scholarly journals First Report of Fusarium Wilt Caused by Fusarium oxysporum f. sp. palmarum on Canary Island Date Palm in Florida

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 356-356 ◽  
Author(s):  
M. L. Elliott
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Cross Sections ◽  
Canary Island ◽  
Date Palm ◽  
Vascular Tissue ◽  
Control Treatment ◽  
Single Spore ◽  
Commercial Property ◽  
First Report

Canary Island date palm (Phoenix canariensis Chabaud) is an ornamental grown throughout the world. In the fall of 2009, a single plant of this species was observed with Fusarium wilt symptoms at a commercial property in Orlando, FL. Individual leaves had chlorotic or necrotic leaflets on one side of the leaf blade and a reddish brown stripe along the petiole and rachis. Petiole cross-sections exhibited discolored vascular tissue. Fusarium oxysporum was isolated from this tissue, with typical characteristics of macroconidia in pale orange sporodochia, microconidia in false heads on short monophialides, and chlamydospores (3). All colonies on potato dextrose agar had pale pinkish-salmon-colored mycelia. Macroconidia were mostly 3-septate, slightly curved, and ranged from 4.1 to 4.6 × 39.5 to 43.7 μm. Microconidia were unicellular, oval to reniform, and ranged from 3.1 to 3.3 × 7.1 to 7.5 μm. Single-spore isolates (PLM-509 and PLM-510A) were selected for molecular characterization, with PCR conducted using ef1 and ef2 primers (2). Resulting products were sequenced and queried for similarity against the NCBI and the FUSARIUM-ID databases (2) using BLAST. In both databases, the isolates did not match F. oxysporum f. sp. canariensis. Rather, the isolates matched F. oxysporum f. sp. palmarum, and of particular interest, were NRRL 46589 (GenBank Accession No. GQ154456) and NRRL 46592 (GenBank Accession No. GQ154468), which the isolates matched with 100% similarity. These NRRL isolates were from the same commercial property but different locations on the property as this Canary Island date palm (1). Prior to this identification, F. oxysporum f. sp. palmarum had only been associated with Fusarium wilt of queen palm (Syagrus romanzoffiana) and Mexican fan palm (Washingtonia robusta) in Florida (1). Furthermore, in September 2008, two of four Mexican fan palms in a concrete planter (not in the ground) at the same location as the diseased Canary Island date palm (in the ground) were symptomatic for Fusarium wilt and the pathogen was confirmed as F. oxysporum f. sp. palmarum. Therefore, pathogenicity studies were conducted on three-leaf seedlings of P. canariensis and W. robusta using PLM-510A. There were five replicate palms per isolate and control treatment, and they were inoculated by the same methodology used previously for seedlings (1). After 3 months, all inoculated W. robusta were dead and one of five inoculated P. canariensis was dead. After 6 months, three more P. canariensis had died for a total of four of five inoculated palms. The pathogen was reisolated from diseased palms of both species. All control palms remained healthy. The sequence for PLM-510A has been deposited in the NCBI database (GenBank Accession No. HQ727681). To our knowledge, this is the first report of Fusarium wilt of Canary Island date palm caused by F. oxysporum f. sp. palmarum. 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) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006.

scholarly journals First Report of Fusarium Wilt Caused by Fusarium oxysporum f. sp. canariensis on Canary Island Date Palm in Texas and South Carolina

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 358-358 ◽  
Author(s):  
M. L. Elliott ◽  
E. Honeycutt ◽  
J. West ◽  
P. Franklin
Keyword(s):  
South Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Canary Island ◽  
Date Palm ◽  
The United States ◽  
Control Treatment ◽  
First Report ◽  
Home Site ◽  
Initial Symptoms

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.

scholarly journals First Report of Fusarium Wilt of Canary Island Date Palm Caused by Fusarium oxysporum f. sp. canariensis in Louisiana

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1192-1192 ◽  
Author(s):  
R. Singh ◽  
A. Castro ◽  
D. M. Ferrin ◽  
R. S. Harris ◽  
B. Olson
Keyword(s):  
South Carolina ◽  
Fusarium Oxysporum ◽  
New Orleans ◽  
Fusarium Wilt ◽  
Canary Island ◽  
Date Palm ◽  
Distilled Water ◽  
Date Palms ◽  
First Report ◽  
Vascular Discoloration

