scholarly journals First Report of Brown Spot Needle Blight on Pinus thunbergii Caused by Lecanosticta acicola in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 914-914 ◽  
Author(s):  
S. T. Seo ◽  
M. J. Park ◽  
J. H. Park ◽  
H. D. Shin
Keyword(s):  
Disease Incidence ◽  
Pinus Thunbergii ◽  
Brown Spot ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Black Pine ◽  
First Report ◽  
Lecanosticta Acicola ◽  
Needle Blight ◽  
Brown Spot Needle Blight

Pinus thunbergii Parl., known as black pine, is a pine native to coastal areas of Japan and Korea. Because of its resistance to pollution and salt, it is planted as windbreakers along the coast. In March 2010, needle blight symptoms were found on several trees of black pine in Naju, southern Korea. Further surveys in 2010 and 2011 showed that these symptoms are rather common but disease incidence is less than 1%. Small, circular grayish green spots first appeared on the needles. The spots developed into brown bands reaching 1 to 2 mm long, sometimes with yellow margins. Dark olivaceous to dark grayish stromata were erumpent and conspicuous on the brown lesions in the later stage of disease development. Conidiophores were simple or occasionally branched, 1- to 2-septate, pale brown to olivaceous brown, and smooth walled. Conidia (n = 30) were olivaceous brown to grayish brown, verrucose, thick-walled, mildly curved, allantoid to fusiform, one- to five-septate (mostly three-septate), and 20 to 45 × 3.5 to 5 μm. Morphological characteristics of the fungus were consistent with those of Lecanosticta acicola (Thüm.) Syd. (anamorph of Mycosphaerella dearnessii M.E. Barr), previously known as the causal agent of brown spot needle blight of pines (2,4). The teleomorph was not observed. On potato dextrose agar, single-spore cultures of three isolates were obtained from conidia sporulating on needles. An isolate was preserved at the Korean Agricultural Culture Collection (Accession No. KACC44982). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA) and the complete internal transcribed spacer (ITS) region of rDNA was amplified and sequenced with the primers ITS1/ITS4. The resulting ITS sequence of 543 bp was deposited in GenBank (Accession No. JQ245448). A GenBank BLAST search produced an exact match for the sequences of M. dearnessii (= L. acicola) on P. mugo Tura from Lithuania (HM367708) and P. radiata D. Don from France (GU214663), with 100% sequence similarity. To conduct a pathogenicity test, a conidial suspension (approx. 2 × 105 conidia/ml) was prepared by harvesting conidia from 5-week-old cultures of KACC44982 and sprayed onto the needles of five 3-year-old healthy seedlings. Five noninoculated seedlings of the same age served as controls. Inoculated and noninoculated plants were kept in humid chambers for 48 h in a glasshouse. After 28 days, typical leaf spot symptoms started to develop on the needles of inoculated plants. The fungus, L. acicola, was reisolated from those lesions, confirming Koch's postulates. No symptoms were observed on control plants. The disease has been previously reported on several species of Pinus in the Americas (1) and recently in China (3), Japan (4), and Europe (2). To our knowledge, this is the first report of the Lecanosticta-Pinus association in Korea. Occurrence of the disease in Korea is a new threat to the health of black pine, especially in nursery plots. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.arsgrin.gov/fungaldatabases/ December 2011. (2) L. Jankovsky et al. Plant Protect. Sci. 45:16, 2009. (3) C. Li et al. J. Nanjing Inst. For. 1986:11, 1986. (4) Y. Suto and D. Ougi. Mycoscience 39:319, 1998.

scholarly journals First Report of Brown Spot Needle Blight on Pinus thunbergii Parl. Caused by Aureobasidium pullulans in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Xiaolei Ding ◽  
Sixi Lin ◽  
Ruiwen Zhao ◽  
Jian-Ren Ye
Keyword(s):  
Aureobasidium Pullulans ◽  
Pinus Thunbergii ◽  
Brown Spot ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Black Pine ◽  
First Report ◽  
Needle Blight ◽  
Brown Spot Needle Blight ◽  
Β Tubulin

