First Report of Anthracnose Caused by Colletotrichum acutatum On Olive Fruits in Pakistan

Anthracnose symptoms on olive (Olea europaea) fruits cv. “Gamlick” were found in farmer orchards in Chakwal, Punjab, Pakistan (32° N and 72° E), with an average prevalence of 59%. Fruit symptoms start as thin, black, sunken lesions with a watery appearance that grow in diameter and coalesce into a large sunken soft zone. Lesions on mature fruit become noticeable in 5 to 6 days after infection, if temperatures are favorable (28°C). On the fruit lesion, orange conidial masses in dispersed or concentric circle arrangement can appear. Fragments (5 mm) were taken from the margins of fruit lesions and surface-sterilized with 70% ethanol (1 min) and 1% NaClO (2 min), cleaned with sterile purified water, blotted dry, and plated on potato dextrose agar (PDA) in Petri dishes. The petri plates were incubated at 27°C. A fungus was consistently isolated, and thirty-five isolates were characterized. Aerial mycelia from olive isolates Colonies were compact, initially white or cream white, then grey, and eventually dark grey, with conidium masses forming in the middle. Mycelium is branched, septate, and hyaline. Conidia are hyaline, aseptate, fusiform, or often cylindrical, with obtuse apices and tapering bases. Their mean size was 8.5µm in length and 3.0 µm in width. Based on morphological features, the fungus was tentatively identified as Colletotrichum acutatum (Agosteo G.E., 2010). The identification was confirmed by amplification and sequencing of a representative isolate's internal transcribed region (ITS), Beta- tubulin region (TUB2), Actin region (ACT), and Glyceraldehyde 3-phosphate dehydrogenase region (GAPDH) with the primers ITS1/ITS4 (Gardes & Bruns 1993), TUB4/TUB5 (Woudenberg et al. 2009), ACT1/ACT3 (Carbone & Kohn 1999) and GDF1/GDR1 (Guerber et al. 2003). BLAST analysis revealed 100% identity for ITS, GAPDH and ACT and 99% identity for TUB, between the sequences of the olive fruit isolate (GenBank Accessions MW647502, MZ436968, MZ714412 and MW810331, respectively) and sequences of C. acutatum reference isolates (GenBank Accessions GO613492, KF975660.1, MT274752.1 and MH547616 respectively). Phylogenetic analysis based on ITS, GAPDH and TUB regions of the olive fruit isolates and reference isolates of various Colletotrichum species using the MEGA X software program confirmed the isolate from olive was C. acutatum. The fungal isolate was deposited as a living culture in the Barani Agricultural Research Institute's fungal culture collection center (BACA.9381). Pathogenicity tests were conducted with this isolate by placing a 20 µl drop of a conidial suspension (3 × 107conidia ml−1) on five healthy olive cv. Gemlik fruits. As a control, five non-inoculated olive fruits were used. Fruits were placed at a temperature of 27°C with artificial light and a photoperiod of 12 hours. Anthracnose symptoms developed only on inoculated fruits after seven days of inoculation. The fungus was re-isolated from symptomatic fruits, and its identity was confirmed through morphological characteristics, thus verifying Koch's postulates. To the best of our knowledge, this is the first report of C. acutatum infecting olive fruits in Chakwal region of Pakistan.

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

Plant Disease ◽

10.1094/pdis-08-11-0658 ◽

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.

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First Report of Colletotrichum acutatum in Blueberry Plants in Spain

Plant Disease ◽

10.1094/pdis.2001.85.12.1285a ◽

2001 ◽

Vol 85 (12) ◽

pp. 1285-1285 ◽

Cited By ~ 3

Author(s):

C. Barrau ◽

B. de los Santos ◽

F. Romero

Keyword(s):

