scholarly journals First Report of Fusarium Wilt of Yellowwood (Cladrastis kentukea) Caused by Fusarium oxysporum in the United States

Plant Disease ◽  
2017 ◽  
Vol 101 (1) ◽  
pp. 258-258
Author(s):  
L. Graney ◽  
W. H. Elmer ◽  
A. L. Loyd
Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 108-108 ◽  
Author(s):  
D. S. Egel ◽  
R. Harikrishnan ◽  
R. Martyn

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.


Plant Disease ◽  
2007 ◽  
Vol 91 (5) ◽  
pp. 639-639 ◽  
Author(s):  
R. C. Ploetz ◽  
A. J. Palmateer ◽  
D. M. Geiser ◽  
J. H. Juba

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.


Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 877-877
Author(s):  
A. Garibaldi ◽  
P. Pensa ◽  
D. Bertetti ◽  
A. Poli ◽  
M. L. Gullino

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.


Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 911-911 ◽  
Author(s):  
M. Williamson ◽  
D. Fernández-Ortuño ◽  
G. Schnabel

During October 2011, wilted and dead strawberry (Fragaria × ananassa cv. Albion) plants from two commercial fields in South Carolina were sent to the Clemson University Plant Problem Clinic in Pendleton, SC. Symptoms consisted of wilting and chlorosis of foliage, scorch and dieback of older leaves, and stunting of plants. Internal vascular and cortical tissues of plant crowns showed a distinct reddish brown discoloration. To isolate the causal agent, necrotic crown tissue selected from two symptomatic plants from one location and four symptomatic plants from the other were placed on acidified potato dextrose agar (APDA) and on quarter strength acidified PDA (QPDA). Colonies with light purple mycelia and beige or orange reverse colony colors developed on APDA after 5 days of incubation at 25°C. Colonies on QPDA were light purple. Morphology, growth, and development of macroconidia and microconida were consistent with descriptions of Fusarium oxysporum Schlechtend emend. Snyder & Hansen (3). Genomic DNA from 3 isolates (11-1246A, 11-1247A, and 11-1247B) was extracted and purified according to Chi et al. (1). The internal transcribed spacer region comprising ITS1, ITS2, and 5.8S rRNA was amplified by primers ITS1 and ITS4 (4). The sequence comparison revealed a 100% match with F. oxysporum sequences in GenBank. To confirm the pathogenicity of the fungus, roots of 15 strawberry plants (cv. Albion) were cut and then five plants were soaked for 10 min in either 500 ml of conidial suspension (104 conidia/ml) of one of the two isolates or in sterile distilled water. All were then potted in 15-cm pots with artificial peat-based soil mix and maintained at 25°C in the greenhouse. After 6 weeks, all plants inoculated with isolates 1247A and B were stunted and developed wilt symptoms similar to those observed in the field, while the control plants remained healthy. Support roots on all affected plants were soft and flaccid and new feeder roots had brown lesions. Crowns of three plants inoculated with isolate 1247A and four plants inoculated with 1247B showed vascular discoloration. To reisolate, crowns were plated as above and roots were surface sterilized in 10% bleach for 1 min and rinsed in sterile distilled water prior to plating on QPDA. F. oxysporum was isolated at frequencies of 70 and 100% from crowns and 100% from roots of all inoculated plants. To our knowledge, this is the first report of the occurrence of Fusarium wilt caused by F. oxysporum on strawberry plants in South Carolina. The presence of Fusarium wilt in South Carolina should alert growers, county agents, and specialists to properly identify Fusarium wilt symptoms, which may be confused with Anthracnose or Phytophthora crown rot of strawberry. The disease has been reported previously in other countries including the United States (2). References: (1) M. H. Chi et al. Plant Pathol. J. 25:108, 2009. (2) S. T. Koike et al. Plant Dis. 93:1077, 2009. (3) W. C. Snyder and H. N. Hansen. Am. J. Bot. 27:64, 1940. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Application. Academic Press, NY, 1993.


Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1511-1511 ◽  
Author(s):  
M. Giesbrecht ◽  
M. McCarthy ◽  
M. L. Elliott ◽  
K. L. Ong