Pinus thunbergii Parl., known as black pine, is widely distributed all over China. This pine variety can prevent soil desertification and promote soil conservation and is excellent for constructing fast-growing forests and shelter belts. The timber of this species can be used for infrastructure construction and furniture production. In August 2020, needle blight symptoms were found on several trees of black pine in Sichuan Province, China. Further surveys showed that these symptoms are common while the disease incidence is less than 30% which indicated the severity of the disease is mild. The tips of old needles first turn grayish green and developed into brown bands ranging from 1 to 2 mm. To determine the pathogen, 20 needle samples with typical symptoms were disinfected with 75% alcohol, and sections of the tissue were cut from joints of diseased and healthy tissues (visually healthy) with a sterilized scalpel, surface sterilized for 45 seconds in 75% alcohol, soaked for 90 seconds in 1.5% NaCIO, rinsed in sterilized water and dried. Small cut tissues were placed on potato dextrose agar (PDA) at 25℃ for 10 days. Pure cultures were obtained by monosporic isolation. The colonies initially appeared white to cream, yeast-like, and later turned to pink and remained at least 10 days. Conidia were hyaline, smooth-walled, single-celled, and ellipsoidal with variable shape and size, 7.5 to 16 × 3.5 to 7 µm (Zalar et al. 2008). DNA was extracted from the mycelium of the isolate by the cetyltriethylammonium bromide (CTAB) method and amplified through polymerase chain reaction (PCR) with the internal transcribed spacer (ITS) region of rDNA and partial β-tubulin genes of a representative isolate (SC05) were amplified using the ITS1/ITS4 and Bt2a/Bt2b primer pairs, respectively(Wu et al. 2017). The sequences submitted to GenBank (Accession Nos. MW228368 for ITS and MW256762 for β-tubulin) showed high similarity with BLAST sequences of Aureobasidium pullulans (ITS, KR704881 [100%]; β-tubulin, MT671934 [99.49%]). For the pathogenicity test, a conidial suspension was prepared with a concentration of 2.0 × 107 conidia/ml. The suspension was sprayed onto 3 annual seedlings’ needles, and the control was sprayed with sterile water. Inoculated and non-inoculated plants were kept in humid chambers in a glasshouse. After 10 days, typical symptoms appeared on inoculated needles, whereas control needles remained symptomless. The fungus, A. pullulans, was reisolated from those lesions, confirming Koch's postulates. No symptoms were observed on control plants. Aureobasidium pullulans, a ubiquitous saprophytic fungus on many fruits and very rarely reported to cause disease on pine needles. Only reported invasion of Ozone‐injured needles in P. strobus (Costonis and Sinclair 1972) and needles damaged by acid rain in P. sylvestris (Ranta 1990). To our knowledge, this is the first report of brown spot needle blight on P. thunbergii caused by A. pullulans in China. The disease represents a threat to pine manufactures and more research on the pathogenesis and management is needed.  

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 Alternaria alternata causing leaf blight on little millet (Panicum sumatrense) in India.

Plant Disease ◽  
2020 ◽  
Author(s):  
Boda Praveen ◽  
A. Nagaraja ◽  
M. K. Prasanna Kumar ◽  
Devanna Pramesh ◽  
K. B. Palanna ◽  
...  
Keyword(s):  
Crop Yields ◽  
Disease Incidence ◽  
Leaf Blight ◽  
Post Inoculation ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Pcr Assay ◽  
Causal Organism ◽  
First Report ◽  
Little Millet

