First Report of White Rust Caused by Albugo tragopogonis on Sunflower in Belgium

Sunflower (Helianthus annuus) is widely used for cut flowers and decoration in Belgium. A serious outbreak of what was suspected to be white rust on sunflower was observed in an East Flemish nursery near the city of Ghent in August 2004. This disease has previously been reported in Europe (southwest of France) (1) and other parts of the world with losses as much as 70 to 80% (Australia, North and South America, and Africa) (2,3). In the Flemish nursery, only single diseased plants (cv. Sunrich) were found. Blister-like pustules containing sporangia were observed on infected leaves. Initially the blisters were pale green to yellow on the abaxial surface and white on the adaxial surface of the leaves. As the disease progressed, white pustules that formed on the adaxial surface of the leaves slowly turned yellow, and the blisters on the abaxial surface became yellow to orange and necrotic in the center. Finally, the pustules coalesced and the leaves withered. Stem lesions were not observed. Short, cylindrical to spherical-cuboid sporangia, recovered from the pustules on the adaxial surface of leaves, measured between 17.5 and 22.5 μm, with an average of 20.2 μm. Sporangial dimensions were similar to those of Albugo tragopogonis (Pers.) S.F. Gray (1). Inoculations were done by spraying a suspension of 1 × 105 sporangia per ml prepared by scraping pustules from naturally infected leaves. Leaves on three 2-month-old healthy plants were sprayed with this inoculum and three plants sprayed with distilled water served as controls. The plants were kept for 48 h under a humid chamber and subsequently at room temperature (20 to 25°C) on the laboratory bench. Initial symptoms of white rust were observed 12 to 14 days after inoculation. On the basis of symptoms, morphological characteristics, and pathogenicity tests, the pathogen was identified as A. tragopogonis. To our knowledge, this is the first record of A. tragopogonis on H. annuus in Belgium. References: (1) K. G. Mukerji. Description of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, England, UK, 1976. (2) A. Pernaud and A. Perny, Phytoma 471:43, 1995. (3) P. S. van Wyk et al. Helia 22:83, 1999.

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First Report of Damping-Off Caused by Rhizoctonia solani AG-4 on Pink Ipê (Tabebuia impetiginosa) in Italy

Plant Disease ◽

10.1094/pdis-10-10-0748 ◽

2011 ◽

Vol 95 (1) ◽

pp. 78-78 ◽

Cited By ~ 2

Author(s):

G. Polizzi ◽

D. Aiello ◽

A. Vitale ◽

V. Guarnaccia ◽

A. Panebianco ◽

...

Keyword(s):

Rhizoctonia Solani ◽

Morphological Characteristics ◽

Fluorescent Light ◽

Damping Off ◽

First Report ◽

Initial Symptoms ◽

Public Areas ◽

Pathogenicity Tests ◽

Stem Lesions ◽

Safranin O

Pink ipê or pink lapacho (Tabebuia impetiginosa Martius ex DC., family Bignoniaceae) is one of the most attractive blooming trees in the world. In Europe, pink ipê is widely used as an ornamental tree in landscaped gardens and public areas. In August 2010, a widespread damping-off was observed in a stock of approximately 100,000 potted 2-month-old seedlings in a nursery in eastern Sicily (Italy). The seedlings were being watered with overhead irrigation. More than 5% of the seedlings showed disease symptoms. Initial symptoms were black lesions at the seedling crown that expanded rapidly to girdle the stem. On infected seedlings, leaves turned black and gradually died. Black extended stem lesions were followed by death of the entire seedling in a few days. A fungus with mycelial and morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from crown and stem lesions when plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 μg/ml. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Mycelium was branched at right angles with a septum near the branch and a slight constriction at the branch base. Hyphal cells removed from cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400. Anastomosis groups were determined by pairing isolates with tester strains AG-1 IA, AG-2-2-1, AG-2-2IIIB, AG-2-2IV, AG-3, AG-4, AG-5, AG-6, and AG-11 on 2% water agar in petri plates (4). Anastomosis was observed only with tester isolates of AG-4, giving both C2 and C3 reactions (2). Pathogenicity tests were performed on container-grown, healthy, 3-month-old seedlings. Forty seedlings of T. impetiginosa were inoculated near the base of the stem with two 1-cm2 PDA plugs from 5-day-old mycelial cultures. The same number of plants only inoculated with PDA plugs served as controls. Plants were incubated in a growth chamber and maintained at 25°C and 95% relative humidity on a 12-h fluorescent light/dark regimen. Crown and stem lesions identical to those observed in the nursery appeared 5 days after inoculation and all plants died within 25 days. No disease was observed on control plants. R. solani AG-4 was reisolated from symptomatic tissues and identified as previously described. R. solani AG-4 was previously detected in the same nursery on Chamaerops humilis (3). To our knowledge, this is the first report of R. solani causing damping-off on T. impetiginosa. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. Carling. Page 37 in: Grouping in Rhizoctonia solani by Hyphal Anastomosis Reactions. Kluwer Academic Publishers, the Netherlands, 1996. (3) G. Polizzi et al. Plant Dis. 94:125, 2010. (4) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

