scholarly journals First Report of Fusarium Wilt Caused by Fusarium oxysporum on Roselle in the United States

Plant Disease ◽  
2007 ◽  
Vol 91 (5) ◽  
pp. 639-639 ◽  
Author(s):  
R. C. Ploetz ◽  
A. J. Palmateer ◽  
D. M. Geiser ◽  
J. H. Juba
Keyword(s):  
United States ◽  
Fusarium Oxysporum ◽  
Plant Pathogens ◽  
Vascular Tissue ◽  
The United States ◽  
South Florida ◽  
Maximum Parsimony Analysis ◽  
Culture Collections ◽  
Early Date ◽  
First Report

Roselle, Hibiscus sabdariffa var. sabdariffa, is an annual that is grown primarily for its inflated calyx, which is used for drinks and jellies. It is native from India to Malaysia, but was taken at an early date to Africa and is now widely grown in the tropics and subtropics (2). In late 2005, dying plants were noted by a producer in South Florida. Plants wilted, became chlorotic, and developed generally unthrifty, sparse canopies. Internally, conspicuous vascular discoloration was evident in these plants from the roots into the canopy. After 5 days on one-half-strength potato dextrose agar (PDA), salmon-colored fungal colonies grew almost exclusively from surface-disinfested 5 mm2 pieces of vascular tissue. On banana leaf agar, single-spored strains produced the following microscopic characters of Fusarium oxysporum: copious microconidia on monophialides, infrequent falcate macroconidia, and terminal and intercalary chlamydospores. Partial, elongation factor 1-α (EF1-α) sequences were generated for two of the strains, O-2424 and O-2425, and compared with previously reported sequences for the gene (3). Maximum parsimony analysis of sequences showed that both strains fell in a large, previously described clade of the F. oxysporum complex (FOC) that contained strains from agricultural hosts, as well as human clinical specimens (2; clade 3 in Fig. 4); many of the strains in this clade have identical EF1-α sequences. Strains of F. oxysporum recovered from wilted roselle in Egypt, O-647 and O-648 in the Fusarium Research Center collection, were distantly related to the Florida strains. We are not aware of other strains of F. oxysporum from roselle in other international culture collections. Roselle seedlings were inoculated with O-2424 and O-2425 by placing a mycelial plug (5 mm2, PDA) over a small incision 5 cm above the soil line and then covering the site with Parafilm. Parafilm was removed after 1 week, and plants were incubated under ambient temperatures (20 to 32°C) in full sun for an additional 5 weeks (experiment 1) or 7 weeks (experiment 2). Compared with mock-inoculated (wound + Parafilm) control plants, both O-2424 and O-2425 caused significant (P < 0.05) vascular disease (linear extension of discolored xylem above and below wound site) and wilting (subjective 1 to 5 scale); both isolates were recovered from affected plants. F. oxysporum-induced wilt of roselle has been reported in Nigeria (1) and Malaysia (4) where the subspecific epithet f. sp. rosellae was used for the pathogen. We are not aware of reports of this disease elsewhere. To our knowledge, this is the first report of F. oxysporum-induced wilt of roselle in the United States. Research to determine whether the closely related strains in clade 3 of the FOC are generalist plant pathogens (i.e., not formae speciales) is warranted. References: (1) N. A. Amusa et al. Plant Pathol. J. 4:122, 2005. (2) J. Morton. Pages 81–286 in: Fruits of Warm Climates. Creative Resource Systems, Inc., Winterville, NC, 1987. (3) K. O'Donnell et al. J. Clin. Microbiol. 42:5109, 2004. (4) K. H. Ooi and B. Salleh. Biotropia 12:31, 1999.

scholarly journals First Report of Dieback Caused by Verticillium dahliae on Blighia sapida in the United States

Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 74-74
Author(s):  
R. T. McMillan ◽  
W. R. Graves ◽  
T. F. Wood ◽  
R. M. Leahy
Keyword(s):  
United States ◽  
Verticillium Dahliae ◽  
Vascular Tissue ◽  
The United States ◽  
South Florida ◽  
First Report ◽  
Disturbed Soil ◽  
Florida Department ◽  
Consumer Services ◽  
Blighia Sapida

Mature akee trees, Blighia sapida K. Koenig, in a local south Florida commercial orchard had wilt and dieback symptoms during spring 1999. A fungus isolated from the gray xylem root tissue on V8 agar was identified as Verticillium dahliae Klebahn at the Division of Plant Industry of the Florida Department of Agriculture and Consumer Services. Twenty akee seedlings were transplanted into 3.85-liter plastic pots and grown in a greenhouse at a daytime temperature of 28°C and nighttime temperature of 23°C. When plants were approximately 25 cm high, a 15-cm knife was used to sever roots in the four quadrants of each pot. Inoculum was made from a 2-week-old culture of V. dahliae on V8 agar and blended with 160 ml of sterile water, and 15 ml of this slurry was poured into the disturbed soil of each of 10 treated plants. A plate of uninoculated V8 agar was applied, as above, to 10 control plants. Plants were kept in the greenhouse. After 6 weeks, inoculated plants showed symptoms of leaf wilt, dieback and plant death. No symptoms were seen on control plants. V. dahliae was isolated directly from the gray vascular tissue of inoculated plants. The inoculation experiment was repeated three times, fulfilling Koch's postulates. To our knowledge, this is the first report of Verticillium dieback on B. sapida in the United States.

scholarly journals First Report of Gaeumannomyces graminis var. graminis on Seashore Paspalum in the United States

Plant Disease ◽  
2002 ◽  
Vol 86 (12) ◽  
pp. 1405-1405 ◽  
Author(s):  
W. C. Elmore ◽  
M. D. Gooch ◽  
C. M. Stiles
Keyword(s):  
United States ◽  
Plant Pathogens ◽  
Warm Season ◽  
The United States ◽  
Gaeumannomyces Graminis ◽  
Sterile Soil ◽  
Seashore Paspalum ◽  
First Report ◽  
Fungal Plant Pathogens ◽  
Rot Disease

Gaeumannomyces graminis var. graminis is an ectotrophic, root-infecting fungus found on some warm-season turfgrass species (1). A sample of seashore paspalum (Paspalum vaginatum) exhibiting rotted roots and stolons was taken from dying patches of turf in a home lawn in Hernando County, FL, and submitted to the Florida Extension Plant Disease Clinic, Gainesville, in October 2001. The lawn had been established within the previous year. Strongly lobed hyphopodia typical of G. graminis var. graminis (3,4) were present on diseased roots and stolons, and no other fungal plant pathogens were detected in the sample. Diseased roots and stolons with lobed hyphopodia were surface-sterilized and placed on one-quarter-strength potato dextrose agar (PDA) amended with rifampicin and streptomycin. One isolate produced structures characteristic of G. graminis var. graminis (3,4), including dark, strongly lobed hyphopodia, and perithecia and ascospores in PDA after incubation. The isolate (PDC 2965) was grown on a sterile ryegrass seed substrate at 25°C for 4 weeks to produce inoculum (2). The isolate was used to inoculate pots of ‘Sea Isle 1’ seashore paspalum grown in sterile soil from sprigs. An inoculum layer, 1 to 2 cm deep, was placed 2 to 4 cm below each sprig and covered with an overlay of sterile soil prior to sprigging (2). Following 4 weeks of plant growth in a greenhouse, dark, necrotic lesions appeared on leaf bases. Very dark lesions developed on roots, and brown runner hyphae and strongly lobed hyphopodia were observed on root and shoot tissues. Selected pieces of symptomatic root and shoot tissue were surface-sterilized and placed on PDA. One week later, dark mycelia and deeply lobed hyphopodia were observed growing from roots and shoots on the PDA. After 1 month, black, flask-shaped perithecia, 156 to 234 μm in body width, developed in cultures. Hyaline, filiform, septate ascospores ranged from 75 to 100 μm (mean = 89 μm; n = 250) long and were approximately 2.5 μm wide. Hyphopodia, perithecia, and ascospores were characteristic of G. graminis var. graminis (3,4). To our knowledge, this is the first report of take-all root rot disease due to G. graminis var. graminis on seashore paspalum in the United States. References: (1) L. E. Datnoff et al. Plant Dis. 81:1127, 1997. (2) M. L. Elliott. Plant Dis. 79:699, 1995. (3) M. L. Elliott and P. J. Landschoot. Plant Dis. 75:238, 1991. (4) P. J. Landschoot. Taxonomy and biology of ectotrophic root-infecting fungi associated with patch diseases of turfgrasses. Pages 41–71 in: Turfgrass Patch Diseases. B. B. Clarke and A. B. Gould, eds. American Phytopathological Society, St. Paul, MN, 1997.

