First Report of Peach Brown Rot Caused by Monilinia fructicola in Central and Western China

Brown rot of peach (Prunus persica) in China has been reported to be caused by at least three Monilinia species (1). In the present study, peaches with symptoms resembling brown rot caused by Monilinia species were collected from commercial orchards in the northwestern province of Gansu in August 2010, the southwestern province of Yunnan in July 2011, and in the central province of Hubei in July 2012. Affected fruit showed the typical symptoms of brown rot with zones of sporulation. Fungal isolates were single-spored and cultured on potato dextrose agar (PDA). Colonies showed grayness with concentric rings of sporulation after incubation at 25°C in the dark. Mean mycelial growth of isolates YHC11-1a and YHC11-2a from Yunnan, GTC10-1a and GTC10-2a from Gansu, and HWC12-14a and HWC12-23a from Hubei, was 4.6 ± 0.4 and 7.5 ± 0.7 cm after 3 and 5 days incubation, respectively. Conidia were lemon shaped and formed in branched monilioid chains, and the mean size was 9.3 (6.7 to 11.5) × 12.5 (7.9 to 17.8) μm, which was consistent with the characteristics of Monilinia fructicola (1,2). The species identification was confirmed by sequencing of the ribosomal ITS sequences. The ribosomal ITS1-5.8S-ITS2 region was amplified from each of the six isolates using primers ITS1 and ITS4 (3). Results indicated that the ITS sequences of these isolates were identical and showed the highest similarity (100%) with M. fructicola ITS sequences from isolates collected in China (GenBank Accession Nos. HQ893748, FJ515894, and AM887528), Slovenia (GU967379), Italy (FJ411109), and Spain (EF207423). The pathogen was also confirmed to be M. fructicola based on the detection of an M. fructicola- specific band (534 bp) using a PCR-based molecular tool developed for distinguishing Chinese Monilinia species affecting peach (1). Pathogenicity was tested on surface-sterilized, mature peaches (Shui Mi Tao) with representative isolates. Fruits were holed at three equidistant positions to a depth of 5 mm using a sterile cork borer. Mycelial plugs (5 mm in diameter) from the periphery of a 4-day-old colony of each isolate were placed upside down into each hole, control fruits received water agar. After 3 days of incubation at 22°C in a moist chamber, inoculated fruits developed typical brown rot symptoms while control fruits remained healthy. Pathogens from the inoculated fruit were confirmed to be M. fructicola based on morphological characteristics. To our knowledge, this is the first report of occurrence of M. fructicola in Gansu, Yunnan, and Hubei provinces, thousands of kilometers away from eastern China where occurrence of peach brown rot caused by M. fructicola has been confirmed (2,4). The results indicated the further geographical spread of the M. fructicola in China. References: (1) M. J. Hu et al. Plos One 6(9):e24990, 2011. (2) M. J. Hu et al. Plant Dis. 95:225, 2011. (3) T. J. White et al. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. Academic Press, San Diego, 1990. (4) X. Q. Zhu et al. Plant Pathol. 54:575, 2005.

Download Full-text

First Report of Brown Rot of Peach Caused by Monilinia fructicola in Southeastern China

Plant Disease ◽

10.1094/pdis-11-10-0779 ◽

2011 ◽

Vol 95 (2) ◽

pp. 225-225 ◽

Cited By ~ 5

Author(s):

M. J. Hu ◽

Y. Chen ◽

S. N. Chen ◽

X. L. Liu ◽

L. F. Yin ◽

...

Keyword(s):

