First Report of Pathogenicity of Fusarium sporotrichioides and Fusarium acuminatum on Sunflowers in the United States

2010 ◽  
Vol 11 (1) ◽  
pp. 42 ◽  
Author(s):  
F. Mathew ◽  
B. Kirkeide ◽  
T. Gulya ◽  
S. Markell
Keyword(s):  
United States ◽  
Helianthus Annuus ◽  
The United States ◽  
Fusarium Sporotrichioides ◽  
Charcoal Rot ◽  
Koch’S Postulates ◽  
First Report ◽  
Fusarium Acuminatum ◽  
Helianthus Annuus L ◽  
Koch's Postulates

Widespread infection of charcoal rot was observed in a commercial sunflower field in Minnesota in September 2009. Based on morphology, isolates were identified as F. sporotrichioides and F. acuminatum. Koch's postulates demonstrated pathogencity of both species. To our knowledge, this is the first report of F. sporotrichoides and F. acuminatum causing disease on Helianthus annuus L. in the United States. Accepted for publication 23 August 2010. Published 15 September 2010.

scholarly journals Recent Outbreak of Soybean Sudden Death Syndrome Caused by Fusarium virguliforme and F. tucumaniae in Argentina

Plant Disease ◽  
2004 ◽  
Vol 88 (9) ◽  
pp. 1044-1044 ◽  
Author(s):  
M. Scandiani ◽  
D. Ruberti ◽  
K. O'Donnell ◽  
T. Aoki ◽  
R. Pioli ◽  
...  
Keyword(s):  
United States ◽  
Phylogenetic Analyses ◽  
The United States ◽  
Positive Control ◽  
Koch’S Postulates ◽  
First Report ◽  
Molecular Phylogenetic ◽  
Soil Infestation ◽  
Pathogenicity Tests ◽  
Koch's Postulates

Sudden death syndrome (SDS) of soybean was detected initially in Argentina during 1991-1992 in the Pampas Region and 1992-1993 in the Northwest Region. The first report of the fulfillment of Koch's postulates of SDS caused by Fusarium solani f. sp. glycines in Argentina was published in 2003 (3). Subsequently, analyses have shown that F. solani f. sp. glycines represents several morphologically and phylogenetically distinct species, including F. tucumaniae in Argentina and F. virguliforme in the United States (1). Isolations were made from plants that exhibited typical SDS symptoms (interveinal foliar chlorosis and necrosis leading to defoliation of the leaflets but not the petioles) from fields in Santa Fe and Buenos Aires provinces in 2001, 2002, and 2003. To determine which species are responsible for SDS in Argentina, cultures of eight slow growing isolates that developed bluish pigmentation and produced abundant macroconidia in sporodochia on potato dextrose agar were subjected to morphological and molecular phylogenetic analyses and pathogenicity tests. Morphological analyses demonstrated that three of the isolates were F. virguliforme and five were F. tucumaniae. Isolates of F. tucumaniae produced long and narrow sporodochial conidia while F. virguliforme produced diagnostic comma-shaped conidia. Molecular phylogenetic analyses of DNA sequences from multiple loci confirmed morphology-based identifications and showed that the soybean SDS pathogen in the United States, F. virguliforme, was also present in Argentina. To our knowledge, this is the first report of F. virguliforme in Argentina and of this pathogen outside the United States. Five isolates of F. tucumaniae and three isolates of F. virguliforme were used for pathogenicity tests. F. virguliforme isolate 171 provided by J. Rupe (University of Arkansas, Fayetteville) was used as a positive control. Soybean cultivars Ripley, RA 702, Pioneer 9492RR, Spencer, and A-6445RG were inoculated with each of the isolates tested in a greenhouse assay using soil infestation and toothpick methods (2). All eight isolates produced typical foliar SDS symptoms 15 to 25 days after inoculation. Severity of foliar symptoms averaged 3.3 for F. virguliforme, 2.6 for F. tucumaniae, and 3.3 for the positive control using a disease severity scale in which 1 = no symptoms and 5 = severely infected or dead plants. Under these conditions, F. virguliforme appeared to be more virulent than F tucumaniae. Noninoculated plants remained symptomless. Koch's postulates were confirmed with soybean cultivars RA 702 and A6445RG. Isolates recovered from symptomatic plants inoculated by the soil infestation and toothpick methods were identical to those used to inoculate the plant. Strains were recovered at frequencies of 100 and 60% from plants inoculated by the toothpick and soil infestation methods, respectively. To our knowledge, this is the first report of the fulfillment of Koch's postulates for F. tucumaniae and F. virguliforme in Argentina. References: (1) T. Aoki et al. Mycologia 95:660, 2003. (2) K. W. Roy et al. Plant Dis. 81:1100, 1997 (3) M. Scandiani et al. Plant Dis. 87:447, 2003.