Pink Salmon ◽

Morphological Characteristics ◽

Vaccinium Corymbosum ◽

Fungal Species ◽

Colletotrichum Acutatum ◽

Enzyme Linked Immunosorbent Assay ◽

Conidial Suspension ◽

First Report ◽

Small Areas ◽

Leaf Tissues

An anthracnose disease was observed affecting leaves of high-bush blueberry plants (Vaccinium corymbosum L. ‘Sharpblue’) in small areas within two production fields in Huelva Province of Andalucía, in southwestern Spain. The first symptoms observed in late spring were circular, necrotic lesions, red to salmon in color, and ranging from 3 to 20 mm in diameter. Later, lesions became salmon colored in the center with a brilliant red halo. Fungal isolations were made from the lesions. Infected tissues were surface-disinfected in 1% sodium hypochlorite for 1 min, blotted dry on sterile filter paper, and plated on 2% water agar. The plates were incubated at 25°C for 5 to 10 days. Fungal colonies isolated from the tissues were transferred to potato dextrose yeast agar (PDYA). Only one fungal species was consistently isolated from affected leaf tissues and was identified as Colletotrichum acutatum J.H. Simmonds based on morphological characteristics (2) and enzyme-linked immunosorbent assay (1). Colonies of the fungus on PDYA showed a white-to-gray dense mycelium covered with salmon-colored spore masses. The reverse of the plates was a pink-salmon color. Colony diameter on PDYA averaged 50 mm after 7 days at 25°C. Conidia were hyaline, aseptate, fusiform to cylindrical, and 12.5 × 3.2 μm. Inoculation of leaves and fruits of blueberry cv. Misty with a conidial suspension (106 conidia per ml) of C. acutatum produced lesions on the leaves and fruits similar to those observed on diseased plants in the field. The pathogen was isolated from lesions on inoculated plants. To our knowledge, this is the first report of C. acutatum in high-bush blueberry plants in Spain. References: (1) T. A. Cooke et al. EPPO Bull. 25:57, 1995. (2) B. C. Sutton. The Coelomycetes. CMI, Kew, England, 1980.

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First Report of Anthracnose of Tricyrtis macropoda Caused by Colletotrichum gloeosporioides in Korea

Plant Disease ◽

10.1094/pdis-03-12-0277-pdn ◽

2012 ◽

Vol 96 (7) ◽

pp. 1070-1070 ◽

Cited By ~ 1

Author(s):

J. H. Park ◽

K. S. Han ◽

Y. D. Kwon ◽

H. D. Shin

Keyword(s):

Colletotrichum Gloeosporioides ◽

Morphological Characteristics ◽

Its Region ◽

Culture Collection ◽

Perennial Herb ◽

Pathogenicity Test ◽

Conidial Suspension ◽

Natural Habitats ◽

First Report ◽

Small Water

Tricyrtis macropoda Miq. (syn. T. dilatata Nakai), known as speckled toadlily, is a perennial herb native to China, Japan, and Korea. The plant has been highly praised for its beautiful flowers and rare populations in natural habitats. In September 2006, several dozen plants were heavily damaged by leaf spots and blight in cultivated plantings in the city of Pocheon, Korea. The infections with the same symptoms were repeated every year. In July 2011, the same symptoms were found on T. macropoda in the cities of Gapyeong and Osan, Korea. The leaf lesions began as small, water-soaked, pale greenish to grayish spots, which enlarged to form concentric rings and ultimately coalesced. A number of blackish acervuli were formed in the lesions. Acervuli were mostly epiphyllous, circular to ellipsoid, and 40 to 200 μm in diameter. Setae were two- to three-septate, dark brown at the base, paler upwards, acicular, and up to 100 μm long. Conidia (n = 30) were long obclavate to oblong-elliptical, sometimes fusiform-elliptical, guttulate, hyaline, and 12 to 20 × 4 to 6.5 μm (mean 15.4 × 5.2 μm). These morphological characteristics of the fungus were consistent with the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. (2). Voucher specimens (n = 7) were deposited in the Korea University herbarium (KUS). Two isolates, KACC46374 (ex KUS-F25916) and KACC46405 (ex KUS-F26063), were deposited in the Korean Agricultural Culture Collection. Fungal DNA was extracted and the complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequences of 549 bp were deposited in Genbank (Accession Nos. JQ619480 and JQ619481). They showed 100% similarity with a sequence of C. gloeosporioides (EU32619). Isolate KACC46374 was used in a pathogenicity test. Inoculum was prepared by harvesting conidia from 3-week-old cultures on potato dextrose agar. A conidial suspension (2 × 106 conidia/ml) was sprayed onto 15 leaves of three plants. Three noninoculated plants served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 24 h and then kept in a greenhouse (22 to 28°C and 70 to 80% RH). After 5 days, typical leaf spot symptoms, identical to the ones observed in the field, started to develop on the leaves of inoculated plants. No symptoms were observed on control plants. C. gloeosporioides was reisolated from the lesions of inoculated plants, thus fulfilling Koch's postulates. An anthracnose associated with C. tricyrtii (Teng) Teng was recorded on T. formosana and T. latifolia in China (3) and on T. formosana in Taiwan (1), respectively, without etiological studies. The morphological features of C. tricyrtii are within the variation of C. gloeosporioides (2). To our knowledge, this is the first report of anthracnose of T. macropoda. This report has significance to indigenous plant resource conservation managers and scientists because T. macropoda has been listed as one of the 126 “Rare and Endangered Plants” by the Korea Forest Service since 1991. References: (1) K. Sawada. Rep. Dept. Agric. Gov. Res. Inst. Formosa 87: 1, 1944. (2) B. C. Sutton. Pages 1–27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, U.K. 1992. (3) S. C. Teng. Contrib. Biol. Lab. Sci. Soc. China 8:36, 1932.