Dna Sequences ◽

Prunus Persica ◽

Morphological Characteristics ◽

Brown Rot ◽

Its Sequences ◽

Monilinia Fructicola ◽

Southeastern China ◽

Fujian Province ◽

First Report ◽

Control Fruit

In 2009 and 2010, peaches (Prunus persica) with brown rot symptoms were collected from Zhejiang Plant Protection State Research Farm and a commercial orchard in Fujian Province in southeastern China. Affected fruit showed brown decay with zones of sporulation. Single-spore isolates from the diseased fruit were cultured on potato dextrose agar. After incubation at 25°C in the dark for 5 days, colonies were gray with concentric rings of sporulation. Mean mycelial growth of isolates MZ09-2a from Zhejiang Province and 0907-a from Fujian Province was 4.46 ± 0.58 and 7.05 ± 0.81 cm after 4 and 7 days of incubation, respectively. Lemon-shaped conidia were formed in branched, monilioid chains and mean size was 14.6 (9.6 to 21.6) × 10.3 (7.2 to 13.2) μm. Mean conidial germination was 97 ± 1% with one straight germ tube per conidium. These characteristics were consistent with descriptions of Monilinia fructicola (G. Wint.) Honey (3). Morphology-based species identification was confirmed by sequencing and analysis of ribosomal internal transcribed spacer (ITS) sequences. A 496-bp fragment including ITS 1 and 2 and the gene encoding the 5.8S small subunit of the ribosomal RNA from isolates MZ09-2a and 0907-a was amplified using the universal primer pair ITS1/ITS4 (4) and sequenced. Nucleotide sequences of both isolates were identical. Blast searches of the ITS sequences in GenBank showed the highest similarity (100%) with sequences of M. fructicola isolates from China (FJ515894), Italy (FJ411109), and Spain (EF207423). The isolates were also identified as M. fructicola using the Monilinia spp. PCR detection protocol based on sequence-characterized amplification region marker DNA sequences (2). Pathogenicity was confirmed by inoculating surface-sterilized, mature cv. Zhonghua 2 peaches with mycelial plugs of representative isolates. Fruit was stabbed at two points with a 5-mm-diameter sterile cork borer, mycelial plugs (5 mm in diameter) were removed from the periphery of a 4-day-old colony of each isolate and placed upside down into each wound; control fruit received water agar. Inoculated fruit developed typical brown rot symptoms with sporulating fungi while control fruit remained healthy after 3 days of incubation at 22°C in a moist chamber. Pathogens were reisolated from the inoculated fruit and confirmed to be M. fructicola on the basis of morphological characteristics. To our knowledge, this is the first report of M. fructicola in Zhejiang and Fujian provinces. Both provinces are located more than 1,000 km south of Beijing, Hebei, and Shandong provinces, where M. fructicola had been reported previously (1). References: (1) J. Y. Fan et al. Acta Phytophylacica Sin. (in Chinese) 34:289, 2007. (2) I. Gell et al. J. Appl. Microbiol. 103:2629, 2007. (3) G. C. M. van Leeuwen and H. A. van Kesteren. Can. J. Bot. 76:2041, 1998. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds., Academic Press, San Diego, 1990.

Download Full-text

First Report of Brown Rot Caused by Monilia mumecola on Chinese Sour Cherry in Chongqing Municipality, China

Plant Disease ◽

10.1094/pdis-01-14-0029-pdn ◽

2014 ◽

Vol 98 (7) ◽

pp. 1009-1009 ◽

Cited By ~ 4

Author(s):

L. F. Yin ◽

G. K. Chen ◽

S. N. Chen ◽

S. F. Du ◽

G. Q. Li ◽

...

Keyword(s):

Eastern China ◽

Morphological Characteristics ◽

Sour Cherry ◽

Brown Rot ◽

Fruit Rot ◽

Western China ◽

First Report ◽

Chongqing Municipality ◽

Average Size ◽

Germ Tubes

Cherry is widely planted in China, from Liaoning, Beijing, Hebei, Shandong, Zhejiang, Jiangsu, and Anhui provinces (eastern China), to Shaanxi, Sichuan, Chongqing, and Guizhou provinces (western China). The brown rot fungus Monilinia fructigena causes considerable production losses in cherry production in Liaoning Province (3). In May 2013, Chinese sour cherry (Prunus pseudocerasus) cv. Wupi displaying symptoms of brown rot was found in an orchard in Chongqing municipality. Diseased cherry fruit had a brown rot sporulating with grayish, conidial tufts. The fruit later succumbed to the soft rot or shivered and became a mummy. Single-spore isolations on PDA resulted in colonies with concentric rings of pigmented mycelium with lobbed margins. Conidia were broadly ellipsoid to subglobose, occasionally even globose, with an average size of 16 × 12.7 μm. Multiple germ tubes were produced from each conidium, a germination pattern unique to Monilia mumecola (1,2,4). The pathogen identity was confirmed by multiplex PCR as described by Hu et al. (2). The PCR resulted in a 712-bp amplicon, which is diagnostic of M. mumecola. Further sequencing of the internal transcribed spacer (ITS) region 1 and 2 and 5.8S gene further indicated 100% identity with that of M. mumecola isolates from China (Accession No. HQ908786) and from Japan (AB125613, AB125614, and AB125620). Koch's postulates were confirmed by inoculating mature cherry fruit with mycelia plugs. Inoculated fruit were placed in a sterilized moist chamber, and incubated at 22°C with 12 h light/dark cycle. Inoculated fruit developed typical brown rot symptoms only 2 days after inoculation, while the control fruit, inoculated with a sterile PDA plug, remained healthy. The pathogen isolated from inoculated symptomatic fruit was confirmed to be M. mumecola based on morphological characteristics and germination pattern. It should be noted that the conidia on inoculated fruit showed an average size of 20 × 15.3 μm, significantly bigger than that of from PDA, and most produced more than three germ tubes. The inoculation experiments were performed in triplicates. M. mumecola was first reported as the causal agent of brown rot of mume in Japan in 2004 (1). Later studies demonstrated that it is also pathogen on other stone fruits, e.g., peach, nectarine (2), and apricot (4). To our knowledge, this is the first report of cherry brown fruit rot caused by M. mumecola, and the first report of M. mumecola in Chongqing municipality. References: (1) Y. Harada et al. J. Gen. Plant Pathol. 70:297, 2004. (2) M. J. Hu et al. Plos One 6(9): e24990, 2011. (3) Z. H. Liu et al. J. Fruit Sci. 29:423, 2012. (4) L. F. Yin et al. Plant Dis. 98:694, 2014.

