scholarly journals First Report of Nigrospora Leaf Blight on Tea Caused by Nigrospora sphaerica in India

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 417-417 ◽  
Author(s):  
J. Dutta ◽  
S. Gupta ◽  
D. Thakur ◽  
P. J. Handique
Keyword(s):  
Camellia Sinensis ◽  
West Bengal ◽  
Morphological Characteristics ◽  
Its Region ◽  
Causative Organism ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Tea Leaves ◽  
First Report ◽  
Initial Symptoms

Tea [Camellia sinensis (L.) O. Kuntze] is an economically important non-alcoholic caffeine-containing beverage crop widely cultivated for leaves in India, especially in the Darjeeling district of West Bengal. In May 2012, distinct blight symptoms were observed on leaves of popular tea cultivars AV-2, Tukdah 78, Rungli Rungliot 17/144, and Bannockburn 157 in commercial tea estates of the Darjeeling district. This disease reduces yield and quality of the leaves. The initial symptoms were frequently observed on the young leaf margins and apices. Foliar symptoms are characterized by grayish to brown, semicircular or irregular shaped lesions, often surrounded by pale yellow zones up to 9 mm in diameter. The lesions later expand and the affected leaves turn grayish to dark brown and eventually the dried tissue falls, leading to complete defoliation of the plant. The disease causes damage to leaves of all ages and is severe in young leaves. A portion of the symptomatic leaf tissues were surface sterilized in 70% ethanol for 30 s, then in 2% NaClO for 3 min, rinsed three times in sterile distilled water, and plated onto potato dextrose agar (PDA). The fungal colonies were initially white and then became grayish to brown with sporulation. Conidia were spherical to sub spherical, single-celled, black, 19 to 21 μm in diameter, and were borne on a hyaline vesicle at the tip of each conidiophore. Morphological characteristics of the isolates were concurring to those of Nigrospora sphaerica (1). Moreover, the internal transcribed spacer (ITS) region of the ribosomal RNA was amplified by using primers ITS1 and ITS4 and sequenced (GenBank Accession No. KJ767520). The sequence was compared to the GenBank database through nucleotide BLAST search and the isolate showed 100% similarity to N. sphaerica (KC519729.1). On the basis of morphological characteristics and nucleotide homology, the isolate was identified as N. sphaerica. Koch's postulates were fulfilled in the laboratory on tea leaves inoculated with N. sphaerica conidial suspension (106 conidia ml−1) collected from a 7-day-old culture on PDA. Six inoculated 8-month-old seedlings of tea cultivars AV-2 and S.3/3 were incubated in a controlled environment chamber at 25°C and 80 to 85% humidity with a 12-h photoperiod. In addition, three plants of each cultivar were sprayed with sterile distilled water to serve as controls. Twelve to 14 days after inoculation, inoculated leaves developed blight symptoms similar to those observed on naturally infected tea leaves in the field. No symptoms were observed on the control leaves. The pathogen was re-isolated from lesions and its identity was confirmed by morphological characteristics. It was reported that N. sphaerica is frequently encountered as a secondary invader or as a saprophyte on many plant species and also as a causative organism of foliar disease on several hosts worldwide (2,3). To our knowledge, this is first report of N. sphaerica as a foliar pathogen of Camellia sinensis in Darjeeling, West Bengal, India, or worldwide. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ July 01, 2013. (3) E. R. Wright et al. Plant Dis. 92:171, 2008.

scholarly journals First report of fruit blight caused by Alternaria alternata on sesame in Northeast China

Plant Disease ◽  
2021 ◽  
Author(s):  
Hongsen Cheng ◽  
De Xue Gao ◽  
Huijie Sun ◽  
Yanbin Na ◽  
Jing Xu
Keyword(s):  
Alternaria Alternata ◽  
Morphological Characteristics ◽  
Its Region ◽  
Liaoning Province ◽  
Oilseed Crop ◽  
Distilled Water ◽  
Conidial Suspension ◽  
First Report ◽  
Health Products ◽  
Blight Disease