scholarly journals Occurrence of Cercospora Blight on Cryptomeria japonica (L.f.) D. Don in the United States

1985 ◽  
Vol 3 (1) ◽  
pp. 18-19
Author(s):  
R.L. Wick ◽  
R.C. Lambe
Keyword(s):  
United States ◽  
Cryptomeria Japonica ◽  
The United States ◽  
Rooted Cuttings ◽  
Koch’S Postulates ◽  
First Report ◽  
Koch's Postulates

This is the first report of the occurrence of Cercospora sequoiae as a pathogen of Cryptomeria japonica in the United States. Koch's postulates were fulfilled on rooted cuttings indoors; the fungus caused dark brown lesions on succulent needles and stems. Conidiophores were fascicled and measured 40-107 μm. Conidia were brown, 33–80 μm × 4–6 μm, echinulate and 3–8 septate.

scholarly journals First Report of Anthracnose of Sunflower Sprouts Caused by Colletotrichum acutatum in New Mexico

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 838-838
Author(s):  
J. M. French ◽  
J. J. Randall ◽  
R. A. Stamler ◽  
A. C. Segura ◽  
N. P. Goldberg
Keyword(s):  
New Mexico ◽  
Sequence Analysis ◽  
The United States ◽  
Disease Diagnosis ◽  
Colletotrichum Acutatum ◽  
Economic Losses ◽  
Distilled Water ◽  
Koch’S Postulates ◽  
First Report ◽  
Koch's Postulates

In December 2011, edible sunflower sprouts (Helianthus annus) of two different commercially grown cultivars (Sungrown and Tiensvold) exhibiting stem and cotyledon lesions were submitted to the New Mexico State University Plant Clinic for disease diagnosis. The sample originated from an organic farm in Santa Fe County where the grower utilizes a small indoor growing facility. Stem lesions were elongate, reddish brown, and often constricted, resulting in stem girdling. Lesions on the cotyledons were dark brown with tan centers and round to irregular in shape. In some cases, the entire cotyledon was blighted. Fungal hyphae were observed on some lesions using a dissecting microscope. Colletotrichum acutatum was isolated from stem and cotyledon lesions when symptomatic tissue was plated on water agar. Conidia were fusiform ranging from 6.4 to 18.4 μm long and 2.1 to 5.1 μm wide and averaged 11.9 μm × 3.4 μm. Spores were measured from cream-colored colonies produced on acidified potato dextrose agar. PCR amplification and sequence analysis of 5.8S ribosomal DNA and internal transcribed spacers I and II was performed using primers ITS4 and ITS6 (2). An amplification product of approximately 600 base pairs in size was directly sequenced (GenBank Accession No. JX444690). A BLAST search of the NCBI total nucleotide collection revealed a 99% identity to multiple C. acutatum (syn: C. simmondsii) isolates. Four isolates were identified as C. acutatum based on morphological characteristics and DNA analysis. Koch's postulates were performed using four isolates of the pathogen and the two commercial sunflower cultivars (Sungrown and Tiensvold) originally submitted for disease analysis. Sunflower seeds were imbibed in distilled water for 24 h then sewn into peat plugs. Prior to seed germination, 5 ml of a C. acutatum spore solution (1 × 106/ml) from each isolate was applied to five peat plugs using an atomizer. Control plants were inoculated with distilled water and otherwise treated identically. Both sunflower cultivars were inoculated with each isolate of the pathogen and the test was replicated twice. The sewn peat plugs were incubated for 5 days at 21°C and 50% relative humidity. Symptoms similar to the original samples were present on 100% of the sprouts after 5 days. PCR and sequence analysis performed on cultures obtained from lesions showed a 100% match to the original New Mexico isolates fulfilling Koch's postulates. In an indoor organic facility, such as the one in NM, this disease has the potential to be very difficult to manage and the potential to infect a high percentage of the crop resulting in significant economic losses. To our knowledge, this is the second report of C. acutatum on sunflower sprouts in the United States (1) and the first report in New Mexico. References: (1) S. T. Koike et al. Plant Dis. 93:1351, 2009. (2) 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.

