scholarly journals First Report of Phytophthora cactorum on Strawberry Plants in Spain

Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 1051-1051 ◽  
Author(s):  
B. de los Santos ◽  
M. Porras ◽  
C. Blanco ◽  
C. Barrau ◽  
F. Romero
Keyword(s):  
Pathogenic Fungi ◽  
Crown Rot ◽  
Phytophthora Cactorum ◽  
First Report ◽  
Thin Walls ◽  
Brown Discoloration ◽  
Crown Tissue ◽  
Symptomatic Tissue ◽  
Red Stele ◽  
Bluish Discoloration

Crown rot of strawberry (Fragaria × ananassa Duch. cv. Camarosa) was observed in three and two production fields in 2000 and 2001, respectively, in Huelva, southwestern Andalucia, Spain. Affected plants did not exhibit typical symptoms of red stele. Instead, there was an internal red-brown discoloration of the upper crown, a bluish discoloration of leaves, and the plants were wilted. Eventually, plants collapsed and died. Fungi were isolated from surface-disinfested necrotic crown tissue on P5ARPH medium (1). Plates were placed at 21°C for 5 to 10 days. One species was isolated consistently from symptomatic tissue. Microscopic observations revealed spherical oogonia with thin walls. Antheridia were paragynous and were attached to the oogonium near the oogonial stalk. Single oospores were spherical and had double-layered, yellow-brown walls (20 to 25 μm in diameter). Sporangia were usually borne terminally and were colorless and papillate (22 to 30 μm in diameter). Based on these characteristics, the causal agent was identified as Phytophthora cactorum (Lebert & Cohn) J. Schröt. (2). The fungus was transferred to V8 juice agar and maintained at 21°C in the dark. Disks (9-mm diameter) were removed from 7-day-old cultures of P. cactoru and used to inoculate five 2-month-old ‘Camarosa’ strawberry plants grown in sterilized peat in the greenhouse. Three disks were placed in the crown of each plant at soil level. Five noninoculated plants were similarly treated with sterile V8 juice agar disks only. After 2 weeks, the pathogen was reisolated from red-brown lesions visible on crowns of all inoculated plants. Noninoculated plants did not show any symptoms. To our knowledge, this is the first report of P. cactorum attacking strawberry plants in Spain. References: (1) S. N. Jeffers and S. B. Martin. Plant Dis. 70:1038, 1986. (2) G. M. Waterhouse and J. M. Waterston. No. 111 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, UK, 1996.

scholarly journals First Report of Rhizoctonia solani Causing a Disease of Sunflower in India

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 488-488 ◽  
Author(s):  
K. Srinivasan ◽  
S. Visalakchi
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Crown Rot ◽  
Pathogenicity Test ◽  
American Phytopathological Society ◽  
First Report ◽  
Leaf Yellowing ◽  
Crown Tissue ◽  
Symptomatic Tissue ◽  
White Mycelium

During the spring of 2009, symptoms including leaf yellowing and wilting, root rot, and death of plants were noted in sunflower (Helianthus annuus L.) crops in Dharmapuri District, Tamilnadu, India. In some fields, approximately 30% of the plants were affected. The disease began when plants were approximately 10 weeks old and occurred on scattered or adjacent plants. The presence of white mycelium was observed on necrotic crowns. Symptomatic tissue was surface disinfested in 70% alcohol for 30 s and 0.5% sodium hypochlorite for 1 min and plated onto potato dextrose agar (PDA) (1). One isolate (coded SV001) had near right-angle branching with basal constriction and adjacent septa and sclerotia typical of Rhizoctonia spp. (2). Cream-colored colonies produced irregular, light brown sclerotia that were 3.0 to 7.3 mm (average 3.8 mm) in diameter. Hyphae were 6.8 to 7.0 μm (average 6.9 μm) wide and multinucleate (8 to 15 nuclei per cell). On the basis of hyphal anastomosis with several known AG testers, the fungus was characterized as Rhizoctonia solani Kühn AG-IV (3). One culture was deposited at the Madras University Botany Laboratory, Center for Advanced Studies in Botany, University of Madras, Chennai, India. In a pathogenicity test, R. solani SV001 was grown on PDA for 5 days at 24°C in the dark. Five-millimeter-diameter disks were placed at the base of sunflower plants (cv. Mordan). Four sunflower plants in each of three pots were inoculated; noninoculated plants served as controls. Plants were placed in a glasshouse maintained at 25 to 27°C. Inoculated plants developed yellow foliage and crown rot and root rot symptoms after 7 to 12 days and died in 17 to 20 days. No symptoms were observed on noninoculated plants. The pathogen was reisolated from fragments of necrotic crown tissue of inoculated plants. To our knowledge, this is the first report of R. solani AG-IV causing a disease of sunflower plants in India. References: (1). R. C. Fenille et al. Plant Pathol. 54:325, 2005. (2). J. R. Parmeter et al. Phytopathology 59:1270, 1969. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St Paul, MN, 1991.