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

Plant Disease ◽

10.1094/pdis-11-13-1140-pdn ◽

2014 ◽

Vol 98 (6) ◽

pp. 854-854 ◽

Cited By ~ 1

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.

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First Report of Stem and Leaf Anthracnose on Blueberry Caused by Colletotrichum gloeosporioides in China

Plant Disease ◽

10.1094/pdis-11-12-1056-pdn ◽

2013 ◽

Vol 97 (6) ◽

pp. 845-845 ◽

Cited By ~ 1

Author(s):

C. N. Xu ◽

Z. S. Zhou ◽

Y. X. Wu ◽

F. M. Chi ◽

Z. R. Ji ◽

...

Keyword(s):

Colletotrichum Gloeosporioides ◽

Morphological Characteristics ◽

Its Region ◽

Pathogenic Fungi ◽

Molecular Characteristics ◽

First Report ◽

Potted Plants ◽

Leaf Spots ◽

Pathogenicity Tests ◽

Highbush Blueberries

Blueberry (Vaccinium spp.) is becoming increasingly popular in China as a nutritional berry crop. With the expansion of blueberry production, many diseases have become widespread in different regions of China. In August of 2012, stem and leaf spots symptomatic of anthracnose were sporadically observed on highbush blueberries in a field located in Liaoning, China, where approximately 15% of plants were diseased. Symptoms first appeared as yellow to reddish, irregularly-shaped lesions on leaves and stems. The lesions then expanded, becoming dark brown in the center and surrounded by a reddish halo. Leaf and stem tissues (5 × 5 mm) were cut from the lesion margins and surface-disinfected in 70% ethanol for 30 s, followed by three rinses with sterile water before placing on potato dextrose agar (PDA). Plates were incubated at 28°C. Colonies were initially white, becoming grayish-white to gray with yellow spore masses. Conidia were one-celled, hyaline, and cylindrical with rounded ends, measuring 15.0 to 25.0 × 4.0 to 7.5 μm. No teleomorph was observed. The fungus was tentatively identified as Colletotrichum gloeosporioides (PenZ.) PenZ & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) based on morphological characteristics of the colony and conidia (1). Genomic DNA was extracted from isolate XCG1 and the internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1–5.8S-ITS2) was amplified with primer pairs ITS1 and ITS4. BLAST searches showed 99% identity with C. gloeosporioides isolates in GenBank (Accession No. AF272779). The sequence of isolate XCG1 (C. gloeosporioides) was deposited into GenBank (JX878503). Pathogenicity tests were conducted on 2-year-old potted blueberries, cv. Berkeley. Stems and leaves of 10 potted blueberry plants were wounded with a sterilized needle and sprayed with a suspension of 105 conidia per ml of sterilized water. Five healthy potted plants were inoculated with sterilized water as control. Dark brown lesions surrounded by reddish halos developed on all inoculated leaves and stems after 7 days, and the pathogen was reisolated from lesions of 50% of inoculated plants as described above. The colony and conidial morphology were identical to the original isolate XCG1. No symptoms developed on the control plants. The causal agent of anthracnose on blueberry was identified as C. gloeosporioides on the basis of morphological and molecular characteristics, and its pathogenicity was confirmed with Koch's postulates. Worldwide, it has been reported that blueberry anthracnose might be caused by C. acutatum and C. gloeosporioides (2). However, we did not isolate C. acutatum during this study. To our knowledge, this is the first report of stem and leaf anthracnose of blueberry caused by C. gloeosporioides in China. References: (1) J. M. E. Mourde. No 315. CMI Descriptions of Pathogenic Fungi and Bacteria. Kew, Surrey, UK, 1971. (2) N. Verma, et al. Plant Pathol. 55:442, 2006.

