First Report of Leaf Spot Caused by Bipolaris spicifera on Switchgrass in the United States

Light-to-dark brown leaf spots and general chlorosis were observed on ‘Alamo’ switchgrass (Panicum virgatum L.) grown in ornamental plantings on the campus of the University of Tennessee in Knoxville in December 2007. Disease distribution was patchy, infecting ~10% of plants. Patches had mild to severely infected plants with stunting in areas of severe infection. Symptomatic leaf tissue was surface sterilized, air dried on sterile filter paper, and plated on 2% water agar amended with 10 mg/liter of rifampicin (Sigma-Aldrich, St. Louis, MO) and 10 μl/liter of 2.4 EC Danitol miticide (Valent Chemical, Walnut Creek, CA). Plates were incubated at 26°C in darkness for 5 days. A sporulating, dematiaceous mitosporic fungus was observed and transferred to potato dextrose agar (PDA). Conidiophores were single, light brown, multiseptate, mostly straight, polytretic, geniculate, and sympodial. Conidia were 17.5 × 12 (22) to 30 × 14 (12.5) μm, oval, light brown, and distoseptate, with one to three septa and a flattened hilum on the basal cell. Conidia germinated from both poles. The causal agent was identified as Bipolaris spicifera (Bainier) Subram. Morphological features were as described for B. spicifera (2). Pathogenicity studies were conducted with 5-week-old ‘Alamo’ switchgrass plants grown from surface-sterilized seed in 9 × 9-cm pots containing 50% ProMix Potting and Seeding Mix (Premier Tech Horticulture, Rivière-du-Loup, Québec, Canada) and 50% Turface ProLeague (Profile Products, Buffalo Grove, IL) (vol/vol). Ten replicate pots with ~20 plants each were sprayed with a spore suspension of 4.5 × 106 spores/ml of sterile water prepared from 6-day-old cultures grown on PDA. Plants were subjected to high humidity for 45 h then incubated at 25/20°C with a 12-h photoperiod in a growth chamber. Leaf spot symptoms similar to the original disease appeared on plants in each of the 10 replicate pots 6 days postinoculation. Lesions were excised from leaves, surface sterilized, plated on water agar, and the resulting cultures were again identified as B. spicifera. The internal transcribed spacer (ITS) region of ribosomal DNA from the original isolate used for inoculation and the reisolated culture recovered from plants in the pathogenicity studies were amplified with PCR using primers ITS4 and ITS5 (3). PCR amplicons of ~560 bp were obtained from both isolates and sequenced. Amplicon sequences were identical and the sequence was submitted to GenBank (Accession No. HQ015445). The DNA sequence had 100% homology to the ITS sequence of B. spicifera strain NRRL 47508 (GenBank Accession No. GU183125.1) that had been isolated from sorghum seed. To our knowledge, leaf spot caused by B. spicifera has not been described on switchgrass (1). B. spicifera can be seedborne and has been reported on turfgrass seed exported from the United States to Korea (2). As switchgrass is transitioned from a prairie grass to a biofuels crop planted in large acreages, disease incidences and severities will likely increase, necessitating rapid disease identification and cost effective management strategies. 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/ , 4 August 2010. (2) H.-M. Koo et al. Plant Pathol. J. 19:133, 2003. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds, Academic Press, San Diego, 1990.

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First Report of Leaf Spot on Switchgrass Caused by Pithomyces chartarum in the United States

Plant Disease ◽

10.1094/pdis-01-13-0117-pdn ◽

2013 ◽

Vol 97 (12) ◽

pp. 1655-1655 ◽

Cited By ~ 2

Author(s):

A. L. Vu ◽

K. D. Gwinn ◽

B. H. Ownley

Keyword(s):