scholarly journals First report of crown rot of Photinia fraseri caused by Phytophthora cactorum

2006 ◽  
Vol 55 (4) ◽  
pp. 573-573 ◽  
Author(s):  
A. M. Vettraino ◽  
L. Antonacci ◽  
L. Flamini ◽  
P. Nipoti ◽  
E. Rossini ◽  
...  
Keyword(s):  
Crown Rot ◽  
Phytophthora Cactorum ◽  
First Report

scholarly journals Paraphoma Crown Rot of Pyrethrum (Tanacetum cinerariifolium)

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2363-2369 ◽  
Author(s):  
Azin Moslemi ◽  
Peter K. Ades ◽  
Tim Groom ◽  
Pedro W. Crous ◽  
Marc E. Nicolas ◽  
...  
Keyword(s):  
Crown Rot ◽  
Total Biomass ◽  
Oil Glands ◽  
Yield Decline ◽  
Commercial Cultivation ◽  
Inoculation Techniques ◽  
Brown Discoloration ◽  
Tanacetum Cinerariifolium ◽  
Crown Tissue ◽  
Rot Disease

Pyrethrum (Tanacetum cinerariifolium) is commercially cultivated for the extraction of natural pyrethrin insecticides from the oil glands inside seed. Yield decline has caused significant yield losses in Tasmania during the last decade. A new pathogen of pyrethrum causing crown rot and reduced growth of the plants in yield decline affected fields of northern Tasmania was isolated from necrotic crown tissue and described as Paraphoma vinacea. Multigene phylogenetic identification of the pathogen also revealed that P. vinacea was a new species different from other Paraphoma type strains. Glasshouse pathogenicity experiments showed that P. vinacea significantly reduced belowground and total biomass of pyrethrum plants 2 months after inoculation. Dull-tan to reddish-brown discoloration of the cortical and subcortical crown tissue was observed in 100% of the infected plants. P. vinacea infected 75% of the plants inoculated with root dip and soil drench inoculation techniques in an inoculation optimization experiment. P. vinacea, the causal agent of Paraphoma crown rot disease, represents an important pathogen that will negatively impact the commercial cultivation of pyrethrum in Tasmania.

scholarly journals First Report of Phytophthora cactorum Causing Crown Rot of Shepherdia × utahensis in the United States

Plant Disease ◽  
2018 ◽  
Vol 102 (3) ◽  
pp. 686
Author(s):  
M. S. Wiseman ◽  
T. Bonar ◽  
M. I. Gordon ◽  
M. Serdani ◽  
M. L. Putnam
Keyword(s):  
United States ◽  
The United States ◽  
Crown Rot ◽  
Phytophthora Cactorum ◽  
First Report

scholarly journals Crown Rot of Strawberry Caused by Macrophomina phaseolina in California

Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1253-1253 ◽  
Author(s):  
S. T. Koike
Keyword(s):  
Disease Incidence ◽  
Pathogenic Fungi ◽  
Macrophomina Phaseolina ◽  
The United States ◽  
Crown Rot ◽  
Charcoal Rot ◽  
Crown Tissue ◽  
Original Field ◽  
Rot Disease ◽  
Eventual Collapse

