scholarly journals First Report of Anthracnose Caused by Colletotrichum liaoningense on Trichosanthes kirilowii in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Lixin Zhang ◽  
Yifan Lin ◽  
Lei Zhang ◽  
Xia Wang ◽  
Jianghua Song
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Culture Collection ◽  
Central China ◽  
Fruit Rot ◽  
First Report ◽  
Plastic Bags ◽  
Fruit Samples ◽  
Pathogenicity Tests ◽  
Trichosanthes Kirilowii

Trichosanthes kirilowii Maxim (T. kirilowii) is widely grown in central China for its medicinal and edible value. In August 2020, an anthracnose-like disease was observed on fruit of T. kirilowii (cv. Wanlou9) in four fields (0.9 ha) located in Taihu county, Anhui Province of China. Approximately 60% of the T. kirilowii plants were affected in the fields. The symptoms initially consisted of small off-white necrotic spots, and later became larger, irregular gray necrotic lesions on green fruit, causing fruit rot and sometimes fruit drop. More than 10 symptomatic fruits were sampled, and small pieces of diseased tissue were surface sterilized in 0.1% HgCl2 for 2 min, 75% ethanol for 45 s, rinsed three times with sterile distilled water, then placed on potato dextrose agar (PDA) and incubated at 25℃in the dark. A fungus was consistently (80%) isolated from symptomatic fruit samples. Aerial mycelia were light gray, and radially black with white in reverse medium. Conidia were rarely produced on PDA, but prolific on water agar. The conidia were cylindrical to clavate, both ends rounded, had obvious circular granule in the center, and ranged from 14.6 to 19.9 μm × 5.4 to 7.3 μm. The morphological characteristics were similar to the descriptions of C. liaoningense by Diao et al. (2017). For molecular identification, representative isolates LG5-4 and LG9-6 were selected. Genomic DNA was extracted, and the internal transcribed spacer (ITS) region, actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and β-tubulin (TUB2) genes were amplified by PCR (White et al. 1990; Duan et al. 2018), and sequenced bidirectionally. A BLAST search of GenBank revealed the ACT and TUB sequences had 95.83% (KP890097), 99.20%, 95.33% (KP890111) and 99.84%, respectively, to C. liaoningense CAUOS2. A phylogenetic analysis was conducted using MEGA7 based on concatenated sequences of the four genes, indicating that the isolates were closely clustered with reference strains of C. liaoningense (98% bootstrap value). The two strains were deposited in the China General Microbiological Culture Collection Center as CGMCC3.20344 and CGMCC3.20345, and their sequences deposited in GeneBank (Accession nos. MW082811-12, MW117926-31), respectively. Pathogenicity tests were conducted on healthy fruit of T. kirilowii (cv. Wanlou9) using the wound inoculation by pinpricking and droplet (106 conidia/mL) on fruit surface. The experiments were done with three fruit per isolate (LG5-4 and LG9-6), and replicated three times. The controls were inoculated with sterile water. The fruit were covered with plastic bags and kept in a chamber (>90% RH, 28 to 30°C) for 14 days. Typical symptoms of yellow-brown lesions appeared 14 days after inoculation. No symptoms were observed on the controls. The fungus was re-isolated from the diseased tissues and identified as C. liaoningense by sequencing of the four genes, confirming Koch’s postulates. C. liaoningense has been reported to cause anthracnose of mango and chili in China (Diao et al. 2017; Li et al. 2019). To our knowledge, this is the first report of C. liaoningense causing anthracnose on T. kirilowii. Due to cultivation of T. kirilowii in the region, further studies are required to develop management strategy of this disease.

scholarly journals First Confirmed Report of Cercospora Blight of Asparagus Caused by Cercospora asparagi in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 428-428 ◽  
Author(s):  
K. S. Han ◽  
B. S. Kim ◽  
J. H. Park ◽  
H. D. Shin
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Culture Collection ◽  
Asparagus Officinalis ◽  
Organic Farm ◽  
Plastic Bags ◽  
Japanese Workers ◽  
Close Phylogenetic Relationship ◽  
Voucher Specimens ◽  
Pathogenicity Tests