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First Report of Volutella Blight on Pachysandra Caused by Volutella pachysandricola in China

Plant Disease ◽

10.1094/pdis-11-11-0997 ◽

2012 ◽

Vol 96 (4) ◽

pp. 584-584

Author(s):

Q. Bai ◽

Y. Xie ◽

R. Dong ◽

J. Gao ◽

Y. Li

Keyword(s):

Morphological Characteristics ◽

Stem Canker ◽

Botanical Garden ◽

The United States ◽

Culture Collection ◽

Leaf Blight ◽

Conidial Suspension ◽

First Report ◽

Leaf Spots ◽

Plastic Bags

Pachysandra (Pachysandra terminalis, Buxaceae) and Japanese Pachysandra, also called Japanese Spurge, is a woody ornamental groundcover plant distributed mostly in Zhejiang, Guizhou, Henan, Hubei, Sichuan, Shanxi, and Gansu provinces in China. In April 2010, P. terminalis asymptomatic plants were shipped from Beijing Botanical Garden Institute of Botany Chinese Academy of Science to the garden nursery of Jilin Agricultural University (43°48′N, 125°23′E), Jilin Province. In June 2011, Volutella blight (sometimes called leaf blight and stem canker) of P. terminalis was observed on these plants. Infected leaves showed circular or irregular, tan-to-brown spots often with concentric rings and dark margins. The spots eventually grew and coalesced until the entire leaf died. Cankers appeared as greenish brown and water-soaked diseased areas, subsequently turning brown or black, and shriveled and often girdled the stems and stolons. During wet, humid weather in autumn, reddish orange, cushion-like fruiting structures of the fungus appeared on the stem cankers and undersides of leaf spots. Symptoms of the disease were consistent with previous descriptions (2–4). Five isolates were obtained from necrotic tissue of leaf spots and cankers of stems and stolons and cultured on potato dextrose agar. The colony surface was salmon colored and slimy. Conidia were hyaline, one celled, spindle shaped, and 12.57 to 22.23 × 3.33 to 4.15 μm with rounded ends. Morphological characteristics of the fungus were consistent with the description by Dodge (2), and the fungus was identified as Volutella pachysandricola (telemorph Pseudonectria pachysandricola). The internal transcribed spacer (ITS) regions of the nuclear rDNA were amplified using primers ITS4/ITS5 (1). The ITS sequences were 553 bp long and identical among these five isolates (GenBank Accession No. HE612114). They were 100% identical to Pseudonectria pachysandricola voucher KUS-F25663 (Accession No. JN797821) and 99% identical to P. pachysandricola culture-collection DAOM (Accession No. HQ897807). Pathogenicity was confirmed by spraying leaves of clonally propagated cuttings of P. terminalis with a conidial suspension (1 × 106 conidia/ml) of the isolated V. pachysandricola. Control leaves were sprayed with sterile water. Plants were covered with plastic bags and kept in a greenhouse at 20 to 25°C for 72 h. After 5 to 8 days, typical disease symptoms appeared on leaves, while the control plants remained healthy. V. pachysandricola was reisolated from the leaf spots of inoculated plants. Pachysandra leaf blight and stem canker also called Volutella blight, is the most destructive disease of P. terminalis and previously reported in the northern humid areas of the United States (Illinois, Connecticut, Ohio, Indiana, Iowa, Massachusetts, Missouri, Kentucky, and Wisconsin), northern Europe (Britain, Germany, and Poland), and the Czech Republic. To our knowledge, this is the first report of the disease caused by V. pachysandricola in China. The disease may become a more significant problem in P. terminalis cultivation areas if the disease spreads on P. terminalis in nursery beds. References: (1) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (2) B. O. Dodge. Mycologia 36:532, 1944. (3) S. M. Douglas. Online publication. Volutella Blight of Pachysandra. The Connecticut Agricultural Experiment Station, 2008. (4) I. Safrankova. Plant Protect. Sci.43:10, 2007.

