First Report of Rust on Switchgrass (Panicum virgatum) Caused by Puccinia emaculata in Tennessee

In the spring of 2007, switchgrass accessions and cultivars Alamo, Kanlow, SL-93-2001, and NSL 2001-1 (lowland), Blackwell (upland), and Grenville, Falcon, and Miami (unknown ploidy levels) were sown at the East Tennessee Research and Extension Center in Knoxville for evaluation and controlled hybridizations. In July and August of 2007, uredinia were observed primarily on the upper leaf surfaces, and to a lesser extent on the undersides of leaves, of switchgrass cvs. Alamo, Blackwell, Grenville, Falcon, Kanlow, and Miami. Uredinia were observed on all cultivars and accessions in 2008. Dimensions of spores are reported as mean ± standard deviation. Uredinia were epiphyllous, adaxial, caulicolous, oblong, and the color of cinnamon brown. Urediniospores were globose to broadly ellipsoid, 26.0 ± 3.0 × 23.2 ± 2.4 μm, with a wall that was cinnamon brown, 1.5 to 2.0 μm thick, finely echinulate with three to four equatorial pores, corresponding to Puccinia emaculata Schw. (3). Abundant teliospores were isolated from Grenville, Falcon, and Blackwell, with fewer teliospores isolated from Alamo. Telia were epiphyllous, adaxial, and caulicolous, densely crowded to scattered, oblong, and dark brown to black. Teliospores were dark brown, two-celled, ellipsoid to oblong, 33.6 ± 4.8 μm long with an apical cell width of 17.5 ± 1.2 μm and basal cell width of 15.9 ± 2.5 μm. Teliospore walls were 1.5 to 2.0 μm wide at the sides and 4 to 6 μm apically. Pedicels were brown or colorless and up to approximately one length of the teliospore, 28.5 ± 7.4 μm. Teliospore morphology confirmed the identification of this rust as P. emaculata (3), which has been reported to infect upland and lowland populations of switchgrass (2). A 2,109-bp fragment containing the internal transcribed spacer (ITS) 1, 5.8S, ITS 2, and D1/D2 region of the large subunit ribosomal DNA was sequenced for a specimen on ‘Falcon’ (GenBank Accession No. EU915294 and BPI No. 878722) from two overlapping PCR fragments amplified with primers PRITS1F (L. A. Castlebury, unpublished data) and ITS4B (1) for one fragment and Rust5.8SF (L. A. Castlebury, unpublished data) and LR7 (4) for the second fragment. No sequences of P. emaculata were available for comparison; however, BLAST searches of the ITS resulted in hits to P. asparagi DC (527 of 576, 91%) and P. andropogonis Schw. (523 of 568, 92%) placing this fungus in the genus Puccinia Pers. The alternate hosts of this rust are species of the Euphorbiaceae (2,3), which are ubiquitous in this area although the aecial stage has not been observed. To our knowledge, this is the first report of P. emaculata on switchgrass in Tennessee. Given the highly susceptible response of certain varieties of switchgrass to this rust in field plots, reduction in total biomass in large acreages is likely and long-standing fields of this perennial grass will compound the problem. References: (1) M. Gardes and T. D. Bruns. Mol. Ecol. 2:113, 1993. (2) D. M. Gustafson et al. Crop Sci. 43:755, 2003. (3) P. Ramachar and G. Cummins. Mycopathol. Mycol. Appl. 25:7, 1965. (4) R. Vilgalys and M. Hester. J. Bacteriol. 172:4238, 1990.

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First Report of Rust Caused by Puccinia emaculata on Switchgrass in Arkansas

Plant Disease ◽

10.1094/pdis-94-3-0381b ◽

2010 ◽

Vol 94 (3) ◽

pp. 381-381 ◽

Cited By ~ 14

Author(s):

R. L. Hirsch ◽

D. O. TeBeest ◽

B. H. Bluhm ◽

C. P. West

Keyword(s):