Canary Island date palm (Phoenix canariensis Hort. Ex Chabaud) is a signature palm planted in New Orleans, LA. Currently, the city has approximately 1,000 mature Canary Island date palms. During the fall of 2009, 153 palms were inspected with 27 palms exhibiting typical symptoms of Fusarium wilt. Symptoms included one-sided death and a reddish brown streak on the rachis of affected fronds and death of the leaflets. Longitudinal sections of affected fronds showed vascular discoloration. Severely infected palms were completely dead. Small pieces of diseased tissue from five palms were surface sterilized with sodium hypochlorite (0.6%) for 2 to 3 min, then rinsed in sterile distilled water, blotted dry, and plated on potato dextrose agar (PDA). Fungal colonies on PDA produced a purple pigment, and both macro- and microconidia that are typical of Fusarium oxysporum were observed under a light microscope. A single-spore culture of isolate PDC-4701 was obtained. DNA from this isolate was extracted with a DNeasy Plant Mini kit (Qiagen Inc., Valencia, CA) and primers ef1 and ef2 were used to amplify and sequence the translation elongation factor 1-α gene (2). NCBI BLAST analysis of the 616-bp sequence resulted in 100% identity with F. oxysporum f. sp. canariensis isolates PLM-385B from Texas and PLM-511A from South Carolina (GenBank Accession Nos. HM 591538 and HM 591537, respectively). Isolate PDC-4701, grown on PDA for 2 weeks, was used to inoculate 10 9-month-old P. canariensis seedlings. An 18-gauge needle was used to inject 15 ml of a 107 conidia/ml suspension into the stem near the soil line. Each seedling was inoculated at two locations and covered with Parafilm at the inoculation sites. Ten control seedlings were injected with sterile distilled water in the same manner. Inoculated and control seedlings were maintained in a greenhouse at 28 ± 2°C. Leaves of all 10 inoculated seedlings started to wilt 3 months after inoculation. Internal vascular discoloration was observed and the pathogen was reisolated from the symptomatic seedlings. No symptoms developed on any of the 10 control seedlings. On the basis of morphology and DNA sequence data, this pathogen is identified as F. oxysporum f. sp. canariensis. Fusarium wilt of Canary Island date palm has been previously reported from California, Florida, Nevada, Texas, and South Carolina (1). To our knowledge, this is the first report of Fusarium wilt of Canary Island date palm caused by F. oxysporum f. sp. canariensis in Louisiana, extending its geographic range. The disease may adversely affect the tradition of planting Canary Island date palms in New Orleans. The sequence of isolate PDC-4701 has been submitted to the NCBI database (GenBank Accession No. JF826442) and a culture specimen has been deposited in the Fusarium Research Center culture collection (Accession No. O-2602) at the Pennsylvania State University, University Park, PA. References: (1) M. L. Elliott et al. Plant Dis. 95:356, 2011. (2) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004.

scholarly journals First Report of Fusarium Wilt of Cilantro Caused by Fusarium oxysporum in California

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1130-1130 ◽  
Author(s):  
S. T. Koike ◽  
T. R. Gordon
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Vascular Tissue ◽  
Fusarium Species ◽  
Wilt Disease ◽  
Apium Graveolens ◽  
Peat Moss ◽  
State University ◽  
First Report ◽  
Vascular Discoloration

