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 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 First Report of Fusarium Wilt of Exacum affine Caused by Fusarium oxysporum

Plant Disease ◽  
2001 ◽  
Vol 85 (10) ◽  
pp. 1120-1120 ◽  
Author(s):  
W. Elmer ◽  
E. O'Dowd
Keyword(s):  
Fusarium Wilt ◽  
Vascular Tissue ◽  
Fusarium Species ◽  
Plant Diseases ◽  
State University ◽  
Pennsylvania State University ◽  
First Report ◽  
Millet Seed ◽  
Soil Mix ◽  
Exacum Affine

Wilting Persian violets (Exacum affine) were observed in a Connecticut retail outlet. Diseased stems developed a dark coloration at the nodes, while the foliage turned papery, whitish tan. The vascular tissue in affected stems was reddish brown and extended from the base of the stem upward in a unilateral pattern. Fusarium grew from the discolored stem tissue when placed on Komada's medium (2). Single spores were cultured on carnation leaf agar and identified as F. oxysporum (2). Koch's postulates were completed by growing 12 2-month-old seedlings of E. affine ‘Midget’ in potting mix amended with ground dried millet seed (2.0 g/liter of soil) that had been colonized for 2 weeks by the fungus. Symptoms appeared slowly after 8 weeks, and F. oxysporum was re-isolated from the vascular tissue. Plants grown in soil mix with sterile millet remained healthy. Similar tests at different times of the year produced the same results. Other tests examined host specificity with two new isolates on seedlings of Persian violet, carnation, lisianthus, and basil. Both isolates caused symptoms only on Persian violets. Although Haematonectria haematococca (synonym Nectria haematococca, anamorph F. solani) causes Nectria canker of Persian violet (1), this is the first report of F. oxysporum causing Fusarium wilt of Persian violet. We propose the formae specialis be F. oxysporum f. sp. exaci. An isolate has been deposited at the Fusarium Research Center at The Pennsylvania State University, University Park, under Accession No. O-2282. References: (1) M. Daughtrey et al. Compendium of Flowering Potted Plant Diseases. American Phytopathological Society, St. Paul, MN, 1995. (2) Nelson et al. Fusarium species: An Illustrated Manual for Identification. The Pennsylvania State University Press, University Park, PA, 1983.

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 disease on Watermelon Caused by Fusarium oxysporum f. sp. niveum (FON) in Malaysia

Plant Disease ◽  
2021 ◽  
Author(s):  
Muhammad Ziaur Rahman ◽  
Khairulmazmi Ahmad ◽  
Yasmeen Siddiqui ◽  
Norsazilawati Saad ◽  
Tan Geok Hun ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Cover Crops ◽  
Fungal Pathogen ◽  
Disease Incidence ◽  
Wilt Disease ◽  
Likelihood Method ◽  
Distilled Water ◽  
First Report ◽  
Fusarium Wilt Disease