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Butia capitata (Mart.) Becc. lamina anatomy as a tool for taxonomic distinction from B. odorata (Barb. Rodr.) Noblick comb. nov (Arecaceae)

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201520130457 ◽

2015 ◽

Vol 87 (1) ◽

pp. 71-81 ◽

Cited By ~ 3

Author(s):

BRUNO F. SANT'ANNA-SANTOS ◽

WELLINGTON G.O. CARVALHO JÚNIOR ◽

VANESSA B. AMARAL

Keyword(s):

Morphological Characteristics ◽

Guard Cells ◽

Plant Anatomy ◽

Vascular Bundles ◽

Epicuticular Waxes ◽

Fibrous Layer ◽

Middle Portion ◽

Abaxial Surface ◽

Adaxial Surface ◽

Subsidiary Cells

The distinction between Butia capitata and B. odorata is based only on a few morphological characteristics, therefore there is a need for additional studies for supporting the separation of the species. As lamina anatomy characteristics are relevant in circumscribing Arecaceae taxa, this work aimed to describe B. capitata lamina anatomy and compare it with B. odorata. Samples from the middle portion of the pinnae were collected and processed in accordance with standard plant anatomy techniques. The epidermis is uniseriate and composed of a thick cuticle and epicuticular waxes into like hooked filaments. The subsidiary cells that arch over the guard cells are located at the hypodermis. The mesophyll is isobilateral and compact. The vascular bundles are collateral with a sclerenchymatic sheath extension that reaches the hypodermis. The stegmata cells have spherical and druse-like silica bodies. The midrib faces the adaxial surface with a thick fibrous layer surrounding the vascular bundles adjacent to the chlorenchyma. The stratified expansion tissue is on the abaxial surface, within the boundary between the mesophyll and midrib. Raphides are only found in B. capitata. Small bundles of the midrib fully surround the fibrous cylinder only in B. odorata. These characteristics are diagnostic and useful for supporting the proposed separation.

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New Record of Ceratocystis fimbriata Causing Wilt of Pomegranate in India

Plant Disease ◽

10.1094/pdis.1999.83.4.400b ◽

1999 ◽

Vol 83 (4) ◽

pp. 400-400 ◽

Cited By ~ 16

Author(s):

Y. M. Somasekhara

Keyword(s):

Latin American ◽

Cross Sections ◽

Morphological Characteristics ◽

Pathogenic Fungi ◽

Punica Granatum ◽

Ceratocystis Fimbriata ◽

Main Trunk ◽

Brown Discoloration ◽

Initial Symptoms ◽

International Mycological Institute

Wilt of pomegranate (Punica granatum L.) was first noticed in two areas of the Bijapur district (16°49′N; 75°43′E) of India in 1990. Around 1993, rapid spread of this disease was observed in the entire Bijapur district. The cause was not identified until 1995. Initial symptoms were yellowing and wilting of leaves on one to several branches leading to death of affected plants in a few weeks. Cross sections of diseased plants revealed brown discoloration in the outer xylem from roots to the main trunk. A survey of 44 locations from 1995 to 1998 showed an approximate loss of Rs. 30 lakhs (ca. US$69,770) and 7.5% (3,474 of 47,096 plants wilted) of the crop. At 13 locations, plants also were severely infested with shot hole borer (Xyleborus spp.). In 1996, the fungus, a Ceratocystis sp., was isolated from discolored stem, root, and branch tissues on wilted plants collected from various locations, e.g., A. Sangapur, Bagalkot, Bijapur, Bilagi, Kanamadi, Tajpur, and Tikota. The fungus isolated from Bagalkot was confirmed by the International Mycological Institute (UK) as C. fimbriata Ellis & Halst. (Specimen No. W 5496, PBUR) in 1997; the strain of this fungus, i.e., Latin American group, was identified in 1998 by T. C. Harrington (Iowa State University). Morphological characteristics of mycelium, conidia, conidiophore, chlamydospores, perithecia, and ascospores were similar to those described previously (1). Pathogenicity of this fungus was confirmed by inoculating wounded roots. This is the first report of C. fimbriata causing wilt on pomegranate. Reference: (1) Anonymous. C.M.I. Descriptions of Pathogenic Fungi and Bacteria. No. 141. CAB, Surrey, England.