Cilantro, or coriander (Coriandrum sativum), is a leafy vegetable in the Apiaceae and is grown commercially in California primarily for use as a fresh herb. During 2002 and 2003 in coastal California (Santa Barbara County), commercial cilantro fields showed symptoms of a wilt disease. Affected plants grew poorly and were stunted. Lower foliage turned yellow with reddish tinges, and plants wilted during warmer times of the day. The main stem, crown, and taproot exhibited vascular discoloration that was reddish to light brown. As disease progressed, plants eventually died. For both years, the disease distribution was limited to isolated small patches (each patch measuring less than 1 m2 in area). A fungus was consistently isolated from symptomatic vascular tissue in crowns and taproots. On the basis of colony and conidial morphology, the isolates were identified as Fusarium oxysporum (2). No other fungi or bacteria were recovered from these plants. To test pathogenicity, suspensions containing 1 × 106 conidia/ml were prepared for five isolates. The roots of 30-day-old cilantro plants of four cultivars (30 plants each of Festival, Leisure, Santo, and LSO 14) were clipped and then soaked in the suspensions for 20 min. The roots of 30 plants of each cultivar were soaked in water as a control. Plants were repotted into new redwood bark + peat moss rooting medium and maintained in a greenhouse setting at 24 to 26°C. After 1 month, 95% or more of the inoculated plants showed yellowing and vascular discoloration symptoms similar to those seen in the field. F. oxysporum was reisolated from all inoculated plants. The four cilantro cultivars did not show differences in disease severity. Control plants showed no symptoms, and the fungus was not recovered from these plants. The experiment was repeated and the results were the same. Experiments also were conducted to determine if cilantro isolates could cause disease in celery (Apium graveolens var. dulce). Celery transplants and cilantro seedlings were prepared and inoculated as described above. However, after 2 months, celery plants did not show any disease symptoms, while the cilantro developed wilt symptoms and eventually died. A Fusarium wilt disease has been reported on coriander in Argentina and India where the pathogen was named F. oxysporum f. sp. coriandrii (1,3). To our knowledge, this is the first report of Fusarium wilt of cilantro in California. References: (1) M. Madia et al. Fitopatologia 34:155, 1999. (2) P. E. Nelson et al. Fusarium species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, 1983. (3) U. S. Srivastava. Indian Phytopathol. 22:406, 1969.

scholarly journals First Report of Fusarium Wilt of Paper Flower (Bougainvillea glabra) Caused by Fusarium oxysporum in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 483-483 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
V. Guarnaccia ◽  
A. Vitale ◽  
G. Perrone ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Disease Incidence ◽  
Elongation Factor ◽  
Gene Sequences ◽  
Single Spore ◽  
Potential Threat ◽  
First Report ◽  
Potted Plants ◽  
Bougainvillea Glabra

Paper flower (Bougainvillea glabra Choisy), native to Brazil, is the most widely and intensively cultivated species of bougainvillea as a potted plant in Sicily (Italy). During 2008 and 2009, a wilting of vegetatively produced B. glabra cv. Sanderiana was observed in several nurseries in eastern Sicily (Catania and Messina provinces). Disease incidence was higher (~10 to 30%) in the tree-shaped potted plants (standards). Occasionally, wilting was detected on plants that were not tree shaped. Internally, symptomatic plants showed conspicuous vascular orange discoloration from the crown to the canopy. Diseased crown and stem tissues were surface disinfested for 30 s in 1% NaOCl, rinsed in sterile water, plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate, and incubated at 25°C. A Fusarium sp. was consistently isolated from affected plant tissue. Colonies with light purple or purple mycelia and violet reverse colony colors developed after 10 days. On carnation leaf agar, single-spore isolates produced microconidia in false heads on short monophialides, macroconidia that were 3-septate with a pedicellate base, and solitary and double-celled or aggregate chlamydospores. A PCR assay was conducted on two representative strains (DISTEF-BGS1 and DISTEF-BGS2) by analyzing sequences of the parzial translation elongation factor alpha gene (TEF-1α) and CaM gene (coding calmodulin protein). The primers used are previously used by O'Donnell et al. (1,2). Calmodulin sequences of BGS1 and BGS2 strains (GenBank Nos. FN645740 and FN645741, respectively) exhibited 99% homology with Fusarium oxysporum strain ITEM 2367 (GenBank No. AJ560774), and have homology of 99.6% between them. TEF-1 gene sequences of BGS1 (GenBank No. FN645739) exhibited an identity of 100% to F. oxysporum f. sp. lycopersici MUCL 22544 GenBank No. EF056785.1) and TEF-1α gene sequences of BGS2 (GenBank No. FN655742) exhibited an identity of 100% to F. oxysporum strain NRRL 45954 (GenBank No. FJ985431.1), whereas the homology between the two strains is 98.5%. Both PCR approaches established the identity of the isolates to the F. oxysporum Schlechtend:Fr (1,2). Pathogenicity tests were performed by placing 1-cm2 plugs of PDA from 10-day-old mycelial cultures near the crown on 40 potted, healthy, 6-month-old cuttings of paper flower. Twenty plants for each isolate were used. The same number of plants served as noninoculated controls. All plants were enclosed for 5 days in plastic bags and placed in a growth chamber at 24 ± 1°C. Plants were then moved to a greenhouse where temperatures ranged from 24 to 26°C. Symptoms identical to those observed in nurseries developed 1 month after inoculation with both strains. Crown and stem orange discoloration was detected in all inoculated plants after 2 months. Control plants remained symptomless. F. oxysporum was consistently reisolated from symptomatic tissues and identified as previously described. To our knowledge, F. oxysporum was previously reported on paper flower in Ghana (3). However, this is the first demonstration of the pathogenicity of F. oxysporum on paper flower and it is the first report in Europe of the disease. The presence of Fusarium wilt in Sicily is a potential threat to paper flower production in nurseries. References: (1) K. O'Donnell et al. Proc. Natl. Acad. Sci. USA 95:2044, 1998. (2) K. O'Donnell et al. Mycoscience 41:61, 2000. (3) P. Spaulding. USDA Agric. Handb. 197:1, 1961.