Little millet (LM) is a minor cereal crop grown in the Indian sub-continent. During October 2018, dark brown, circular to oval necrotic spots surrounded by concentric rings were observed on the upper leaf surface of the LM (cv. VS-13) grown in the fields of the University of Agricultural Sciences, Bengaluru, India (13.0784oN, 77.5793oE). As the disease progressed, infected leaves became blighted. Disease incidence up to 53% was recorded in 3 fields of 0.4-hectare area each. Thirty symptomatic leaves were collected to isolate the associated causal organism. The margins of diseased tissue were cut into 5 × 5-mm pieces, surface-sterilized in 75% ethanol for 45 seconds followed by 1% sodium hypochlorite for 1 min, finally rinsed in sterile distilled water five times and placed on PDA. After 7 days of incubation at 25°C, greyish fungal colonies appeared on PDA. Single-spore isolations were performed to obtain ten isolates. Pure cultures of the fungus initially produced light gray aerial mycelia that later turned to dark grey. All isolates formed obclavate to pyriform conidia measured 22.66-48.97μm long and 6.55-13.79µm wide with 1-3 longitudinal and 2-7 transverse septa with a short beak (2.55-13.26µm) (n=50). Based on the conidial morphology, the fungus was identified as Alternaria sp. Further, the taxonomic identity of all ten isolates was confirmed as A. alternata using species-specific primers (AAF2/AAR3, Konstantinova et al. 2002) in a PCR assay. Later, one of the isolate UASB1 was selected, and its internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (gapdh), major allergen Alt a 1 (Alt a 1), major endo-polygalacturonase (endoPG), OPA10-2, and KOG1058 genes were amplified in PCR (White et al. 1990; Berbee et al. 1999; Woudenberg et al. 2015), and the resultant products were sequenced and deposited in the NCBI GenBank (ITS, MN919390; gapdh, MT637185; Alt a 1, MT882339; endoPG, MT882340; OPA10-2, MT882341; KOG1058, MT882342). Blastn analysis of ITS, gapdh, Alt a 1, endoPG, OPA10-2, KOG1058 gene sequences showed 99.62% (with AF347031), 97.36% (with AY278808), 99.58% (with AY563301), 99.10% (with JQ811978), 99.05% (with KP124632) and 99.23% (with KP125233) respectively, identity with reference strain CBS916.96 of A. alternata, confirming UASB1 isolate to be A. alternata. For pathogenicity assay, conidial suspension of UASB1 isolate was spray inoculated to ten healthy LM (cv. VS-13) plants (45 days old) maintained under protected conditions. The spore suspension was sprayed until runoff on healthy leaves, and ten healthy plants sprayed with sterile water served as controls. Later, all inoculated and control plants were covered with transparent polyethylene bags and were maintained in a greenhouse at 28±2 ◦C and 90% RH. The pathogenicity test was repeated three times. After 8 days post-inoculation, inoculated plants showed leaf blight symptoms as observed in the field, whereas no disease symptoms were observed on non-inoculated plants. Re-isolations were performed from inoculated plants, and the re-isolated pathogen was confirmed as A. alternata based on morphological and PCR assay (Konstantinova et al. 2002). No pathogens were isolated from control plants. There is an increasing acreage of LM crop in India, and this first report indicates the need for further studies on leaf blight management and the disease impacts on crop yields.

scholarly journals First Report of Passalora Leaf Spot Caused by Passalora bougainvilleae on Bougainvillea in Mexico

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 775-775 ◽  
Author(s):  
V. Ayala-Escobar ◽  
V. Santiago-Santiago ◽  
A. Madariaga-Navarrete ◽  
A. Castañeda-Vildozola ◽  
C. Nava-Diaz
Keyword(s):  
Uv Light ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
The United States ◽  
Pathogenicity Test ◽  
Commonwealth Mycological Institute ◽  
Conidial Suspension ◽  
Single Spore ◽  
First Report ◽  
Bougainvillea Spectabilis