In September 2011, hundreds of asparagus (Asparagus officinalis L.) showing symptoms of blight with nearly 100% incidence (percentage of plants affected) were found in polyethylene tunnels at an organic farm in Gangneung City of Korea. Lesions on needles and branches of the ferns were small, elliptic to subcircular, pale tan to brown with reddish brown borders, and became gray and cottony due to heavy sporulation under continuous high humidity. Infection caused premature defoliation and weakened plant vigor. The damage purportedly due to this disease has reappeared with confirmation of the causal agent made again in 2012. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were well developed, consisting of brown cells, and were 10 to 30 μm wide. Conidiophores were fasciculate (n = 2 to 12), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones, or 1 to 2 times geniculate in longer ones, 40 to 260 μm long, 3.5 to 5.5 μm wide, and 1- to 6-septate. Conidia were hyaline, cylindric to acicular, straight in shorter ones, curved in longer ones, truncate to obconically truncate at the base with darkened hila, guttulate, 2- to 12-septate, and 40 to 220 × 3 to 5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora asparagi Sacc. (1). Voucher specimens were housed at the Korea University herbarium (KUS). An isolate from KUS-F26046 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46400). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 497 bp was deposited in GenBank (Accession No. JX964995). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. For pathogenicity tests, conidial suspensions (105 conidia/ml) were prepared by culturing the fungus on V8 juice agar (2) for 3 weeks. Five plants were inoculated with conidial suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain 100% RH for 24 h and then transferred to a greenhouse. Typical symptoms of necrotic lesions appeared on the inoculated plants 6 days after treatment, and were identical to the ones observed in the field. C. asparagi was reisolated from symptomatic tissues, confirming Koch's postulates. No symptoms were observed on control plants. The disease has been reported through the regions of the world where asparagus is grown (3). In Korea, the disease was recorded in 1928 by Japanese workers under Cercosporina asparagicola Speg. (regarded as synonymous with Cercospora asparagi) with brief notes (4). Though one sample of asparagus was sent to the author (KSH) for diagnosis in 2009 summer and determined to be infected with C. asparagi (unpublished data), there has been no additional finding of the disease in Korea for the last 82 years. To our knowledge, this is the first confirmed report of Cercospora blight of asparagus caused by C. asparagi in Korea. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) C. J. Cooperman and S. F. Jenkins. Phytopathology 76:617, 1986. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved October 20, 2012. (4) K. Nakata and S. Takimoto. Bull. Agric. Exp. Stat. Korea 15:1, 1928.

scholarly journals First Report of Fruit Rot in Pear Caused by Botryosphaeria dothidea in Italy

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 910-910 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
A. Poli ◽  
M. L. Gullino
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
The United States ◽  
Fruit Rot ◽  
Pathogenicity Test ◽  
Botryosphaeria Dothidea ◽  
First Report ◽  
Irregular Margin ◽  
Pyrus Communis L ◽  
Pathogenicity Tests

Pear (Pyrus communis L.) is widely grown in Italy, the leading producer in Europe. In summer 2011, a previously unknown rot was observed on fruit of an old cultivar, Spadoncina, in a garden in Torino Province (northern Italy). The decayed area of the fruit was soft, dark brown, slightly sunken, circular, and surrounded by an irregular margin. The internal decayed area appeared rotten and brown and rotted fruit eventually fell. To isolate the causal agent, fruits were soaked in 1% NaOCl for 30 s and 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 20 and 28°C under alternating light and darkness. Colonies of the fungus initially appeared whitish, then turned dark gray. After about 30 days of growth, unicellular elliptical hyaline conidia were produced in pycnidia. Conidia measured 16 to 24 × 5 to 7 (average 20.1 × 5.7) μm (n = 50). The morphological characteristics are similar to those of the fungus Botryosphaeria dothidea (Moug.: Fr.) Ces. & De Not. (4). The internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 473-bp segment showed a 100% similarity with the sequence of the epitype of B. dothidea AY236949. The nucleotide sequence has been assigned the GenBank Accession No. JQ418493. Pathogenicity tests were performed by inoculating six pear fruits of the same cultivar (Spadoncina) after surface disinfesting in 1% sodium hypochlorite and wounding. Mycelial disks (8 mm diameter), obtained from 10-day-old PDA cultures of one strain, were placed on wounds. Six control fruits were inoculated with plain PDA. Fruits were incubated at 25 ± 1°C in plastic boxes. The first symptoms developed 3 days after inoculation. After 5 days, the rot was very evident and B. dothidea was consistently reisolated. Noninoculated fruits remained healthy. The pathogenicity test was performed twice. B. dothidea was identified on decayed pears in the United States (2), South Africa, New Zealand, Japan, and Taiwan (3). To our knowledge, this is the first report of the presence of B. dothidea on pear in Italy, as well as in Europe. In Italy, the economic importance of the disease on pear fruit is at present limited, although the pathogen could represent a risk for this crop. References: (1) S. F. Altschul et al. Nucleic Acids Res., 25:3389, 1997. (2) L. F. Grand. Agr. Res. Serv. Techn. Bull. 240:1, 1985. (3) Y. Ko et al. Plant Prot. Bull. (Taiwan) 35:211, 1993. (4) B. Slippers et al. Mycologia 96:83, 2004.