Fusarium wilt disease incited by Fusarium oxysporum f. sp. niveum (FON) is the utmost devastating soil-inhabiting fungal pathogen limiting watermelon (Citrullus lanatus) production in Malaysia and globally. The field disease survey of fusarium wilt was carried out during December 2019 and November 2020, in three major production areas (3 farmer fields per location) in Peninsular Malaysia namely, Mersing, Serdang and Kuantan and disease incidence of 30 and 45%, was recorded for each year, respectively. Infected watermelon plants showed symptoms such as vascular discoloration, brown necrotic lesions to the soil line or the crown, one-sided wilt of a plant, or a runner or the whole plant. Infected root and stem tissues, 1-2 cm pieces were surface sterilized with 0.6% NaOCl for 1 minute followed by double washing with sterile water. The disinfected tissues were air-dried and transferred onto semi-selective Komada’s medium (Komada 1975) and incubated for 5 days. The fungal colonies produced were placed on potato dextrose agar (PDA) to attain a pure culture and incubated at 25±2℃ for 15 days. The pure fungal colony was flat, round and light purple in color. Macroconidia were straight to slightly curved, 18.56-42.22 µm in length, 2.69-4.08 µm width, predominantly 3 septate and formed in sporodochia. Microconidia measured 6.16-10.86 µm in length and 2.49-3.83 µm in width, kidney-shaped, aseptate and were formed on short monophialides in false-heads. Chlamydospores were single or in pairs with smooth or rough walls, found both terminally or intercalary. To confirm their pathogenicity, two-week-old watermelon seedlings (cv. NEW BEAUTY) were dipped into spore suspension (1 ˟ 106 spores/ml) of representative isolates of JO20 (Mersing), UPM4 (Serdang) and KU41 (Kuantan) for 30 second and then moved into 10 cm diameter plastic pots containing 300 g sterilized soil mix. Disease symptoms were assessed weekly for one month. Control seedlings were immersed in sterile distilled water before transplanting. The inoculated seedlings showed typical Fusarium wilt symptoms like yellowing, stunted growth, and wilting, which is similar to the farmer field infected plants. However, the seedlings inoculated by sterile distilled water remained asymptomatic. The pathogen was successfully re-isolated from the infected seedlings onto Komada’s medium, fulfilling the Koch’s postulate. For the PCR amplification, primers EF-1 and EF-2 were used to amplify the tef1-α region. A Blastn analysis of the tef1-α sequences of the isolates JO20 (accession nos. MW315902), UPM4 (MW839560) and KU41 (MW839562) showed 100% similarity; with e-value of zero, to the reference sequences of F. oxysporum isolate FJAT-31690 (MN507110) and F. oxysporum f. sp. niveum isolate FON2 790-2 (MN057702). In Fusarium MLST database, isolates JO20, UPM4 and KU41 revealed 100% identity with the reference isolate of NRRL 22518 (accession no. FJ985265). Though isolate FJ985265 belongs to the f. sp. melonis, earlier findings had revealed Fusarium oxysporum f. sp. are naturally polyphyletic and making clusters with diverse groups of the Fusarium oxysporum species complex (O’Donnell et al. 2015). The isolates JO20, UPM4 and KU41 were identified as F. oxysporum f. sp. niveum based on the aligned sequences of tef1-α and molecular phylogenetic exploration by the maximum likelihood method. To the best of our knowledge, this is the first report of F. oxysporum f. sp. niveum as a causative pathogen of Fusarium wilt disease of watermelon in Malaysia. Malaysia enables to export watermelon all-year-round in different countries like Singapore, Hong-Kong, The United Arab Emirates (UAE), and Netherlands. The outburst of this destructive soil-borne fungal pathogen could cause hindrance to watermelon cultivation in Malaysia. Thus, growers need to choice multiple management tactics such as resistant varieties, cultural practices (soil amendments and solarization), grafting, cover crops and fungicide application to control this new pathogen.

scholarly journals First Report of Fusarium oxysporum Causing Yellows on Sugar Beet in the Red River Valley of Minnesota and North Dakota

Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 341-341 ◽  
Author(s):  
C. E. Windels ◽  
J. R. Brantner ◽  
C. A. Bradley ◽  
M. F. R. Khan
Keyword(s):  
Sugar Beet ◽  
North Dakota ◽  
Vascular Tissue ◽  
Fusarium Species ◽  
River Valley ◽  
Red River ◽  
State University ◽  
Water Control ◽  
First Report ◽  
Red River Valley