Download Full-text

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.

Download Full-text

First Report of Brown Rot Caused by Monilinia fructicola on Various Stone and Pome Fruits in the Czech Republic

Plant Disease ◽

10.1094/pdis-91-7-0907b ◽

2007 ◽

Vol 91 (7) ◽

pp. 907-907 ◽

Cited By ~ 23

Author(s):

J. Duchoslavová ◽

I. Širučková ◽

E. Zapletalová ◽

M. Navrátil ◽

D. Šafářová

Keyword(s):

Czech Republic ◽

Malus Domestica ◽

Prunus Persica ◽

Brown Rot ◽

Prunus Armeniaca ◽

Molecular Characteristics ◽

Morphological Identification ◽

Monilinia Fructicola ◽

The Czech Republic ◽

First Report

Monilinia fructicola, a causal agent of brown rot, is one of the most important fungal pathogens of stone fruits. The disease causes major crop losses in peach, plum, prune, nectarine, and apricot. M. fructicola is commonly present in Asia, North and South America, and Australia. This is a quarantined pathogen in Europe; restricted occurrence has been observed in Austria and France. Recently, it was detected in Hungary and Switzerland on peach and nectarine fruits imported from Italy and Spain (1,4). During a survey in the summer of 2006, 56 samples were tested for the presence of Monilinia spp. M. fructicola was detected in 15 samples from 11 locations in the western area (Bohemia) of the Czech Republic, mainly on peaches (Prunus persica), apples (Malus × domestica), and sweet and sour cherries (Cerasus avium and C. vulgaris) and rarely on flowering plum (Prunus triloba) and Malus × moerlandsii cv. Liset. On the other hand, the pathogen was not detected on fruits of apricot (Prunus armeniaca) or pear (Pyrus communis). In all cases, M. fructicola was detected on fruits except for a single occurrence of the pathogen on a shoot of the Malus × domestica. The pathogen was always detected in mixed infections with M. fructigena and/or M. laxa. On both fruits and the shoot, symptoms appeared as brown, sunken lesions covered with grayish pustules. Many infected fruits became dry and mummified because rot progressed through the fruit surface. The infected shoot died back (3). M. fructicola was identified by means of colony and conidial morphology and molecular characteristics. The colonies cultivated on potato dextrose agar were entire and the colony surface was even. The color of the colony was gray, and sporulating colonies showed concentric rings that changed to a hazel color. Conidia were ellipsoid, hyaline, and 13.5 to 17.7 × 8.3 to 10.5 μm. Preliminary morphological identification was confirmed by PCR (2) on DNA isolated directly from mycelium on the examined fruits. A product that was 280 bp long was obtained in all cases. The BLAST analysis of our PCR product sequences showed 100% homology to sequences of M. fructicola (GenBank Accession Nos. DQ491506, AY2891185, Z73778, and AB125615). One sequence from our study was deposited in GenBank (Accession No. EF378628). To our knowledge, this is the first report of the quarantined fungus M. fructicola in the Czech Republic. References: (1) E. Bosshard et al. Plant Dis. 90:1554, 2006. (2) K. J. D. Hughes et al. EPPO Bull. 30:507, 2000. (3) J. M. Ogawa et al., eds. Compendium of Stone Fruit Diseases. The American Phytopathological Society, St. Paul, MN, 1995. (4) M. Petróczy and L. Palkovics. Plant Dis. 90:375, 2006.