Leaf Spot ◽

Panicum Virgatum ◽

Leaf Tissue ◽

Its Region ◽

The United States ◽

Growth Chamber ◽

Post Inoculation ◽

Commonwealth Mycological Institute ◽

Sterile Water ◽

Plastic Bag

There are few reports on diseases of switchgrass. In November 2009, light brown to white bleached spots (1 to 2 × 3 to 4 μm) were observed on ‘Alamo’ switchgrass (Panicum virgatum L.) grown in a growth chamber in Knoxville, TN, from surface-disinfested seed produced in Colorado. Symptomatic leaf tissue was surface sterilized, air dried, and plated on 2% water agar (WA) amended with 6.9 mg fenpropathrin/liter (Danitol 2.4 EC, Valent Chemical, Walnut Creek, CA) and 10 mg/liter rifampicin (Sigma-Aldrich, St. Louis, MO). Plates were incubated at 26°C in the dark for 5 days. A sporulating, dematiaceous, mitosporic fungus was observed and transferred to potato dextrose agar. Colonies were white to gray, with brown as conidia increased. Conidia ranged in size from 10 to 22.5 × 20 to 37.5 (average 15.2 × 26.5) μm. Conidia were golden to dark brown, broadly ellipsoidal, some pyriform, with one longitudinal septum and two to three transverse septa, sometimes constricted at the transverse septa. Based on microscopic examination, the fungus was identified as Pithomyces chartarum (Berk. & Curt.) M.B. Ellis (1); observations were consistent with the authority (2). Pathogenicity assays were conducted with 5-week-old ‘Alamo’ switchgrass grown from seed scarified with 60% sulfuric acid and surface-sterilized with 50% bleach. Seed were sown in 9 × 9-cm pots containing 50% (v/v) ProMix Potting and Seeding Mix (Premier Tech Horticulture, Québec, Canada) and 50% Turface ProLeague (Profile Products, Buffalo Grove, IL). Eight replicate pots with ~20 plants each were sprayed with a spore suspension of 5.7 × 105 spores/ml sterile water prepared from 6-day-old cultures grown on V8 juice agar in the dark. Two more pots were sprayed with sterile water to serve as controls. All plants were subjected to high humidity for 72 h by enclosure in a plastic bag. Plants were placed in a growth chamber at 25/20°C with a 12-h photoperiod. Leaf spot symptoms similar to the original disease were evident on plants in each of the eight replicate pots 6 to 10 days post-inoculation. Control plants had no symptoms. Lesions were excised from leaves, surface sterilized, and plated on WA. The resulting cultures were again identified as P. chartarum based on morphology. The internal transcribed spacer (ITS) region of rDNA from the original isolate and the pathogen recovered from plants in the pathogenicity tests were amplified with PCR using primers ITS4 and ITS5. PCR amplicons were obtained from both isolates, sequenced, and found to have 100% identity. A 580-bp sequence was deposited at GenBank (Accession No. JQ406588). The nucleotide sequence had 98 to 100% identity to the ITS sequences of isolates of Leptosphaerulina chartarum (anamorph: P. chartarum), including isolate Mxg-KY09-s4 (GU195649) from leaf spot on Miscanthus × giganteus in Kentucky (1), and isolates from leaf lesions on wheat (EF489400 and JX442978). To our knowledge, leaf spot caused by P. chartarum has not been described on switchgrass (3). Pithomyces chartarum is a seedborne pathogen of switchgrass, and may play a role in stand establishment. References: (1) M. O. Ahonsi et al. Plant Dis. 94:480, 2010. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England. 1971. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA, Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 18 January 2013.

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First Report of Leaf Spot of Milky Bellflower (Campanula lactiflora) Caused by a Phoma sp. in Italy

Plant Disease ◽

10.1094/pdis-94-5-0638a ◽

2010 ◽

Vol 94 (5) ◽

pp. 638-638

Author(s):

A. Garibaldi ◽

D. Bertetti ◽

C. Pellegrino ◽

M. L. Gullino

Keyword(s):