Sesame (Sesamum indicum L.) is an important oilseed crop in China and it is also used in food and health products. In August of 2019, a blight sesame fruit was observed in a field of Liaoyang city, Liaoning province of China. Initial disease symptoms consisted of brown or dark brown spots on fruit. With time, lesions coalesced and the whole fruit turned dark brown or black. Most of the diseased fruit had thin and small, deformed, necrotic, hardened cracked epidermal lesions. Lesions were also produced on stem and petioles leading to leaf abscission. The disease results in premature fruit death, and in turn, considerable yield losses. To determine the causal agent, symptomatic fruit with developing lesions were collected, and surface sterilized in 2% NaClO for 3 min, rinsed three times in distilled water, and plated onto PDA medium. After incubation at 25°C for 5 days, a dark olivaceous fungus with abundant, branched, brown to black, and septate hyphae was consistently isolated. Twenty single spores were separated with an inoculation needle under stereomicroscope. The conidia were in chains, brown, obclavate, ovoid or ellipsoid, with 1-6 transverse septa and 0-4 longitudinal or oblique septa 12.5 to 45 × 6.5 to 14.5 μm in size. Conidiophores were septate, light brown to olive brown, measuring 22-60 μm × 2-4 μm. The morphological characteristics of the 20 isolates all matched the description of Alternaria alternata (Simmons, 2007). The internal transcribed spacer (ITS) region of rDNA of 15 isolates was amplified using primers ITS1/ITS4 (White et al. 1990) and EF1-728F/EF1-986R (Carbone et al. 1999) and sequenced. Identical sequences were obtained and the sequence of the isolate ZMHG12 was submitted to GenBank (Accession no. MW418181 and MW700316). BLAST analysis of the sequences of the isolates of ZMHG12 showed 100% to A. alternata (KP739875 and LC132712). In pathogenicity tests, a conidial suspension (2.5 × 105 conidia per ml) was prepared from 7 days-old cultures of isolate ZMHG12 grown on PDA at 25°C. Fruit of 10 two-month-old potted sesame plants (Variety “Liaozhi 8”) were sprayed with the conidia suspension until runoff. Another 10 plants sprayed with distilled water to served as non-inoculated controls. All plants were maintained for 48 h in a humid chamber with a temperature of 25°C to 26°C, and then moved to a greenhouse. Ten days after inoculation, all fruit of inoculated plants exhibited symptoms similar to those observed in the field and non-inoculated control plants remained symptomless. The experiment was repeated twice with similar results. A. alternata has been reported as a pathogen caused leaf blight disease of sesame in Pakistan (Nayyar et al. 2017). To our knowledge, this is the first report of A.alternata causing fruit blight of sesame in China. To date, we have observed the disease on sesames in fields of Fuxin, Chaoyang and Tieling city in Liaoning Province, and Tongliao city in Inner Mongolia of China, and it has become an important disease in sesame production of China. References : Simmons E. G. 2007. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands. White T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego. Carbone I., et al. 1999. Mycologia, 91: 553-556. Nayyar, B. G., et al. 2017. Plant Pathology Journal, 33 (6): 543-553.

scholarly journals First Report of Septoria Leaf Spot of Lavandin Caused by Septoria lavandulae in Croatia

Plant Disease ◽  
2014 ◽  
Vol 98 (2) ◽  
pp. 282-282
Author(s):  
K. Vrandečić ◽  
J. Ćosić ◽  
D. Jurković ◽  
I. Stanković ◽  
A. Vučurović ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Antibacterial Properties ◽  
Morphological Characteristics ◽  
Its Region ◽  
Morphological Identification ◽  
Conidial Suspension ◽  
Necrotic Tissue ◽  
First Report ◽  
Initial Symptoms ◽  
Septoria Leaf Spot