In 2002, somel sugar beet (Beta vulgaris L.) fields in the Red River Valley (RRV) of Minnesota and North Dakota had symptoms characteristic of Fusarium yellows (4). In 2004, ≈5% of fields in the RRV had symptomatic plants. Interveinal yellowing of older leaves typically began in mid-July and as the disease progressed, younger leaves turned yellow. Sometimes, one side of the leaf was yellow or necrotic while the other side remained green. As leaves died, they remained attached to the crown. Transverse sections of roots revealed a light gray-brown discoloration of the vascular tissue but no external rotting of roots. Isolations from 35 symptomatic roots collected in eight fields yielded 25 isolates identified as F. oxysporum (from single conidia grown on homemade potato dextrose agar and carnation leaf agar) (3). Pathogenicity was determined by dipping roots of 5-week-old sugar beet plants (cv. ACH 9363) in a suspension of 104 conidia per ml for 8 min (12 isolates, 10 to 12 plants per isolate). Plants were planted in Cone-tainers (3.8 cm diameter × 21 cm; Stuewe and Sons, Inc. Corvallis, OR) containing sterile soil. Three known cultures of F. oxysporum Schlecht. emend. Snyd. & Hans. f. sp. betae Stewart (= F. conglutinans var. betae Stewart [4]) also were included (13 and 216c from L. Hanson, USDA-ARS, Fort Collins, CO; 0-1122 from The Pennyslvania State University Fusarium Research Center). The control was sterile water. Plants were placed in a greenhouse at 24 to 27°C with natural light supplemented with illumination from high-pressure sodium-vapor lamps for 16 h daily and lightly fertilized biweekly to avoid chlorosis from nutrient deficiency. After 6 to 7 weeks, plants were rated for disease on a 0 to 4 scale: 0 = no disease; 1 = slight to extreme plant stunting, leaves may be wilted; 2 = chlorotic leaves, some with necrosis at margins; 3 = tap root dried and brown to black in color, leaves dying; and 4 = plant dead (1). The experiment was repeated. Disease severity differed between trials, but all isolates of F. oxysporum and F. oxysporum f. sp. betae resulted in disease ratings statistically (P < 0.05) greater than that of the water control. In Trial 1, isolates of F. oxysporum averaged a rating of 2.1 (range of 1.8 to 3.3) and F. oxysporum f. sp. betae averaged 2.1 (range of 2.0 to 2.2) compared with 0.1 for the water control. One isolate of F. oxysporum had a statistically higher rating than did the cultures of F. oxysporum f. sp. betae. In Trial 2, isolates of F. oxysporum averaged a rating of 3.3 (range of 2.7 to 3.7) and F. oxysporum f. sp. betae averaged 3.1 (range of 2.7 to 3.4) compared with 0.2 for the water control. Cultures of F. oxysporum (8 of 12) resulted in ratings statistically higher than that of the least pathogenic culture of F. oxysporum f. sp. betae. Cultures of F. oxysporum and F. oxysporum f. sp. betae recovered from inoculated plants were identical to those used to inoculate plants. To our knowledge, this is the first report of F. oxysporum f. sp. betae on sugar beet in the Red River Valley of Minnesota and North Dakota. The disease has been reported in California, Colorado, Montana, Nebraska, Oregon, Texas, and Wyoming (1,2). References: (1) R. A. Cramer et al. J. Phytopathol. 151:352, 2003. (2) G. A. Fisher and J. S. Gerik. Phytopathology 84:1098, 1994. (3) P. E. Nelson et al. Fusarium Species: An illustrated Manual for Identification. The Pennsylvania State University Press. University Park, 1983. (4) D. Stewart. Phytopathology 21:59, 1931.

scholarly journals First Report of Fusarium Wilt of Chicory (Cichorium intybus) Caused by Fusarium oxysporum in Italy

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 496-496 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
A. Poli ◽  
M. L. Gullino
Keyword(s):  
Fusarium Oxysporum ◽  
Vascular Tissue ◽  
Vascular System ◽  
Fusarium Species ◽  
Apical Cell ◽  
Selective Medium ◽  
Cichorium Intybus ◽  
Pathogenicity Test ◽  
First Report ◽  
Sequence Identity