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First Report of Zonate Leaf Spot of Vigna vexillata var. tsusimensis Caused by Cristulariella moricola

Plant Disease ◽

10.1094/pdis.2002.86.4.440c ◽

2002 ◽

Vol 86 (4) ◽

pp. 440-440 ◽

Cited By ~ 3

Author(s):

H. B. Lee ◽

C.-J. Kim

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Leaf Spot Disease ◽

Eastern United States ◽

Leaf Spots ◽

Vigna Vexillata ◽

Initial Symptoms ◽

Pathogenicity Tests ◽

Basal Septum ◽

Bull's Eye

A zonate leaf spot disease on a wild bean variety, Vigna vexillata L. var. tsusimensis Mat., occurred in the patch fields and foothills of Chungnam and Kyonggi districts in Korea during late September, October, and early November of 1999 to 2001. The zonate lesions were particularly prevalent in October following periods of heavy dew accumulation. Initial symptoms were small, circular lesions with darkbrown marginal rings that later developed into large spots with characteristic target-shaped rings. The spots were gray to bright or blackish brown, progressed rapidly, and sometimes fused together to form lesions of up to 20 mm in diameter. Sporophores on the natural host were generally hypophyllous but sometimes amphigenous, abundant on large spots, fewer on small spots, solitary, erect, easily detachable, and up to 864 μm long. The upper portion of the sporophore is considered an individual conidium and consisted of a pyramidal head that was fusiform to ventricose and cristulate, 495 to 534 μm long, and 210 to 290 μm wide at the broadest point. Branches within the pyramidal head were short and compact, and dichotomously or trichotomously branched. The central axis within the conidium was hyaline, broad, septate, tapering toward an acute apex, and sometimes constricted at the basal septum. Conidiophores were 272 to 330 μm long and up to 24 μm wide. The fungus was identified as Cristulariella moricola (Hino) Redhead based on morphological characteristics (1,2). The fungus was isolated from Vigna leaf spots, placed on 2% water agar or potato dextrose agar (PDA), and maintained on PDA amended with 2% Vigna leaf extract. For pathogenicity tests, 4- to 5-week-old leaves of V. vexillata var. tsusimensis were surface-sterilized in 1% NaOCl. Agar disks (approximately 10 mm diameter) containing mycelia of the fungus were placed on the upper leaf surface. The inoculated plants (two leaflets per plant × 2) were then sprayed with distilled water, covered with premoistened polyethylene bags, and incubated at 15 to 25°C. Within 5 days, small leaf spots appeared that were similar to those originally observed on all inoculated leaflets. Uninoculated control leaves exposed to the same environmental conditions remained healthy. C. moricola was consistently reisolated from the infected leaves. The hyphomycete fungus C. moricola has been known to cause a bull's eye or zonate leaf spot and defoliation on woody and annual plants, including at least 73 host species and 36 families distributed in the central and eastern United States and Japan (1). In Asia, the occurrence of Cristulariella spp. on several hosts has been reported only in Taiwan and Japan (3,4). No species in the genus has ever been reported from Korea. To our knowledge, V. vexillata var. tsusimensis represents a previously unreported host for C. moricola. References: (1) M. C. Niedbalski et al. Mycologia 75:988, 1983. (2) S. A. Redhead. Mycologia 71:1248, 1979. (3). H. J. Su and S. C. Leu. Plant Dis. 67:915, 1983. (4) T. Yokoyama and K. Tubaki. Trans. Mycol. Soc. Jpn. 15:189, 1974.