Lavandula × intermedia Emeric ex Loiseleur, commonly known as lavandin, is an aromatic and medicinal perennial shrub widely and traditionally grown in Croatia. The lavandin essential oil is primarily used in perfumery and cosmetic industries, but also possesses anti-inflammatory, sedative, and antibacterial properties. In June 2012, severe foliar and stem symptoms were observed on approximately 40% of plants growing in a commercial lavandin crop in the locality of Banovo Brdo, Republic of Croatia. Initial symptoms on lower leaves included numerous, small, oval to irregular, grayish brown lesions with a slightly darker brown margin of necrotic tissue. Further development of the disease resulted in yellowing and necrosis of the infected leaves followed by premature defoliation. Similar necrotic oval-shaped lesions were observed on stems as well. The lesions contained numerous, dark, sub-globose pycnidia that were immersed in the necrotic tissue or partly erumpent. Small pieces of infected internal tissues were superficially disinfected with 50% commercial bleach (4% NaOCl) and placed on potato dextrose agar (PDA). A total of 10 isolates from leaves and five from stems of lavandin formed a slow-growing, dark, circular colonies with raised center that produced pycnidia at 23°C, under 12 h of fluorescent light per day. All 15 recovered isolates formed uniform hyaline, elongate, straight or slightly curved conidia with 3 to 4 septa, with average dimensions of 17.5 to 35 × 1.5 to 2.5 μm. Based on the morphological characteristics, the pathogen was identified as Septoria lavandulae Desm., the causal agent of lavender leaf spot (1,2). Pathogenicity of one selected isolate (428-12) was tested by spraying 10 lavandin seedlings (8 weeks old) with a conidial suspension (106 conidia/ml) harvested from a 4-week-old monoconidial culture on PDA. Five lavandin seedlings, sprayed with sterile distilled water, were used as negative control. After 5 to 7 days, leaf spot symptoms identical to those observed on the source plants developed on all inoculated seedlings and the pathogen was successfully re-isolated. No symptoms were observed on any of the control plants. Morphological identification was confirmed by amplification and sequencing of the internal transcribed spacer (ITS) region of rDNA (3). Total DNA was extracted directly from fungal mycelium with a DNeasy Plant Mini Kit (Qiagen, Hilden, Germany) and PCR amplification performed with primers ITS1F/ITS4. Sequence analysis of ITS region revealed at least 99% identity between the isolate 428-12 (GenBank Accession No. KF373078) and isolates of many Septoria species; however, no information was available for S. lavandulae. To our knowledge, this is the first report of Septoria leaf spot of lavandin caused by S. lavandulae in Croatia. Since the cultivation area of lavandin plants has been increasing in many continental parts of Croatia, especially in Slavonia and Baranja counties, the presence of a new and potentially harmful disease may represent a serious constraint for lavandin production and further monitoring is needed. References: (1) T. V. Andrianova and D. W. Minter. IMI Descriptions of Fungi and Bacteria, 142, Sheet 1416, 1999. (2) R. Bounaurio et al. Petria 6:183, 1996. (3) G. J. M. Verkley et al. Mycologia 96:558, 2004.

scholarly journals First Report of Verticillium Wilt Caused by Verticillium dahliae on Figmarigold in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 129-129
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
P. Pensa ◽  
M. L. Gullino
Keyword(s):  
Verticillium Wilt ◽  
Cross Sections ◽  
Vascular Tissue ◽  
Morphological Characteristics ◽  
Ground Cover ◽  
Its Region ◽  
Peat Moss ◽  
Conidial Suspension ◽  
First Report ◽  
Initial Symptoms

Lampranthus spp. N.B. Brown (figmarigold) belongs to the Aizoaceae family and is grown as a ground cover in gardens or as a potted plant. In January 2009, severe outbreaks of a previously unknown wilt were observed at a commercial farm in Liguria (northern Italy) where 7-month-old potted plants were grown outdoors in a mix of peat/clay/pumice at pH 6.5. In cultivars with pink flowers, 12% of plants were affected, while only a few cultivars with red flowers were diseased. Initial symptoms were yellowing of external leaves and brown or black streaks in the vascular tissue of roots, crown, and leaves. Subsequently, infected tissues wilted and stopped growing, stems and leaves appeared desiccated, and infected plants died. Stems of 10 pink-flowered plants were severed with a knife, cut ends sealed with wax, and surfaces disinfected with 1% sodium hypochlorite. Cross-sections (1 mm long) through symptomatic vascular tissue were plated onto potato dextrose agar. After 10 days at 22°C, 90% of the stems tested positive for Verticillium. Irregular, dark microsclerotia, 22 to 128 × 13 to 66 (average 51 × 29) μm, developed in hyaline hyphae after 10 days of growth at 22 ± 1°C (12-h photoperiod). Hyaline, elliptical, single-celled conidia, 2.9 to 4.8 × 1.3 to 2.4 (average 4.1 × 1.7) μm, developed on verticillate conidiophores. On the basis of these morphological characteristics, the fungus was identified as V. dahliae (3). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 (2) and sequenced. BLASTn analysis (1) of the 476-bp segment showed a 100% homology with the sequence of V. dahliae. The nucleotide sequence has been assigned GenBank Accession No. GQ 149479. Pathogenicity tests were performed twice using five 40-day-old plants of a pink-flower cultivar of a Lampranthus sp. grown in 1-liter pots containing a 50:20:20:10 mix of peat moss/pumice/pine bark cortex/clay. The substrate was infested with a conidial suspension (1.0 × 107/ml) of one isolate of V. dahliae recovered from infected plants. Inoculum (50 ml) were added to each pot, drenching the top of the soil. Noninoculated plants served as controls. Plants (five per treatment) were maintained in a glasshouse at daily average temperatures between 20 and 26°C and at 50 to 70% relative humidity. The first wilt symptoms and a vascular discoloration in the roots, crown, and veins developed 30 days after inoculation. V. dahliae was consistently reisolated. Noninoculated plants remained healthy. In a second test, the susceptibility of purple-, white-, yellow-, red-, and orange-flowered cultivars was tested. Ten rooted cuttings of each cultivar were inoculated as described above. The severity of Verticillium wilt was evaluated and each cultivar was classified as resistant, partially resistant, average susceptible, susceptible, or highly susceptible. All tested cultivars were susceptible or highly susceptible to Verticillium. Only the purple cultivar showed an average susceptibility. To our knowledge, this is the first report of Verticillium wilt on Lampranthus spp. in Italy as well as worldwide. Today, the economic importance of Verticillium wilt on figmarigold in Italy is still limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) M. A. Innis et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (3) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002.