Survey Reveals a Broad Range of Fungal Pathogens and an Oomycete on Peonies in the United States

2019 ◽  
Vol 20 (4) ◽  
pp. 250-254
Author(s):  
Andrea R. Garfinkel ◽  
Gary A. Chastagner
Keyword(s):  
United States ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Large Subunit ◽  
Ornamental Plants ◽  
The United States ◽  
Cut Flowers ◽  
Koch’S Postulates ◽  
Colletotrichum Spp ◽  
Koch's Postulates

Peonies, Paeonia lactiflora and hybrids, are popular ornamental plants grown in landscapes and as cut flowers. As with many ornamental plants, the information on the etiology of peony diseases is incomplete with varying amounts of detailed descriptive material; sometimes validation of Koch’s postulates is also lacking. In a survey to identify the range of diseases of peony in the United States, samples were obtained from 12 states. Fungal and oomycete plant pathogens recovered from symptomatic, diseased tissue were identified by morphology and BLAST identification of the internal transcribed spacer, glyceraldehyde 3-phosphate dehydrogenase, the 28s large subunit, and/or cytochrome c oxidase subunit 1 gene nucleotide sequences for representative isolates. Ten fungal or oomycete genera were identified, and Koch’s postulates were confirmed for selected plant pathogens found during this survey. New disease reports are generated for several states, including five genera never previously reported on peonies in the United States: a Botryosphaeria sp., multiple Colletotrichum spp., Mycocentrospora acerina, a Phoma sp., and Pilidium concavum. The information gained from this survey will provide plant disease diagnosticians and growers a more comprehensive resource for understanding the regional prevalence of peony diseases and subsequently making better disease management decisions.

scholarly journals First Report of Alternaria alternata Causing Postharvest Decay on Apple Fruit During Cold Storage in Pennsylvania

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 690-690 ◽  
Author(s):  
W. M. Jurick ◽  
L. P. Kou ◽  
V. L. Gaskins ◽  
Y. G. Luo
Keyword(s):  
Cold Storage ◽  
Alternaria Alternata ◽  
The United States ◽  
Apple Fruit ◽  
Conidial Suspension ◽  
Single Spore ◽  
Koch’S Postulates ◽  
First Report ◽  
Postharvest Decay ◽  
Koch's Postulates