United States ◽

Internal Transcribed Spacer ◽

Agricultural Research ◽

Apical Cell ◽

The United States ◽

The State ◽

Cell Width ◽

First Report ◽

Northwest Arkansas ◽

Extension Center

In May 2007, switchgrass (Panicum virgatum L.) cv. Alamo and a breeding line, OSU-NSL 2001-1, were planted at the Arkansas Agricultural Research and Extension Center, Fayetteville. In August 2008, a high incidence of dark brown-to-black rectangular foliar lesions delineated by major veins was observed throughout plots of both lines. Lesions covered 25% to nearly 100% of total leaf tissue. Similar symptoms were also observed on unknown switchgrass cultivars in Benton County in northwest Arkansas and in St. Francis County in east-central Arkansas, suggesting that the disease was widely distributed throughout the state. The pathogen produced epiphyllous and adaxial masses of dark brown-to-black telia from erumpent fissures on leaf surfaces. Dark brown teliospores were observed under magnification and were two-celled, oblong to ellipsoid, and 33 ± 3.5 μm long with an apical cell width of 17.5 ± 2.7 μm and basal cell width of 16.2 ± 2.8 μm (reported as mean ± standard deviation, n = 25). Pedicles were colorless to light brown and measured 25.4 ± 9.2 μm (n = 25). In June 2009, at the Fayetteville Research and Extension Center, several second-year stands of switchgrass developed amphigenous and adaxial foliar lesions containing urediniospores. The uredia were globose and finely echinulate, measuring 23.1 ± 2.2 μm (n = 25) with brown cell walls. Teliospore and urediniospore morphology from all collections was consistent with Puccinia emaculata Schw. (2). Genomic DNA was extracted from a representative infected leaf of cv. Alamo, collected in Fayetteville, AR in June 2009, and amplified by PCR with primer sets PRITS1F (3) and ITS4B (1), which amplified an 803-bp fragment of rDNA encoding the first internal transcribed spacer (ITS1), 5.8S subunit, and second internal transcribed spacer (ITS2). The fragment was cloned into pGEM T Easy (Promega Corp, Madison, WI) and sequenced. A BLAST search of GenBank revealed that the fragment was most similar to the rDNA of P. emaculata (GenBank Accession No. EU915294.1; 755 of 758 bases matching; 99% identity) previously reported as a pathogen on switchgrass in Tennessee (3). The incidence and severity of rust on the widely planted switchgrass cv. Alamo is considerable cause for concern as efforts are made to increase acreage and production. Climatic conditions in St. Francis County are generally consistent with locations in Tennessee where switchgrass rust was previously reported (3). However, northwest Arkansas represents the eastern edge of the southwestern United States, suggesting that P. emaculata may affect switchgrass in geographically diverse areas of the United States. To our knowledge, this study represents the first report of rust on switchgrass in Arkansas. Managing this disease will be an important consideration for large-scale switchgrass cultivation in the state. References: (1) M. Gardes and T. D. Bruns. Mol. Ecol. 2:113, 1993. (2) P. Ramachar and G. Cummins. Mycopathol. Mycol. Appl. 25:7, 1965. (3) J. Zale et al. Plant. Dis. 92:1710, 2008.

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First Report of Stemphylium botryosum Causing Leaf Blight of Kiwi in the Province Imathia, Northern Greece

Plant Disease ◽

10.1094/pdis-92-4-0650b ◽

2008 ◽

Vol 92 (4) ◽

pp. 650-650 ◽

Cited By ~ 1

Author(s):

T. Thomidis ◽

T. J. Michailides

Keyword(s):