In 2006 and 2007, severely diseased strawberry (Fragaria × ananassa) plants were observed in five commercial fields in southern California (Orange County). Disease generally occurred in discrete patches. Within such patches, disease incidence ranged from 10 to 75%. Symptoms consisted of wilting of foliage, drying and death of older leaves, plant stunting, and eventual collapse and death of plants. When plant crowns were dissected, internal vascular and cortex tissues were dark brown to orange brown. Fruiting bodies or other fungal structures were not observed. A fungus was consistently isolated from symptomatic crown tissue that had been surface sterilized and placed on acidified corn meal agar (LA-CMA). All isolates produced numerous, dark, irregularly shaped sclerotia that were 67 to 170 μm long and 44 to 133 μm wide. When isolates were grown on 1.5% water agar with dried and sterilized wheat straw, dark, ostiolate pycnidia and hyaline, single-celled, cylindrical conidia were produced. On the basis of these characters, all isolates were identified as Macrophomina phaseolina (1). The symptomatic plants tested negative for Colletotrichum spp., Phytophthora spp., Verticillium dahliae, and other pathogens. Inoculum for pathogenicity tests was produced by growing six isolates on CMA on which sterilized wood toothpicks were placed on the agar surface. After 1 week, toothpicks were removed and inserted 4 to 5 mm deep into the basal crown tissue of potted strawberry plants (cv. Camarosa) grown in soilless, peatmoss-based rooting medium. Ten plants were inoculated per isolate and one toothpick was inserted per plant. Ten control strawberry plants were treated by inserting one sterile toothpick into each crown. All plants were then grown in a shadehouse. After 2 weeks, all inoculated plants began to show wilting and decline of foliage. By 4 weeks, all inoculated plants had collapsed. Internal crown tissue was discolored and similar in appearance to the original field plants. M. phaseolina was isolated from all inoculated plants. Control plants did not exhibit any disease symptoms, and crown tissue was symptomless. The test was repeated and the results were similar. While M. phaseolina has been periodically associated with strawberry in California (3), to my knowledge, this is the first report of charcoal rot disease on commercial strawberry in California. Charcoal rot of strawberry has been reported in Egypt, France, India, Israel, and the United States (Florida and Illinois) (2,4). Similar to previous reports (2,4), many of the affected California fields were not preplant fumigated with methyl bromide + chloropicrin fumigants, and it is possible that under these changing production practices this pathogen may increase in importance in California. References: (1) P. Holliday and E. Punithalingam. No. 275 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1970. (2) J. Mertely et al. Plant Dis.89:434, 2005. (3) S. Wilhelm. Plant Dis. Rep. 41:941, 1957. (4) A. Zveibil and S. Freeman. Plant Dis. 89:1014, 2005.

scholarly journals First Report of Crown Rot and Stem Rot Caused by Rhizoctonia solani AG-4 on Marmalade Bush in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 486-486 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
I. Castello ◽  
V. Guarnaccia ◽  
A. Vitale
Keyword(s):  
Rhizoctonia Solani ◽  
Anastomosis Group ◽  
Crown Rot ◽  
Fluorescent Light ◽  
First Report ◽  
Brown Discoloration ◽  
The Family ◽  
Perennial Shrub ◽  
Pathogenicity Tests ◽  
Safranin O

Marmalade bush (Streptosolen jamesonii (Benth.) Miers), also known as fire bush, is an evergreen, perennial shrub in the family Solanaceae, which is native to South America (Colombia, Ecuador, and Peru). In Italy, this species is cultivated as an ornamental creeper or bush. During September 2009, a new disease was observed in a stock of ~10,000 pot-grown, 2-month-old plants of marmalade bush in a nursery in eastern Sicily, Italy. More than 50% of the plants exhibited symptoms of disease. Disease symptoms consisted of extensive water-soaked, dark brown lesions at the crown level that girdled entire stems and an internal brown discoloration of cortical tissue. Infected plants died within a few days. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 mg/liter. Fungal colonies were initially white, turned brown after 2 to 3 days, and produced irregularly shaped, brown sclerotia. Microscopic examination showed mycelium consistent with Rhizoctonia solani Kühn that branched at right angles, constricted at the base of the branch originating from primary hyphae, and septate near the constriction. The number of nuclei per hyphal cell was determined on cultures grown at 25°C on 2% water agar in petri plates by staining with 1% safranin O and 3% KOH solution (1) and examined at ×400. The hyphal cells were all multinucleate. Anastomosis group was determined by pairing isolates on 2% water agar in petri plates (2). Pairings were made with tester strains AG-1 IA, AG-2-2-1, AG-2-2IIIB, AG-2-2IV, AG-3, AG-4, AG-5, AG-6, and AG-11. Anastomosis was observed only with tester isolates of AG-4. Pathogenicity tests were performed by placing 1-cm2 plugs of PDA from 5-day-old mycelial cultures near the base of the stem on 25 potted, healthy, 2-month-old rooted cuttings of marmalade bush. The same number of plants treated with 1-cm2 PDA plugs served as controls. Following inoculation, all plants were maintained for 20 days at 25°C and 95% relative humidity under a 12-h fluorescent light/dark regimen. Crown and stem symptoms, identical to those observed in the nursery, developed 5 days after inoculation on all inoculated plants. Control plants remained symptomless. R. solani was consistently reisolated from symptomatic tissues and identified as previously described. To our knowledge, this is the first report of R. solani causing disease on marmalade bush. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