Bougainvillea (Bougainvillea spectabilis Willd) growing in 28 gardens during 2009 showed 100% disease incidence and 3 to 7% disease severity. Bougainvilleas with white flowers were the most affected. Symptoms consisted of light brown spots with dark brown margins visible on adaxial and abaxial sides of the leaves. Spots were circular, 2 to 7 mm in diameter, often surrounded by a chlorotic halo, and delimited by major leaf veins. Single-spore cultures were incubated at 24°C under near UV light for 7 days to obtain conidia. Pathogenicity was confirmed by spraying a conidial suspension (1 × 104 spores/ml) on leaves of potted bougainvillea plants (white, red, yellow, and purple flowers), incubating the plants in a dew chamber for 48 h and maintaining them in a greenhouse (20 to 24°C). Identical symptoms to those observed at the residential gardens appeared on inoculated plants after 45 to 60 days. The fungus was reisolated from inoculated plants that showed typical symptoms. No symptoms developed on control plants treated with sterile distilled water. The fungus produced distinct stromata that were dark brown, spherical to irregular, and 20 to 24 μm in diameter. Conidiophores were simple, born from the stromata, loose to dense fascicles, brown, straight to curved, not branched, zero to two septate, 14 × 2 μm, with two to four conspicuous and darkened scars. The conidia formed singly, were brown, broad, ellipsoid, obclavate, straight to curved with three to four septa, 40 × 4 μm, and finely verrucous with thick hilum at the end. Fungal DNA from the single-spore cultures was obtained using a commercial DNA Extraction Kit (Qiagen, Valencia, CA); ribosomal DNA was amplified with ITS5 and ITS4 primers and sequenced. The sequence was deposited at the National Center for Biotechnology Information Database (GenBank Accession Nos. HQ231216 and HQ231217). The symptoms (4), morphological characteristics (1,2,4), and pathogenicity test confirm the identity of the fungus as Passalora bougainvilleae (Muntañola) Castañeda & Braun (= Cercosporidium bougainvilleae Muntañola). This pathogen has been reported from Argentina, Brazil, Brunei, China, Cuba, El Salvador, India, Indonesia, Jamaica, Japan, Thailand, the United States, and Venezuela (3). To our knowledge, this is the first report of this disease on B. spectabilis Willd in Mexico. P. bougainvilleae may become an important disease of bougainvillea plants in tropical and subtropical areas of Mexico. References: (1) U. Braun and R. R. Castañeda. Cryptogam. Bot. 2/3:289, 1991. (2) M. B. Ellis. More Dematiaceous Hypomycetes. Commonwealth Mycological Institute, Kew, Surrey, UK, 1976. (3) C. Nakashima et al. Fungal Divers. 26:257, 2007. (4) K. L. Nechet and B. A. Halfeld-Vieira. Acta Amazonica 38:585, 2008.

scholarly journals Spread of the invasive pathogen Lecanosticta acicola on species of Pinus in Bulgaria

2020 ◽  
Vol 21 (1) ◽  
pp. 83-90
Author(s):  
Margarita Georgieva
Keyword(s):  
Fungal Pathogen ◽  
Brown Spot ◽  
Emerging Pathogen ◽  
Invasive Pathogen ◽  
New Hosts ◽  
Lecanosticta Acicola ◽  
Eastern Rhodopes ◽  
First Time ◽  
Needle Blight ◽  
Brown Spot Needle Blight

The brown spot needle blight, caused by the fungal pathogen Lecanosticta acicola, has been the most serious and damaging disease on needles of Pinus spp. in recent years. In Bulgaria, the pathogen was reported for the first time in 2017 in a generative plantation of Pinus sylvestris in the region of the State Forestry Ardino, the Eastern Rhodopes. The newly- established invasive pathogen is considered highly adaptable to new hosts and environmental conditions. The life cycle and symptoms of the disease strongly suggest that the new emerging pathogen has the potential to cause severe damages and is a serious threat to naturally distributed species of Pinus in the country. In the period 2018-2019, a spread of L. acicola from the initial outbreak was established throughout stands of P. sylvestris and P. nigra on the territory of Kardzhali District.

scholarly journals Records of Brown spot needle blight related to Lecanosticta acicola in the Czech Republic

2009 ◽  
Vol 45 (No. 1) ◽  
pp. 16-18 ◽  
Author(s):  
L. Jankovský ◽  
D. Palovčíková ◽  
M. Dvořák ◽  
M. Tomšovský
Keyword(s):  
Nature Conservation ◽  
Czech Republic ◽  
Pinus Sylvestris ◽  
Nature Reserve ◽  
Brown Spot ◽  
The Czech Republic ◽  
Lecanosticta Acicola ◽  
Needle Blight ◽  
South Bohemia ◽  
Brown Spot Needle Blight