United States ◽

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

The United States ◽

Fluorescent Light ◽

Herbaceous Plant ◽

Pathogenicity Test ◽

First Report ◽

Perennial Herbaceous Plant

Campanula lactiflora (milky bellflower), a perennial herbaceous plant in the Campanulaceae, is used in park and gardens and sometimes cultivated for cut flower production. In June 2008, a previously unknown leaf spot was observed on C. lactiflora ‘New Hybrids’ plants from an experimental nursery located near Carmagnola (Torino, northern Italy). Leaves of infected plants showed extensive and irregular, dark brown, necrotic lesions that were slightly sunken with well-defined borders. Lesions initially ranged from 0.5 to 3 mm, eventually coalesced, and covered the entire leaf. Black pycnidia (107 to 116 μm in diameter) containing hyaline, ellipsoid, nonseptate conidia measuring 3.7 to 4.7 × 1.2 to 2.0 (average 4.3 × 1.6) μm were observed. On the basis of these morphological characteristics, the fungal causal agent of the disease could be related to the genus Phoma. In some cases, the basal leaves turned completely necrotic and the plant died. The disease affected 50% of plants. Diseased tissue was excised, immersed in a solution containing 1% sodium hypochlorite for 2 to 3 s, rinsed in water, and then cultured on potato dextrose agar (PDA) medium. A fungus developed that produced a greenish gray mycelium with a white border when incubated under 12 h/day of fluorescent light at 22 to 25°C. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 459-bp segment showed a 100% similarity with the sequence of a Didymella sp. (synonym Mycosphaerella), anamorphic stage of Phoma spp. The nucleotide sequence has been assigned GenBank Accession No. GU128503. Pathogenicity tests were performed by placing 8-mm-diameter mycelial disks removed from PDA cultures of the fungus isolated from infected plants on leaves of healthy potted 4-month-old C. lactiflora ‘New Hybrids’ plants. Eight disks were placed on each plant. Plants inoculated with PDA alone served as controls. Six plants per treatment were used. Plants were covered with plastic bags for 4 days after inoculation and maintained in a growth chamber with daily average temperatures ranging between 23 and 24°C. The first foliar lesions developed on leaves 5 days after inoculation, and after 8 days, 80% of leaves were severely infected. Control plants remained healthy. A Didymella sp. was consistently reisolated from leaf lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of a Didymella sp. on C. lactiflora in Italy. Mycosphaerella campanulae and M. minor were reported on C. americana and C. lasiocarpa in the United States (2). The economic importance of the disease currently is limited, but could become a more significant problem in the future if the cultivation of this species becomes more widespread. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989.

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First Report of Botrytis cinerea Causing Leaf Spot of Aquilegia vulgaris in Japan

Plant Disease ◽

10.1094/pdis-93-4-0425a ◽

2009 ◽

Vol 93 (4) ◽

pp. 425-425 ◽

Cited By ~ 2

Author(s):

M. Zhang ◽

T. Tsukiboshi ◽

I. Okabe

Keyword(s):