Download Full-text

First Report of Monilinia fructicola Causing Brown Rot on Stored Japanese Plum Fruit in Chile

Plant Disease ◽

10.1094/pdis-06-13-0647-pdn ◽

2014 ◽

Vol 98 (1) ◽

pp. 160-160 ◽

Cited By ~ 3

Author(s):

B. A. Latorre ◽

G. A. Díaz ◽

A. L. Valencia ◽

P. Naranjo ◽

E. E. Ferrada ◽

...

Keyword(s):

San Francisco ◽

Brown Rot ◽

Soft Rot ◽

The United States ◽

Its2 Region ◽

Monilinia Fructicola ◽

Conidial Suspension ◽

First Report ◽

Japanese Plum ◽

Official Control

In autumn 2013, fruit of Japanese plum (Prunus salicina) cvs. Angelino and Black Kat developed an unusual brown and soft rot after 2 months in cold storage (0°C) on nearly 1% of the fruit. Fruit showed small, circular, light brown spots that eventually destroyed the entire fruit. Small sporodochia appeared on the fruit surface. Fruit was harvested from orchards located near San Francisco de Mostazal (33°59′ S, 70°41′ W), Chile. Small pieces of diseased tissue were selected from margins of lesions of surface disinfected (96% ethanol) fruit (n = 7) and placed on acidified potato dextrose agar (PDA) plates for 5 days at 20°C. Light brown colonies with even margins and concentric rings of spores were obtained. The conidia of five isolates were one-celled, hyaline, lemon-shaped, (min. 10.7) 14.9 ± 1.5 (max. 18.6) × (min. 8.1) 9.4 ± 0.8 (max. 10.8) μm (n = 30), and borne in branched monilioid chains. This fungus was identified as Monilinia fructicola (G. Winter) Honey (1). Identification was confirmed by amplifying and sequencing the ribosomal ITS1-5.8S-ITS2 region using ITS1 and ITS4 primers (3). BLAST analysis of Chilean plum isolates (GenBank Accession Nos. KF148610 and KF148611) were 99 to 100% identical to isolates of M. fructicola originating from the United States (DQ314727 and HQ846966, respectively) and 100% identical to the first Chilean isolate (JN001480) found in nectarines originating from California at the supermarkets in Santiago in June 2009. Koch's postulates were fulfilled by reproducing brown rot symptoms on mature wounded Japanese plums cv. Angelino (n = 8) inoculated with 10 μl of a conidial suspension (105 conidia/ml) or with a mycelium plug (5-mm diameter). After 2 days in humid chambers (>80% relative humidity) at 25°C, all inoculated fruit developed brown rot symptoms with necrotic lesion means of 15.8 and 21.5 mm in diameter in fruit inoculated with conidia and mycelium, respectively. Non-inoculated control fruit remained healthy. Re-isolations were performed on PDA and the presence of M. fructicola was morphologically confirmed in 100% of the symptomatic fruits. To our knowledge, this is the first report demonstrating the presence of M. fructicola causing brown rot in stored Japanese plums in Chile after its first interception in 2009 in Chile, suggesting that this pathogen has been established in the field. Currently, M. fructicola is a quarantine organism under official control, restricted to Prunus orchards between Santiago and Nancagua in central Chile (2). References: (1) EPPO. EPPO Bull. 39:337, 2009. (2) Servicio Agrícola y Ganadero, SAG, Ministerio de Agricultura, Gobierno de Chile. www.sag.cl , accessed 15 November 2013. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, NY, 1990.

Download Full-text

First Report of Brown Rot Caused by Monilinia fructicola on Apple in Italy

Plant Disease ◽

10.1094/pdis-09-12-0869-pdn ◽

2013 ◽

Vol 97 (5) ◽

pp. 689-689 ◽

Cited By ~ 6

Author(s):

C. Martini ◽

A. Spadoni ◽

M. Mari

Keyword(s):