There are two records of brown spot needle blight caused by <I>L. acicola</I> in the Czech Republic up to date. Disease was first reported on June 2007 in National Nature Reserve (NNR) Červená Blata, South Bohemia. A more recent discovery of <I>L. acicola</I> took place on August 2008 in the NNR Borkovická Blata. The disease was observed on 10-60 year old <I>Pinus rotundata</I>. Both locations with infected trees are situated inside nature conservation sites under strict protection regimes that are located approximately 50 km apart. In both sites, <I>L. acicola</I> occurred simultaneously with <I>Dothistroma septospora</I>, the red band needle blight causal agent on Scots pine (<I>Pinus sylvestris</I>), bog pine (<I>P. rotundata</I>) and their hybrid (<I>P. × digenea</I>). However, infections of both diseases on the same tree have not yet been observed.

scholarly journals First Report of Colletotrichum aenigma Causing Anthracnose of Grape in Korea

Plant Disease ◽  
2021 ◽  
Author(s):  
Ju Sung Kim ◽  
Oliul Hassan ◽  
Taehyun Chang
Keyword(s):  
South Korea ◽  
Disease Incidence ◽  
Juglans Regia ◽  
Morphological Characteristics ◽  
Causal Agent ◽  
Effective Control ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
First Report ◽  
Colletotrichum Species

Grape (cv. Kyoho) is one of the most popular dessert fruits in South Korea. Anthracnose caused by Colletotrichum species is a common and very destructive disease of grape in the country. In 2019, severe outbreaks of anthracnose was observed in different grape orchards in Gimcheon (36º09´N, 128º00´ E), South Korea. The disease incidence on fruit was up to 50% in the orchards with most severe outbreaks and infected fruit displayed typical anthracnose symptoms including sunken necrotic lesions with orange-like conidial mass. For isolation of putative causal agents, nine diseased fruits were collected from three commercial orchards. A total of nineisolates were made from nine of the infected fruit by spreading spore masses (1x106 conidia mL-1) from each fruit on water agar and collecting single germinated spores after incubation at 25 ºC overnigh. The single germinated spores were transferred on to fresh potato dextrose agar (PDA) (Difco, Becton Dickinson) and incubated at 25ºC in the dark. Seven day old colonies were cottony white on the upper side and gray at the center on the reverse side. Conidia were cylindrical with round ends and measured 13.9 – 20.1 × 5.4 – 8.1 μm (mean = 16.5 × 6.6 μm, n = 30). Appressoria were brownish, sub-cylindrical with a few lobes and 10.3 –16.7 × 6.6 – 10.9 μm (mean = 13.1 × 8.1 μm, n = 30). The morphological characteristics of the solates resembled those of Colletotrichum species within the C. gloeosporioides complex (Weir et al. 2012). DNA was amplified using the following primer pairs: ITS1/ITS4, GDF / GDR, ACT-512F / ACT-783R, Bt2a/ Bt2b, and CHS79-F/CHS-354R (Weir et al. 2012). Accession numbers, LC586811 to LC586825 were obtained after depositing all the resulting sequences in GenBank. A 50% majority rules phylogenetic tree (Bayesian phylogenic analysis) was constructed based on concatenated sequences of ITS, GAPDH, ACT, TUB, and CHS using MrBayes 3.2.10. The present isolates formed a single clade with the reference isolates of C. aenigma (isolate ICMP 18608 and ICMP 18686). For a pathogenicity test, healthy grapefruits were collected from an orchards, surface sterilized by dipping in 1% sodium hypochlorite, rinsed with sterilized water and dried by blotting. A conidial suspension (1×106 conidia mL-1) in sterilized water were prepared from one week old colonies of isolates GRAP10 and GRAP12. A small wound was made on sterilized detached fruit by punching with a sterile pin. A drop of the conidial suspension was placed on the wound, while the control fruit received a drop of sterile water. Similarly, unwounded fruit were also inoculated with a single droplet of conidial suspension. For each isolate and method (wounded and unwounded), ten fruit were inoculated, and ten non-inoculated fruit were used as control. All the treated fruit were kept in a plastic box containing moist tissue and incubated at 25º C in the dark. Typical anthracnose lesions appeared on all inoculated wounded fruit while non-inoculated and inoculated unwounded fruits remained asymptotic. Koch postulates were fulfilled by re-isolating and re-identifying the causal agent from inoculated fruit. Colletotrichum aenigma has been reported as the causal agent of anthracnose on Juglans regia, Camellia sinensis and Actinidia arguta in China (Weir et al. 2012; Wang et al. 2016; Wang et al. 2018). Previous studies reported four Colletotrichum species (C. acutatum, C. gloeosporioides, C. fructicola, and C. viniferum) to cause this disease on grapes in South Korea (Oo and Oh 2017; Lim et al. 2020). To the best of our knowledge, this is the first report on grape anthracnose caused by C. aenigma in South Korea. This finding may help to take effective control measures of this disease.