scholarly journals First Report of Verticillium Wilt Caused by Verticillium dahliae on Rudbeckia fulgida (Orange Coneflower) in Italy

Plant Disease ◽  
2008 ◽  
Vol 92 (9) ◽  
pp. 1367-1367 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Vascular Tissue ◽  
Morphological Characteristics ◽  
Its Region ◽  
The United States ◽  
Conidial Suspension ◽  
First Report ◽  
Initial Symptoms

Rudbeckia fulgida (common name orange coneflower) is an herbaceous perennial (Asteraceae) grown in full sun in perennial borders in gardens. At the end of the summer of 2007, in a public garden located in Turin (northern Italy), symptoms of vascular wilt and stunting were observed on approximately 80% of the plants grown in a mixed border. Initial symptoms were yellowing of external leaves and brown or black streaks in the vascular tissue of roots, crown, and leaves. A fungus was consistently and readily isolated on potato dextrose agar from symptomatic vascular tissue previously disinfested in 1% sodium hypochloride. Ovoid, dark microsclerotia, 41 to 108 μm, developed in hyaline hyphae after 10 days of growth at 23°C (12 h of light and 12 h of dark). Hyaline, elliptical, single-celled conidia, 3.2 to 7.3 × 2.1 to 3.7 (average 4.7 × 2.8) μm, developed on verticillate conidiophores. On the basis of these morphological characteristics, the fungus was identified as Verticillium dahliae (4). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 530 bp showed a 100% homology with the sequence of V. dahliae. The nucleotide sequence has been assigned GenBank Accession No. EU 627007. Healthy, 30-day-old R. fulgida plants were grown in a steam-disinfested mix of sphagnum peat:pomix:pine bark:clay (50:20:20:10) infested with a conidial suspension (1.5 × 106/ml) of three isolates of V. dahliae isolated from infected plants. Noninoculated plants served as controls. Plants (16 per treatment) were grown in pots (3 liter vol) and maintained in a glasshouse at temperatures between 22 and 25°C and relative humidity between 50 and 70%. First wilt symptoms and vascular discoloration in the roots, crown, and veins developed 17 days after inoculation. Noninoculated plants remained healthy. The pathogenicity tests were carried out twice. To our knowledge, this is the first report in Italy of Verticillium wilt on R. fulgida. Wilts caused by V. dahliae on R. laciniata in Poland (3) and V. albo-atrum on R. hirta in the United States (2) were previously reported. The importance and economic impact of this disease is currently limited but may increase because of the popularity of Rudbeckia spp. in private and public parks. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. F. Farr et al. Fungi on Plants and Their Products in the United States. The American Phytopathological Society, St Paul, MN, 1989. (3) B. Leski. Rocz. Nauk Roln. 253, 1974. (4) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002.

scholarly journals First Report of Anthracnose Caused by Colletotrichum brasiliense on Violet Passion Fruit in China

Plant Disease ◽  
2021 ◽  
Author(s):  
G. Y. Shi ◽  
Quan Zeng ◽  
Y. W. Wei ◽  
Chun Jin Hu ◽  
X. L. Ye ◽  
...  
Keyword(s):  
Large Scale ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Internal Transcribed Spacers ◽  
Passion Fruit ◽  
Fluorescent Light ◽  
Distilled Water ◽  
Conidial Suspension ◽  
First Report ◽  
Initial Symptoms