scholarly journals First Report of Race 2 of Fusarium oxysporum f. sp. lycopersici, the Causal Agent of Fusarium Wilt on Tomato in Taiwan

Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 111-111 ◽  
Author(s):  
Z. M. Sheu ◽  
T. C. Wang
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Banding Pattern ◽  
Vascular Tissue ◽  
First Report ◽  
Intergenic Spacer Region ◽  
Stunted Growth ◽  
Vascular Discoloration ◽  
Race 1 ◽  
Race 2

Fusarium wilt caused by Fusarium oxysporum Schlechtend.:Fr. f. sp. lycopersici (Sacc.) W.C. Snyder & N.H. Hans. is a destructive disease of tomato crops worldwide. The use of resistant varieties is the best strategy for disease control. There are three reported races of the pathogen. Recent surveys indicated that many of the commercial cultivars with resistance to F. oxysporum f. sp. lycopersici race 1 planted in Taiwan displayed Fusarium wilt symptoms. Yellowing on the older leaves was observed on one side of the stems close to fruit maturity. The yellowing gradually affected most of the foliage and was accompanied by wilting of the plants. The vascular tissue was usually dark brown and discoloration extended to the apex. The wilting became more extensive until plants collapsed and died. A total of 87 isolates obtained from typical diseased plants throughout Taiwan from 2002 to 2005 were analyzed to determine the race and distribution of this pathogen in Taiwan. Isolates were confirmed at the species level using F. oxysporum-specific primers FOF1 and FOR1 (4). Subsequently, isolates were characterized for pathogenicity, race and restriction fragment length polymorphisms of the intergenic spacer region of rDNA (IGS-RFLP) with two reference isolates, Fol 11A (race 1) and Fol 34-1 (race 2). Pathogenicity tests and race determination were conducted using root-dip inoculation (3) on 2-week-old seedlings of host differentials Bonny Best (no resistance), UC82-L (resistant to race 1), and Florida MH-1 (resistant to races 1 and 2). Thirty-six seedlings of each cultivar were arranged into three replications and inoculated with each isolate. Disease reaction was evaluated 3 weeks after inoculation. The disease severity rating (DSR) was determined on individual plants according to the following scale: 0 = plant healthy without external symptoms; 1 = slight vascular discoloration with or without stunted growth; 2 = severe vascular discoloration usually with stunted growth; and 3 = plant wilted beyond recovery or dead. The presence of severe vascular discoloration indicated a susceptible reaction. All isolates were race 2, and over 70% of the isolates showed strong virulence with a DSR >2 on cvs. Bonny Best and UC-82L. This result was different from a previous report of race 1 from Taiwan (2). Two IGS-RFLP haplotypes generated by EcoRI, RsaI, and HaeIII digestions (1) were identified. Eighty-six isolates displayed one banding pattern, and one unique isolate displayed a second banding pattern. The results demonstrated the predominance of race 2 and low diversity within the Taiwan population. To our knowledge, this is the first report regarding the predominant race and IGS-RFLP haplotype identification of F. oxysporum f. sp. lycopersici in Taiwan. Our study indicates that tomato varieties in Taiwan should possess resistance to race 2. References: (1) G. Cai et al. Phytopathology 93:1014, 2003. (2) K. S. Elias and R. W. Schneider. Phytopathology 82:1421, 1992. (3) J. W. Gerdemann and A. M. Finley. Phytopathology 41:238, 1951. (4) P. K. Mishra et al. FEMS Microbiol. Lett. 218:329, 2003.