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First Report of Leaf Blight on Rubus brasiliensis Caused by Colletotrichum acutatum in Brazil

Plant Disease ◽

10.1094/pdis-06-10-0441 ◽

2010 ◽

Vol 94 (11) ◽

pp. 1378-1378 ◽

Cited By ~ 1

Author(s):

U. P. Lopes ◽

L. Zambolim ◽

H. S. S. Duarte ◽

P. G. C. Cabral ◽

O. L. Pereira ◽

...

Keyword(s):

Native Species ◽

Morphological Characteristics ◽

Minas Gerais ◽

Leaf Blight ◽

Colletotrichum Acutatum ◽

Conidial Suspension ◽

Specific Primer ◽

First Report ◽

Young Leaves ◽

Necrotic Spots

There are more than 300 blackberry (Rubus) species worldwide. Rubus brasiliensis Mart. is a native Brazilian species found in tropical forests. In January 2009, samples of R. brasiliensis with severe leaf blight were collected from an area of rain forest in the city of São Miguel do Anta, State of Minas Gerais, Brazil. Dark spots began developing in the young leaves and progressed to necrotic spots with occasional twig dieback. From the spots, a fungus was isolated with the following morphology: acervuli that were 20 to 50.0 × 50 to 125.0 μm and hyaline amerospores that were ellipsoid and fusiform and 7.5 to 23.75 × 2.5 to 5.0 μm. On the basis of these morphological characteristics, the fungus was identified as Colletotrichum acutatum. In Brazil, C. acutatum is reported in apple, citrus, strawberry, peach, plum, nectarine, olive, medlar, and yerba-mate, but it was not reported as the causal agent of leaf blight in R. brasiliensis. A sample was deposited in the herbarium at the Universidade Federal de Viçosa, Minas Gerais, Brazil (VIC 31210). One representative isolate, OLP 571, was used for pathogenicity testing and molecular studies. Identity was confirmed by amplifying the internal transcribed spacer (ITS) regions of the ribosomal RNA with primers ITS4 (3), CaInt2 (a specific primer for C. acutatum [2]) and CgInt (a specific primer for C. gloeosporioides [1]). Isolates of C. acutatum (DAR78874 and DAR78876) and C. gloeosporioides (DAR78875) obtained from Australian olive trees were used as positive controls. The primers ITS4 and CaInt2 amplified a single DNA product of 500 bp expected for C. acutatum. OLP 571 was grown for 7 days on potato dextrose agar. Young leaves of R. brasiliensis were inoculated with a conidial suspension (106 conidia/ml) on young leaves. Inoculated plants were maintained in a moist chamber for 2 days and subsequently in a greenhouse at 25°C. Necrotic spots similar to those described were detected on young leaves 3 days after the inoculation. Control leaves, on which only water was sprayed, remained healthy. The same fungus was reisolated from the inoculated symptomatic tissues. To our knowledge, this is the first report of C. acutatum causing leaf blight in the native species of R. brasiliensis in Brazil. References: (1) P. R. Mills et al. FEMS Microbiol. Lett. 98:137, 1999. (2) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

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First Report of Oak Anthracnose Caused by Apiognomonia errabunda on Oriental White Oak in Korea

Plant Disease ◽

10.1094/pdis-02-13-0181-pdn ◽

2013 ◽

Vol 97 (8) ◽

pp. 1121-1121

Author(s):

C. K. Lee ◽

S. H. Lee ◽

J. H. Park ◽

S. E. Cho ◽

H. D. Shin

Keyword(s):