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

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 382-382 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
M. L. Gullino
Keyword(s):  
Leaf Surface ◽  
Morphological Characteristics ◽  
Its Region ◽  
Northern Italy ◽  
Pathogenicity Test ◽  
First Report ◽  
Plastic Bags ◽  
Pathogenicity Tests ◽  
Necrotic Spots ◽  
Mycelial Suspension

Fuchsia × hybrida (Onagraceae) is widely used in gardens and very much appreciated as a potted plant. During the summer of 2008, a severe foliar disease was observed on 1- to 2-year-old plants in several gardens located near Biella (northern Italy). Small necrotic spots were observed on the upper and lower sides of infected leaves. Spots enlarged to form round areas of 2 to 12 mm in diameter and were well defined by a brown-purple margin at temperatures between 15 and 25°C. Severely infected leaves wilted and abscised as disease progressed. The disease occurred on 100% of the plants and at least 30% of the leaf surface was affected. Stems and flowers were not affected by the disease. A fungus was consistently isolated from infected leaves on potato dextrose agar amended with 25 mg/liter of streptomycin. The fungus was grown on leaf extract agar, including 30 g of autoclaved fuchsia leaves per liter, and maintained at 22°C (12-h light, 12-h dark). After 30 days, black pycnidia 150 to 450 μm in diameter developed, releasing abundant hyaline, elliptical, nonseptate conidia measuring 5.6 to 14.3 (10.3) × 1.9 to 5.6 (3.5) μm. On the basis of these morphological characteristics, the fungus was identified as a Phoma sp. (2). The internal transcribed spacer (ITS) region of rDNA of the isolate coded FuHy1 was amplified using primers ITS4/ITS6 (3) and sequenced. BLAST analysis (1) of the 488-bp segment obtained showed an E-value of 0.0 with Phoma multirostrata. The nucleotide sequence has been assigned GenBank Accession No. GU220539. Pathogenicity tests were performed by spraying leaves of healthy 6-month-old potted Fuchsia × hybrida plants with a spore and mycelial suspension (1 × 106 spores or mycelial fragments per milliliter). Noninoculated plants sprayed with water served as controls. Five plants were used for each treatment. Plants were covered with plastic bags for 5 days after inoculation and kept under greenhouse conditions at 20 to 24°C. Symptoms previously described developed on leaves 12 days after inoculation, whereas control plants remained healthy. The fungus was consistently reisolated from the lesions of the inoculated plants. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of P. multirostrata on fuchsia in Italy as well as worldwide. The importance of the disease is still limited in Italy. References: (1) S. F. Altschud et al. Nucleic Acids Res. 25:3389, 1997. (2) G. H. Boerema and G. J. Bollen. Persoonia 8:111, 1975. (3) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997.

scholarly journals First Report of Leaf Spot Caused by Cercospora fukushiana on New Guinea Impatiens in Korea

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1280-1280
Author(s):  
B. S. Kim ◽  
K. S. Baek ◽  
C. H. Pak ◽  
J. H. Park ◽  
H. D. Shin
Keyword(s):  
Leaf Spot ◽  
Morphological Characteristics ◽  
Its Region ◽  
New Guinea ◽  
Culture Collection ◽  
Distilled Water ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags ◽  
New Guinea Impatiens