scholarly journals Emerging Palm Diseases in Florida

2009 ◽  
Vol 19 (4) ◽  
pp. 717-718 ◽  
Author(s):  
Monica L. Elliott
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Canary Island ◽  
Date Palm ◽  
Phoenix Canariensis ◽  
Sabal Palmetto ◽  
Palm Species ◽  
Lethal Yellowing ◽  
Syagrus Romanzoffiana ◽  
Cabbage Palm

Since the mid-1990s, several new pathogens and diseases have emerged on palms (Arecaceae) growing in Florida. These include two formae speciales of Fusarium oxysporum, with f. sp. canariensis causing fusarium wilt of canary island date palm (Phoenix canariensis) and a new forma specialis causing Fusarium wilt of queen palm (Syagrus romanzoffiana) and mexican fan palm (Washingtonia robusta). The texas phoenix palm decline phytoplasma (‘Candidatus Phytoplasma palmae’ subgroup 16SrIV-D), which causes a lethal yellowing-type disease, has been detected in date palms (Phoenix spp.), queen palm, and cabbage palm (Sabal palmetto). New rachis (petiole) blight pathogens include Cocoicola californica on mexican fan palm and Serenomyces species on several palm species.

scholarly journals First Report of Fusarium Wilt of Basil Caused by Fusarium oxysporum f. sp. basilici in Argentina

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1432-1432 ◽  
Author(s):  
G. A. Lori ◽  
I. Malbrán ◽  
C. A. Mourelos
Keyword(s):  
Fusarium Oxysporum ◽  
Species Identification ◽  
Vascular Tissue ◽  
Morphological Characteristics ◽  
Control Treatment ◽  
Pcr Assay ◽  
First Report ◽  
La Plata ◽  
Sweet Basil ◽  
Polished Rice

Annually, ~20 ha of sweet basil (Ocimum basilicum L.) are cultivated in greenhouses in the green belt area surrounding La Plata, Argentina, mainly for fresh consumption. In 2004 to 2007, basil plants of cv. Genovese showed wilt symptoms, necrosis of leaves and stems, asymmetrical growth, and discolored vascular tissue in greenhouses in La Plata. In 2007, the same symptoms were observed on plants of cv. Morada grown from seeds that were produced in Italy. Isolations were completed from root, crown, and stem sections of diseased plants of cv. Genovese from three greenhouses in 2004 to 2007, and from commercial seeds, stem sections, flowers, and seeds of diseased plants of cv. Morada in 2007. Seeds and portions of symptomatic tissues were surface-disinfested with 0.5% NaOCl for 1 min, rinsed in sterilized distilled water, air dried, and plated on 2% potato dextrose agar (PDA). Twenty-seven isolates were identified as Fusarium oxysporum Schltdl. based on morphological characteristics (4), and the species identification confirmed by PCR assay using a F. oxysporum f. sp. basilici-specific primer pair, Bik 1 and Bik 2 (1). Vegetative compatibility groups (VCGs) were determined for the 27 isolates through complementation of nitrate-nonutilizing mutants generated from these isolates (2) and paired with two Italian tester strains from an international collection (PVS-Fu 220 and PVS-Fu 125, provided by V. Balmas, Univeristà degli Studi di Sassari, Italy). All 27 isolates from Argentina belonged to VCG 0200. This is a unique VCG for F. oxysporum f. sp. basilici and has been identified in Israeli, American, and Italian isolates of the fungus (3). To fulfill Koch's postulates, pathogenicity tests were conducted with 12 isolates selected to reflect the multiple sources of fungal recovery, including root, crown, and stem sections, and leaves of diseased plants of cv. Genovese and commercial seeds, stem sections, flowers, and seeds of cv. Morada. Isolates were each grown on moistened (40% w/w), autoclaved, polished rice for 10 days, dried, and ground in a grinder. The number of CFU/g rice was determined by serial dilution plating onto PDA plates. The inoculum was added to autoclaved soil at 104 CFU/g dry soil. For each isolate, 8 healthy basil seedlings of each of cvs. Genovese and Morada were planted in pots, each containing 1 liter of inoculated soil. The control treatment consisted of 8 basil seedlings of each of the same cultivars planted in autoclaved soil mixed with sterilized, ground, polished rice. Plants were grown in a greenhouse with natural daylight for 45 to 50 days after inoculation. All inoculated plants showed the same symptoms described for the original basil plants. No symptoms were observed on the control plants. F. oxysporum f. sp. basilici was re-isolated from the vascular tissue of stems of symptomatic plants but not from control plants, and species identification confirmed by PCR assay as previously described. The presence of the pathogen was verified in the seed lot produced in Italy, suggesting that this could have been a source of inoculum that introduced the pathogen into La Plata, Argentina, as supported by the hypothesis that infested seed resulted in spread of a clonal population of F. oxysporum f. sp. basilici internationally (1). To our knowledge, this is the first report of F. oxysporum f. sp. basilici infecting sweet basil in Argentina. References: (1) A. Chiocchetti et al. Plant Dis. 85:607, 2001. (2) J. C. Correll et al. Phytopathology 77:1640, 1987. (3) A. Garibaldi et al. Plant Dis. 81:124, 1997. (4) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006.