scholarly journals First Report of a Root and Crown Rot Disease of Myrtle in California Caused by Cylindrocladium pauciramosum

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 448-448 ◽  
Author(s):  
S. T. Koike ◽  
P. W. Crous
Keyword(s):  
Species Complex ◽  
The United States ◽  
Crown Rot ◽  
Conidial Suspension ◽  
First Report ◽  
Potted Plants ◽  
Crown Tissue ◽  
Root And Crown Rot ◽  
Plant Pathol ◽  
Rot Disease

Myrtle (Myrtus communis) is a woody, evergreen plant used in California as a landscape shrub or potted plant. In 2000, a new root and crown disease was found in commercial nursery myrtle being grown as potted plants. Roots were necrotic and crown tissue was brown. Affected plants became gray-green in color, withered, and died. A Cylindrocladium sp. was consistently isolated from roots, crowns, and lower stems of symptomatic plants. Isolates were characterized by having penicillate conidiophores terminating in obpyriform to broadly ellipsoidal vesicles. Conidia were hyaline, 1-septate, straight with rounded ends, (50-) 53 to 56 (-58) × (3.5-) 4 to 6 μm, placing it in the Cylindrocladium candelabrum Viégas species complex. Single-conidial isolates (STE-U 4012 to 4018) produced perithecia with viable progeny of Calonectria pauciramosa C.L. Schoch & Crous when mated on carnation leaf agar with tester strains of Cylindrocladium pauciramosum C.L. Schoch & Crous (2). Matings with tester strains of all other species in this complex proved unsuccessful. Only one mating type of C. pauciramosum has thus far been found in the United States. Pathogenicity of representative isolates was confirmed by applying 5 ml of a conidial suspension (1.0 × 106 conidia/ml) to the crowns of potted, 5-month-old, rooted mytle cuttings that were subsequently maintained in a greenhouse (23 to 25°C). After 4 weeks, plant crowns and roots developed symptoms similar to those observed in the nursery, and plants later wilted and died. C. pauciramosum was re-isolated from all plants. Control plants, which were treated with water, did not develop any symptoms. The tests were repeated and the results were similar. This is the first report of C. pauciramosum as a pathogen of myrtle in California. The disease has been reported on myrtle in Europe (1). References: (1) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105:407, 1999. (2) C. L. Schoch et al. Mycologia 91:286, 1999.

scholarly journals First Report of Resistance to Mefenoxam in Phytophthora cactorum in the United States and Elsewhere

Plant Disease ◽  
2004 ◽  
Vol 88 (5) ◽  
pp. 576-576 ◽  
Author(s):  
S. N. Jeffers ◽  
G. Schnabel ◽  
J. P. Smith
Keyword(s):  
United States ◽  
South Carolina ◽  
Tap Water ◽  
Southeastern United States ◽  
Crop Protection ◽  
The United States ◽  
Crown Rot ◽  
Phytophthora Cactorum ◽  
Mycelium Growth ◽  
First Report