scholarly journals First Report of Basal Stem Rot of Apple Cactus (Cereus peruvianus monstruosus) Caused by Fusarium oxysporum in Italy

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 877-877
Author(s):  
A. Garibaldi ◽  
P. Pensa ◽  
D. Bertetti ◽  
A. Poli ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Fusarium Oxysporum ◽  
The United States ◽  
Stem Rot ◽  
Fluorescent Light ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Single Spore ◽  
Basal Stem Rot ◽  
First Report

During the summer of 2010, 20% of 7,000 4-month-old plants of apple cactus (Cereus peruvianus monstruosus) showed symptoms of a basal stem rot in a commercial nursery located in Liguria (northern Italy). Affected plants showed yellow orange-to-pale brown color from the crown level to the stem apex and a water-soaked rot was observed on the stem starting from the base. Brown discoloration was observed in the vascular system. Eventually stems bent, plants collapsed and died, and affected tissues dried out. A Fusarium sp. was consistently and readily isolated from symptomatic tissue on Komada selective medium. Isolates were purified and subcultured on potato dextrose agar (PDA). Single-spore cultures on PDA, Spezieller Nährstoffarmer agar (SNA) (3), and carnation leaf-piece agar (CLA) (2) were incubated at 26 ± 1°C (12-h fluorescent light, 12-h dark). On PDA, cultures produced a thick growth of white-to-pink mycelium and pale pink pigments in the agar. On SNA, cultures produced short monophialides with unicellular, ovoid-elliptical microconidia measuring 4.3 to 8.2 × 2.3 to 3.8 (average 6.0 × 2.8) μm. Chlamydospores were abundant, single or paired, terminal and intercalary, rough walled, and 6 to 8 μm in diameter. On CLA, cultures produced orange sporodochia with macroconidia that were 3 to 4 septate, nearly straight with a foot-shaped basal cell and a short apical cell, and measured 31.1 to 51.5 × 4.4 to 3.5 (average 43.2 × 3.8) μm. Such characteristics are typical of Fusarium oxysporum (3). Amplification of the ITS (internal transcribed spacer) of the rDNA using primers ITS1/ITS4 (4) yielded a 498-bp band. Sequencing and BLASTn analysis of this band showed an E-value of 0.0 with F. oxysporum. The nucleotide sequence has been assigned GenBank Accession No. JF422071. To confirm pathogenicity, five 6-month-old healthy plants of C. peruvianus monstruosus were inoculated by dipping roots in a conidial suspension (2.4 × 106 CFU/ml) of F. oxysporum isolated from affected plants. Inoculum was obtained from pure cultures of three single-spore isolates grown for 10 days on casein hydrolysate liquid medium. Roots were not wounded before the inoculation. Plants were transplanted into pots filled with steam-sterilized substrate (sphagnum peat/perlite/pine bark/clay 50:20:20:10). Five noninoculated plants served as a control. Plants were placed in a climatic chamber at 25 ± 1°C (12-h fluorescent light, 12 h-dark). Basal stem rot and vascular discoloration in the crown and stem developed within 30 days on each inoculated plant. Noninoculated plants remained healthy. F. oxysporum was consistently isolated from symptomatic plants. The pathogenicity test was conducted twice. F. oxysporum has been reported on Cereus spp. in the United States (1). To our knowledge, this is the first report of F. oxysporum on C. peruvianus monstruosus in Italy as well as in Europe. Currently, this disease is present in a few nurseries in Liguria. 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) N. L. Fisher et al. Phytopathology 72:151, 1982. (3) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell, Ames, IA, 2006. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