New Guinea impatiens, Impatiens hawkeri W. Bull, is widely cultivated as a potted plant and garden plant. In July 2013, hundreds of young plants (cv. Fanfare) showing symptoms of leaf spot with approximately 50% incidence were found in polyethylene tunnels in Yongin City, Korea. Leaf spots were circular to oblong, reaching 6 mm or more in diameter. The spots were initially uniformly brown to reddish brown, turning gray with reddish brown margin. Diseased plants defoliated prematurely and were abandoned without marketing due to signs of discoloration and yellowing on leaves. A cercosporoid fungus was consistently observed in association with disease symptoms. Stromata were brown, small, and composed of a few swollen hyphal cells. Conidiophores were emerging through the cuticle, fasciculate (n = 2 to 20), olivaceous to brown, paler toward the apex, straight to mildly curved, geniculate, 30 to 260 μm long, 3.5 to 5 μm wide, 1- to 6-septate, and with conspicuous conidial scars. Conidia were hyaline and acicular. Smaller conidia were straight and longer conidia were mildly curved. Conidia were subacute to obtuse at the apex, truncate to obconically truncate at the base, 2- to 18-septate, 30 to 320 × 3.5 to 5.5 μm, and with thickened, darkened hila at the base. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora fukushiana (Matsuura) W. Yamam. (1). Voucher specimens were housed in the Korea University herbarium (KUS). An isolate from KUS-F27438 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47640). Fungal DNA was extracted with DNeasy Plant Mini Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 (4) and sequenced. The resulting sequence of 497 bp was deposited in GenBank (Accession No. KJ620981). This showed >99% similarity with sequence of C. fukushiana (EF600954) on I. balsamina from Korea. Isolate of KACC47640 was used in the pathogenicity tests. Hyphal suspensions were prepared by grinding 3-week-old colonies grown on PDA with distilled water using a mortar and pestle. Five plants were inoculated with hyphal suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 24 h and then transferred to a 25 ± 2°C greenhouse with a 12-h photoperiod. Typical symptoms of necrotic spots appeared on the inoculated leaves 10 days after inoculation, and were identical to the symptoms observed in the field. C. fukushiana was re-isolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on water-inoculated control plants. Previously, leaf spots of Impatiens spp. associated with C. apii, C. balsaminae, and C. fukushiana have been reported (1,2,3). To our knowledge, this is the first report of C. fukushiana on I. hawkeri in Korea. Our observations in the nurseries of I. hawkeri suggest that low humidity with good ventilation as well as plant hygiene in greenhouses might be main strategies for preventing this disease. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., online publication, ARS, USDA, retrieved March 25, 2014. (3) J. M. Soares et al. Plant Dis. 93:1214, 2009. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

scholarly journals First Report of Leaf Blight and Stem Canker of Pachysandra terminalis Caused by Pseudonectria pachysandricola in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 287-287
Author(s):  
K. S. Han ◽  
J. H. Park ◽  
S. E. Cho ◽  
H. D. Shin
Keyword(s):  
United States ◽  
Its Region ◽  
Stem Canker ◽  
The United States ◽  
Culture Collection ◽  
Leaf Blight ◽  
First Report ◽  
Cornell University ◽  
Plastic Bags ◽  
Young Leaves