scholarly journals First Report of Fusarium oxysporum f. sp. lycopersici Race 2 on Tomato in Italy

Plant Disease ◽  
1999 ◽  
Vol 83 (10) ◽  
pp. 967-967 ◽  
Author(s):  
V. M. Stravato ◽  
R. Buonaurio ◽  
C. Cappelli
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Vascular Tissue ◽  
Morphological Features ◽  
Pathogenicity Test ◽  
First Report ◽  
Fungal Isolates ◽  
Race 1 ◽  
Race 2 ◽  
I Gene

During the summer of 1997, symptoms of Fusarium wilt were observed on tomato (Lycopersicon esculentum Mill.) cvs. Monica F1 and PS 110, which bear the I gene for resistance to race 1 of Fusarium oxysporum Schlechtend.:Fr. f. sp. lycopersici (Sacc.) W.C. Snyder & H.N. Hans., in two commercial production greenhouses in Latium (Fondi) and one greenhouse in Sardinia (Oristano). Infected plants showed yellowing, stunting, vascular discoloration, and premature death. A fungus from tomato stems with discolored vascular tissue was consistently isolated on potato dextrose agar (PDA) and, based on morphological features, was identified as F. oxysporum. To verify the pathogenicity of four fungal isolates, cv. Bonny Best tomato plants, which do not carry genes for Fusarium wilt resistance, were inoculated by dipping roots of 2-week-old seedlings in a suspension of 105 microconidia per ml for 30 s. Inocula were obtained from 1-week-old fungal cultures grown on PDA. Roots of control plants were dipped in water. Seedlings were transplanted to pots containing peat and river sand (1:1, vol/vol) and placed in a greenhouse at 20 to 25°C. One month after inoculation, all fungal isolates provoked wilting of inoculated plants. No symptoms were observed on control plants. The morphological features of the fungus reisolated from diseased plants were similar to those of the original isolates. Based on the pathogenicity test, we concluded that the fungal isolates belong to F. oxysporum f. sp. lycopersici. To determine the races of the fungal isolates, differential tomato lines VFN8 (I gene for resistance to race 1), Florida MH-1 (I and I2 genes for resistance to races 1 and 2), and I3R (I, I2, and I3 genes for resistance to races 1, 2, and 3) were inoculated with the four fungal isolates, using the same procedure described for the pathogenicity test. Because disease symptoms were detected on VFN8 but not on Florida MH-1 and I3R, we deduced that the fungal isolates belong to F. oxysporum race 2. This is the first report of F. oxysporum f. sp. lycopersici race 2 in Italy. Previous research indicated that race 1 is present in Italy (1). Currently, many commercially acceptable cultivars resistant to races 1 and 2 are available to Italian greenhouse growers. Reference: (1) M. Cirulli. Phytopathol. Mediterr. 4:63, 1965.

scholarly journals First Report of Fusarium oxysporum f. sp. palmarum in Texas Causing Fusarium Wilt of Washingtonia robusta

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1511-1511 ◽  
Author(s):  
M. Giesbrecht ◽  
M. McCarthy ◽  
M. L. Elliott ◽  
K. L. Ong
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Sequence Similarity ◽  
The United States ◽  
Plant Sample ◽  
Post Inoculation ◽  
Single Spore ◽  
Diagnostic Laboratory ◽  
First Report ◽  
Foliar Tissue

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.

Sign in / Sign up

Export Citation Format

Share Document