Fungal Pathogens ◽

Brown Rot ◽

Its2 Region ◽

Monilinia Fructicola ◽

Malt Extract ◽

Conidial Suspension ◽

First Report ◽

Molecular Features ◽

Sterile Needle ◽

Emilia Romagna Region

Monilinia fructicola (G. Wint.) Honey, the causal agent of brown rot, is one of the most important fungal pathogens of stone fruit but may also affect pome fruits. The pathogen is common in North America, Oceania, South America, and Asia. It is a quarantined pathogen in Europe (3), but was recently detected in apple from the Czech Republic, Germany, and Serbia (1,2,4). In January 2012, during a survey for fungal postharvest pathogens, stored apple (Malus domestica Borkh.) belonging to the cultivars Gala and Pink Lady showing brown rot symptoms were observed in the Emilia Romagna region, Italy. Typical decay spots were circular and brown, tending toward black. Decayed tissues remained firm, and numerous grayish pustules containing spores appeared on rotted areas. The pathogen was isolated on V8 juice agar and culture plates were incubated at 25°C in darkness for 5 days. A conidial suspension was spread on malt extract agar and single spores were selected. The colonies were morphologically identified as M. fructigena. Two colonies developing a gray mass of spores in concentric rings with the reverse side black were further studied by molecular tools. The colony margins were even and the conidia were one-celled, limoniform, hyaline, and 12.1 to 17.4 × 8.4 to 11.2 μm. The ribosomal ITS1-5.8S-ITS2 region was PCR-amplified from genomic DNA obtained from mycelium using primers ITS1 and ITS4. A BLAST search in GenBank revealed the highest similarity (99%) to M. fructicola sequences (GenBank Accession Nos. HQ893748.1 and FJ515894.1). Pathogenicity was confirmed using surface-sterilized mature ‘Gala’ apples, wounded with a sterile needle, and inoculated with an isolate conidial suspension (103 spores/ml). A 20 μl droplet was placed in the wound; control fruits received sterile water without conidia. After 5 days of incubation at 20°C in plastic containers with high humidity, typical symptoms of brown rot developed on inoculated fruits, while control fruits remained symptomless. The fungus isolated from inoculated fruit exhibited the same morphological and molecular features shown by the original isolates. To our knowledge, this is the first report of the fungus M. fructicola on apple in Italy. Further studies are necessary to determine geographic distribution, prevalence and economic importance of this quarantine organism in Italy. References: (1) J. Duchoslavovà et al. Plant Dis.91:907, 2007. (2) A. Grabke et al. Plant Dis. 95:772, 2011. (3) OEPP/EPPO. EPPO A2 list of pests recommended for regulation as quarantine pests. Version 2010-09. Retrieved from http://www.eppo.int/QUARANTINE/listA2.htm , 2010. (4) M. Vasic et al. Plant Dis. 96:456, 2012.

Download Full-text

First Report of Brown Rot Caused by Monilinia fructicola on Stored Apple in Serbia

Plant Disease ◽

10.1094/pdis-06-11-0531 ◽

2012 ◽

Vol 96 (3) ◽

pp. 456-456 ◽

Cited By ~ 10

Author(s):

M. Vasić ◽

N. Duduk ◽

M. M. Ivanović ◽

A. Obradović ◽

M. S. Ivanović

Keyword(s):

Online Publication ◽

Slovak Republic ◽

Brown Rot ◽

Pathogenic Fungi ◽

Its2 Region ◽

Morphological Identification ◽

Monilinia Fructicola ◽

First Report ◽

Molecular Features ◽

Quarantine Organism

Monilinia fructicola (G. Winter) Honey is a causal agent of brown rot of stone fruits, occasionally affecting pome fruits as well. The pathogen is commonly present in North and South America, Oceania, and Asia, but listed as a quarantine organism in Europe (4). After its first discovery in France in 2001, its occurrence has been reported in Germany, Hungary, Italy, Poland, Romania, Slovenia, Spain, Switzerland, Austria, and the Slovak Republic (1). In February 2011, during a survey for fungal postharvest pathogens in cold storage conditions, apple fruits (Malus domestica Borkh.) grown and stored in the Grocka Region, Serbia, were collected. All pathogens from symptomatic fruits were isolated on potato dextrose agar (PDA). One isolate from apple fruit cv. Golden Delicious with brown rot symptoms was identified as M. fructicola based on morphological and molecular characters. Colonies cultivated on PDA at 22°C in darkness were colorless, but later became grayish, developing mass of spores in concentric rings. Colony margins were even. Conidia were one-celled, limoniform, hyaline, measured 12.19 to 17.37 (mean 13.8) × 8.62 to 11.43 μm (mean 9.9), and were produced in branched monilioid chains (3). Morphological identification was confirmed by PCR (2) using genomic DNA extracted from the mycelium of pure culture, and an amplified product of 535 bp, specific for the species M. fructicola, was obtained. Sequence of the ribosomal (internal transcribed spacer) ITS1-5.8S-ITS2 region was obtained using primers ITS1 and ITS4 and deposited in GenBank (Accession No. JN176564). Control fruits were inoculated with sterile PDA plugs. After 3 days of incubation in plastic containers with high humidity at room temperature, typical symptoms of brown rot developed on inoculated fruits, while control fruits remained symptomless. The isolate recovered from symptomatic fruits showed the same morphological and molecular features of the original isolate. To our knowledge, this is the first report of M. fructicola in Serbia. Further studies are necessary for estimation of economic importance and geographic distribution of this quarantine organism in Serbia. References: (1) R. Baker et al. European Food Safety Authority. Online publication. www.efsa.europa.eu/efsajournal . EFSA J. 9(4):2119, 2011. (2) M.-J. Côté et al. Plant Dis. 88:1219, 2004. (3) J. E. M. Mordue. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 616, 1979. (4) OEPP/EPPO. EPPO A2 List of Pests Recommended for Regulation as Quarantine Pests. Online publication. Version 2010-09. Retrieved from http://www.eppo.org/QUARANTINE/listA2.htm , June 27, 2011.