Fusarium wilt of palms occurs worldwide, caused by different Fusarium oxysporum ff. spp. including F. oxysporum f. sp. elaeidis, F. oxysporum f. sp. canariensis, and F. oxysporum f. sp. albedinis (3). Prior to 2010, F. oxysporum f. sp. canariensis was the only palm infecting species known to occur in the United States. In 2010, isolates of F. oxysporum were reported from dying Syagrus romanzoffiana and Washingtonia robusta in Florida. Based on morphological and molecular data, as well as the unique host species affected by the pathogen, this fungus was determined to be a new forma specialis of F. oxysporum, designated f. sp. palmarum (1). The pathogen infects foliar tissue, causing complete necrosis of the crown and leading to tree death within 2 to 3 months. In June 2012, the Texas Plant Disease Diagnostic Laboratory (TPDDL) received a plant sample from a dying W. robusta palm, exhibiting reddish-brown stripes on the petiole with chlorotic and necrotic leaves, from an established palm in the landscape from Harris County, Texas. Fungal cultures were obtained from symptomatic foliar tissue and identified as F. oxysporum based on morphology. Microconidia were oval to reniform, 1- to 2-septate, measuring 5 to 18 × 2.5 to 5 μm. Phialides were short with microconidia produced in false heads. Macroconidia were curved and slender with a foot-shaped basal cell, usually 3-septate, and 22 to 37 × 2.5 to 5 μm. Chlamydospores were roundish and ranged from 7 to 13 μm in diameter. Fungal colonies had white to purple mycelia when grown on potato dextrose agar. DNA from a single spore culture was extracted, amplified by PCR using primers corresponding to a segment of the translation elongation factor 1α (EF-1α) gene, and the PCR product sequenced (2). Using the sequence alignment tool (BLASTn) in GenBank, the TPDDL's sequence (GenBank Accession No. KC897693) was aligned with EF-1α regions from F. oxysporum f. sp. palmarum isolates previously entered into the database ([1]; accessions GQ154455[=NRRL53544] and GQ154456[=NRRL46589]), revealing 100% homology between the isolates. Based on host source and sequence similarity, the fungus was tentatively identified as F. oxysporum f. sp. palmarum. Pathogenicity tests were performed on three leaf seedlings of W. robusta and W. filifera. Fifteen plants of each species were inoculated with the suspect isolate (designated KB2012) and 10 control plants were mock-inoculated as described by (1). Plants were grown in a greenhouse for 8 weeks post-inoculation. During this time, 83% of inoculated plants developed foliar lesions and died or severely declined, and all control plants remained healthy. F. oxysporum was recovered in culture from 100% of the symptomatic plants. DNA was extracted from fungal cultures, and EF-1α was amplified by PCR and sequenced, as described above. The amplicon was determined to share 100% homology with known F. oxysporum f. sp. palmarum isolates, confirming this fungus as the cause of disease in W. robusta. This is the first report of this pathogen in Texas, as well as the first report outside of Florida. This is also the first documentation of W. filifera as a host of this pathogen. References: (1) M. L. Elliott et al. Plant Dis. 94:31, 2010. (2) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (3) G. W. Simone. Pages 17-19 in: Compendium of Ornamental Palm Diseases and Disorders, M. L. Elliott et al., eds. The American Phytopathological Society, St. Paul, MN, 2004.


Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 358-358 ◽  
Author(s):  
M. L. Elliott ◽  
E. Honeycutt ◽  
J. West ◽  
P. Franklin

Canary Island date palm (Phoenix canariensis) is native to the Canary Islands and widely grown throughout the world as an ornamental. At a home site in Austin, TX in May 2008 and a commercial site near Charleston, SC in December 2009, declining Canary Island date palms were observed. Symptoms included individual leaves with chlorotic or necrotic leaflets on one side of the leaf blade (one-sided wilt or death) and a distinct reddish brown stripe along the petiole and rachis. Cross-sections through the petiole or rachis exhibited discoloration of internal tissue. Fusarium oxysporum was isolated from the internal petiole or rachis tissue of each palm sample onto one-quarter-strength potato dextrose agar (PDA). Typical macroconidia in pale orange sporodochia, microconidia in false heads on short monophialides, and chlamydospores were observed (2). Macroconidia were mostly 3-septate, slightly curved, and ranged from 3.8 to 4.2 × 42.9 to 46.5 μm. Microconidia were single cell, oval to reniform, and ranged from 2.5 to 2.9 × 7.2 to 7.8 μm. Single-spore isolates grown on full-strength PDA (12-h light and 26°C) produced abundant white-to-pale lavender mycelia with a purple pigment in the agar. One isolate from each location (PLM-385B from Texas and PLM-511A from South Carolina) was selected for pathogenicity tests and molecular characterization. The translation elongation factor 1-α gene (EF-1α) was amplified in each isolate by PCR using the ef1 and ef2 primers (1). Products were sequenced and queried for similarity against the NCBI database and the FUSARIUM-ID database ( http://isolate.fusariumdb.org/index.php ) (1) using the BLAST search tool. In both databases, both isolates matched F. oxysporum f. sp. canariensis strain NRRL 26035 (GenBank Accession No. AF008485; FD_01211) at 100% sequence similarity. Sequences for PLM-385B and PLM-511A have been deposited in the NCBI database (GenBank Accession Nos. HM591537 and HM591538, respectively). Pathogenicity of these two isolates was tested on three-leaf Canary Island date palm seedlings. There were five replicate palms per isolate and control treatment. All potting mix was shaken from the roots and three groups of five seedlings were placed in small buckets. Twenty-five milliliters of a 106 conidia ml–1 suspension was pipetted down among the leaf bases and the excess drained onto the roots. Control palms received sterile water. Seedlings were covered with plastic for 48 h and then transplanted into separate growing containers. Ten weeks after inoculation, initial symptoms of a leaf wilt (off-color and folded over) were observed on some of the inoculated palms. After 4 months, all palms inoculated with PLM-511A were dead and three of the five palms inoculated with PLM-385B were dead. The pathogen was reisolated from diseased palms. All five control palms remained healthy. While the symptomatic palm in Texas had been in the home site approximately 2 years, which implied the palm could have been already infected when transplanted, the palm in South Carolina had been planted in 1990. To our knowledge, this is the first report of Fusarium wilt of Canary Island date palm in Texas and South Carolina. Previously in the United States, the disease had only been noted in California, Florida, and Nevada. References: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006.


2010 ◽  
Vol 11 (1) ◽  
pp. 42 ◽  
Author(s):  
F. Mathew ◽  
B. Kirkeide ◽  
T. Gulya ◽  
S. Markell

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.


2008 ◽  
Vol 9 (1) ◽  
pp. 42 ◽  
Author(s):  
Rayapati A. Naidu ◽  
Gandhi Karthikeyan

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.


2011 ◽  
Vol 12 (1) ◽  
pp. 34 ◽  
Author(s):  
Craig G. Webster ◽  
William W. Turechek ◽  
H. Charles Mellinger ◽  
Galen Frantz ◽  
Nancy Roe ◽  
...  

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.


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

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