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

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 381-381 ◽  
Author(s):  
R. L. Hirsch ◽  
D. O. TeBeest ◽  
B. H. Bluhm ◽  
C. P. West

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.

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 1034-1034
Author(s):  
M. A. Delaney ◽  
E. J. Sikora ◽  
D. P. Delaney ◽  
M. E. Palm ◽  
J. Roscoe ◽  
...  

Soybean rust, caused by the fungus Phakopsora pachyrhizi, was detected on jicama (Pachyrhizus erosus L. Urban) for the first time in the United States in November 2009. The pathogen was observed on leaves of a single, potted jicama plant grown outdoors in a residential area and on leaves of all plants in a 12-m2 demonstration plot located at the Auburn University Teaching Garden in Auburn, AL. Symptoms on the upper leaf surfaces were isolated chlorotic areas near the leaf edges in the lower part of the canopy. The abaxial surface was first observed to exhibit brown lesions and subsequently produced volcano-shaped uredinia. These symptoms are consistent with a rust previously described on jicama in Mexico (1). Representative symptomatic plant tissue was sent to the USDA National Identification Services (Mycology) Laboratory in Beltsville, MD for diagnostic confirmation at both the Urbana, IL lab and the USDA National Plant Germplasm and Biotechnology Laboratory for DNA testing. From an infected leaf, samples of approximately 5 mm2 were excised from a microscopically observed rust lesion and an apparently noninfected area. Total DNA was purified with the FastDNA Spin Kit (MP Biomedicals, Solon, OH) followed by the E.Z.N.A. MicroElute DNA Clean-Up Kit (Omega Bio-tek, Inc, Doraville, GA) per manufacturer's instructions. Detection of P. pachyrhizi and P. meibomiae DNA was achieved by quantitative PCR using the method of Frederick et al. (2) and a DNA standard of previously prepared P. pachyrhizi spores. The observed rust pustule was found to contain P. pachyrhizi DNA in excess of 28,000 genomes, while no P. pachyrhizi DNA was observed from the asymptomatic sample. Both samples were negative for P. meibomiae. The fungal structures present were confirmed to be Phakopsora spp. DNA was extracted from sori aseptically removed from leaves with a Qiagen (Valencia, CA) DNeasy Plant Mini Kit and amplified with primers Ppa1 and NL4. The resulting partial ITS2 and 28S ribosomal RNA sequences were 100% identical to GenBank entry DQ354537 P. pachyrhizi internal transcribed spacer 2 and 28S ribosomal RNA gene, partial sequence. Sequences from jicama from Alabama were deposited in GenBank. Voucher specimens were deposited in the USDA Agricultural Research Service, National Fungus Collection (BPI). To our knowledge, this is the first report of the disease on jicama in the United States. References: (1) A. Cárcamo Rodriguez et al. Plant Dis. 90:1260, 2006. (2) R. D. Frederick et al. Phytopathology 92:217, 2002.


Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 423-423 ◽  
Author(s):  
S. Uppala ◽  
B. M. Wu ◽  
T. N. Temple