Pachysandra terminalis Siebold & Zucc., known as Japanese pachysandra, is a creeping evergreen perennial belonging to the family Buxaceae. In April 2011, hundreds of plants showing symptoms of leaf blight and stem canker with nearly 100% incidence were found in a private garden in Suwon, Korea. Plants with the same symptoms were found in Seoul in May and Hongcheon in August. Affected leaves contained tan-to-yellow brown blotches. Stem and stolon cankers first appeared as water soaked and developed into necrotic lesions. Sporodochia were solitary, erumpent, circular, 50 to 150 μm in diameter, salmon-colored, pink-orange when wet, and with or without setae. Setae were hyaline, acicular, 60 to 100 μm long, and had a base that was 4 to 6 μm wide. Conidiophores were in a dense fascicle, not branched, hyaline, aseptate or uniseptate, and 8 to 20 × 2 to 3.5 μm. Conidia were long, ellipsoid to cylindric, fusiform, rounded at the apex, subtruncate at the base, straight to slightly bent, guttulate, hyaline, aseptate, 11 to 26 × 2.5 to 4.0 μm. A single-conidial isolate formed cream-colored colonies that turned into salmon-colored colonies on potato dextrose agar (PDA). Morphological and cultural characteristics of the fungus were consistent with previous reports of Pseudonectria pachysandricola B.O. Dodge (1,3,4). Voucher specimens were housed at Korea University (KUS). Two isolates, KACC46110 (ex KUS-F25663) and KACC46111 (ex KUS-F25683), were accessioned in the Korean Agricultural Culture Collection. Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced using ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequence of 487 bp was deposited in GenBank (Accession No. JN797821). This showed 100% similarity with a sequence of P. pachysandricola from the United States (HQ897807). Isolate KACC46110 was used in pathogenicity tests. Inoculum was prepared by harvesting conidia from 2-week-old cultures on PDA. Ten young leaves wounded with needles were sprayed with conidial suspensions (~1 × 106 conidia/ml). Ten young leaves that served as the control were treated with sterile distilled water. Plants were covered with plastic bags to maintain a relative humidity of 100% at 25 ± 2°C for 24 h. Typical symptoms of brown spots appeared on the inoculated leaves 4 days after inoculation and were identical to the ones observed in the field. P. pachysandricola was reisolated from 10 symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in the United States, Britain, Japan, and the Czech Republic (2,3), but not in Korea. To our knowledge, this is the first report of P. pachysandricola on Pachysandra terminalis in Korea. Since this plant is popular and widely planted in Korea, this disease could cause significant damage to nurseries and the landscape. References: (1) B. O. Dodge. Mycologia 36:532, 1944. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 24, 2011. (3) I. Safrankova. Plant Prot. Sci. 43:10, 2007. (4) W. A. Sinclair and H. H. Lyon. Disease of Trees and Shrubs. 2nd ed. Cornell University Press, Ithaca, NY, 2005.

scholarly journals First Report of Leaf Spot of Sweet Basil Caused by Cercospora guatemalensis in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (10) ◽  
pp. 1580-1580
Author(s):  
J. H. Park ◽  
K. S. Han ◽  
J. Y. Kim ◽  
H. D. Shin
Keyword(s):  
Leaf Spot ◽  
Morphological Characteristics ◽  
Its Region ◽  
Culture Collection ◽  
Distilled Water ◽  
First Report ◽  
Sweet Basil ◽  
Organic Farm ◽  
Leaf Spots ◽  
Close Phylogenetic Relationship

Sweet basil, Ocimum basilicum L., is a fragrant herb belonging to the family Lamiaceae. Originated in India 5,000 years ago, sweet basil plays a significant role in diverse cuisines across the world, especially in Asian and Italian cooking. In October 2008, hundreds of plants showing symptoms of leaf spot with nearly 100% incidence were found in polyethylene tunnels at an organic farm in Icheon, Korea. Leaf spots were circular to subcircular, water-soaked, dark brown with grayish center, and reached 10 mm or more in diameter. Diseased leaves defoliated prematurely. The damage purportedly due to this disease has reappeared every year with confirmation of the causal agent made again in 2011. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were brown, consisting of brown cells, and 10 to 40 μm in width. Conidiophores were fasciculate (n = 2 to 10), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones or one to two times geniculate in longer ones, 40 to 200 μm long, occasionally reaching up to 350 μm long, 3.5 to 6 μm wide, and two- to six-septate. Conidia were hyaline, acicular to cylindric, straight in shorter ones, flexuous to curved in longer ones, truncate to obconically truncate at the base, three- to 16-septate, and 50 to 300 × 3.5 to 4.5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora guatemalensis A.S. Mull. & Chupp (1,3). Voucher specimens were housed at Korea University herbarium (KUS). An isolate from KUS-F23757 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC43980). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 548 bp was deposited in GenBank (Accession No. JQ995781). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. Isolate of KACC43980 was used in the pathogenicity tests. Hyphal suspensions were prepared by grinding 3-week-old colonies grown on PDA with distilled water using a mortar and pestle. Five plants were inoculated with hyphal suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 24 h and then transferred to a 25 ± 2°C greenhouse with a 12-h photoperiod. Typical symptoms of necrotic spots appeared on the inoculated leaves 6 days after inoculation, and were identical to the ones observed in the field. C. guatemalensis was reisolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in Malawi, India, China, and Japan (2,3), but not in Korea. To our knowledge, this is the first report of C. guatemalensis on sweet basil in Korea. Since farming of sweet basil has recently started on a commercial scale in Korea, the disease poses a serious threat to safe production of this herb, especially in organic farming. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , May 5, 2012. (3) J. Nishikawa et al. J. Gen. Plant Pathol. 68:46, 2002.