Download Full-text

First Report of Brown Rot of Apple Caused by Monilinia fructicola in Germany

Plant Disease ◽

10.1094/pdis-02-11-0113 ◽

2011 ◽

Vol 95 (6) ◽

pp. 772-772 ◽

Cited By ~ 14

Author(s):

A. Grabke ◽

M. J. Hu ◽

C. X. Luo ◽

P. K. Bryson ◽

G. Schnabel

Keyword(s):

Brown Rot ◽

The State ◽

Its2 Region ◽

Monilinia Fructicola ◽

Conidial Suspension ◽

First Report ◽

Plastic Bags ◽

Sterile Needle ◽

Average Size ◽

Equidistant Points

Monilinia fructicola (G. Wint.) Honey is a causal agent of brown rot of stone fruits but may also affect pome fruits. M. fructicola is common in North America, Oceania, and South America as well as in Asia, but it is listed as a quarantine pathogen in Europe (3). Since its first discovery in Europe in 2001 (France), it has been reported in Spain, Slovenia, Italy, and Switzerland. Recently, the fungus was also detected in orchards of blackberries and plums in the State of Baden-Württemberg, Germany (4). In July 2010, apples (Malus domestica Borkh.) of the cultivar Jonagold were found in a residential backyard in Fronhausen an der Lahn located in the State of Hessen, Germany with symptoms resembling brown rot caused by Monilinia species. Affected apples were at or near maturity with brown decay that had spread throughout the fruits. On the surface of the decaying apples was tan to white zones of sporulation. Upon isolation, the mycelium grew at a linear rate of 9.2 mm per day at 22°C on potato dextrose agar forming branched, monilioid chains of grayish colonies with concentric rings and little sporulation. The lemon-shaped spores had an average size of 14 × 9 μm, a shape and size consistent with M. fructicola. The ribosomal ITS1-5.8S-ITS2 region was PCR-amplified from genomic DNA obtained from mycelium using primers ITS1 and ITS4. A BLAST search in GenBank revealed highest similarity (99%) to M. fructicola sequences from isolates collected in China, Italy, and Slovenia (GenBank Accession Nos. FJ515894.1, FJ411109.1, GU967379.1). The M. fructicola sequence from the apple isolate was submitted to GenBank (Accession No. JF325841). The pathogen was also identified to the species level and confirmed to be M. fructicola using two novel PCR techniques based on cytochrome b sequences (1,2). Pathogenicity was confirmed by inoculating three surface-sterilized, mature apples cv. Gala with a conidial suspension (105 spores/ml) of the apple isolate. Fruit were stab inoculated at three equidistant points to a depth of 10 mm using a sterile needle. A 30-μl droplet was placed on each wound; control fruit received sterile water without conidia. After 5 days of incubation at room temperature in air-tight plastic bags, the inoculated fruits developed typical brown rot symptoms with sporulating areas (as described above). The developing spores on inoculated fruit were confirmed to be M. fructicola. All control fruits remained healthy. To our knowledge, this is the first report of M. fructicola on apple in Germany and more indication of further geographical spread of the quarantine disease in Germany. References: (1) J.-M. Hily et al. Pest Manag. Sci. Online publication. doi 10.1002/ps.2074, 2011. (2) S. Miessner and G. Stammler. J. Plant Dis. Prot. 117:162, 2010. (3) OEPP/EPPO. EPPO A2 list of pests recommended for regulation as quarantine pests. Version 2009-09. Retrieved from http://www.eppo.org/QUARANTINE/listA2.htm , September 22, 2010. (4) OEPP/EPPO. Reporting Service. No. 1, January 2010. Retrieved from http://archives.eppo.org/EPPOReporting/2010/Rse-1001.pdf , September 22, 2010.