Apical Cell ◽

Morphological Characteristics ◽

Leaf Blight ◽

Width Ratio ◽

Northern Greece ◽

Cell Width ◽

Koch’S Postulates ◽

First Report ◽

Stemphylium Botryosum ◽

Koch's Postulates

In Greece, kiwi (Actinidia deliciosa) is mostly found in the northern part of the country where approximately 440,000 ha are grown. In the summer of 2006, a Stemphylium sp. was frequently isolated from leaves of kiwi (cv. Hayward) grown in the province of Imathia. Symptomatic leaves were covered with irregular, necrotic, brown areas. Lesions had a distinct margin that, in some cases, covered a wide part of the diseased leaves. Intense symptoms were frequently observed and associated with defoliation. This Stemphylium sp. was consistently isolated from diseased leaves onto potato dextrose agar (PDA) after surface sterilization with 0.1% chlorine solution. On the basis of morphological characteristics of mycelia, dimensions (length 20 to 29 μm and width 14 to 21 μm) and mean length/width ratio (1.42 μm) of conidia, and width and apical cell width of condiophores, the fungus was identified as Stemphylium botryosum (Wallr.) (2,3) Koch's postulates were completed in the laboratory by inoculating leaves of kiwi (cv. Hayward) with an isolate of S. botryosum originated from a symptomatic leaf of a Hayward kiwi. Twenty leaves were surface sterilized by dipping them into 0.1% chlorine solution for 2 to 3 min, washing in sterile distilled water, and allowing them to dry in a laminar flow hood. A leaf was then placed into a petri plate containing a wet, sterilized paper towel. Inoculation was made by transferring a 5-mm-diameter mycelial disc from the margins of a 7-day-old culture onto the center of each leaf surface. Petri plates were closed and incubated at 25°C with 12 h of light for 6 days. Koch's postulates were satisfied when the same S. botryosum was reisolated from 100% of inoculated leaves that developed symptoms similar to those observed in the vineyards. Leaves inoculated with a PDA plug alone (with no S. botryosum) did not develop any symptoms. Previously, Alternaria alternata was reported as the causal agent of a leaf spot pathogen of kiwi (1,4). To our knowledge, this is the first report of the occurrence of S. botryosum causing leaf blight of kiwi in Greece and worldwide. This pathogen can cause a high level of defoliation in diseased plants. References: (1) L. Corazza et al. Plant Dis. 83:487, 1999. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Mycology Institute. London, England, 1971. (3) E. G. Simmons. Mycologia 61:1, 1969. (4) C. Tsahouridou and C. C. Thanassoulopoulos. Plant Dis. 84:371, 2000

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First Report of Rust Caused by Puccinia nakanishikii on Lemongrass, Cymbopogon citratus, in Florida

Plant Disease ◽

10.1094/pdis-04-13-0448-pdn ◽

2014 ◽

Vol 98 (1) ◽

pp. 156-156

Author(s):

R. C. Ploetz ◽

A. J. Palmateer ◽

P. Lopez ◽

M. C. Aime

Keyword(s):

Dna Analysis ◽

Large Subunit ◽

South Florida ◽

Dade County ◽

Cymbopogon Citratus ◽

Abaxial Side ◽

First Report ◽

Leaf Surfaces ◽

Voucher Specimens ◽

The Tropics

Lemongrass, Cymbopogon citratus (DC.) Stapf. (Poaceae), is grown widely in the tropics and subtropics as an ornamental, flavoring ingredient in Asian cooking, and for tea and fragrant oil (3). In February 2013, rust symptoms were observed on lemongrass in several gardens in Miami-Dade County, Florida. Symptoms began as small chlorotic flecks on both leaf surfaces that became crimson and enlarged to streaks ~1 cm in length. On the abaxial side of leaves, erumpent streaks ruptured to produce pustules in which urediniospores formed. Eventually, streaks coalesced to produce large patches of tan to purplish necrotic tissue that blighted most of the leaf surface and was often surrounded by chlorotic borders. These symptoms, fungal morphology, and nuclear ribosomal large subunit (28S) DNA analysis were used to identify the pathogen as Puccinia nakanishikii Dietel. Urediniospores were pyriform to globose, orange to crimson, slightly echinulate, and somewhat longer than a previous report (32.1 ± 3.4 (27 to 42) × 23.3 ± 2.4 (21 to 27) μm vs. 22 to 28 × 22 to 25 μm) (2). Uredinia contained clavate paraphyses, but teliospores were not observed. No aecial host is known for this pathogen. A 28S DNA sequence that was generated with the NL1 and LR3 primers (1,4) was deposited in GenBank under accession no. KC990123; it shared 99% identity with GenBank accession GU058002, which came from a specimen of P. nakanishikii in Hawaii. Voucher specimens of affected leaves of lemongrass have been deposited at the Arthur Herbarium, Purdue University. Although this disease has been reported in California, Hawaii, New Zealand, and Thailand, this is believed to be the first report from Florida (2). Based on rainfall and temperature conditions that are conducive to its development in South Florida, it has the potential to significantly reduce the health and production of this plant in area gardens. References: (1) C. P. Kurtzman and C. J. Robnett. Antonie Van Leeuwenhoek 73:331. 1998. (2) S. Nelson. Rust of Lemongrass. Univ. Hawaii PD-57, 2008. (3) USDA, ARS, GRIN Online Database. URL: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?12797 , accessed 25 April 2013. (4) R. Vilgalys and M. Hester. J Bacteriol. 172:4238, 1990.