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

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1515-1515 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
Beta Vulgaris ◽  
Morphological Characteristics ◽  
Its Region ◽  
Pathogenicity Test ◽  
Vegetable Crops ◽  
Plastic Bags ◽  
Blastn Analysis ◽  
Commercial Farms ◽  
Pathogenicity Tests ◽  
Phoma Betae

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

scholarly journals First Report of Fruit Rot of Melon Caused by Fusarium asiaticum in China

Plant Disease ◽  
2020 ◽  
Author(s):  
Fangmin Hao ◽  
Quanyu Zang ◽  
Weihong Ding ◽  
Erlei Ma ◽  
Yunping Huang ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Its Region ◽  
Fruit Rot ◽  
Post Inoculation ◽  
Basal Cells ◽  
First Report ◽  
Fusarium Asiaticum ◽  
Sterile Needle

Melon (Cucumis melo L.) is a member of the Cucurbitaceae family, an important economical and horticultural crop, which is widely grown in China. In May 2020, fruit rot disease with water-soaked lesions and pink molds on cantaloupe melons was observed in several greenhouses with 50% disease incidence in Ningbo, Zhejiang Province in China. In order to know the causal agent, diseased fruits were cut into pieces, surface sterilized for 1 min with 1% sodium hypochlorite (NaClO), 2 min with 75% ethyl alcohol, rinsed in sterile distilled water three times (Zhou et al. 2018), and then placed on potato dextrose agar (PDA) medium amended with streptomycin sulfate (100 μg/ml) plates at 25°C for 4 days. The growing hyphae were transferred to new PDA plates using the hyphal tip method, putative Fusarium colonies were purified by single-sporing. Twenty-five fungal isolates were obtained and formed red colonies with white aerial mycelia at 25°C for 7 days, which were identified as Fusarium isolates based on the morphological characteristics and microscopic examination. The average radial mycelial growth rate of Fusarium isolate Fa-25 was 11.44 mm/day at 25°C in the dark on PDA. Macroconidia were stout with curved apical and basal cells, usually with 4 to 6 septa, and 29.5 to 44.2 × 3.7 to 5.2 μm on Spezieller Nährstoffarmer agar (SNA) medium at 25°C for 10 days (Leslie and Summerell 2006). To identify the species, the internal transcribed spacer (ITS) region and translational elongation factor 1-alpha (TEF1-α) gene of the isolates were amplified and cloned. ITS and TEF1-α was amplified using primers ITS1/ITS4 and EF1/EF2 (O’Donnell et al. 1998), respectively. Sequences of ITS (545 bp, GenBank Accession No. MT811812) and TEF1-α (707 bp, GenBank Acc. No. MT856659) for isolate Fa-25 were 100% and 99.72% identical to those of F. asiaticum strains MSBL-4 (ITS, GenBank Acc. MT322117.1) and Daya350-3 (TEF1-α, GenBank Acc. KT380124.1) in GenBank, respectively. A phylogenetic tree was established based on the TEF1-α sequences of Fa-25 and other Fusarium spp., and Fa-25 was clustered with F. asiaticum. Thus, both morphological and molecular characterizations supported the isolate as F. asiaticum. To confirm the pathogenicity, mycelium agar plugs (6 mm in diameter) removed from the colony margin of a 2-day-old culture of strain Fa-25 were used to inoculate melon fruits. Before inoculation, healthy melon fruits were selected, soaked in 2% NaClO solution for 2 min, and washed in sterile water. After wounding the melon fruits with a sterile needle, the fruits were inoculated by placing mycelium agar plugs on the wounds, and mock inoculation with mycelium-free PDA plugs was used as control. Five fruits were used in each treatment. The inoculated and mock-inoculated fruits were incubated at 25°C with high relative humidity. Symptoms were observed on all inoculated melon fruits 10 days post inoculation, which were similar to those naturally infected fruits, whereas the mock-inoculated fruits remained symptomless. The fungus re-isolated from the diseased fruits resembled colony morphology of the original isolate. The experiment was conducted three times and produced the same results. To our knowledge, this is the first report of fruit rot of melon caused by F. asiaticum in China.