In the summer of 2009, a wilt of chicory was observed on 25 to 30% of 30-day-old Cichorium intybus L. cv. Clio plants grown outdoors on a commercial farm in Piedmont (northern Italy). Affected plants were chlorotic and stunted with poorly developed root systems compared with healthy plants. Black streaks were observed in the stem and proximal part of the leaf vascular system in wilted plants. Fusarium oxysporum Schltdl. was isolated from symptomatic vascular tissue on a Fusarium-selective medium (1) from 80% of samples. Grown on potato dextrose agar (PDA) for 4 days at 23°C, the colonies, initially white and later pale pink, produced hyaline microconidia that were oval-elliptical and cylindrical in shape measuring 5.6 to 14.9 (average 10.2) × 2.1 to 4.5 (3.0) μm, borne on short monophialides measuring 8.2 to 16.1 (average 13.2) × 2.1 to 4.2 (3.3) μm. Macroconidia were slightly curved, three-septate, with a slightly hooked apical cell and a foot-shaped basal cell measuring 24.9 to 41.6 (average 32.2) × 3.2 to 5.2 (4.3) μm. Chlamydospores were both terminally and intercalary, solitary but also in short chains (2 to 4 elements) measuring 21.1 to 41.0 (average 27.2) μm (2). The internal transcribed spacer (ITS) rDNA region was amplified using the primers ITS1/ITS4 and sequenced. BLASTn analysis of the 527-bp amplicon (GenBank Accession No. HQ644423) obtained had 98% sequence identity with F. oxysporum (GenBank Accession No. FJ605247). The translation elongation factor-1α (EF-1α) gene was amplified using primers EF-1/EF-2 and sequenced (GenBank Accession No. GU564259). The 663-bp fragment had 99% sequence identity with F. oxysporum (GenBank Accession Nos. EU313540, EU313539, and DQ837696). Pathogenicity tests were conducted on 15-day-old chicory plants from two cultivars (Clio and Katia). Thirty-five plants per cultivar were inoculated by dipping their roots in a 1 × 106 CFU/ml suspension of isolate FusCic45B recovered from wilted chicory. Inoculated and noninoculated plants were transplanted into five pots filled with 10 liters of steamed mix (peat/perlite/sand, 60:20:20 vol/vol) and were maintained in a glasshouse at 25 to 27°C. Wilt symptoms and vascular discoloration of the roots, crown, and veins developed 15 days after inoculation on all inoculated plants. Plants of cv. Clio were more susceptible. F. oxysporum was always reisolated from infected plants using the Fusarium-selective medium. All noninoculated plants remained healthy. The pathogenicity test was conducted twice. To our knowledge, this is the first report of wilt caused by F. oxysporum on chicory, C. intybus, in Italy as well as worldwide. References: (1) H. Komada. Rev. Plant Prot. Res. 8:114, 1975. (2) E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. The Pennsylvania State University Press, University Park, 1983.

scholarly journals First Report of Ziziphus jujuba Wilt Caused by Fusarium oxysporum in China

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 586-586 ◽  
Author(s):  
F. Gao ◽  
Z. Xiang ◽  
Y. L. Zhang
Keyword(s):  
Fusarium Oxysporum ◽  
Vascular Tissue ◽  
Herbal Remedy ◽  
Wilt Disease ◽  
Healthy Plant ◽  
Natural Occurrence ◽  
Chinese Jujube ◽  
First Report ◽  
Stunted Growth ◽  
Ziziphus Jujuba