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First Report of a Leaf Spot Caused by Bipolaris oryzae on Switchgrass in New York

Plant Disease ◽

10.1094/pdis-03-11-0231 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1192-1192 ◽

Cited By ~ 8

Author(s):

K. D. Waxman ◽

G. C. Bergstrom

Keyword(s):

New York ◽

North Dakota ◽

Leaf Spot ◽

Panicum Virgatum ◽

Perennial Grass ◽

Leaf Tissue ◽

Nucleotide Identity ◽

Bipolaris Oryzae ◽

First Report ◽

Mist Chamber

Switchgrass (Panicum virgatum L.) is a perennial grass with biofuel potential. From 2007 to 2010, foliar lesions were observed on first year and mature stands of switchgrass in various locations in New York. Foliar lesions were purple, elliptical (up to 1 cm) with either distinct or diffuse margins, and occasionally with yellow halos and/or white necrotic centers. After 2 to 5 days of moist chamber incubation, surface-sterilized, symptomatic leaf tissue produced conidia that when streaked onto potato dextrose agar containing 0.3 g of streptomycin per liter gave rise to cultures with gray-to-black mycelium that developed brown conidia. The fungus was identified as Bipolaris oryzae (Breda de Haan) Shoemaker on the basis of conidial morphology (1,2). Conidiophores were brown, straight, cylindrical, and multiseptate. Conidia were brown, curved, ellipsoidal tapering to rounded ends, with 3 to 14 septa. Conidia averaged 105 μm (54 to 160 μm) long and 16 μm (12 to 20 μm) wide. Sequences of the glyceraldehyde-3-phosphate dehydrogenase (GDP) gene of three isolates from Tompkins County (Cornell Accession and corresponding GenBank Nos.: Bo005NY07 [cv. Cave-in-Rock], JF521648; Bo006NY07 [cv. Kanlow], JF521649; and Bo038NY07 [cv. Shawnee], JF521650) exhibited 100% nucleotide identity to B. oryzae isolates (GenBank Nos. AY277282–AY277285) collected from switchgrass in North Dakota (1). Sequences of the rDNA internal transcribed spacer (ITS) regions of the isolates (Cornell Accession and corresponding GenBank Nos.: Bo005NY07, JF693908; Bo006NY07, JF693909; and Bo038NY07, JF693910) exhibited 100% nucleotide identity to B. oryzae isolates (GenBank Nos. GU222690–GU222693) collected from switchgrass in Mississippi (3). Pathogenicity of two of the sequenced isolates (Bo006NY07 and Bo038NY07) along with one other isolate (Bo116NY09 from ‘Cave-in-Rock’ in Cayuga County) was evaluated in the greenhouse. Six- to eight-week-old switchgrass plants were inoculated with conidial suspensions (40,000 conidia/ml) of B. oryzae. Inoculum or sterilized water was applied until runoff. There were three plants per treatment of each of ‘Blackwell’, ‘Carthage’, ‘Cave-in-Rock’, ‘Kanlow’, ‘Shawnee’, ‘Shelter’, and ‘Sunburst’. After inoculum had dried, plants were placed in a mist chamber for 24 h and then returned to the greenhouse. Symptoms developed 2 to 4 days after inoculation for all cultivars. No symptoms developed on the control plants. Foliar lesions closely resembled those observed in the field. B. oryzae was consistently reisolated from symptomatic tissue collected from greenhouse experiments. B. oryzae was first reported as a pathogen of switchgrass in North Dakota (1) and more recently in Mississippi (3). To our knowledge, this is the first report of B. oryzae causing a leaf spot on switchgrass in New York. Observation of severe leaf spot in several field plots suggests that switchgrass populations should be screened for their reaction to regional isolates of B. oryzae prior to expanded production of switchgrass as a biofuel crop. References: (1) J. M. Krupinsky et al. Can. J. Plant Pathol. 26:371 2004. (2) R. A. Shoemaker. Can. J. Bot. 37:883, 1959. (3) M. Tomaso-Peterson and C. J. Balbalian. Plant Dis. 94:643 2010.