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First Report of Didymella bryoniae Causing Gummy Stem Blight of Chayote in Taiwan

Plant Disease ◽

10.1094/pdis-02-12-0185-pdn ◽

2012 ◽

Vol 96 (10) ◽

pp. 1578-1578 ◽

Cited By ~ 2

Author(s):

Y. C. Tsai ◽

J. F. Chen

Keyword(s):

Morphological Characteristics ◽

Pathogenic Fungi ◽

Molecular Data ◽

Pathogenicity Test ◽

Didymella Bryoniae ◽

Stem Blight ◽

Gummy Stem Blight ◽

Plastic Bags ◽

Pathogenicity Tests ◽

Stems And Leaves

Chayote (Sechium edule (Jacq.) Swartz, Cucurbitaceae), originally native to Mexico, is an important vegetable known as “dragon-whisker vegetable” and is cultivated for its shoots in Ji-an, Hualien County in eastern Taiwan. In June 2010, 70 to 80% of the chayote plants grown in Ji-an developed necrotic spots on stems, leaves, and fruits. The disease was severe during the warm and rainy season from June to August. The symptoms on stems, leaves, and fruits were water-soaked lesions that eventually dried up, cracked, and produced perithecia on necrotic tissues. A single ascospore was isolated from perithecia harvested from diseased stems and cultured on potato dextrose agar (PDA) at 25°C for 1 month. Colonies of three isolates (SE5, SE6, and SE7) were white to olivaceous green bearing unicellular conidia measuring 2 to 5 × 3 to 10 μm, which is consistent with the morphological characteristics of Didymella bryoniae (Auersw.) Rehm (anamorph Phoma cucurbitacearum (Fr.:Fr.) Sacc.) (1,2,3). DNA of SE5, SE6, and SE7 isolates were obtained using microwave-based method (4). The internal transcribed spacer (ITS) rDNA (GenBank accessions AB714984, AB714985, and AB714986), PCR-amplified using primers ITS1 and ITS4, had 98 to 99% nucleotide sequence identity with D. bryoniae (GenBank Accession Nos. GU045304 and GU592001). A pathogenicity test was conducted in a greenhouse with temperature ranging from 20 to 30°C. Three-day-old mycelial plugs (5 × 5 mm) of the three isolates were placed on the needle-pricked wounds of stems and leaves of 36 4-month-old potted chayote plants wrapped in plastic bags to maintain 100% relative humidity for 2 days. Six days after inoculation, water-soaked lesions formed on the stems and leaves. Controls inoculated with sterile water had no symptoms. The fungus reisolated from the lesions of diseased stems and leaves had morphological characteristics of D. bryoniae. Based on the results of morphology, molecular data, and pathogenicity tests, we reported for the first time to our knowledge that gummy stem blight of chayote is caused by D. bryoniae in Taiwan. References: (1) J. W. Huang and W. R. Hsieh. Plant Prot. Bull. 27:325, 1985. (2) A. P. Keinath et al. Phytopathology 85:364, 1995. (3) E. Punithalingam and P. Holliday. P. 332 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972. (4) S. R. Tendulkar et al. Biotechnol. Lett. 22:1941, 2003.

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First Report of Colletotrichum gloeosporioides on Russian-thistle

Plant Disease ◽

10.1094/pdis.1998.82.12.1405b ◽

1998 ◽

Vol 82 (12) ◽

pp. 1405-1405 ◽

Cited By ~ 6

Author(s):

I. Schwarczinger ◽

L. Vajna ◽

W. L. Bruckart

Keyword(s):