North America ◽

Morphological Characteristics ◽

Its Region ◽

Culture Collection ◽

Deciduous Tree ◽

Pathogenicity Test ◽

Conidial Suspension ◽

Natural Forests ◽

White Oak ◽

First Report

Oriental white oak, Quercus aliena Blume, is native to East Asia including Korea. It is one of the major deciduous tree species in natural forests in Korea. In May 2012, several hundred trees were found to be heavily damaged by a previously unknown leaf disease in a forest near Songjiho Lake in Goseong County of central Korea. Leaf symptoms began as small, water-soaked, pale greenish to grayish lesions, which enlarged to follow the veins or midribs and to be bounded by them, often killing part of the leaf. Leaf distortion and blight resulted in the later stage of disease development. A number of grayish brown to nearly black acervuli were formed on the lesions, especially on the midribs and veins. Acervuli were mostly hypophyllous, intraepidermal, erumpent, circular to ellipsoid in outline, cushion-like, and 70 to 220 μm in diameter. Conidia (n = 30) were elliptical to fusiform-elliptical, occasionally obclavate, aguttulate or guttulate, hyaline, aseptate, and 7.5 to 20 × 5 to 7.5 μm (mean 14.6 × 6.1 μm). These morphological characteristics of the fungus were consistent with the description of conidial state of Apiognomonia errabunda (Roberge ex Desm.) Höhn. (3,4). Voucher specimens were deposited in the Korea University Herbarium (KUS). An isolate obtained from KUS-F26690 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46842). 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 549-bp sequence was deposited in GenBank (KC426947). This showed >99% similarity with sequences of A. errabunda (AJ888475 to 888477). For pathogenicity test, inoculum was prepared by harvesting conidia from 4-week-old cultures on potato dextrose agar. A conidial suspension (1 × 106 conidia/ml) was sprayed onto young leaves of three potted seedlings. Three seedlings treated with sterile distilled water served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 24 h and then kept in a greenhouse (20 to 26°C and 60 to 80% RH). After 26 days, typical leaf spot symptoms, identical to the ones observed in the field, developed on the inoculated leaves. No symptoms were observed on controls. A. errabunda was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. Oak anthracnose associated with A. errabunda (including A. quercina) has been recorded in Europe and North America (1,4). Oak anthracnose of evergreen Quercus glauca Thunb. (syn. Cyclobalanopsis glauca (Thunb.) Oerst.) associated with A. supraseptata in Japan is not related to this disease (2). To our knowledge, this is the first report of oak anthracnose of Q. aliena globally and also the first finding of A. errabunda in Asia as well as in Korea. This pathogen is known as one of the major forest pathogens in oak stand in Europe and North America (3). Pending further studies, including a risk assessment, A. errabunda may be considered as a potentially new and serious threat in native and planted ranges of Q. aliena in Korea. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved February 18, 2013. (2) S. Kaneko and T. Kobayashi. Trans. Mycol. Soc. Japan 25:11, 1984. (3) A. Ragazzi et al. Phytopathol. Mediterr. 46:295, 2007. (4) M. V. Sogonov et al. Mycol. Res. 111:693, 2007.

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First Report of Curvularia lunata Causing Root Rot of Strawberry in India

Plant Disease ◽

10.1094/pdis-94-4-0477c ◽

2010 ◽

Vol 94 (4) ◽

pp. 477-477 ◽

Cited By ~ 4

Author(s):

V. S. Verma ◽

V. K. Gupta

Keyword(s):

Root Rot ◽

Root Zone ◽

Agricultural Research ◽

Indian Agricultural Research Institute ◽

Culture Collection ◽

Peat Moss ◽

Curvularia Lunata ◽

Conidial Suspension ◽

Jammu And Kashmir ◽

First Report

Diseased strawberry (Fragaria × ananassa Dutch) plants were observed during semimonthly surveys in the Jammu District of Jammu and Kashmir State, India from November 2007 to May 2008. Symptoms included leaf wilt, necrotic roots, and plant death. Small pieces of symptomatic roots were cut from the junction of diseased and healthy tissue, surface sterilized in 0.1% mercuric chloride solution for 1 min, washed in three changes of sterile distilled water, and transferred to potato dextrose agar plates. Cultures were maintained in an incubator at 25 ± 1°C. Dark brown fungal colonies developed in a few days. Mycelium was septate, dark brown-to-blackish brown, and branched. Conidiophores were dark brown, unbranched and septate. Conidia were boat shaped or curved, dark brown, and four-celled with the two central cells larger than the terminal cells. Apical cells were light brown, rounded at the tips, slightly constricted at the base, and 19 to 30 × 9 to 14 μm. The pathogen was identified by the Indian Type Culture Collection, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India (ITCC Accession No. 6680-07) as Curvularia lunata (Wakkar) Boevijn. To conduct pathogenicity tests, 10 healthy runners of strawberry cv. Chandler were planted separately in sterilized pot mix containing loam soil, sand, and peat moss (1:1:1 vol/vol) and allowed to root for a month. Soil near the root zone was then removed to access roots that were gently injured by pricking with a sterilized needle. The soil was replaced after 20 ml of a conidial suspension of 106 conidia/ml of one of the isolates was applied to the roots. Ten healthy strawberry plants grown in noninoculated soil served as controls. After inoculation, the plants were regularly watered. Symptoms similar to those observed in the field developed on all inoculated plants. Roots of the diseased plants turned brown and finally black. Noninoculated plants remained healthy. The pathogen was reisolated from roots of the diseased plants. Curvularia spp. are ubiquitous and are typically considered to be weak pathogens or saprophytes; however they have been reported as minor pathogens of several plants (1,2). Root rot of strawberry caused by Curvularia spp. has been reported (3), but to our knowledge, this is the first report of C. lunata (Wakkar) Boevijn causing root rot of strawberry in India. References: (1) F. C. Butler. Ann. App. Biol. 40:298, 1953. (2) C. F. Hodges and D. A. Campbell. J. Phytopathol. 143:639, 1995. (3) T. Watanabe et al. Phytopathology 67:1324, 1977.