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First Report of Puccinia emaculata Infection on Switchgrass in Virginia

Plant Disease ◽

10.1094/pdis-09-12-0814-pdn ◽

2013 ◽

Vol 97 (3) ◽

pp. 424-424 ◽

Cited By ~ 7

Author(s):

T. Frazier ◽

Z. Shen ◽

B. Zhao ◽

E. Bush

Keyword(s):

18S Rdna ◽

Plant Genetic Resources ◽

Apical Cell ◽

Rdna Sequence ◽

Infected Leaf ◽

Cell Width ◽

First Report ◽

Wide Range ◽

Rust Pathogen ◽

18S Rdna Sequence

During the spring of 2007, approximately 2,000 switchgrass plants, representing 168 core switchgrass germplasm, were established in a field nursery at the Virginia Tech Kentland Farm Research Center in Montgomery County, VA. These germplasms were originally obtained from the USDA Plant Genetic Resources Conservation Unit (Griffin, GA) and included both lowland and upland ecotypes. After planting, the switchgrass plants were allowed to establish for 3 years. In the summers of 2009, 2010, and 2011, a substantial infection of a foliar rust pathogen was observed on more than 90% of switchgrass lines in the field. The infected leaves had dark brown pustules that were arranged in a linear fashion between the veins and mainly located on the adaxial surface of the leaf. We observed the infected leaf samples under a microscope and isolated the urediniospores. The urediniospores were brown, round, and averaged 26.08 ± 1.67 μm long and 24.65 ± 1.66 μm wide. Teliospores were observed late in the summers of 2009 and 2010. The teliospores were two-celled, oblong to ellipsoid in shape, and averaged 32.23 ± 3.07 μm in length. The apical cell width averaged 17.6 ± 1.83 μm and the basal cell width averaged 15.08 ± 1.75 μm. The morphology of both the urediniospores and teliospores were similar to Puccinia emaculata Schw. (P. emaculata) (2,3). Using previously established rust disease scoring methods (1), the infected switchgrass lines were evaluated and scored for infection severity on a 0 to 9 scale based on the percentage of leaf area infected, with 0 being either highly resistant or escaping infection and 9 being highly susceptible. The majority of upland switchgrass cultivars, including Caddo, Cave-in-rock, Blackwell, Sunburst, Pathfinder, and Dacotah, were moderately to highly susceptible to this rust pathogen and on average, scored between 7 and 8. However, the majority of lowland switchgrass cultivars, including Alamo, Kanlow, TEM-SEC, TEM-SLC, and TEM-LoDorm, were moderately to highly resistant and scored on average between 3 and 4. This result is consistent with previous reports that show that lowland ecotypes are more resistant to rust diseases (1). To further validate the identity of the rust pathogen, we designed two primers (5′-CCAGTAACGGCGAGTGAAGAG-3′ and 5′-CGACTTCCATGGCCACCGTGCGGCTGTCT-3′) based on the 18S rDNA sequence of P. emaculata (3). DNA was extracted from bulk infected leaf material for PCR amplification. The 1.2 kb PCR product was isolated and sent for DNA sequencing. The DNA sequence was 98% identical to the 18S rDNA sequence of P. emaculata (EU915294.1). To our knowledge, this study represents the first report of rust on a wide range of various switchgrass cultivars in Virginia. References: (1) D. M. Gustafson et al. Crop Sci. 43:755, 2003. (2) R. L. Hirsch et al. Plant Dis. 94:381, 2010. (3) J. Zale et al. Plant Dis. 92:1710, 2008.