Violet passion fruit (Passiflora edulis Sims) is an important tropical and subtropical perennial evergreen vine with large-scale cultivation in Guangxi, China. Between May and September 2020, anthracnose symptoms occurred on passion fruit (cultivar Tainong No. 1) in Xingye county (22°77′13″N, 110°07′80″E) in Guangxi province, China. The disease incidence varied from 25 to 60% in different orchards. Initial symptoms on young fruits appeared as multiple tiny water-soaked, oval to irregular pale greenish spots. As the disease progressed, the lesions became medium brown, with sunken cavities. Under humid conditions, acervuli containing masses of conidia and dark setae were found on the lesions. The affected fruits became shriveled. Tissue pieces (5 × 5 mm) were cut out from infected fruits, surface sterilized in 75% ethanol for 15 s and 0.1% HgCl2 for 2 min, washed three times with sterile water, placed onto potato dextrose agar (PDA), and incubated at 28 °C for three days. Of the 29 Colletotrichum isolates obtained , the isolate B13 was selected for morphological characterization. B13 was purified by single spore isolation and incubated on PDA at 25°C under continuous fluorescent light irradiation, producing white to pale yellow colonies with dense aerial mycelia. The reverse side of the colony was pale yellowish to olive. Conidia were hyaline, unicellular, straight, cylindrical, with both ends slightly round or one end round and the other slightly pointed, measuring 10.5 to 18.8 (average 16.4) × 5.4 to 7.2 (average 6.3) µm (n = 50). Appressoria were light brown to dark black, smooth-walled, lobed, often with a roundish outline, sometimes also triangular, 7.2 to 10.9 (average 9.1) × 6.8 to 9.2 (average 8.2) µm (n = 50). Morphological characteristics of the isolate matched those of Colletotrichum brasiliense (Damm et al. 2012). The internal transcribed spacers (ITS), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-tubulin (TUB2) genes of strain B13 were sequenced using the method and primers of Damm et al. (2012). Sequences of the amplified DNA regions were submitted to GenBank (ITS: MW198820; ACT: MW266083; GAPDH: MW266084; and TUB2: MW266085). A concatenated maximum likelihood phylogenetic tree was built using MEGA 7.0.21 in which B13 clustered with C. brasiliense and clearly separated from other Colletotrichum spp. Pathogenicity of B13 was assayed using one-year-old plants of violet passion fruit cultivar ‘Tainong No. 1’. Conidial suspensions were prepared from 7-day-old cultures grown on PDA at 28°C Sterile distilled water was used to dislodge conidia from the culture dish and the conidial concentration was adjusted to 1 × 106 spores mL-1 using a haemocytometer. Fruits were rinsed with sterilized water and wounded with a sterile needle at three locations. Three fruits were inoculated by spraying with 20 mL of the conidial suspension. Control fruits were sprayed with distilled water. Fruits were then covered with plastic bags to maintain high relative humidity . After 9 days, all inoculated fruits developed brown spots with sunken cavities, resembling symptoms observed in the field, and controls remained symptomless. Fungal cultures with phenotypic features similar to C. brasiliense were re-isolated from the symptomatic fruits, verifying C. brasiliense as the causal agent of the disease based on Koch’s postulates. C. boninense, C. gloeosporioides, C.queenslandicum, C. brevisporum, and C. karstii were reported as causal agents of anthracnose on passion fruit (Júnior et al.2010; Power et al. 2010; James et al.2014; Du et al.2017; Ran et al.2020). To the best of our knowledge, this is the first report of C. brasiliense causing anthracnose on passion fruit in China.

scholarly journals First Report of Black Stem of Avicennia marina Caused by Fusarium equiseti in China

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 843-843 ◽  
Author(s):  
N.-H. Lu ◽  
Q.-Z. Huang ◽  
H. He ◽  
K.-W. Li ◽  
Y.-B. Zhang
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Avicennia Marina ◽  
Optical Microscope ◽  
Ethanol Solution ◽  
Morphological Observation ◽  
Fusarium Equiseti ◽  
First Report ◽  
Initial Symptoms ◽  
Β Tubulin