United States ◽

Botrytis Cinerea ◽

Leaf Spot ◽

Leaf Tissue ◽

The United States ◽

Plant Diseases ◽

Its2 Region ◽

Commonwealth Mycological Institute ◽

First Report ◽

Leaf Spots

European columbine, Aquilegia vulgaris L., Ranunculaceae, is an herbaceous flower widely used in gardens, parterres, and courtyards and is a traditional herbal plant. During the summer of 2008, leaf spots were observed on a plant cultivated along a roadside area in Nasushiobara, Tochigi, Japan. In some courtyards, the leaf spot affected more than 60% of the plants. Early symptoms appeared as small, round or elliptic, brown lesions on the leaves. Lesions expanded to 5 to 15 × 4 to 10 mm, irregular spots that were dark brown to black in the middle, with pale yellow-brown or purple-brown margins. In continuously wet or humid conditions, thick, gray mycelium and conidia appeared on the surface of leaf spots. Conidiophores were melanized at the base and hyaline near the apex, branched, and septated (approximately 3 mm × 16 to 18 μm). Conidia were hyaline, aseptate, ellipsoidal to obovoid, with a slightly protuberant hilum, and ranged from 9 to 14.5 × 5.5 to 6.5 μm. The pathogen was identified as Botrytis cinerea Pers.:Fr on the basis of morphology and sequence of ITS1-5.8s-ITS2 region of rDNA. The sequence (GenBank Accession No. FJ424510) exactly matched the sequences of two Botryotinia fuckeliana (anamorph Botrytis cinerea), (e.g., GenBank Accession Nos. AY686865 and FJ169666) (2). The fungus was isolated on potato dextrose agar (PDA) from a single conidium found on the symptomatic leaf tissue. Colonies of B. cinerea were first hyaline and later turned gray to black when the spores differentiated. Koch's postulates were performed with three whole plants of potted aquilegia. Leaves were inoculated with mycelia plugs harvested from the periphery of a 7-day-old colony; an equal number of plants were inoculated with the plugs of PDA medium only and served as controls. All plants were covered with plastic bags for 24 h to maintain high relative humidity and incubated at 25°C. After 8 days, all mycelium-inoculated plants showed symptoms identical to those observed on leaves from A. vulgaris infected in the field, whereas controls remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was B. cinerea. B. cinerea has been previously reported on A. vulgaris in the United States and China (1,3). To our knowledge, this is the first report of leaf spots caused by B. cinerea on A. vulgaris in Japan. References: (1) Anonymous. Index of Plant Diseases in the United States. USDA Agric. Handb. No 165, 1960. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) Z. Y. Zhang. Flora Fungorum Sinicorum. Vol. 26. Botrytis, Ramularia. Science Press, Beijing, 2006.

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First Report of Leaf Spot Caused by Alternaria alternata on Switchgrass in Tennessee

Plant Disease ◽

10.1094/pdis-09-11-0785 ◽

2012 ◽

Vol 96 (5) ◽

pp. 763-763 ◽

Cited By ~ 2

Author(s):

A. L. Vu ◽

M. M. Dee ◽

T. Russell ◽

J. Zale ◽

K. D. Gwinn ◽

...

Keyword(s):

Alternaria Alternata ◽

Leaf Spot ◽

Panicum Virgatum ◽

Leaf Tissue ◽

Its Region ◽

Sporulation Medium ◽

Sterile Water ◽

One Pot ◽

First Report ◽

Leaf Spots

Field-grown seedlings of ‘Alamo’ switchgrass (Panicum virgatum L.) from Vonore, TN exhibited light brown-to-dark brown leaf spots and general chlorosis in June 2009. Symptomatic leaf tissue was surface sterilized (95% ethanol for 1 min, 20% commercial bleach for 3 min, and 95% ethanol for 1 min), air dried on sterile filter paper, and plated on 2% water agar amended with 10 mg/liter rifampicin (Sigma-Aldrich, St. Louis, MO) and 5 μl/liter miticide (2.4 EC Danitol, Valent Chemical, Walnut Creek, CA). Plates were incubated at 26°C for 4 days in darkness. An asexual, dematiaceous mitosporic fungus was isolated and transferred to potato dextrose agar. Cultures were transferred to Alternaria sporulation medium (3) to induce conidial production. Club-shaped conidia were produced in chains with branching of chains present. Conidia were 27 to 50 × 10 to 15 μm, with an average of 42.5 × 12.5 μm. Morphological features and growth on dichloran rose bengal yeast extract sucrose agar were consistent with characteristics described previously for Alternaria alternata (1). Pathogenicity studies were conducted with 5-week-old ‘Alamo’ switchgrass plants grown from surface-sterilized seed. Nine pots with approximately 20 plants each were prepared. Plants were wounded by trimming the tops. Eight replicate pots were sprayed with a conidial spore suspension of 5.0 × 106 spores/ml sterile water and subjected to high humidity by enclosure in a plastic bag for 7 days. One pot was sprayed with sterile water and subjected to the same conditions to serve as a control. Plants were maintained in a growth chamber at 25/20°C with a 12-h photoperiod. Foliar leaf spot symptoms appeared 5 to 10 days postinoculation for all replicate pots inoculated with A. alternata. Symptoms of A. alternata infection were not observed on the control. Lesions were excised, surface sterilized, plated on water agar, and identified in the same manner as previously described. The internal transcribed spacer (ITS) region of ribosomal DNA and the mitochondrial small sub-unit region (SSU) from the original isolate and the reisolate recovered from the pathogenicity assay were amplified with PCR, with primer pairs ITS4 and ITS5 and NMS1 and NMS2, respectively. Resultant DNA fragments were sequenced and submitted to GenBank (Accession Nos. HQ130485.1 and HQ130486.1). A BLAST search (BLASTn, NCBI) was run against GenBank isolates. The ITS region sequences were 537 bp and matched 100% max identity with eight A. alternata isolates, including GenBank Accession No. AB470838. The SSU sequences were 551 bp and matched 100% max identity with seven A. alternata isolates, including GenBank Accession No. AF229648. A. alternata has been reported from switchgrass in Iowa and Oklahoma (2); however, this is the first report of A. alternata causing leaf spot on switchgrass in Tennessee. Switchgrass is being studied in several countries as a potentially important biofuel source, but understanding of the scope of its key diseases is limited. References: (1) B. Andersen et al. Mycol. Res. 105:291, 2001. (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/ , September 22, 2011. (3) E. A. Shahin and J. F. Shepard. Phytopathology 69:618, 1979.