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First Report of Puccinia thaliae Rust on Canna Lily in Louisiana

Plant Disease ◽

10.1094/pdis-03-10-0209 ◽

2011 ◽

Vol 95 (3) ◽

pp. 353-353 ◽

Cited By ~ 4

Author(s):

R. Kaur ◽

T. A. Rush ◽

D. M. Ferrin ◽

M. C. Aime

Keyword(s):

Baton Rouge ◽

Large Subunit ◽

Microbiology Laboratory ◽

Rust Disease ◽

Specific Primers ◽

First Report ◽

East Baton Rouge Parish ◽

Leaf Surfaces ◽

Herbaceous Perennial ◽

Single Insertion

Canna lily is a monocot, herbaceous perennial ornamental plant in the Cannaceae that is native to tropical South America and cultivated throughout the southern United States. Canna lily is a popular garden and landscaping plant and a large horticultural industry depends on this plant. In September 2008 and again in November 2009, two species of Canna lily (Canna × generalis L.H. Bailey and C. indica L.) were found to be severely infected with rust disease in three garden locations in southern Louisiana (East Baton Rouge Parish, Lafayette Parish, and Orleans Parish). Diseased samples from both host species and all locations exhibited similar symptoms of numerous, yellowish brown, subepidermal, erumpent, and irregular-shaped uredinia on both leaf surfaces. Initially, sori were scattered, later covering the entire leaf with coalescing pustules. Urediniospores were subglobose to ovoid or pyriform, echinulate, and measured 25.74 to 37.18 (–38.61) × 17.16 to 27.17 (–28.6) μm, with thickened apical walls, 1.3 to 1.6 μm, and one to two equatorial germ pores. Telia and teliospores were not observed on any of the collected samples. Pathogen identity was confirmed as Puccinia thaliae Dietel by nuclear ribosomal large subunit (28S) DNA sequencing with rust-specific primers (1). The sequence (deposited in GenBank as No. HQ434482), when blasted, was found to match sequence No. EU851154 of P. thaliae from C. indica with 98% identity (719 of 730 bp), the differences being attributed to a single insertion at bp 423 to 436 of sequence No. EU851154. The sequences of P. thaliae obtained from two different samples from Louisiana were identical and did not match any other sequence in GenBank. In North America P. thaliae is reported to cause rust on C. indica L. in Florida and C. × generalis in Texas, as well as on two members of the Marantaceae (Maranta arundinacea L. and Thalia geniculata L.) in Florida and M. arundinaceae in Mexico (2). To our knowledge, this is the first report of P. thaliae in Louisiana on Canna lily. Voucher materials (C. × generalis = LSU00123378 and C. indica = LSU00123384) have been deposited in the Bernard Lowy Mycological Herbarium (LSUM). References: (1) M. C. Aime. Mycoscience 47:112, 2006. (2) D. F. Farr and A.Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved 12 February from http://nt.ars-grin.gov/fungaldatabases/ , 2010.

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First Report of Anthracnose Caused by Colletotrichum navitas on Switchgrass in New York

Plant Disease ◽

10.1094/pdis-03-11-0164 ◽

2011 ◽

Vol 95 (8) ◽

pp. 1032-1032 ◽

Cited By ~ 2

Author(s):

K. D. Waxman ◽

G. C. Bergstrom

Keyword(s):