Utah sweetvetch (Hedysarum boreale Nutt.) is a native American perennial nitrogen fixing legume used mainly in rangeland reclamation, soil rejuvenation, and erosion control. In June 2011, a field of Utah sweetvetch grown for seeds in central Oregon had approximately 15% of the plants exhibiting chlorosis, defoliation, stunting, wilting, and/or death. Dissection of the crown of symptomatic plants revealed discolored pinkish brown vascular tissue. Symptomatic tissues from six random plants were surface sterilized, placed on acidified potato dextrose agar (PDA) medium, and cultured for 7 days at room temperature, which allowed six fungal isolates (SS1 through SS6) to be collected. On PDA, all six isolates had rapid, creamy white colored growth. Based on observations of 1-week-old isolates, microconidia were oval to kidney shaped, single celled, 8 to 10 × 2.5 to 4 μm, and formed at the tips of long unbranched monophialides. Macroconidia were three to four septate, cylindrical to slightly curved, with characteristic foot shaped basal cell and blunt apical cell, 37 to 49 × 4.4 to 5.3 μm. Chlaymydospores observed were 8.5 to 11 × 7.6 to 9 μm. Based on fungal references (1,2,3), the isolates were identified as Fusarium solani (Mart.) Sacc. Identification of the isolates at the molecular level was determined by amplification of the internal transcribed spacer (ITS) region using PCR and amplicon sequencing. Botrytis cinerea and F. graminearum cultures were used as controls for the extraction, amplification, and sequencing steps. Genomic DNA was extracted from mycelia using protocols of the MOBIO Ultraclean Soil DNA Isolation Kit (MO-BIO Laboratories Inc, Carlsbad, CA, USA). PCR was performed using ITS1/ITS4 primers and resulted in 563- to 573-bp amplicons, which were sequenced. Analysis of the ITS sequences (GenBank Accession Nos. JX524018 to JX524023) for the six fungal isolates using BLASTn revealed a 99% sequence identity with F. solani strains (AB470903, AB513851, AJ608989, EF152426, EU029589, and HM214456). Pathogenicity was confirmed on Utah sweetvetch plants in the greenhouse. Seeds of Utah sweetvetch were first plated on acidified PDA for germination; healthy seedlings were then selected and transplanted into pots with sterilized soil after 2 weeks of growth. The plants were kept in a greenhouse at Central Oregon Agricultural Research Center, Madras, Oregon. Ten 40-day-old healthy vetch plants were inoculated by drenching with a mixed conidial suspension (107 conidia/ml) of the six F. solani isolates. Ten plants drenched with sterile distilled water were included as controls. Symptoms of chlorosis and stunting similar to those in the commercial field were observed within 30 days of inoculation on 8 of 10 inoculated plants, while control plants were symptomless. Fungal isolates identical to F. solani were reisolated from the symptomatic plants. To our knowledge, this is the first report of F. solani on Utah sweetvetch plants. References: (1) C. Booth. The Genus Fusarium. CMI, Kew, Surrey, UK, 1971. (2) P. E. Nelson et al. Fusarium species: An illustrated manual for identification. The Pennsylvania State University Press, USA, 1983. (3) H. I. Nirenberg. A simplified method for identifying Fusarium spp. occurring on wheat. Can. J. Bot. 59:1599, 1980.


2021 ◽  
Vol 3 (197) ◽  
pp. 9-16
Author(s):  
V.N. Minat ◽  

The innovation-oriented effective development of US agriculture is determined by the quantity and quality of the implemented results of agricultural research, funded by the main funds holder – the state. The purpose of the study is to identify trends in government funding of agricultural science in the United States. The rationale for these trends is considered in the unity of the dynamics and structure of state financing of agricultural research in 1889–2019 and the system characteristics of this process as an economic phenomenon. Using the techniques of statistical-economic and abstract- logical methods of research, combined with a historical approach to the subject of study, the author obtained empirical results reflecting the dynamics of structural changes in the state financing of agricultural research in the United States in different time periods. The trends towards regionalization of agricultural science subsidies within the federal state are also identified.


Plant Disease ◽  
2003 ◽  
Vol 87 (3) ◽  
pp. 313-313 ◽  
Author(s):  
C. X. Hong ◽  
T. J. Banko