Alternaria rot, caused by Alternaria alternata (Fr.) Keissl., occurs on apple fruit (Malus × domestica Borkh) worldwide and is not controlled with postharvest fungicides currently registered for apple in the United States (1). Initial infections can occur in the orchard prior to harvest, or during cold storage, and appear as small red dots located around lenticels (1). The symptoms appear on fruits within a 2 month period after placement into cold storage (3). In February 2013, ‘Nittany’ apple fruit with round, dark, dry, spongy lesions were collected from bins at commercial storage facility located in Pennsylvania. Symptomatic apples (n = 2 fruits) were placed on paper trays in an 80 count apple box and immediately transported to the laboratory. Fruit were rinsed with sterile water, and the lesions were superficially disinfected with 70% ethanol. The skin was removed with a sterile scalpel, and tissues underneath the lesion were cultured on potato dextrose agar (PDA) and incubated at 25°C with constant light. Two single-spore isolates were propagated on PDA, and permanent cultures were maintained on PDA slants and stored at 4°C in darkness. Colonies varied from light gray to olive green in color, produced abundant aerial hyphae, and had fluffy mycelial growth on PDA after 14 days. Both isolates were tentatively identified as Alternaria based on multicelled conidial morphology resembling “fragmentation grenades” that were medium brown in color, and obclavate to obpyriform catentulate with longitudinal and transverse septa attached in chains on simple conidiophores (2). Conidia ranged from 15 to 60 μm (mean 25.5 μm) long and 10 to 25 μm (mean 13.6 μm) wide (n = 50) with 1 to 6 transverse and 0 to 1 longitudinal septa per spore. To identify both isolates to the species level, genomic DNA was extracted from mycelial plugs and gene specific primers (ALT-HIS3F/R) were used via conventional PCR to amplify a portion of the histone gene (357 bp) (Jurick II, unpublished). Amplicons were sequenced using the Sanger method, and the forward and reverse sequences of each amplicon were assembled into a consensus representing 2× coverage. A megaBLAST analysis revealed that the isolates were 99% identical to Alternaria alternata sequences in GenBank (Accession No. AF404617), which was previously identified to cause decay on stored apple fruit in South Africa. To prove pathogenicity, Koch's postulates were conducted using organic ‘Gala’ apples. The fruit were surface disinfested with soap and water and sprayed with 70% ethanol to runoff. Wounds, 3 mm deep, were done using a sterile nail and 50 μl of a conidial suspension (1 × 104 conidia/ml) was introduced into each wound per fruit. Fruit were then stored at 25°C in 80 count boxes on paper trays for 21 days. Water only was used as a control. Ten fruit were inoculated with each isolate or water only (control) and the experiment was repeated once. Symptoms of decay observed on inoculated were ‘Gala’ apple fruit were identical to the symptoms initially observed on ‘Nittany’ apples obtained from cold storage after 21 days. No symptoms developed on fruit in the controls. A. alternata was re-isolated 100% from apple inoculated with the fungus, completing Koch's postulates. A. alternata has been documented as a pre- and postharvest pathogen on Malus spp. (3). To our knowledge, this is the first report of postharvest decay caused by A. alternata on apple fruit during cold storage in Pennsylvania. References: (1) A. L. Biggs et al. Plant Dis. 77:976, 1993. (2) E. G. Simmons. Alternaria: An Identification Manual. CBS Fungal Biodiversity Center, Utrecht, the Netherlands, 2007. (3) R. S. Spotts. Pages 56-57 in: Compendium of Apple and Pear Diseases, A. L. Jones and H. S. Aldwinkle, eds. American Phytopathological Society, St. Paul, MN, 1990.

scholarly journals First Report of Wisteria vein mosaic virus in Wisteria sinensis in the United States of America

2008 ◽  
Vol 9 (1) ◽  
pp. 42 ◽  
Author(s):  
Rayapati A. Naidu ◽  
Gandhi Karthikeyan
Keyword(s):  
United States ◽  
Mosaic Virus ◽  
United States Of America ◽  
The United States ◽  
Home Gardens ◽  
First Report ◽  
Woody Perennial ◽  
Wisteria Sinensis ◽  
First Time ◽  
Wisteria Vein Mosaic Virus

The ornamental Chinese wisteria (Wisteria sinensis) is a woody perennial grown for its flowering habit in home gardens and landscape settings. In this brief, the occurrence of Wisteria vein mosaic virus (WVMV) was reported for the first time in Chinese wisteria in the United States of America. Accepted for publication 18 June 2008. Published 18 August 2008.