Colletotrichum Gloeosporioides ◽

Morphological Characteristics ◽

Ground Level ◽

Conidial Suspension ◽

First Report ◽

High Virulence ◽

Pathogenicity Tests ◽

Stem Lesions ◽

And Control ◽

The U.S

A pathogen identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. was isolated from foliar and stem lesions on Russian-thistle (Salsola tragus Torner ex L.) collected in Bugac, Hungary, in 1996. Symptoms on leaves and stems began as discrete, sunken, 2- to 10-mm-diameter chlorotic spots, followed by formation of circular buff-colored lesions that eventually coalesced, desiccated, and caused plant tissue death above the lesions. Lesions that occurred near ground level usually killed the plant. Salmon-colored spore masses developed in setose acervuli in the center of the necrotic lesions. Conidia were hyaline, one-celled, falcate to nearly straight, and measured 15 to 25 × 5 to 6 μm. The teleomorph stage of the pathogen (Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) was not observed in the field or on inoculated plants. These morphological characteristics of the isolate were consistent with the description of C. gloeosporioides (1). Pathogenicity was proved by completing Koch's postulates in Hungary and the U.S. Inoculation with conidial suspension (106 conidia per ml) sprayed on S. tragus plants in the greenhouse at the three- to four-leaf stage caused severe necrosis and wilting within 6 days and plant death in 2 weeks. Symptoms did not appear on control plants inoculated with sterile, distilled water. Inoculation test was repeated on 6-week-old plants and at the stage of flowering. All treated plants were killed at both stages within 4 weeks. Because of high virulence and host specificity of this isolate of C. gloeosporioides in preliminary pathogenicity tests it is being evaluated for use as a mycoherbicide for Russian-thistle control in the U.S. This is the first report of C. gloeosporioides causing anthracnose on S. tragus. Reference: (1) B. C. Sutton. Pages 1–27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailei and M. J. Jeger, eds. CAB Int., Wallingford, UK, 1992.

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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 Albugo tragopogonis on Cultivated Sunflower in North America

Plant Disease ◽

10.1094/pdis.2002.86.5.559a ◽

2002 ◽

Vol 86 (5) ◽

pp. 559-559

Author(s):

T. J. Gulya ◽

F. Viranyi ◽

J. Appel ◽

D. Jardine ◽

H. F. Schwartz ◽

...

Keyword(s):

North America ◽

Pathogenic Fungi ◽

The United States ◽

Adjacent Area ◽

American Phytopathological Society ◽

First Report ◽

White Rust ◽

Production Area ◽

Stem Lesions ◽

First Time

White rust, caused by Albugo tragopogonis (Pers.) S.F. Gray, was observed on a few plants of both oilseed and confection sunflowers (Helianthus annuus L.) in northwestern Kansas (Cheyenne County) in 1992. The disease was observed again from 1993 to1995 in nine counties in western Kansas, with incidence per field ranging up to 35%. White rust was found only on late-planted fields in 1996 and 1997 and was not found at all from 1998 to 2001. White rust was also observed on cultivated and wild sunflower (H. annuus) for the first time in eastern Colorado (Kit Carson and Yuma counties) from 1994 to 1997, but was absent from 1998 to 2001. Leaf pustules on both cultivated and wild sunflowers were similar in appearance. Pustules were convex, chlorotic on the upper side of the leaf, and concave and dull white on the under side of the leaf. Pustules on cultivated sunflower were generally limited to three to six leaves in the middle of the plant and affected 10 to 40% of the leaf area. Sporangial dimensions fell within the reported dimensions for A. tragopogonis (2). In 1997, water-soaked lesions 1 to 2 cm long containing oospores of A. tragopogonia were observed on the lower to middle portions of stems of cultivated sunflower in western Kansas and the adjacent area of Colorado. Stem lesions were observed much less frequently than foliar lesions and only in 1997. Sporangia were not observed in stem lesions, nor were any other fungi isolated from these lesions. To our knowledge, this is the first report of white rust occurring on cultivated sunflower in any production area of North America; the disease has not been observed in the major U.S. sunflower production area of North Dakota, South Dakota, and Minnesota. Foliar white rust lesions generally have little economic impact on sunflower, but the presence of stem lesions is significant because stem lesions may lead to lodging (3). Lodging due to A. tragopogonia was not observed in either Kansas or Colorado. White rust has previously only been reported on wild H. annuus in Wisconsin and on perennial Helianthus spp. in Missouri and Illinois (1). References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN 1989. (2) K. G. Mukeri. Description of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK 1976. (2) P. S. van Wyk et al. Helia 22:83, 1995.

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