scholarly journals First Report of Fusarium oxysporum f. sp. niveum Race 2 as Causal Agent of Fusarium Wilt of Watermelon in Indiana

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 108-108 ◽  
Author(s):  
D. S. Egel ◽  
R. Harikrishnan ◽  
R. Martyn
Keyword(s):  
United States ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Citrullus Lanatus ◽  
The United States ◽  
Mineral Salts ◽  
First Report ◽  
Race 1 ◽  
Race 2 ◽  
Greenhouse Assay

Fusarium oxysporum f. sp. niveum race 1 is uniformly distributed throughout watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) growing regions, but F. oxysporum f. sp. niveum race 2 has a limited known distribution in the United States (Texas, Florida, Oklahoma, Maryland, and Delaware) (3,4). Since the spring of 2001, commercial watermelon fields in Knox and Gibson counties in southwestern Indiana have been observed with symptoms of one-sided wilt and vascular discoloration typical of Fusarium wilt. Race 2 of F. oxysporum f. sp. niveum was suspected as the casual agent since the diseased watermelon cultivars are considered resistant to races 0 and 1. Two isolates of F. oxysporum obtained from wilted watermelon plants in two different commercial fields and one isolate obtained from a wilted seedling in a transplant house were compared for pathogenicity in a greenhouse assay. Known isolates of F. oxysporum f. sp. niveum races 0, 1, and 2 were obtained from Don Hopkins (University of Florida, Apopka), Kate Everts (University of Maryland/University of Delaware, Salisbury, MD), and Ray Martyn (Purdue University, West Lafayette, IN), respectively, and were used for comparison. All isolates were grown in shake cultures in a mineral salts liquid medium. (1). After 72 hr, the predominately microconidal suspensions were filtered through cheesecloth and adjusted to 1 × 105 conidia/ml with the aid of a hemacytometer. A concentration of 1 × 105 condia/ml was shown previously to cause the desired disease reaction in the standard cultivars. Seedlings of the differential cvs, Black Diamond (universal susceptible), Charleston Gray (race 0 resistant), and Calhoun Gray (race 0 and 1 resistant) were grown in a 1:1, (v:v) sand/ vermiculite mixture to the first true-leaf stage after which the plants were uprooted and the roots carefully washed prior to root dip inoculation. Subsequent to inoculation, seedlings were planted in a sand/vermiculite/ peat mixture (4:1:1, [v:v:v]) with four seedlings to a 15-cm-diameter pot. The experimental design was a randomized complete block with five replications. Two isolates from the commercial field plants caused an average of 100% wilt on cv. Black Diamond, 95% wilt on cv. Charleston Gray, and 80% wilt on cv. Calhoun Gray, resulting in a designation of race 2. The isolate from a commercial transplant house resulted in 100, 60, and 15% wilt, respectively, on the three standard cultivars resulting in a race 1 designation. The presence of F. oxysporum f. sp. niveum race 2 in Indiana is significant because Indiana currently ranks fifth in the United States in watermelon production and there are no commercially available cultivars that possess resistance to race 2. To our knowledge, this is the first report of F. oxysporum f. sp. niveum race 2 in Indiana and the first report of race 2 from the Midwest region of the United States. Race 2, first described from the United States in 1985 (2), has now been confirmed in six states. References: (1) R. Esposito and A. Fletcher. Arch. Biochem. Biophys. 93:369, 1961. (2) R. Martyn, Plant Dis. 69:1007, 1985. (3) R. Martyn, Plant Dis. 71:233, 1987. (4) X. Zhou and K. Everts. Plant Dis. 87:692, 2003.