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First Report of Passalora Leaf Spot of Quinoa Caused by Passalora dubia in the United States

Plant Disease ◽

10.1094/pdis-05-12-0472-pdn ◽

2013 ◽

Vol 97 (1) ◽

pp. 139-139 ◽

Cited By ~ 3

Author(s):

A. L. Testen ◽

J. M. McKemy ◽

P. A. Backman

Keyword(s):

United States ◽

Leaf Spot ◽

Biological Control Agent ◽

Chenopodium Quinoa ◽

Its Region ◽

The United States ◽

Tween 20 ◽

Potato Dextrose Broth ◽

First Report ◽

Rainy Period

The Andean seed crop quinoa, Chenopodium quinoa Willd., is an important export of Bolivia, Ecuador, and Peru. Key foliar diseases of quinoa include quinoa downy mildew (caused by Peronospora variabilis Gäum) (1), Ascochyta leaf spot (caused by Ascochyta sp.) (1), and a Cercospora-like leaf spot, the latter of which has been observed on cultivated quinoa (Jose B. Ochoa, unpublished) and native Chenopodium species. Passalora dubia (Riess) U. Braun (syn. Cercospora dubia) was tested in Europe as a biological control agent for Chenopodium album (3) and has been reported on C. album in the United States (U.S. National Fungus Collections). Quinoa field plots were established in Pennsylvania during summer 2011 and Cercospora-like leaf spot symptoms were first observed on quinoa in Centre Co. and Lancaster Co. in August 2011, after an extended rainy period. Foliar symptoms were round to oval, brown to grey-black lesions, less than 1 cm in diameter, with darker brown, reddish margins. Similar symptoms were observed on C. album weeds within both fields. Using a hand lens, conidia were observed within sporulating lesions. Conidia were hyaline and septate, 25 to 98 μm × 5 to 10 μm, and had an average of six cells per conidium. The fungus was isolated by picking single conidia from sporulating lesions (under a dissecting scope) and incubated on V8 agar in the dark at 20°C to induce sporulation. For DNA extraction, cultures were grown in potato dextrose broth amended with yeast extract. The internal transcribed spacer (ITS) region was amplified using primers ITS4 and ITS5 (2), and the resulting sequence shared 99% maximum identity with a vouchered isolate of P. dubia (GenBank EF535655). To test the pathogenicity of our P. dubia isolate, 5.9 × 103 conidia/ml (suspended in sterile water with 0.1% Tween 20) or the control solution with no conidia were sprayed, using an atomizer, onto 2-month-old quinoa plants, with 18 replications per treatment. Plants were covered with a humidity dome and maintained at >99% RH for 48 h. Plants were grown in the greenhouse at approximately 65% RH. After 1 month, circular to oval light brown lesions (<1 cm diameter) with darker margins were observed on approximately 10% of the leaves of inoculated plants, whereas no symptoms were observed on the control plants. Infected leaves were collected, incubated in a humidity chamber, and conidia were picked from sporulating lesions and inoculated onto V8 agar amended with 3% (w/v) fresh, ground quinoa plant tissue (4). Cultures were maintained at 20°C with 16-h photoperiod to induce sporulation. The identity of the reisolated fungus was confirmed morphologically and by DNA sequencing to be identical to the isolate used to test Koch's postulates. P. dubia was also isolated from C. album lesions and infected C. album may have served as a source of inoculum for quinoa. To our knowledge, this is the first report of Passalora leaf spot of quinoa in the United States. References: (1) S. Danielsen. Food Rev. Int. 19:43, 2003. (2) S. Goodwin et al. Phytopathology 91:648, 2001. (3) P. Scheepens et al. Integ. Pest. Man. Rev. 2:71, 1997. (4) M. Vathakos. Phytopathology 69:832, 1979.