Avicennia marina is a pioneer species of mangroves, a woody plant community that periodically emerges in the intertidal zone of estuarine regions in tropical and subtropical regions. In February 2013, a new disease that caused the stems of A. marina to blacken and die was found in Techeng Island of Zhanjiang, Guangdong Province, China. Initial symptoms of the disease were water-soaked brown spots on the biennial stems that coalesced so whole stems browned, twigs and branches withered, leaves defoliated, and finally trees died. This disease has the potential to threaten the ecology of the local A. marina community. From February to May 2013, 11 symptomatic trees were collected in three locations on the island and the pathogen was isolated as followed: tissues were surface disinfected with 75% ethanol solution (v/v) for 20 s, soaked in 0.1% mercuric chloride solution for 45 s, rinsed with sterilized water three times, dried, placed on potato dextrose agar (PDA), and incubated for 3 to 5 days at 28°C without light. Five isolates (KW1 to KW5) with different morphological characteristics were obtained, and pathogenic tests were done according Koch's postulates. Fresh wounds were made with a sterile needle on healthy biennial stems of A. marina, and mycelial plugs of each isolate were applied and covered with a piece of wet cotton to maintain moisture. All treated plants were incubated at room temperature. Similar symptoms of black stem were observed only on the stems inoculated the isolate KW5 after 35 days, while the control and all stems inoculated with the other isolates remained symptomless. An isolate similar to KW5 was re-isolated from the affected materials. The pathogenic test was repeated three times with the same conditions and it was confirmed that KW5 was the pathogen causing the black stem of A. marina. Hyphal tips of KW5 were transferred to PDA medium in petri dishes for morphological observation. After 48 to 72 h, white, orange, or brown flocculence patches of KW5 mycelium, 5.0 to 6.0 cm in diameter, grew. Tapering and spindle falciform macroconidia (11 to 17.3 μm long × 1.5 to 2.5 μm wide) with an obviously swelled central cell and narrow strips of apical cells and distinctive foot cells were visible under the optical microscope. The conidiogenous cells were intertwined with mycelia and the chlamydospores were globose and formed in clusters. These morphological characteristics of the isolate KW5 are characteristic of Fusarium equiseti (1). For molecular identification, the ITS of ribosomal DNA, β-tubulin, and EF-1α genes were amplified using the ITS4/ITS5 (5), T1/T2 (2), and EF1/EF2 (3) primer pairs. These sequences were deposited in GenBank (KF515650 for the ITS region; KF747330 for β-tubulin region, and KF747331 for EF-1α region) and showed 98 to 99% identity to F. equiseti strains (HQ332532 for ITS region, JX241676 for β-tubulin gene, and GQ505666 for EF-1α region). According to both morphological and sequences analysis, the pathogen of the black stem of A. marina was identified as F. equiseti. Similar symptoms on absorbing rootlets and trunks of A. marina had been reported in central coastal Queensland, but the pathogen was identified as Phytophthora sp. (4). Therefore, the disease reported in this paper differs from that reported in central coastal Queensland. To our knowledge, this is the first report of black stems of A. marina caused by F. equiseti in China. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual, 1st ed. Wiley-Blackwell, Hoboken, NJ, 2006. (2) K. O'Donnell and E. Cigelnik. Mol. Phylogenet. Evol. 7:103, 1997. (3) K. O'Donnell et al. Proc. Natl. Acad. Sci. USA. 95:2044, 1998. (4) K. G. Pegg. Aust et al. Plant Pathol. 3:6, 1980. (5) A. W. Zhang et al. Plant Dis. 81:1143, 1997.

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 Curvularia aeria on Etlingera linguiformis from Nagaland, India

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1580-1580 ◽  
Author(s):  
C. Kithan ◽  
L. Daiho
Keyword(s):  
Leaf Surface ◽  
Agricultural Research ◽  
Disease Incidence ◽  
Indian Agricultural Research Institute ◽  
Mountain Range ◽  
Pathogenicity Test ◽  
Distilled Water ◽  
Conidial Suspension ◽  
First Report ◽  
Initial Symptoms