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First report of Colletotrichum fructicola and Colletotrichum nymphaeae causing leaf spot on Rubus corchorifolius in Zhejiang province, China

Plant Disease ◽

10.1094/pdis-01-21-0198-pdn ◽

2021 ◽

Author(s):

Ju Wu ◽

Hanrong Wang ◽

Li Fang ◽

Yunye Xie ◽

Lianping Wang

Keyword(s):

Leaf Spot ◽

Type Strain ◽

Disease Incidence ◽

Morphological Characteristics ◽

Pathogenic Fungi ◽

Zhejiang Province ◽

Colletotrichum Acutatum ◽

Leaf Spot Disease ◽

Conidial Suspension ◽

First Report

Rubus corchorifolius is one of the most economically important fruit trees, (Tian et al. 2021). A severe leaf spot disease on leaves of R. corchorifolius was observed in Longquan county, Zhejiang province (118°42’E, 27°42’N) in 2019, with disease incidence of more than 20% on affected plants. The symptoms on leaves of the naturally affected plants were early necrotic lesion with white centers, surrounded by yellow halos (< 5 mm). Later, lesions were expanded with yellowish-brown centers, surrounded by yellow halos (< 5 mm). Putative pathogenic fungi were isolated as described by Fang (1998) and two pure single-colony fungal strains (FPZ1 and FPZ2) were selected for further analysis. The fungi was cultured on potato dextrose agar (PDA) medium for 6 days, at 25°C. The colonies had gray-green centers, white aerial mycelium and gelatinous orange conidial masses. The conidia were unicellular, smooth-walled, hyaline, cylindrical with obtuse to rounded ends, the size 10.15 to 14.09 µm (mean = 12.95 µm, n = 50) × 4.36 to 6.19 µm (mean = 5.19 µm, n = 50) were single, brown to dark brown, ovoid or irregular in shape, and 5.59 to 12.99 µm (mean = 8.77 µm, n = 50) × 4.68 to 10.36 µm (mean = 6.50 µm, n = 50). The characteristics of FPZ1 were consistent with the description of species in the Colletotrichum gloeosporioides complex (Weir et al. 2012). The conidia of FPZ2 were hyaline, smooth-walled, one-celled, fusiform, the size 9.34 to 14.09 µm (mean = 11.92 µm, n = 50) × 3.26 to 6.15 µm (mean = 4.89 µm, n = 50). Appressoria were single, darker brown, elliptical or irregular in outline, and 4.49 to 15.06 µm (mean = 9.88 µm, n = 50) × 3.23 to 7.42 µm (mean = 5.72 µm, n = 50) in size. The characteristics of FPZ2 were consistent with species of the Colletotrichum acutatum complex (Damn et al. 2012). For molecular identification of strains, the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-tubulin (TUB), chitin synthase (CHS-1), and actin (ACT) genes were sequenced (Weir et al. 2012). For the strain FPZ1, the five sequences obtain were deposited in GenBank (MT846907, MT849313, MT849317, MT849315 and MT849319, respectively). A BLAST search of FPZ1 sequences showed 99% identity with the five loci sequences of type strain C. fructicola ICMP 18581 (JX010165, JX010033, JX010405, JX009866 and FJ907426) (Jayawardena et al. 2016). Similarly, for the strain FPZ2, the five sequences (MT846885, MT849314, MT849318, MT849316 and MT849320, respectively) had 99% identity with the five loci sequences of type strain C. nymphaeae CBS 515.78 (JQ948197, JQ948527, JQ949848, JQ948858 and JQ949518, respectively) (Jayawardena et al. 2016). Based on morphological characteristics and phylogenetic analysis, FPZ1 was identified as C. fructicola and FPZ2 as C. nymphaeae, respestively. For pathogenicity tests, 10 μL conidial suspension (1 × 106 conidia per ml) of FPZ1 was used to inoculate five healthy, non-wounded detached leaves, while five leaves inoculated with sterilized water served as control. The experiment was repeated three times, and all leaves were kept on a mist bench at 27°C and relative humidity 80% for 6 days. The inoculation sites of both FPZ1 and FPZ2 became brown and necrotic, while control leaves developed no symptoms. C. fructicola and C. nymphaeae were re-isolated from the lesions of inoculated leaves, fulfilling Koch’s postulates. To our knowledge, this is the first report of C. fructicola and C. nymphaeae causing leaf spot on Rubus corchorifolius in China, and reports on the prevalence of C. gloeosporioides and C. acutatum species complexes will be beneficial to management of anthracnose in R. corchorifolius.