Download Full-text

First Report of Rhizoctonia solani AG-2-2 IIIB Causing Foliar Blight on Bletilla striata in China

Plant Disease ◽

10.1094/pdis-02-21-0270-pdn ◽

2021 ◽

Author(s):

Hao Zhou ◽

Shuang-Feng Yang ◽

Shao-Mei Wang ◽

Ke Yao ◽

Xiao-Yu Ye ◽

...

Keyword(s):

Rhizoctonia Solani ◽

Its Sequences ◽

Nucleotide Sequence Analysis ◽

Peat Moss ◽

Its2 Region ◽

Post Inoculation ◽

Bletilla Striata ◽

First Report ◽

Foliar Blight ◽

Initial Symptoms

Bletilla striata (Thunb.) Rchb. f. (Orchidaceae), a perennial plant, is a traditional Chinese herb (known as baiji) used to treat hemorrhage, scalding injuries, gastric ulcers, pulmonary diseases, and inflammation (Zu et al. 2019). In May 2019, foliar blight symptoms were observed on approximately 25% of B. striata (cv. Guiji No.1) plants in three plantations (∼4.5 hectares in total) in Ziyuan County, Guangxi Province, China. Initial symptoms were light brown, irregular, water-soaked spots on the plant leaves. Several spots often merged, forming large, irregular, lesions that extended onto the stem after a week and led to leaf abscission, and even plant death. To determine the causal agent, 5-mm squares cut from the margin of 6 infected leaves were surface disinfected in 1% sodium hypochlorite solution for 2 min, rinsed three times with sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 28°C (12-h light-dark cycle) for 3 days. The emerging hyphal tip of a single mycelium was transferred to PDA to obtain pure cultures of the isolates. Twenty isolates were obtained, and 10 isolates (50%) were initially white before turning light brown (∼4 days). Septate hyphae were 4.29 to 10.75 μm (average 6.42 μm) in diameter and branched at right angles with a constriction at the origin of the branch point. Staining with 1% safranin O and 3% KOH solution (Bandoni 1979) revealed multinucleated cells (3 to 9 nuclei per cell, n = 142). This morphology was typical of Rhizoctonia solani Kühn (Meyer et al. 1990). For species confirmation by molecular identification, three isolates (BJ101.6, BJ101.11, and BJ102.2) were cultured on PDA for 4 days, then DNA was extracted from the mycelium using the CTAB method (Guo et al. 2000), and the ribosomal ITS1-5.8S-ITS2 region was amplified by PCR using the universal fungal primers ITS1 and ITS4 (White et al. 1990). Internal transcribed spacer (ITS) sequences of strains BJ101.6, BJ101.11, and BJ102 (deposited in GenBank under accession nos MT406271, MT892815, and MT892814, respectively) had over 99% similarity with those of R. solani AG-2-2 IIIB in GenBank (accession nos JX913810 and AB054858) (Carling et al. 2002; Hong et al. 2012). Phylogenetic analysis using ITS sequences showed that the isolates clustered monophyletically with strains of R. solani AG-2-2 IIIB. The AG of the isolates was confirmed by their ability to grow well on PDA at 35°C, which separates AG-2-2 IIIB from AG-2-2 IV (Inokuti et al. 2019). Based on morphological characteristics and nucleotide sequence analysis, the isolates were identified as R. solani AG-2-2 IIIB. Pathogenicity was tested using 1.5-year-old B. striata (cv. Guiji No.1) plants grown in a perlite and peat moss mixture (1:3) in 7-cm pots. Healthy leaves on plants were inoculated with an aqueous suspension (approximately 1 × 105 hyphal fragments/mL, 100 μL) prepared from cultures of strains BJ101.6, BJ101.11, and BJ102.2, each isolate was inoculated onto three plants; three other plants with sterile water served as controls. All plants were enclosed in transparent plastic bags and incubated in a greenhouse at 28°C for 14 days (12-h photoperiod). Three days post-inoculation, leaves exposed to the mycelial fragments had symptoms similar to those originally observed in the field. No symptoms were detected on control plants. Experiments were replicated three times with similar results. To fulfill Koch’s postulates, R. solani AG-2-2 IIIB was re-isolated on PDA from symptomatic leaves and confirmed by sequencing, whereas no fungus was isolated from the control plants. To our knowledge, this is the first report of R. solani AG-2-2 IIIB causing foliar blight on B. striata in China, and these findings will be useful for further control strategies and research.