scholarly journals First Report of Anthracnose Caused by Colletotrichum lupini on Yellow Lupin in Korea

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1158-1158 ◽  
Author(s):  
K. S. Han ◽  
B. S. Kim ◽  
I. Y. Choi ◽  
J. H. Park ◽  
H. D. Shin
Keyword(s):  
Disease Incidence ◽  
Its Region ◽  
The United States ◽  
Lupinus Luteus ◽  
Width Ratio ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Yellow Lupin ◽  
First Report ◽  
Colletotrichum Lupini

Yellow lupin (Lupinus luteus L.) is native to the Mediterranean region of southern Europe. In Korea, yellow lupins are cultivated for ornamental purposes. In May 2013, hundreds of yellow lupins that were grown in pots for 7 weeks in polyethylene-film-covered greenhouses were observed severely damaged by a previously unknown disease with about 30% disease incidence in a flower farm in Yongin City, Korea. Voucher specimens were deposited in the Korea University Herbarium (KUS). Early symptoms on petioles and stems appeared as small, slightly sunken, water-soaked, and circular spots. Lesions increased in size (4 to 12 μm in diameter), became more depressed, with a darkened central portion. As the disease progressed, affected areas sometimes girdled the stem and killed the shoot. Leaves were partly blighted, but less damaged. The darkened areas contained blackish acervuli from which masses of pale salmon-colored conidia were released in moist weather. Acervuli were circular to ellipsoid, 80 to 400 μm in diameter. Acervular setae were not observed. Conidia (n = 30) were long obclavate to oblong-elliptical, aguttulate, hyaline, and 10 to 18 × 3.6 to 5.2 μm with a length/width ratio of 2.6 to 3.6. Appressoria were single or occasionally in small dense clusters, medium brown, elliptical to round in outline with a smooth to lobate margin, and 8 to 14 × 6 to 9 μm. These characters were consistent with the description of Colletotrichum lupini (Bondar) Damm, P.F. Cannon & Crous (1,3). An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47254). 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 545-bp sequence was deposited in GenBank (Accession No. KJ447119). The sequence showed 100% identity with sequences of C. lupini (e.g., GenBank AJ301968, JN943480, JQ948162, and KF207599). To confirm pathogenicity, inoculum was prepared by harvesting conidia with sterile distilled water from 3-week-old cultures on potato dextrose agar. A conidial suspension (2 × 105 conidia/ml) was sprayed until runoff onto the aerial parts of five healthy plants. Control plants were sprayed with sterile water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 48 h and then transferred to a greenhouse. 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. lupini was re-isolated from symptomatic leaf tissues. No symptoms were observed on control plants. The pathogenicity test was repeated twice. Anthracnose associated with C. lupini on lupins has been known from Europe (Germany, Ukraine, Austria, and Netherlands), North America (Canada and the United States), South America (Bolivia and Brazil), and Oceania (Australia and New Zealand) (2,4). To our knowledge, this is the first report of C. lupini on yellow lupins in Asia as well as in Korea. The presence of C. lupini on lupins in Asia can be considered as a potentially new and serious threat to this ornamental plant. References: (1) U. Damm et al. Stud. Mycol. 73:37, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 17, 2014. (3) H. I. Nirenberg et al. Mycologia 94:307, 2002. (4) E. Rosskopf et al. Plant Dis. 98:161, 2014.