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First Report of Colletotrichum gloeosporioides Causing Anthracnose of Banana (Musa spp.) in Malaysia

Plant Disease ◽

10.1094/pdis-10-12-0985-pdn ◽

2013 ◽

Vol 97 (7) ◽

pp. 991-991 ◽

Cited By ~ 5

Author(s):

M. A. Intan Sakinah ◽

I. V. Suzianti ◽

Z. Latiffah

Keyword(s):

Morphological Characteristics ◽

Pathogenic Fungi ◽

Culture Collection ◽

Postharvest Disease ◽

Conidial Suspension ◽

First Report ◽

Musa Spp ◽

Initial Symptoms ◽

Dark Green ◽

Average Size

Banana is the second largest cultivated fruit crop in Malaysia, and is cultivated for both the domestic market and also for export. Anthranose is a well-known postharvest disease of banana and with high potential for damaging market value, as infection commonly occurs during storage. Anthracnose symptoms were observed on several varieties of banana such as mas, berangan, awak, nangka, and rastali in the states of Perak and Penang between August and October 2011. Approximately 80% of the fruits became infected with initial symptoms characterized as brown to black spots that later became sunken lesions with orange or salmon-colored conidial masses. Infected tissues (5 × 5 mm) were surface sterilized by dipping in 1% sodium hypochlorite (NaOCl) for 3 to 5 min, rinsed with sterile distilled water, and plated onto potato dextrose agar (PDA). Direct isolation was done by transferring the conidia from conidial masses using an inoculation loop and plating onto PDA. For both methods, the PDA plates were incubated at 27 ± 1°C with cycles of 12 h light and 12 h darkness. Visible growth of mycelium was observed after 4 to 5 days of incubation. Twenty isolates with conidial masses were recovered after 7 days of incubation. The isolates produced grayish white to grayish green and grey to moss dark green colony on PDA, pale orange conidial masses, and fusiform to cylindrical and hyaline conidia with an average size of 15 to 19 × 5 to 6 μm. Appresoria were ovate to obovate, dark brown, and 9 to 15 × 7 to 12 μm and setae were present, slightly swollen at the base, with a tapered apex, and brown. The cultural and morphological characteristics of the isolates were similar to those described for C. gleosporioides (1,2,3). All the C. gloeosporioides isolates were deposited in culture collection at Plant Pathology Lab, University Sains Malaysia. For confirmation of the identity of the isolates, ITS regions were sequenced using ITS4 and ITS5 primers. The isolates were deposited in GenBank with accessions JX163228, JX163231, JX163201, JX163230, JX163215, JX163223, JX163219, JX163202, JX163225, JX163222, JX163206, JX163218, JX163208, JX163209, JX163210, JX431560, JX163212, JX163213, JX431540, and JX431562. The resulting sequences showed 99% to 100% similarity with multiple C. gloeosporioides isolates in GenBank. Pathogenicity tests were conducted using mas, berangan, awak, nangka, and rastali bananas. Fruit surfaces were sterilized with 70% ethanol and wounded using a sterile scalpel. Two inoculation techniques were performed separately: mycelia plug and conidial suspension. Mycelial disc (5 mm) and a drop of 20 μl spore suspension (106 conidia/ml) were prepared from 7-day-old culture and placed on the fruit surface. The inoculated fruits were incubated at 27 ± 1°C for 10 days at 96.1% humidity. After 3 to 4 days of inoculation, brown to black spotted lesions were observed and coalesced to become black sunken lesions. Similar anthracnose symptoms were observed on all banana varieties tested. C. gloeosporioides was reisolated from the anthracnose lesions of all the inoculated fruit in which the cultural and morphological characteristics were the same as the original isolates. To our knowledge, this is the first report of C. gloeosporioides causing anthracnose of Musa spp. in Malaysia. References: (1) P. F. Cannon et al. Mycotaxon 104:189, 2008. (2) J. E. M. Mordue. Glomerella cingulata. CMI Description of Pathogenic Fungi and Bacteria, No. 315. CAB International,1971. (3) H. Prihastuti et al. Fungal Diversity 39:89, 2009.