Download Full-text

First Report of Botryosphaeria dothidea, Diplodia seriata, and Neofusicoccum luteum Associated with Canker and Dieback of Grapevines in Tunisia

Plant Disease ◽

10.1094/pdis-05-13-0530-pdn ◽

2014 ◽

Vol 98 (3) ◽

pp. 420-420 ◽

Cited By ~ 6

Author(s):

S. Chebil ◽

R. Fersi ◽

A. Yakoub ◽

S. Chenenaoui ◽

M. Chattaoui ◽

...

Keyword(s):

Morphological Characteristics ◽

Aerial Mycelium ◽

Its2 Region ◽

Pathogenicity Test ◽

Botryosphaeria Dothidea ◽

Diplodia Seriata ◽

First Report ◽

Grapevine Dieback ◽

Pinus Spp ◽

Neofusicoccum Luteum

In 2011, common symptoms of grapevine dieback were frequently observed in 2- to 5-year-old table grape (Vitis vinifera L.) cvs. in four vineyards located in northern Tunisia. The symptoms included dead spur and cordons, shoot dieback, and sunken necrotic bark lesions, which progressed into the trunk resulting in the death of large sections of the vine. Longitudinal and transversal sections of cordons and spurs from symptomatic vines revealed brown wedge-shaped cankers of hard consistency. Twelve symptomatic samples from spur and cordons were collected, surface disinfected by dipping into 5% (v/v) sodium hypochlorite for 2 min, and small pieces from the edge of necrotic and healthy tissue were removed and plated onto potato dextrose agar (PDA) at 25°C in the dark. Based on colony and conidia morphological characteristics, isolates were divided in three species, named Diplodia seriata, Botryosphaeria dothidea, and Neofusicoccum luteum. D. seriata colonies were gray-brown with dense aerial mycelium producing brown cylindric to ellipsoid conidia rounded at both ends and averaged 22.4 × 11.7 μm (n = 50). B. dothidea colonies were initially white with abundant aerial mycelium, gradually becoming dark green olivaceous. Conidia were fusiform to fusiform elliptical with a subobtuse apex and averaged 24.8 × 4.7 μm (n = 50). N. luteum colonies were initially pale to colorless, gradually darkening with age and becoming gray to dark gray producing a yellow pigment that diffuses into the agar. Conidia were hyaline, thin-walled, aseptate, fusiform to fusiform elliptical, and averaged 19.8 × 5.5 μm (n = 50). Identity of the different taxa was confirmed by sequence analyses of the internal transcribed spacer (ITS1-5.8S-ITS2) region of the rDNA and part of the elongation factor 1-alpha (EF1-α) gene. BLAST analysis of sequences indicated that six isolates were identified as D. seriata (GenBank: AY259094, AY343353), one isolate as B. dothidea (AY236949, AY786319) and one isolate as N. luteum (AY259091, AY573217). Sequences were deposited in GenBank under accessions from KC178817 to KC178824 and from KF546829 to KF546836 for ITS region and EF1-α gene, respectively. A pathogenicity test was conducted on detached green shoots cv. Italia for the eight Botryosphaeriaceae isolates. Shoots were inoculated by placing a colonized agar plug (5 mm diameter) from the margin of a 7-day-old colony on fresh wound sites made with a sterilized scalpel. Each wound was covered with moisturized cotton and sealed with Parafilm. Control shoots were inoculated using non-colonized PDA plugs. After 6 weeks, discoloration of xylem and phloem and necrosis with average length of 38.8, 17.6, and 11.2 mm were observed from inoculated shoots with D. seriata, N. luteum, and B. dothidea, respectively, and all three fungi were re-isolated from necrotic tissue, satisfying Koch's postulates. Control shoots showed no symptoms of the disease and no fungus was re-isolated. In Tunisia, Botryosphaeria-related dieback was reported only on citrus tree caused by B. ribis (2), on Pinus spp. caused by D. pinea (4), on Quercus spp. caused by D. corticola (3), and on olive tree (Olea europea) caused by D. seriata (1). To our knowledge, this is the first report of D. seriata, B. dothidea, and N. luteum associated with grapevine dieback in Tunisia. References: (1) M. Chattaoui et al. Plant Dis. 96:905, 2012. (2) H. S. Fawcett. Calif. Citrogr. 16:208, 1931. (3) B. T. Linaldeddu et al. J. Plant Pathol. 91:234. 2009. (4) B. T. Linaldeddu et al. Phytopathol. Mediterr. 47:258, 2008.

Download Full-text