Chinese jujube (Ziziphus jujuba Mill.) is widely planted in Xinjiang Province of China for fruit and as an effective herbal remedy. Wilt symptoms were observed on field-grown Z. jujuba during the spring and fall of 2010 and 2011. Diseased plants exhibited symptoms including wilted leaves, stunted growth, extensive brown discoloration on stems, and eventually death. In severe cases, approximately 60% of the plants in the field died. Repeated isolations from discolored stem vascular tissues were made on potato dextrose agar (PDA) after disinfestation in 1% HgCl2 for 1 min and dipping in 70% ethanol for 10 s. Petri dishes were then incubated in complete darkness at 26°C for 7 days. All colonies on PDA had pale pink-salmon-colored mycelia. Macroconidia were mostly three to five septate, slightly curved, and ranged from 2.9 to 11.9 × 29.5 to 45 μm. Microconidia were abundant, generally single celled, oval to kidney shaped, and ranged from 2.5 to 5 × 7.5 to 11.5 μm in false heads on short monophialides. Chlamydospores were single or in pairs and profusely distributed. These characteristics were similar to those of Fusarium oxysporum (2). The internal transcribed spacer (ITS) rDNA region was amplified with primers ITS1/ITS4 and sequenced (1). BLASTn analysis of the sequence (GenBank Accession No. JQ039331) showed a 99% homology with several isolates of F. oxysporum in the GenBank database. Pathogenicity tests were conducted on healthy, 2-month-old seedlings and 1-month-old rooted cuttings of Z. jujuba under greenhouse conditions. Plants were inoculated with sterilized mixtures of wheat and barley seeds (1:1) that were incubated in a F. oxysporum isolate spore suspension (1 × 107 conidia/ml) at 25°C for 7 to 10 days. The seeds (3 g per plant) were placed around the collar of each healthy plant under the soil surface and incubated at 25 to 28°C in a greenhouse. Control plants were sown in sterile soil without inoculated seeds. In 3 weeks, inoculated plants developed leaf wilt and chlorosis, stunted growth, brown discolored vascular tissue on stems, and finally died, which is similar to that observed in the field. F. oxysporum was reisolated from the stems of diseased plants, confirming Koch's postulates. Control seedlings were symptom free. F. oxysporum has been known to cause wilt disease on cotton and tomato in Xinjiang Province (3). However, to our knowledge, this is the first report of a natural occurrence of Chinese jujube wilt disease on commercial fields caused by F. oxysporum in China. References: (1) G. M. Arruda et al. Plant Pathol. 54:53, 2005. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (3) F. X. Tian et al. Acta Phytopathol. Sin. 11:27, 1981.

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 oxysporum Causing Vascular Wilt of Lamb's Lettuce (Valerianella olitoria) in Italy

Plant Disease ◽  
2004 ◽  
Vol 88 (1) ◽  
pp. 83-83 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
M. L. Gullino
Keyword(s):  
Fusarium Oxysporum ◽  
Vascular Tissue ◽  
Selective Medium ◽  
Northern Italy ◽  
Growth Chamber ◽  
Pathogenicity Test ◽  
Vascular Wilt ◽  
First Report ◽  
Forma Specialis ◽  
Vascular Discoloration

Lamb's lettuce (Valerianella olitoria), also known as corn salad, is increasingly grown in Italy and used primarily in the preparation of mixed processed salad. In the summer of 2003, plants of lamb's lettuce cvs. Trophy and Palmares exhibiting wilt symptoms were observed in several commercial greenhouses near Bergamo in northern Italy. Wilted 30-day-old plants were observed first during the month of June, at the time of thinning when temperatures ranged between 28 and 35°C. Disease was generally uniform in the greenhouses and 30 to 50% of the plants were affected. Vascular tissue of affected seedlings appeared red or brown but later turned brown or black. Affected plants were stunted and developed yellowed leaves. Vascular discoloration was continuous from the upper taproot through the crown to the leaf. Fusarium oxysporum was consistently isolated from symptomatic vascular tissue onto a Fusarium-selective medium (1). Seeds of the same cultivars (Trophy and Palmares) affected by the wilt in the field were artificially inoculated by dipping them for 15 min into spore suspensions (1 × 106 conidia per ml) of three isolates of F. oxysporum obtained from infected plants. Noninoculated seeds served as control treatments. Forty seeds per treatment were sown in pots (1-liter volume) containing steam-sterilized soil and maintained at 25°C in a growth chamber programmed for 12 hours of light per day. Wilt symptoms developed on both cultivars 20 days after seeding, and F. oxysporum was consistently reisolated from infected plants. The plants obtained from noninoculated seeds remained healthy. The pathogenicity test was carried out twice with similar results. To our knowledge, this is the first report of F. oxysporum causing vascular wilt of lamb's lettuce and may warrant a new forma specialis designation. Reference: (1) H. Komada. Rev. Plant Prot. Res. 8:114, 1975.

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