Etlingera linguiformis (Roxb.) R.M.Sm. of Zingiberaceae family is an important indigenous medicinal and aromatic plant of Nagaland, India, that grows well in warm climates with loamy soil rich in humus (1). The plant rhizome has medicinal benefits in treating sore throats, stomachache, rheumatism, and respiratory complaints, while its essential oil is used in perfumery. A severe disease incidence of leaf blight was observed on the foliar portion of E. linguiformis at the Patkai mountain range of northeast India in September 2012. Initial symptoms of the disease are small brown water soaked flecks appearing on the upper leaf surface with diameter ranging from 0.5 to 3 cm, which later coalesced to form dark brown lesions with a well-defined border. Lesions often merged to form large necrotic areas, covering more than 90% of the leaf surface, which contributed to plant death. The disease significantly reduces the number of functional leaves. As disease progresses, stems and rhizomes were also affected, reducing quality and yield. The diseased leaf tissues were surface sterilized with 0.2% sodium hypochlorite for 2 min followed by rinsing in sterile distilled water and transferred into potato dextrose agar (PDA) medium. After 3 days, the growing tips of the mycelium were transferred to PDA slants and incubated at 25 ± 2°C until conidia formation. Fungal colonies on PDA were dark gray to dark brown, usually zonate; stromata regularly and abundantly formed in culture. Conidia were straight to curved, ellipsoidal, 3-septate, rarely 4-septate, middle cells broad and darker than other two end cells, middle septum not median, smooth, 18 to 32 × 8 to 16 μm (mean 25.15 × 12.10 μm). Conidiophores were terminal and lateral on hyphae and stromata, simple or branched, straight or flexuous, often geniculate, septate, pale brown to brown, smooth, and up to 800 μm thick (2,3). Pathogen identification was performed by the Indian Type Culture Collection, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi (ITCC Accession No. 7895.10). Further molecular identity of the pathogen was confirmed as Curvularia aeria by PCR amplification and sequencing of the internal transcribed spacer (ITS) regions of the ribosomal DNA by using primers ITS4 and ITS5 (4). The sequence was submitted to GenBank (Accession No. MTCC11875). BLAST analysis of the fungal sequence showed 100% nucleotide similarity with Cochliobolus lunatus and Curvularia aeria. Pathogenicity tests were performed by spraying with an aqueous conidial suspension (1 × 106 conidia /ml) on leaves of three healthy Etlingera plants. Three plants sprayed with sterile distilled water served as controls. The first foliar lesions developed on leaves 7 days after inoculation and after 10 to 12 days, 80% of the leaves were severely infected. Control plants remained healthy. The inoculated leaves developed similar blight symptoms to those observed on naturally infected leaves. C. aeria was re-isolated from the inoculated leaves, thus fulfilling Koch's postulates. The pathogenicity test was repeated twice. To our knowledge, this is the first report of the presence of C. aeria on E. linguiformis. References: (1) M. H. Arafat et al. Pharm. J. 16:33, 2013. (2) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (3) K. J. Martin and P. T. Rygiewicz. BMC Microbiol. 5:28, 2005. (4) C. V. Suberamanian. Proc. Indian Acad. Sci. 38:27, 1955.

scholarly journals First Report of Myrothecium roridum Causing Leaf Spot on Zantedeschia aethiopica in China

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 854-854 ◽  
Author(s):  
B.-J. Li ◽  
H.-Y. Ben ◽  
Y.-X. Shi ◽  
X.-W. Xie ◽  
A.-L. Chai
Keyword(s):  
Leaf Spot ◽  
Morphological Characteristics ◽  
Its Region ◽  
First Record ◽  
Conidial Suspension ◽  
Isolation And Identification ◽  
Zantedeschia Aethiopica ◽  
Calla Lily ◽  
Initial Symptoms ◽  
Myrothecium Roridum

Zantedeschia aethiopica (L.) Spreng. (calla lily), belonging to family Araceae, is a popular ornamental plant in China. In the summer of 2010, leaves of calla lily with typical symptoms of necrotic lesions were observed in a commercial glasshouse in Beijing, China (116°20′ E, 39°44′ N). The initial symptoms were circular to subcircular, 1 to 3 mm, and dark brown lesions on the leaf lamina. Under high humidity, lesions expanded rapidly to 5 to 10 mm with distinct concentric zones and produced black sporodochia, especially on the backs of leaves. Later, the infected leaves were developing a combination of leaf lesions, yellowing, and falling off; as a result, the aesthetic value of the plant was significantly impacted. Leaf samples were used in pathogen isolation. Symptomatic leaf tissues were cut into small pieces and surface sterilized with 70% ethanol for 30 s and then in 0.1% mercuric chloride solution for 1 to 3 min. After being washed in sterile distilled water three times, the pieces were plated on potato dextrose agar (PDA) and incubated at 25°C in darkness for 7 days (5). Initial colonies of isolates were white, floccose mycelium and developed dark green to black concentric rings that were sporodochia bearing viscid spore masses after incubating 5 days. Conidiophores branched repeatedly. Conidiogenous cells were hyaline, clavate, and 10.0 to 16.0 × 1.4 to 2.0 μm. Conidia were hyaline, cylindrical, both rounded ends, and 6.0 to 8.2 × 1.9 to 2.4 μm. Morphological characteristics of the fungus were consistent with the description of Myrothecium roridum Tode ex Fr. (3,4). To confirm the pathogenicity, three healthy plants of calla lily were inoculated with a conidial suspension (1 × 106 conidia per ml) brushed from a 7-day-old culture of the fungus. Control plants were sprayed with sterile water. The inoculated plants were individual with clear plastic bags and placed in a glass cabinet at 25°C. After 7 days, all inoculated leaves developed symptoms similar to the original samples, but control plants remained disease free. Re-isolation and identification confirmed Koch's postulates. For molecular identification, genomic DNA of a representative isolate (MTL07081001) was extracted by modified CTAB method (1), and the rDNA-ITS region was amplified by using primers ITS1 (5-TCCGTAGGTGAACCTGCGG-3) and ITS4 (5-TCCTCCGCTTATTGATATGC-3). The 465-bp amplicon (GenBank Accession No. KF761293) was 100% identity to the sequence of M. roridum (JF724158.1) from GenBank. M. roridum has an extensive host range, covering 294 host plants (2). To our knowledge, this is the first record of leaf spot caused by M. roridum on calla lily in China. References: (1) F. M. Ausubel et al. Current Protocols in Molecular Biology. John Wiley & Sons Inc, New York, 1994. (2) D. F. Farr and A. Y. Rossman, Fungal Databases. Syst. Mycol. Microbiol. Lab., ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , October 2013. (3) M. T. Mmbaga et al. Plant Dis. 94:1266, 2010. (4) Y. X. Zhang et al. Plant Dis. 95:1030, 2011. (5) L. Zhu et al. J. Phytopathol. 161:59, 2013.

