report of C. acutatum causing strawberry anthracnose in northwestern Argentina. Reference: (1) B. Smith and L. L. Black. Plant Dis. 74:69, 1990.

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First Report of Fusarium Blight on Majesty Palm Caused by Fusarium proliferatum in Italy

Plant Disease ◽

10.1094/pdis.2003.87.9.1149a ◽

2003 ◽

Vol 87 (9) ◽

pp. 1149-1149 ◽

Cited By ~ 6

Author(s):

G. Polizzi ◽

A. Vitale

Keyword(s):

Fusarium Proliferatum ◽

Conidial Suspension ◽

First Report ◽

Leaf Spots ◽

Initial Symptoms ◽

Mt Etna ◽

Young Leaves ◽

Pure Cultures ◽

Severe Infections ◽

Fusarium Sp

During spring 2002, a new disease of majesty palm (Ravenea rivularis Jumelle & H. Perrier) was observed on young, container-grown plants (3 to 4 years old with five to seven expanded leaves) in a nursery in eastern Sicily. Initial symptoms on the youngest, expanded leaves and especially on the unopened, spear leaves were small, reddish-brown necrotic lesions (2 to 4 mm in diameter) with a yellow halo. In high humidity, lesions increased in size and number, coalescing into large, irregular dead areas. These symptoms developed into blights of the youngest, unopened leaves. As a consequence, infected leaves would dieback and only a few plants recovered from these severe infections. On the surviving plants, reddish-brown necrotic lesions appeared on the rachis. From these lesions, 30 pieces of tissue were cut, surface sterilized (30 s in 1.2% wt/vol of NaOCl), washed with sterile water, and plated on potato dextrose agar supplemented with 1.1 μl/ml of lactic acid (stock 88 to 92%) (A-PDA). Conidia and conidiophores were collected directly from the tissue with a flamed needle and placed on A-PDA. Fusarium sp. was consistently isolated from the necrotic tissue, and after 3 days, single hyphal tips were transferred to pure cultures from which were obtained two single, conidial isolates. These fungal isolates were forwarded to the CABI Bioscience U.K. Centre, Bakeham Lane (Egham), Surrey, U.K., where both isolates were identified as Fusarium proliferatum (T. Matsushima) Nirenberg. A morpho-biometrical characterization was performed on carnation leaf agar with a photoperiod of 10 h. Macroconidia were slender, lightly falcate to almost straight, 3- to 5-septate, and ranged from 37 to 53 × 2.5 to 3 μm (average 44.1 × 2.8 μm). Microconidia, clavate or oval with a truncated base, were formed in chains from mono- or polyphialides. Chlamydospores were absent. Eight 2-year-old seedlings (three to five expanded leaves) of majesty palm had the unopened spear leaves needle-wounded and another eight were unwounded. All were sprayed with a conidial suspension (1.5 × 106 CFU/ml). An equal number of noninoculated plants were used as a control. All plants were covered with polyethylene bags and incubated in a greenhouse at 25 ± 2°C for 72 h. All wounded majesty palms showed brown areas on unopened spear leaves. When natural injures were present, reddish leaf spots appeared as early as 4 days after inoculation. Macroscopic observations revealed the presence of white mycelium on the necrotic areas and reddish spots. Koch's postulates were satisfied by reisolation of the fungus on A-PDA from artificially infected tissues. On the basis of 3 months of field observations in Sicily, spread of Fusarium blight on majesty palm was always greater when plants were injured on the tender and unopened leaves by volcanic cinders from Mt. Etna, which caused bruises on young leaves. The disease does not represent a major threat to nurseries, but it could cause loss in the cultivation of the majesty palm. F. proliferatum was previously recorded in Saudi Arabia as the causal agent of wilt and dieback of date palm (1). To our knowledge, this is the first report of F. proliferatum on palms in Italy and the first outbreak of the disease on majesty palm. Reference: (1)M. Y. Abdalla et al. Plant Dis. 84:321, 2000.

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