Expansion of Groundnut ringspot virus Host and Geographic Ranges in Solanaceous Vegetables in Peninsular Florida

2011 ◽  
Vol 12 (1) ◽  
pp. 34 ◽  
Author(s):  
Craig G. Webster ◽  
William W. Turechek ◽  
H. Charles Mellinger ◽  
Galen Frantz ◽  
Nancy Roe ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Vegetable Production ◽  
Viral Pathogen ◽  
Geographic Ranges ◽  
First Report ◽  
Geographic Spread ◽  
Wide Range ◽  
Production Areas ◽  
Solanaceous Plants

To the best of our knowledge, this is the first report of GRSV infecting tomatillo and eggplant, and it is the first report of GRSV infecting pepper in the United States. This first identification of GRSV-infected crop plants in commercial fields in Palm Beach and Manatee Counties demonstrates the continuing geographic spread of the virus into additional vegetable production areas of Florida. This information indicates that a wide range of solanaceous plants is likely to be infected by this emerging viral pathogen in Florida and beyond. Accepted for publication 27 June 2011. Published 25 July 2011.

scholarly journals First Report of Colletotrichum queenslandicum on Persian Lime Causing Leaf Anthracnose in the United States

Plant Disease ◽  
2018 ◽  
Vol 102 (3) ◽  
pp. 677 ◽  
Author(s):  
M. Kunta ◽  
J.-W. Park ◽  
P. Vedasharan ◽  
J. V. da Graça ◽  
M. D. Terry
Keyword(s):  
United States ◽  
The United States ◽  
First Report

scholarly journals Fungicide Sensitivity of Pythium spp. Associated with Cavity Spot of Carrot in California and Michigan

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Xiao Hong Lu ◽  
R. Michael Davis ◽  
S. Livingston ◽  
J. Nunez ◽  
Jianjun J. Hao
Keyword(s):  
United States ◽  
Growth Inhibition ◽  
Active Ingredient ◽  
Mycelial Growth ◽  
The United States ◽  
Fungicide Sensitivity ◽  
First Report ◽  
Cavity Spot ◽  
Pythium Violae

The identity of 172 isolates of Pythium spp. from cavity spot lesions on carrot produced in California and Michigan was determined, and their sensitivity to three fungicides was examined. Pythium violae accounted for 85% of California isolates, with P. irregulare, P. dissotocum (the first report as a carrot pathogen in the United States), P. ultimum, and P. sulcatum making the balance. P. sulcatum, P. sylvaticum, and P. intermedium were the most commonly recovered (85%) species in Michigan; others from Michigan included P. intermedium, P. irregulare, and an unclassified strain, M2-05. On fungicide-amended media, 93% of isolates were sensitive to mefenoxam (inhibition of mycelial growth was >60% at 10 μg active ingredient [a.i.]/ml); however, two of five isolates of P. irregulare from California were highly resistant (≤60% inhibition at 100 μg a.i./ml); about half of the isolates of P. intermedium and P. sylvaticum and a single isolate of P. violae were highly or intermediately resistant to mefenoxam (>60% inhibition at 100 μg a.i./ml, or ≤60% inhibition at 10 μg a.i./ml). P. dissotocum, P. irregulare, P. sulcatum, M2-05, and three of seven isolates of P. intermedium were insensitive to fluopicolide (effective concentrations for 50% growth inhibition [EC50] were >50 μg a.i./ml), while P. sylvaticum, P. ultimum, P. violae, and some isolates in P. intermedium were sensitive (EC50 < 1 μg a.i./ml). All isolates were sensitive to zoxamide (EC50 < 1 μg a.i./ml). Sensitivity baselines of P. violae to zoxamide and fluopicolide were established.

scholarly journals First Report of Macrophomina phaseolina Causing Trunk and Cordon Canker Disease of Grapevine in the United States

Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 579-579 ◽  
Author(s):  
M. T. Nouri ◽  
G. Zhuang ◽  
C. M. Culumber ◽  
F. P. Trouillas
Keyword(s):  
United States ◽  
Macrophomina Phaseolina ◽  
The United States ◽  
Canker Disease ◽  
First Report
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