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Field Evaluations of Leaf Spot Resistance and Yield in Peanut Genotypes in the United States and Bolivia

Plant Disease ◽

10.1094/pdis-06-10-0454 ◽

2011 ◽

Vol 95 (3) ◽

pp. 263-268 ◽

Cited By ~ 4

Author(s):

S. K. Gremillion ◽

A. K. Culbreath ◽

D. W. Gorbet ◽

B. G. Mullinix ◽

R. N. Pittman ◽

...

Keyword(s):

United States ◽

Disease Resistance ◽

Leaf Spot ◽

Field Experiments ◽

Disease Incidence ◽

The United States ◽

Yield Potential ◽

Cercospora Arachidicola ◽

Breeding Lines ◽

Progress Curve

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.

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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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Comparative Genetic Analysis of Magnaporthe oryzae Isolates Causing Gray Leaf Spot of Perennial Ryegrass Turf in the United States and Japan

Plant Disease ◽

10.1094/pdis-91-5-0517 ◽

2007 ◽

Vol 91 (5) ◽

pp. 517-524 ◽

Cited By ~ 15

Author(s):

Y. Tosa ◽

W. Uddin ◽

G. Viji ◽

S. Kang ◽

S. Mayama

Keyword(s):

United States ◽

Perennial Ryegrass ◽

Magnaporthe Oryzae ◽

Leaf Spot ◽

Genetic Relationships ◽

The United States ◽

Gray Leaf Spot ◽

Genetic Lineage ◽

Type I ◽

Type Ii

Gray leaf spot caused by Magnaporthe oryzae is a serious disease of perennial ryegrass (Lolium perenne) turf in golf course fairways in the United States and Japan. Genetic relationships among M. oryzae isolates from perennial ryegrass (prg) isolates within and between the two countries were examined using the repetitive DNA elements MGR586, Pot2, and MAGGY as DNA fingerprinting probes. In all, 82 isolates of M. oryzae, including 57 prg isolates from the United States collected from 1995 to 2001, 1 annual ryegrass (Lolium multiflorum) isolate from the United States collected in 1972, and 24 prg isolates from Japan collected from 1996 to 1999 were analyzed in this study. Hybridization with the MGR586 probe resulted in approximately 30 DNA fragments in 75 isolates (designated major MGR586 group) and less than 15 fragments in the remaining 7 isolates (designated minor MGR586 group). Both groups were represented among the 24 isolates from Japan. All isolates from the United States, with the exception of one isolate from Maryland, belonged to the major MGR586 group. Some isolates from Japan exhibited MGR586 fingerprints that were identical to several isolates collected in Pennsylvania. Similarly, fingerprinting analysis with the Pot2 probe also indicated the presence of two distinct groups: isolates in the major MGR586 group showed fingerprinting profiles comprising 20 to 25 bands, whereas the isolates in the minor MGR586 group had less than 10 fragments. When MAGGY was used as a probe, two distinct fingerprint types, one exhibiting more than 30 hybridizing bands (type I) and the other with only 2 to 4 bands (type II), were identified. Although isolates of both types were present in the major MGR586 group, only the type II isolates were identified in the minor MGR586 group. The parsimony tree obtained from combined MGR586 and Pot2 data showed that 71 of the 82 isolates belonged to a single lineage, 5 isolates formed four different lineages, and the remaining 6 (from Japan) formed a separate lineage. This study indicates that the predominant groups of M. oryzae associated with the recent outbreaks of gray leaf spot in Japan and the United States belong to the same genetic lineage.