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First Report of Leaf Spot Caused by Septoria erigerontis on Erigeron strigosus in Korea

Plant Disease ◽

10.1094/pdis-08-12-0755-pdn ◽

2012 ◽

Vol 96 (12) ◽

pp. 1827-1827

Author(s):

J. H. Park ◽

K. S. Han ◽

S. H. Hong ◽

H. D. Shin

Keyword(s):

North America ◽

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

The United States ◽

Culture Collection ◽

Leaf Spot Disease ◽

Conidial Suspension ◽

Voucher Specimen ◽

First Report

Erigeron strigosus Muhl. ex Willd., known as daisy fleabane, is native to North America and was accidently introduced to Korea in the 1990s (2). It is increasingly invasive in natural and managed ecosystems throughout Korea. In June 2011, a leaf spot was first observed on daisy fleabanes growing wild in Hongcheon County of Korea. A voucher specimen was deposited in the Korea University Herbarium (KUS-F25759). Symptoms developed on lower leaves as small, distinct, reddish brown lesions, which enlarged progressively and turned into pale, dull brown spots surrounded by dark purplish-brown margins. Black pycnidia became visible in the lesions. Pycnidia were epigenous, occasionally hypogenous, scattered, dark brown to rusty brown, globose, embedded in host tissue or partly erumpent, 60 to 160 μm in diameter, with ostioles measuring 10 to 30 μm in diameter. Conidia were straight to mildly curved or even flexuous, guttulate, hyaline, 30 to 75 × 1.5 to 2 μm, and one- to seven-septate. Based on the morphological characteristics, the fungus was consistent with Septoria erigerontis Peck (3,4). Conidia were harvested from cirrhi of pycnidia on leaf lesions with a drop of sterile water and then directly streaked onto water agar media using a bacterial loop. Isolates were incubated at 24°C for 48 h. Germinating conidia were individually transferred to potato dextrose agar (PDA) plates. An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46120). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1/ITS4 primers and sequenced. The resulting sequence of 505 bp was deposited in GenBank (Accession No. JX480493). A GenBank BLAST search was conducted with the 505-bp sequence showing 100% identity with the sequences of S. erigerontis ex Erigeron annuus (EF535638, GU269862). Pathogenicity was tested by spraying leaves of three potted plants with a conidial suspension (2 × 105 conidia/ml) harvested from a 4-week-old PDA culture. Control leaves were sprayed with sterile distilled water. The plants were placed in a dew chamber at 26°C in darkness and continuous dew for the first 24 h and then moved to a greenhouse bench. After 7 days, leaf spot symptoms identical to those observed in the field developed on the leaves inoculated with the fungus. No symptoms were observed on control plants. S. erigerontis was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. A leaf spot disease of E. strigosus associated with S. erigerontis has been reported in the United States and Canada (1). To our knowledge, this is the first report of leaf spot on E. strigosus caused by S. erigerontis outside of North America as well as in Korea. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA, Retrieved June 2, 2012. (2) S. H. Park. Colored Illustrations of Naturalized Plants of Korea. Ilchokak Publishers, Seoul, Korea, 1995. (3) M. J. Priest. Fungi of Australia: Septoria. ABRS/CSIRO Publishing, Melbourne, Australia, 1997. (4) E. Radulescu et al. Septoriozele din Romania. Ed. Acad. Rep. Soc. Romania, Bucuresti, Romania, 1973.

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