New York ◽

New Jersey ◽

Panicum Virgatum ◽

Molecular Phylogenetics ◽

Perennial Grass ◽

Leaf Tissue ◽

Morphological Characters ◽

Sensu Stricto ◽

First Report ◽

Greenhouse Experiments

Switchgrass (Panicum virgatum L.) is a perennial grass with significant potential as a biofuel crop. From 2007 to 2010, foliar lesions were observed in new and mature stands of switchgrass in various locations in New York. Lesions were elliptical with purple margins and white necrotic centers, generally <3 cm long, ~1 mm wide, often coalesced, and containing black setae. Upon incubation, symptomatic leaf tissue developed acervuli with masses of salmon-colored spores. The fungus was identified as Colletotrichum nativas Crouch on the basis of typical cultural characteristics and conidial morphology (1). Conidia were one-celled, hyaline, fusiform, and generally falcate. Conidial length averaged 40 μm (22 to 47 μm) and width averaged 5 μm (4 to 7 μm). Compared with other graminicolous species of Colletotrichum, the conidia were larger and varied from straight to irregularly bent. Sequences of the rDNA internal transcribed spacer (ITS) regions of three isolates (Cornell accession and corresponding GenBank Nos.: Cn071NY08 (from a >20-year-old naturalized stand of switchgrass in Steuben County), JF437053; Cn080NY08 (from ‘Pathfinder’ in Chemung County), JF437054; and Cn101NY09 (from ‘Blackwell’ in Chemung County), JF437055) exhibited 100% nucleotide identity to the type isolate of C. nativas (GenBank No. GQ919068) collected from switchgrass selection ‘Brooklyn’ in New Jersey (1). Pathogenicity of the sequenced isolates along with seven other isolates (Cn105NY09 from ‘Sunburst’ in Tompkins County; Cn107NY09 from ‘Trailblazer’ in Tompkins County; Cn109NY09 from ‘Forestburg’ in Tompkins County; Cn111NY09 and Cn112NY09 from ‘Shelter’ in Tompkins County; and Cn122NY09 and Cn123NY09 from ‘Cave-in-Rock’ in Genesee County) was evaluated in greenhouse experiments. Seven- to eight-week-old switchgrass plants were inoculated with conidial suspensions (1 × 106 conidia/ml) of C. nativas. Inoculum or sterilized water was sprayed until runoff. Three plants of each of ‘Cave-in-Rock’ and ‘Kanlow’ were sprayed per treatment and the experiment was repeated for 3 of the 10 isolates. Inoculated plants were placed in a mist chamber for 48 h before they were returned to the greenhouse and observed for disease development, which occurred within 1 week of inoculation for both cultivars. No symptoms developed on the control plants. Foliar lesions closely resembled those observed in the field. C. nativas was consistently reisolated from symptomatic tissue collected from greenhouse experiments. Switchgrass anthracnose associated with C. graminicola sensu lata has been reported in many U.S. states (2). On the basis of molecular phylogenetics and distinguishing morphological characters, Crouch et al. erected C. navitas as a novel species distinct from C. graminicola sensu stricto, a taxon restricted to the corn anthracnose pathogen (1). C. nativas was first documented on switchgrass in New Jersey (1) and appears to be the same pathogen causing anthracnose of switchgrass in the adjoining state of Pennsylvania (1,3). To our knowledge, this is the first report of C. nativas causing anthracnose of switchgrass in New York. References: (1) J. A. Crouch et al. Mycol. Res. 113:1411, 2009. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , May 5, 2011. (3) M. A. Sanderson et al. Agron. J. 100:510, 2008.

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First report of Rhizoctonia cerealis causing sharp eyespot in Panicum virgatum in the UK

Plant Pathology ◽

10.1046/j.1365-3059.2001.00630.x ◽

2001 ◽

Vol 50 (6) ◽

pp. 807-807 ◽

Cited By ~ 6

Author(s):

J. V. Etheridge ◽

L. Davey ◽

D. G. Christian

Keyword(s):

Panicum Virgatum ◽

First Report ◽

Sharp Eyespot ◽

The Uk ◽

Rhizoctonia Cerealis

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First Report of Powdery Mildew of Kalanchoe blossfeldiana caused by Sphaerotheca fuliginea (Podosphaera fuliginea) in the Pacific Northwest

Plant Health Progress ◽

10.1094/php-2003-0417-02-hn ◽

2003 ◽

Vol 4 (1) ◽

pp. 39

Author(s):

Dean A. Glawe ◽

Rita Hummel ◽

Grace Jack

Keyword(s):

Powdery Mildew ◽

Pacific Northwest ◽

Sphaerotheca Fuliginea ◽

First Report ◽

Major Disease ◽

The Pacific ◽

Kalanchoe Blossfeldiana ◽

Extension Center ◽

Kalanchoë Blossfeldiana

Kalanchoe blossfeldiana Poelln. is a common ornamental houseplant. Although powdery mildew is a major disease of this species, there are no published reports of it in the Pacific Northwest. In August, 2002, powdery mildew was observed on six indoor K. blossfeldiana plants in an office and adjacent laboratory at the Puyallup Research and Extension Center. Accepted for publication 25 March 2003. Published 17 April 2003.