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Surgical instrumentation: the true cost of instrument trays and a potential strategy for optimization

Journal of Hospital Administration ◽

10.5430/jha.v4n6p82 ◽

2015 ◽

Vol 4 (6) ◽

pp. 82 ◽

Cited By ~ 6

Author(s):

Julie M. Mhlaba ◽

Emily W. Stockert ◽

Martin Coronel ◽

Alexander J. Langerman

Keyword(s):

United States ◽

Cost Savings ◽

Cost Effective ◽

The United States ◽

Waste Reduction ◽

Significant Cost ◽

Instrument Type ◽

Hospital Revenue ◽

Potential Strategy ◽

The Cost

Objective: Operating rooms (OR) generate a large portion of hospital revenue and waste. Consequently, improving efficiency and reducing waste is a high priority. Our objective was to quantify waste associated with opened but unused instruments from trays and to compare this with the cost of individually wrapping instruments.Methods: Data was collected from June to November of 2013 in a 550-bed hospital in the United States. We recorded the instrument usage of two commonly-used trays for ten cases each. The time to decontaminate and reassemble instrument trays and peel packs was measured, and the cost to reprocess one instrument was calculated.Results: Average utilization was 14% for the Plastic Soft Tissue Tray and 29% for the Major Laparotomy Tray. Of 98 instruments in the Plastics tray (n = 10), 0% was used in all cases observed and 59% were used in no observed cases. Of 110 instruments in the Major Tray (n = 10), 0% was used in all cases observed and 25% were used in no observed cases. Average cost to reprocess one instrument was $0.34-$0.47 in a tray and $0.81-$0.84 in a peel pack, or individually-wrapped instrument.Conclusions: We estimate that the cost of peel packing an instrument is roughly two times the cost of tray packing. Therefore, it becomes more cost effective from a processing standpoint to package an instrument in a peel pack when there is less than a 42%-56% probability of use depending on instrument type. This study demonstrates an opportunity for reorganization of instrument delivery that could result in a significant cost-savings and waste reduction.

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Pension Enhancements and the Retention of Public Employees

ILR Review ◽

10.1177/0019793916650452 ◽

2016 ◽

Vol 70 (2) ◽

pp. 519-551 ◽

Cited By ~ 6

Author(s):

Cory Koedel ◽

P. Brett Xiang

Keyword(s):

United States ◽

Public Sector ◽

Employee Retention ◽

Cost Effective ◽

The United States ◽

Pension Plans ◽

Public Employees ◽

Public School Teachers ◽

School Teachers ◽

Public Pension Plans

The authors use data from workers in the largest public-sector occupation in the United States—teaching—to examine the effect of pension enhancements on employee retention. Specifically, they study a 1999 enhancement to the benefit formula for public school teachers in St. Louis, Missouri, that resulted in an immediate and dramatic increase in their incentives to remain in covered employment. To identify the effect of the enhancement on teacher retention, the analysis leverages the fact that the strength of the incentive increase varied across the workforce depending on how far teachers were from retirement eligibility when it was enacted. The results indicate that the St. Louis enhancement—which was structurally similar to enhancements that were enacted in other public pension plans across the United States in the late 1990s and early 2000s—was not a cost-effective way to increase employee retention.

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