scholarly journals First Report of Leaf Spot Caused by Ascochyta marginata on Aralia elata in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 147-147
Author(s):  
S. H. Lee ◽  
C. K. Lee ◽  
M. J. Park ◽  
H. D. Shin
Keyword(s):  
East Asia ◽  
Leaf Spot ◽  
Morphological Characteristics ◽  
Culture Collection ◽  
Research Report ◽  
Conidial Suspension ◽  
First Report ◽  
Commercial Cultivation ◽  
Aralia Elata ◽  
Initial Symptoms

Aralia elata (Miq.) Seem., known as Japanese angelica tree, is a deciduous shrub belonging to the Araliaceae, which is native to East Asia. The young shoots have long been used in various dishes in East Asia. Commercial cultivation of this shrub, especially in polytunnels, is expanding in Korea. Several diseases including Sclerotinia rot have been known to be present on this plant (1,2). In early September 2007, leaf spot symptoms were first observed on several trees in Hongcheon, Korea. Microscopic observations revealed that the leaf spots were associated with an Ascochyta sp. Further surveys of the Ascochyta leaf spot showed the occurrence of the disease in approximately 5 to 10% of the trees in the 3 ha of commercial fields surveyed in Chuncheon, Gapyeong, Inje, and Jinju, Korea. Initial symptoms on leaves were circular to irregular, brown to dark brown, becoming zonate, and finally fading to grayish brown in the center with a yellow halo. Representative samples were deposited in the herbarium of Korea University. Conidiomata on leaf lesions were pycnidial, amphigenous, but mostly epiphyllous, immersed or semi-immersed in host tissue, light brown to olive brown, and 60 to 200 μm in diameter. Ostioles were papillate, 20 to 35 μm wide, and surrounded by a ring of darker cells. Conidia were hyaline, smooth, cylindrical to clavate, straight to mildly curved, slightly constricted at the septa, medianly one-septate, sometimes aseptate, 8 to 16 × 2.5 to 3.5 μm, and contained small oil drops. These morphological characteristics were consistent with the previous reports of Ascochyta marginata J.J. Davis (3,4). A monoconidial isolate was cultured on potato dextrose agar (PDA) plates and accessioned in the Korea Agricultural Culture Collection (Accession KACC43082). The conidia were readily formed on PDA. Inoculum for the pathogenicity tests was prepared by harvesting conidia from 30-day-old cultures of KACC43082 and a conidial suspension (approximately 2 × 106 conidia/ml) was sprayed onto leaves of three healthy seedlings. Three noninoculated seedlings served as controls. Inoculated and noninoculated plants were covered with plastic bags for 48 h in a glasshouse. After 7 days, typical leaf spot symptoms started to develop on the leaves of the inoculated plants. The fungus, A. marginata, was reisolated from those lesions, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in Japan (4) and China (3). To our knowledge, this is the first report of A. marginata on Japanese angelica trees in Korea. According to our field observations in Korea, the Ascochyta leaf spot mostly occurred on plants growing in a humid environment, especially during the rainy season. The seedlings as well as the trees growing in sunny, well-ventilated plots were nearly free from this disease. Therefore, the growing conditions seemed to be the most important factor for the development and severity of the disease. References: (1) C. K. Lee et al. Plant Pathol. J. 26:426, 2010. (2) S. H. Lee et al. Diseases of Japanese Angelica Tree and Their Control. Research Report 08-10. Korea Forest Research Institute. Seoul, Korea, 2008. (3) J. Sun et al. Acta Mycol. Sin. 14:107, 1995. (4) M. Yoshikawa and T. Yokoyama. Mycoscience 36:67, 1995.

Sign in / Sign up

Export Citation Format

Share Document