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First Report of Leaf Spot caused by Bipolaris oryzae on Switchgrass in Tennessee

Plant Disease ◽

10.1094/pdis-01-13-0070-pdn ◽

2013 ◽

Vol 97 (12) ◽

pp. 1654-1654 ◽

Cited By ~ 3

Author(s):

A. L. Vu ◽

M. M. Dee ◽

J. Zale ◽

K. D. Gwinn ◽

B. H. Ownley

Keyword(s):

Leaf Spot ◽

Panicum Virgatum ◽

Morphological Characteristics ◽

Its Region ◽

Spore Production ◽

Post Inoculation ◽

Sterile Water ◽

Bipolaris Oryzae ◽

First Report ◽

Symptomatic Leaf

Knowledge of pathogens in switchgrass, a potential biofuels crop, is limited. In December 2007, dark brown to black irregularly shaped foliar spots were observed on ‘Alamo’ switchgrass (Panicum virgatum L.) on the campus of the University of Tennessee. Symptomatic leaf samples were surface-sterilized (95% ethanol, 1 min; 20% commercial bleach, 3 min; 95% ethanol, 1 min), rinsed in sterile water, air-dried, and plated on 2% water agar amended with 3.45 mg fenpropathrin/liter (Danitol 2.4 EC, Valent Chemical, Walnut Creek, CA) and 10 mg/liter rifampicin (Sigma-Aldrich, St. Louis, MO). A sparsely sporulating, dematiaceous mitosporic fungus was observed. Fungal plugs were transferred to surface-sterilized detached ‘Alamo’ leaves on sterile filter paper in a moist chamber to increase spore production. Conidia were ovate, oblong, mostly straight to slightly curved, and light to olive-brown with 3 to 10 septa. Conidial dimensions were 12.5 to 17 × 27.5 to 95 (average 14.5 × 72) μm. Conidiophores were light brown, single, multiseptate, and geniculate. Conidial production was polytretic. Morphological characteristics and disease symptoms were similar to those described for Bipolaris oryzae (Breda de Haan) Shoemaker (2). Disease assays were done with 6-week-old ‘Alamo’ switchgrass grown from seed scarified with 60% sulfuric acid and surface-sterilized in 50% bleach. Nine 9 × 9-cm square pots with approximately 20 plants per pot were inoculated with a mycelial slurry (due to low spore production) prepared from cultures grown on potato dextrose agar for 7 days. Cultures were flooded with sterile water and rubbed gently to loosen mycelium. Two additional pots were inoculated with sterile water and subjected to the same conditions to serve as controls. Plants were exposed to high humidity by enclosure in a plastic bag for 72 h. Bags were removed, and plants were incubated at 25/20°C with 50 to 60% relative humidity. During the disease assay, plants were kept in a growth chamber with a 12-h photoperiod of fluorescent and incandescent lighting. Foliar leaf spot symptoms appeared 5 to 14 days post-inoculation for eight of nine replicates. Control plants had no symptoms. Symptomatic leaf tissue was processed and plated as described above. The original fungal isolate and the pathogen recovered in the disease assay were identified using internal transcribed spacer (ITS) region sequences. The ITS region of rDNA was amplified with PCR and primer pairs ITS4 and ITS5 (4). PCR amplicons of 553 bp were sequenced, and sequences from the original isolate and the reisolated pathogen were identical (GenBank Accession No. JQ237248). The sequence had 100% nucleotide identity to B. oryzae from switchgrass in Mississippi (GU222690, GU222691, GU222692, and GU222693) and New York (JF693908). Leaf spot caused by B. oryzae on switchgrass has also been described in North Dakota (1) and was seedborne in Mississippi (3). To our knowledge, this is the first report of B. oryzae from switchgrass in Tennessee. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/, 28 June 2012. (2) J. M. Krupinsky et al. Can. J. Plant Pathol. 26:371, 2004. (3) M. Tomaso-Peterson and C. J. Balbalian. Plant Dis. 94:643, 2010. (4) T. J. White et al. Pages 315-322 in: PCR Protocols: a Guide to Methods and Applications. M. A. Innis et al. (eds), Acad. Press, San Diego, 1990.

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