scholarly journals First Report of Powdery Mildew Caused by Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii on Papaya in Taiwan

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1188-1188 ◽  
Author(s):  
J.-G. Tsay ◽  
R.-S. Chen ◽  
H.-L. Wang ◽  
W.-L. Wang ◽  
B.-C. Weng
Keyword(s):  
Powdery Mildew ◽  
Morphological Characteristics ◽  
Its Region ◽  
Podosphaera Xanthii ◽  
Oidium Neolycopersici ◽  
First Report ◽  
Plastic Bags ◽  
The World ◽  
Golovinomyces Cichoracearum ◽  
Powdery Mildew Fungi

Powdery mildew can be found in most papaya (Carica papaya L.) fields during the winter and spring seasons in Taiwan. It usually causes severe yellowing of the leaf lamina and petiole and serious defoliation. Three types of powdery mildew fungi were isolated from papaya leaves in Chiayi City (23.28°N, 120.28°E) at the beginning of 2008. Conidia of the first one were single, globose, hyaline, and 24 to 36 × 14 to 18 μm (average 30.2 × 15.6 μm) without fibrosin bodies and with straight or occasionally flexuous conidiophores at the base. The second one had short pseudo-chains of two to four conidia which were ellipsoidal to ovoid, hyaline, and 24 to 40 × 12 to 16 μm (average 29.7 × 13.4 μm) without fibrosin bodies. The third type had chains of ellipsoidal conidia that were hyaline, 24 to 28 × 12 to 16 μm (average 26.3 × 14.4 μm) and contained fibrosin bodies. To confirm the identity of the three fungi, the internal transcribed spacer (ITS) region of rDNA was amplified using the primer pairs G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/Ed2 (5′-CGC GTA GAG CCC ACG TCG GA-3′), G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/On2 (5′-TGT GAT CCA TGT GAC TGG AA-3′), and S1 (5′-GGA TCA TTA CTG AGC GCG AGG CCC CG-3′)/S2 (5′-CGC CGC CCT GGC GCG AGA TAC A-3′). The alignment of obtained sequences (GenBank Accession Nos. GU358452, 507 bp; GU358451, 580 bp; and GU358450, 455 bp) showed a sequence identity of 100, 99, and 99% with the ITS sequences of Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii (GenBank Accession Nos. FJ378880, EU909694, and GQ927254), respectively. On the basis of morphological characteristics and ITS sequence similarities, these fungi were identified as E. diffusa (Cooke & Peck) U. Braun & S. Takam., O. neolycopersici L. Kiss, and P. xanthii (Castagne) U. Braun & S. Takam., respectively (1,3). Single colonies on papaya leaves infected with powdery mildew were identified in the laboratory and maintained on papaya leaves as inoculum. Pathogenicity was confirmed through inoculations by gently pressing a single colony of each fungus onto leaves of healthy papaya seedlings (cv. Horng-Fe). Five seedlings were inoculated for each fungus and then covered with plastic bags for 2 days. Five noninoculated seedlings served as control. After inoculation, treated plants were maintained separately from the control in different rooms of a greenhouse at 25°C under natural daylight conditions. Seven days after inoculation, typical symptoms of powdery mildew were observed on inoculated plants, but not on noninoculated plants. The same species from diseased lesions following artificial inoculation with each fungus were identified with light microscopy. Papaya was previously described as a host to O. caricae Noack in many tropical and subtropical areas of the world including Taiwan (2). However E. cruciferarum, Golovinomyces cichoracearum, Oidiopsis sicula, O. caricae, O. caricae-papayae, O. caricicola, O. indicum, O. papayae, Ovulariopsis papayae, P. caricae-papayae, P. macularis, P. xanthii, and Streptopodium caricae were reported to infect papaya (4). To our knowledge, this is the first report of papaya powdery mildew caused by E. diffusa and O. neolycopersici in the world and the first report of the three fungi found on papaya in Taiwan. References: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (2) H. S. Chien and H. L. Wang. J. Agric. Res. China 33:320, 1984. (3) L. Kiss et al. Mycol. Res. 105:684, 2001. (4) J. R. Liberato et al. Mycol. Res. 108:1185, 2004.