Disease samples of Gaillardia × grandiflora cvs. Goblin and Baby Cole were received at the Hampton Roads Agricultural Research and Extension Center in Virginia Beach in early April 2002. Samples were from a nursery in eastern Virginia, and most diseased plants had several to more than a dozen, round, flat, white to tan spots with indistinct margins up to 1 cm in diameter on their leaves. The spots later turned brown and necrotic, followed by necrosis of the entire leaf. Leaves of ‘Baby Cole’ were beginning to wilt and were more spotted than those of ‘Goblin’. Fungal fruiting bodies were not observed on the surface of diseased leaves. However, microscopic examination of internal leaf tissues revealed masses of round, double-walled, pale green-to-yellow spores approximately 12 μm in diameter and typical of the ustilospores of Entyloma polysporum (2,3). Inoculum for pathogenicity tests was prepared by blending 10 diseased leaves in 200 ml of sterile distilled water (SDW) for 2 min in a blender at low speed. The spore suspension was adjusted to 5 × 105 spores per ml with SDW. Healthy ‘Goblin’ gaillardia plants were obtained from a nursery where smut symptoms had never been seen. Four plants in one-gallon containers were inoculated by spraying them to runoff with the spore suspension. Four control plants were sprayed with SDW only. All plants were maintained in a greenhouse (15 to 35°C) and covered with a clean polyethylene plastic sheet overnight (14 h) to maintain high humidity and separated to avoid potential cross contamination. Inoculated and uninoculated plants were hand-watered separately, with application of water to the foliage to enhance spread of the disease. Typical white smut symptoms were observed on inoculated plants 2 weeks after inoculation, and numerous spores of E. polysporum were observed in the diseased tissues. No disease symptoms were seen on control plants. White smut has been reported on gaillardia in a few other states (1), but to our knowledge, this is the first report of the disease on gaillardia in Virginia. Growers at the affected nursery reported observing white smut symptoms on gaillardia in previous years, but in the spring of 2002, almost the entire gaillardia crop was destroyed. The disease has not been seen on gaillardia in any other nurseries, but it could have significant impact on production if it spreads. 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) W. Fischer. Manual of the North American Smut Fungi. Ronald Press, New York, 1953. (3) D. B. O. Savile. Can. J. Res. 25(C):109,1947.


Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 125-125 ◽  
Author(s):  
L. X. Zelaya-Molina ◽  
M. L. Ellis ◽  
S. A. Berry ◽  
A. E. Dorrance

During the spring of 2004, corn seedlings with symptoms of wilting and stunting were observed in corn fields with emergence problems in Madison and Brown counties, Ohio. Phytophthora isolates were recovered from sections of root tissue of diseased seedlings placed on dilute V8 media amended with pentachloronitrobenzene, iprodione, benlate, neomycin sulfate, and chloramphenicol. Colonies were rosaceous on potato dextrose agar, with a growth rate of 5 mm per day. Homothallic isolates with paragynous antheridia were observed on lima bean agar (LBA); oogonia were 35 to 50 μm in diameter. Sporangia were ovoid to obpyriform, nonpapillate, with an average size of 49 × 30 μm. Pathogenicity was tested on corn seeds using a petri dish assay with 3-day-old cultures on LBA and a sand-cornmeal cup test amended with inoculum from 7-day-old cultures on LBA (1). After 1 week in the petri dish assay, the seeds failed to germinate completely and were covered with white, fungal-like, aerial mycelia and the pathogen was recovered from brown discolored radicle roots. In the cup assay, 2-week-old seedlings developed the same symptoms observed in the field; the pathogen was also isolated from brown discolored roots. In both assays, no symptoms developed in the noninoculated controls. Both pathogenicity tests were repeated two times. Genomic DNA was extracted from mycelia of two isolates and the internal transcribed spacer (ITS) region was amplified and sequenced using ITS6/ITS4 primers (2). Both isolates had identical ITS sequences (GenBank Accession No. GQ853880). A BLAST search of the NCBI database showed 100% homology with the sequence of the haplotype isolate of Phytophthora sansomeana (Accession No. EU925375). P. sansomeana is a new species characterized principally by a large oogonial diameter (37 to 45 μm), rapid growth rate (7 to 10 mm/day), and an ITS sequence falling in Cooke's clade 8 (4). Pathogenicity tests, morphological characteristics, and the ITS sequence analysis indicate that P. samsomena is the causal agent of the symptoms observed on corn seedlings. P. sansomeana has been reported as a pathogen of soybean in Indiana, Douglas-fir in Oregon, and weeds in alfalfa fields in New York (4). To our knowledge, this is the first report of P. sansomeana infecting corn in Ohio, albeit other isolates have previously been recovered from soybean in the state. There are four previous reports of Phytophthora spp. affecting corn in the United States and Mexico (3). Crop rotation will have little effect in management of this pathogen since corn and soybean are produced in the same fields continuously throughout the state. References: (1) K. E. Broders et al. Plant. Dis. 91:727, 2007. (2) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (3) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. 1989. (4) E. M. Hansen et al. Mycologia 101:129, 2009.


Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1510-1510 ◽  
Author(s):  
J. H. Park ◽  
K. S. Han ◽  
J. Y. Kim ◽  
H. D. Shin

Sansevieria, Sansevieria trifasciata Prain, is cultivated in greenhouses and is used as a potted interior foliage plant in Korea. In April 2012, several plants (cv. Moonshine) exhibiting typical anthracnose symptoms from a local nursery were sent to the plant clinic of Gyeonggi-Do Agricultural Research and Extension Services for diagnosis. The leaf lesions began as round, partly water-soaked, pale greenish to grayish spots, which enlarged and ultimately coalesced, resulting in severe leaf blight. Concentric rings of blackish acervuli were formed in the expanding lesions of mostly 2 to 4 cm in diameter. Acervuli were mostly epiphyllous, circular to ellipsoid. Setae were aseptate to 3-septate, dark brown at the base, paler upwards, acicular, and up to 180 μm long. Conidia (n = 30) were oblong-elliptical to obovate, sometimes fusiform-elliptical, guttulate, hyaline, and 14 to 24 × 5 to 7.5 μm (mean 18.6 × 6.4 μm). Hyphopodial appressoria were dark brown to blackish, globose to clavate in outline, and 5 to 12 × 4 to 8 μm. Colonies on potato dextrose agar (PDA) were grayish-white, felted with cottony-white aerial mycelium on a gray to olivaceous gray background in culture. Gelatinous salmon- to orange-colored conidial masses were produced abundantly after one week's incubation. The morphological and cultural characteristics of the fungus were consistent with the description of Colletotrichum sansevieriae M. Nakamura & M. Ohzono (2,3). A voucher specimen was deposited in the Korea University herbarium (KUS-F26637). An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46835). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting 569-bp sequences were deposited in GenBank (Accession No. KC847065). A BLAST search in GenBank exhibited 100% nucleotide identity with sequence of C. sansevieriae (JF911349) from the United States and >99% similarity with that of HQ433226 from Australia. To confirm pathogenicity, inoculum was prepared by harvesting conidia from 3-week-old cultures on PDA. A conidial suspension (2 × 106 conidia/ml) was sprayed over the five leaves of sansevieria ‘Moonshine’ wounded with a fine needle. Five leaves sprayed with sterile water served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 48 h and then kept in a greenhouse (22 to 28°C and 70 to 80% RH). Within 12 days, symptoms identical to those observed in originally infected leaf developed on all inoculated leaves. No symptoms were observed on control plants. C. sansevieriae was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. Sansevieria anthracnose associated with C. sansevieriae has been reported in Japan (2), Australia (1), and the United States (3). To our knowledge, this is the first report of sansevieria anthracnose in Korea. Our observations in sansevieria nurseries suggest that preventing wound infection as well as maintaining good plant hygiene in greenhouses might be main strategies for this disease. References: (1) R. Aldaoud et al. Australas. Plant Dis. Notes 6:60, 2011. (2) M. Nakamura et al. J. Gen. Plant Pathol. 72:253, 2006. (3) A. J. Palmateer et al. Plant Dis. 96:293, 2012.


Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1710-1710 ◽  
Author(s):  
J. Zale ◽  
L. Freshour ◽  
S. Agarwal ◽  
J. Sorochan ◽  
B. H. Ownley ◽  
...  

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.


Commonwealth ◽  
2017 ◽  
Vol 19 (2) ◽  
Author(s):  
Jennie Sweet-Cushman ◽  
Ashley Harden

For many families across Pennsylvania, child care is an ever-present concern. Since the 1970s, when Richard Nixon vetoed a national childcare program, child care has received little time in the policy spotlight. Instead, funding for child care in the United States now comes from a mixture of federal, state, and local programs that do not help all families. This article explores childcare options available to families in the state of Pennsylvania and highlights gaps in the current system. Specifically, we examine the state of child care available to families in the Commonwealth in terms of quality, accessibility, flexibility, and affordability. We also incorporate survey data from a nonrepresentative sample of registered Pennsylvania voters conducted by the Pennsylvania Center for Women and Politics. As these results support the need for improvements in the current childcare system, we discuss recommendations for the future.


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