Phytophthora cactorum causes crown rot of strawberry (Fragaria × ananassa) (2), a disease that has been particularly severe during the last 5 years in the southeastern United States. In the fall of 2001, strawberry plants (cv. Camarosa) in a field in Lexington County, South Carolina exhibited typical crown rot symptoms (2) 1 to 2 weeks after transplanting, even though plants had been drenched with mefenoxam (Ridomil Gold; Syngenta Crop Protection, Greensboro, NC) immediately after transplanting. Initially, we observed leaves that had marginal necrosis, were smaller than normal, and were discolored. Soon after, diseased plants appeared stunted and unthrifty compared with other plants in the field, and some of these plants eventually wilted and died. Severely affected plants had necrotic roots and decayed crowns. Ten symptomatic plants were collected for isolation. In the laboratory, root and crown tissues were rinsed in running tap water and blotted dry, small pieces of necrotic tissue were placed aseptically on PAR-V8 selective medium (1), and isolation plates were placed at 20°C in the dark for up to 7 days. P. cactorum was recovered from six plants. Isolates produced characteristic asexual and sexual structures directly on the isolation plates (i.e., papillate sporangia on sympodial sporangiophores and oospores with paragynous antheridia) (2). A single hypha of an isolate from each plant was transferred to fresh PAR-V8, and pure cultures were stored on cornmeal agar in glass vials at 15°C in the dark. All six isolates from the Lexington County field and nine other isolates of P. cactorum from strawberry (three from South Carolina, three from North Carolina, and three from Florida) were tested for sensitivity to mefenoxam on fungicide-amended medium. Mefenoxam was added to 10% clarified V8 juice agar (cV8A) after autoclaving so the concentration in the medium was 100 ppm. Agar plugs from active colonies were transferred to mefenoxam-amended and nonamended cV8A (three replicates per treatment), plates were placed at 25°C in the dark for 3 days, and linear mycelium growth was measured. All six isolates from Lexington County were highly resistant to mefenoxam with mycelium growth relatively unrestricted on mefenoxam-amended medium (73 to 89% of that on nonamended medium). In comparison, the other nine isolates were sensitive to mefenoxam with mycelium growth severely restricted by 100 ppm of mefenoxam (0 to 7% of that on nonamended medium). To our knowledge, this is the first report of mefenoxam resistance in P. cactorum on strawberry or any other crop in the United States and elsewhere. Because mefenoxam is the primary fungicide used to manage Phytophthora crown rot in the southeastern United States, resistance may limit use of this fungicide in strawberry production. References: (1) A. J. Ferguson and S. N. Jeffers. Plant Dis. 83:1129, 1999. (2) E. Seemüller. Crown rot. Pages 50–51 in: Compendium of Strawberry Diseases, 2nd ed. J. L. Maas, ed. The American Phytopathological Society, St. Paul, MN, 1998.

Reemergence of Cylindrocladium Crown Rot of Roses in Florida

2021 ◽  
Author(s):  
Fanny B. Iriarte ◽  
Mathews L. Paret ◽  
Susannah Da Silva
Keyword(s):  
Infected Plant ◽  
Crown Rot ◽  
Woody Tissue ◽  
Tubulin Gene ◽  
Knock Out ◽  
Plant Parts ◽  
Blast Analysis ◽  
Brown Discoloration ◽  
Crown Tissue ◽  
Β Tubulin

On April 2017, four out of 10,000 Double Knock Out Red roses were observed presenting partially wilted and chlorotic foliage in a commercial nursery in Gadsden Co., Florida. Closer examination of the plant crown revealed brown discoloration of the woody tissue. Under high temperature (85°F) and humidity (70%), shoots progressively turned chlorotic and necrotic, leading to plant death in 4 months. A rapid-growing fungus presenting orange-brown mycelium and abundant cylindrical spores was isolated from infected woody crown tissue. BLAST analysis of the resulting sequence (GenBank no. MT019606) of this pathogen had 100% identity to Calonectria cylindrospora β-tubulin gene (GenBank no. FJ918509.1). Koch’s postulates were conducted on healthy Double Knock Out roses. Two weeks after inoculation, shoots of inoculated plants turned progressively chlorotic and then necrotic, leading to plant death in 2 months. The same pathogen was reisolated from infected plant parts, which sequence also had 100% identity to C. cylindrospora β-tubulin gene (GenBank no. FJ918509.1). This pathogen is the same as one of three isolated from crown rot of roses back in 1994 and identified as Cylindrocladium scoparium (teleomorph: C. cylindrospora [Ellis & Everh.]). In this new occurrence, all infected plants were removed from the nursery, and no further infections were detected. This finding is important for commercial growers to be aware of the potential presence of this pathogen in their nurseries. Knowing the symptoms will help them recognize the disease and take action to prevent spread of the disease.

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