scholarly journals First Report of Alternaria heveae Causing Black Leaf Spot of Rubber Tree in China

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1011-1011 ◽  
Author(s):  
Z. Y. Cai ◽  
Y. X. Liu ◽  
G. X. Huang ◽  
M. Zhou ◽  
G. Z. Jiang ◽  
...  
Keyword(s):  
Rubber Tree ◽  
Morphological Characteristics ◽  
Black Spot ◽  
Its Region ◽  
Post Inoculation ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Manual Pressure ◽  
Tree Leaf

Rubber tree (Hevea brasiliensis Muell. Arg.) is an important industrial crop of tropical areas for natural rubber production. In October 2013, foliar spots (0.1 to 0.4 mm in diameter), black surrounded by a yellow halo, and with lesions slightly sunken were observed on the rubber tree leaf in a growing area in Heikou County of Yunnan Province. Lesion tissues removed from the border between symptomatic and healthy tissue were surface sterilized in 75% ethanol and air-dried, plated on PDA plates, and incubated at 28°C with alternating day/night cycles of light. The pathogen was observed growing out of many of the leaf pieces, and produced abundant conidia. Colonies 6.1 cm in diameter developed on potato carrot agar (PCA) after 7 days, with well-defined concentric rings of growth. Colonies on PCA were composed of fine, dark, radiating, surface and subsurface hyphae. Conidia produced in PCA culture were mostly solitary or in short chains of 2 to 5 spores, long ovoid to clavate, and light brown, 40 to 81.25 × 8 to 20 μm (200 colonies were measured), with 3 to 6 transverse septa and 0 to 2 longitudinal or oblique septa. Morphological characteristics were similar to those described for Alternaria heveae (3,4). A disease of rubber tree caused by Alternaria sp. had been reported in Mexico in 1947 (2). DNA of Ah01HK13 isolate was extracted for PCR and sequencing of the ITS region with ITS1 and ITS4 primers was completed. From the BLAST analysis, the sequence of Ah01HK13 (GenBank Accession No. KF953884), had 97% similarity to A. dauci, 96% identical to A. macrospora (AY154701.1 and DQ156342.1, respectively), indicating the pathogen belonged to Alternaria genus. According to morphological characteristics, this pathogen was identified as A. heveae. Pathogenicity of representative isolate, Ah01HK13 was confirmed using a field rubber tree inoculation method. Three rubber plants (the clone of rubber tree Yunyan77-4) were grown to the copper-colored leaf stage and inoculated by spraying spore suspension (concentration = 104 conidia/ml) to the copper-colored leaves until drops were equally distributed on it using manual pressure sprayer. Three rubber plants sprayed with sterile distilled water were used as controls. After inoculation, the plants were covered with plastic bags. The plastic bags were removed after 2 days post-inoculation (dpi) and monitored daily for symptom development (1). The experiment was repeated three times. The typical 0.1 to 0.4 mm black leaf spots were observed 7 dpi. No symptoms were observed on control plants. A fungus with the same colony and conidial morphology as A. heveae were re-isolated from leaf lesions on inoculated rubber plants, but not from asymptomatic leaves of control plants, fulfilling Koch's postulates. Based on these results, the disease was identified as black spot of rubber tree caused by A. heveae. To our knowledge, this is the first report of A. heveae on rubber tree in China. References: (1) Z. Y. Cai et al. Microbiol Res. 168:340, 2013. (2) W. J. Martin. Plant Dis. Rep. 31:155, 1947. (3) E. G. Simmons. Mycotaxon 50:262, 1994. (4) T. Y. Zhang. Page 111 in: Flora Fungorum Sinicorum: Alternaria, Science Press, Beijing, 2003.

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