scholarly journals First Report of Rice Brown Spot Caused by Exserohilum rostratum in Mali

Plant Disease ◽  
2021 ◽  
Author(s):  
Kouka Hilaire Kaboré ◽  
Diariatou Diagne ◽  
Joelle Milazzo ◽  
Henri Adreit ◽  
Marc-Henri Lebrun ◽  
...  
Keyword(s):  
Sequence Similarity ◽  
Peat Soil ◽  
Morphological Characteristics ◽  
Brown Spot ◽  
Pathogenicity Test ◽  
Rice Seed ◽  
Conidial Suspension ◽  
First Report ◽  
Wide Range ◽  
Exserohilum Rostratum

Rice brown spot is an emerging disease of concern in many rice-growing countries. Different fungal species of the genera Bipolaris and Exserohilum were reported as the causal agents of this disease. These fungal pathogens cause similar necrotic lesions on leaves and infect grains with a significant effect on seed germination. In 2018, samples of rice seed and leaves with typical brown spot symptoms were collected from irrigated (Manikoura and Niono) and lowlands (M’pegnesso and Loulouni) rice fields in Mali and incubated for 5 to 7 days on wet filter paper at 25°C with 12 h photoperiod. Conidia observed under microscope were straight or slightly curved and light-brown or dark. They were also rostrate or obclavate and measured 31.4 to 275.6 x 7.3 to 18 µm (n=40). These morphological characteristics are identical to those of Exserohilum rostratum (Hernández-Restrepo et al. 2018). DNA from eight single-spored isolates was extracted by a CTAB-based protocol (Doyle and Doyle, 1987). Internal transcribed spacer (ITS) rDNA region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and translation elongation factor 1 alpha (TEF1-α) genes were amplified by PCR with the primers ITS5/ITS4 (White et al. 1990), GPD1/GPD2 (Berbee et al. 1999) and EF1 983/EF1 2218 (Rehner et al. 2005), respectively. The amplicons were sequenced and deposited in NCBI GenBank. Sequence similarity between Malian strain was 100% for ITS and GAPDH, and 99.8-100% for TEF1. Sequence similarity between Malian strains and reference E. rostratum sequences BRIP 11417 (GenBank acc. no. LT837836, LT882553 and LT896656) and CBS 128061 (GenBank acc. no. KT265240, LT715900 and LT896658) were 99.6-100%. The maximum-likelihood phylogenetic tree generated with ITS, GAPDH and TEF1-α concatenated sequences, using MEGA-X 10.1.7 grouped all eight strains from Mali in the E. rostratum clade with a bootstrap value of 100%. For pathogenicity test, four strains from leaves and seed were grown on rabbit food agar (50 g/liter steeped filtrate of rabbit food pellets, Kaytee Products, Inc. Chilton, WI, USA, and 15 g agar) for 14 days at 25°C with a 12 h photoperiod (Hau and Rush 1980). Spores were collected and the concentration of spore suspension adjusted to 1.5 x 105 conidia/ml with 0.5% gelatin. The rice varieties ADNY 11, ARICA 9 and Shwetasoké were grown in pots with peat soil and NPK 13-5-18 at 3.5 g/liter of soil for 21 days. Four pots of each variety (5 seedlings/pot) were placed in a tray (60 plants per tray) and the leaves were sprayed with 30 ml of the conidial suspension or water at 0.5% gelatin (negative control). Plants were kept at maximum humidity (100%) at 21°C for one night and then transferred to a phytotron at 27°C. Seven days after inoculation, circular or oval foliar lesions of less than 5 mm long, either brown or dark, sometimes whitish in their centers were observed . These lesions were identical to those observed in the field. E. rostratum was reisolated from these lesions. E. rostratum affects a wide range of plant species, particularly grasses and has been observed on rice in many countries (Cardona and Gonzàlez 2007; Majeed et al. 2016; Silva et al. 2016; Toher et al. 2016). However, to our knowledge, this is the first report of E. rostratum causing brown spot in rice in Mali.

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