First Report of Groundnut ringspot virus Infecting Tomato in South Florida

2010 ◽  
Vol 11 (1) ◽  
pp. 49 ◽  
Author(s):  
Craig G. Webster ◽  
Keith L. Perry ◽  
Xiaoyun Lu ◽  
Loren Horsman ◽  
Galen Frantz ◽  
...  
Keyword(s):  
United States ◽  
Disease Management ◽  
Management Strategies ◽  
The United States ◽  
South Florida ◽  
Ringspot Virus ◽  
Integrated Disease Management ◽  
First Report ◽  
Close Relationship ◽  
Relationship Of

To the best of our knowledge this is the first report of GRSV in the United States in any host, although TSWV has been present in Florida for many years. Although the detection of GRSV in Florida tomatoes is cause for concern, the close relationship of GRSV and TSWV may allow successful adaptation of the integrated disease management strategies currently in use for TSWV in tomatoes for management of GRSV. Accepted for publication 17 May 2010. Published 7 July 2010.

scholarly journals First Report of Verticillium Wilt Caused by Verticillium dahliae on Rudbeckia fulgida (Orange Coneflower) in Italy

Plant Disease ◽  
2008 ◽  
Vol 92 (9) ◽  
pp. 1367-1367 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Vascular Tissue ◽  
Morphological Characteristics ◽  
Its Region ◽  
The United States ◽  
Conidial Suspension ◽  
First Report ◽  
Initial Symptoms

Rudbeckia fulgida (common name orange coneflower) is an herbaceous perennial (Asteraceae) grown in full sun in perennial borders in gardens. At the end of the summer of 2007, in a public garden located in Turin (northern Italy), symptoms of vascular wilt and stunting were observed on approximately 80% of the plants grown in a mixed border. Initial symptoms were yellowing of external leaves and brown or black streaks in the vascular tissue of roots, crown, and leaves. A fungus was consistently and readily isolated on potato dextrose agar from symptomatic vascular tissue previously disinfested in 1% sodium hypochloride. Ovoid, dark microsclerotia, 41 to 108 μm, developed in hyaline hyphae after 10 days of growth at 23°C (12 h of light and 12 h of dark). Hyaline, elliptical, single-celled conidia, 3.2 to 7.3 × 2.1 to 3.7 (average 4.7 × 2.8) μm, developed on verticillate conidiophores. On the basis of these morphological characteristics, the fungus was identified as Verticillium dahliae (4). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 530 bp showed a 100% homology with the sequence of V. dahliae. The nucleotide sequence has been assigned GenBank Accession No. EU 627007. Healthy, 30-day-old R. fulgida plants were grown in a steam-disinfested mix of sphagnum peat:pomix:pine bark:clay (50:20:20:10) infested with a conidial suspension (1.5 × 106/ml) of three isolates of V. dahliae isolated from infected plants. Noninoculated plants served as controls. Plants (16 per treatment) were grown in pots (3 liter vol) and maintained in a glasshouse at temperatures between 22 and 25°C and relative humidity between 50 and 70%. First wilt symptoms and vascular discoloration in the roots, crown, and veins developed 17 days after inoculation. Noninoculated plants remained healthy. The pathogenicity tests were carried out twice. To our knowledge, this is the first report in Italy of Verticillium wilt on R. fulgida. Wilts caused by V. dahliae on R. laciniata in Poland (3) and V. albo-atrum on R. hirta in the United States (2) were previously reported. The importance and economic impact of this disease is currently limited but may increase because of the popularity of Rudbeckia spp. in private and public parks. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. F. Farr et al. Fungi on Plants and Their Products in the United States. The American Phytopathological Society, St Paul, MN, 1989. (3) B. Leski. Rocz. Nauk Roln. 253, 1974. (4) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002.

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 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.

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