scholarly journals First Record of the Perfect Stage Calonectria pauciramosa on Mastic Tree in Italy

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 328-328 ◽  
Author(s):  
A. Vitale ◽  
G. Polizzi
Keyword(s):  
South African ◽  
First Record ◽  
Crown Rot ◽  
Natural Occurrence ◽  
Damping Off ◽  
Perfect Stage ◽  
Leaf Spots ◽  
Leaf Tissues ◽  
Plant Pathol ◽  
Stem Lesions

Leaf spots, stem lesions, crown rot, and root rot, caused by heterothallic fungus Cylindrocladium pauciramosum C.L. Schoch & Crous,, on young plants in a nursery represent an important problem in many representative ornamental plant-growing areas of Italy since the disease was first reported in 1993 (2). Symptoms observed during surveys in Italy from 1993 to 2005 were attributed solely to the asexual stage, and the teleomorph (Calonectria pauciramosa C.L. Schoch & Crous) was never found. In October 2005, orange-to-red brown fungal fruiting bodies pertaining to the genus Calonectria were observed in belowground regions and at the soil line on collar and stem tissues of seedlings of the mastic tree (Pistacia lentiscus L., Anacardiaceae) affected by damping off in two nurseries of eastern Sicily. The sexual structures were solitary or in groups, orange-to-red brown, subglobose to ovoid. On the basis of 50 microscopic observations of leaf tissues, they ranged from 180 to 280 μm in diameter and from 270 to 400 μm high. In the presence of adequate moisture, ascospores were discharged from mature perithecia in visible, viscous, and white droplets. Asci containing eight ascospores were clavate and tapering to a long thin stalk. Fusoid ascospores were hyaline and guttulate with rounded ends, slightly curved, 1-septate, not or slightly constricted at the septum, and measured 33 to 39 μm long and 6 to 8 μm wide. However, measurements show that perithecia, asci, and ascospores also fall within the range described by Schoch et al. (3). Single ascospore cultures did not produce perithecia. On the basis of these descriptions and the ability of single-ascospore cultures to mate with two Italian (DISTEF-G87 and DISTEF-G128) and two South African (STE-U 971 and STE-U 1670) selected tester strains of Cylindrocladium pauciramosum (2), the perithecia were identified as C. pauciramosa. To our knowledge, this is the first natural occurrence of the perfect stage of Cylindrocladium pauciramosum in Italy. The presence of the teleomorph is very important because it represents a second means of spread after conidia. Furthermore, the occurrence of the teleomorph also could lead to a 1:1 mating type ratio. In this case, lower percentages of hermaphrodites should be expected (1,4). References: (1) G. Polizzi et al. J. Plant Pathol. 80:262, 1998. (2) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105:413, 1999. (3) C. L. Schoch et al. Mycologia 91:286, 1999. (4) C. L. Schoch et al. Plant Dis. 85:941, 2001.

scholarly journals First Record of Crown and Root Rot Caused by Cylindrocladium pauciramosum on California Lilac in Italy

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1459-1459 ◽  
Author(s):  
G. Polizzi ◽  
A. Vitale ◽  
D. Aiello ◽  
G. Parlavecchio
Keyword(s):  
Root Rot ◽  
First Record ◽  
Selective Medium ◽  
Crown Rot ◽  
Stem Rot ◽  
Single Spore ◽  
Centraalbureau Voor ◽  
Basal Stem Rot ◽  
Plant Pathol ◽  
Stem Lesions

California lilacs, or Ceanothus, are evergreen, drought tolerant, colorful ornamental shrubs belonging to the Rhamnaceae family. Ceanothus thyrsiflorus var. repens is the most common species grown in Italy. In October 2005, a severe wilting was noticed on approximately 3,000 potted, 6-month-old plants obtained from cuttings produced by a commercial nursery in Lecco Province (northern Italy). Wilting was always associated with root rot and brown discoloration at the base of the stem. No leaf spots or stem lesions were detected. A Cylindrocladium sp. was isolated consistently from crown, basal stems, and roots of symptomatic plants with potato dextrose agar. Although many crown rots are caused by Phytophthora spp., this pathogen was not found associated with rotten roots and crown plating small pieces of diseased root tissue and crowns onto selective medium. A random selection of five Cylindrocladium sp. isolates was obtained from the infected crown and basal stem. Subsequently, they were identified on carnation leaf agar (CLA) as Cylindrocladium pauciramosum C.L. Schoch & Crous on the basis of their obpyriform to broadly ellipsoidal terminal vesicles, conidiophore branching pattern, conidium, and perithecial morphology, as well as mating type with tester strains of C. pauciramosum selected isolates (1,4). All single-conidial isolates were mated with tester strains DISTEF-G87 (MAT1-1) and DISTEF-G128 (MAT1-2) of C. pauciramosum on CLA, which confirmed both mating types to be present. Two of the isolates were deposited at Fungal Biodiversity Centre, Centraalbureau voor Schimmelcultures (CBS-120145 and CBS-120146). Pathogenicity tests were performed by macerating CLA cultures of C. pauciramosum, obtained from a single-spore isolate and incorporating them on the soil surface of 20 8-month-old C. thyrsiflorus var. repens potted plants. The same number of plants was used as the control. Following inoculation, plants were well irrigated and kept in a growth chamber at 25 ± 1°C. All inoculated plants developed crown rot, basal stem rot, and root rot 25 days after inoculation. Uninoculated control plants remained healthy. C. pauciramosum was reisolated from the artificially inoculated plants. C. pauciramosum causes considerable damage to the ornamental industry in Italy, where projects have been carried out since the first record of the fungus in Europe (3). C. pauciramosum was previously detected on Ceanothus sp. in the United Kingdom (2), where foliar and stem lesions were described. To our knowledge, this is the first record of the pathogen on C. thyrsiflorus var. repens and the first report of wilting due to crown and basal stem rot. References: (1) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul MN, 2002. (2) C. R. Lane et al. Plant Pathol. 55:582, 2006. (3) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105, 407, 1999. (4) C. L. Schoch et al. Plant Dis. 85:941, 2001.

scholarly journals First Report of Leaf Spot and Shoot Blight Caused by Cylindrocladium scoparium on Mallee Honeymyrtle in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1078-1078 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
V. Guarnaccia ◽  
G. Parlavecchio ◽  
A. Vitale
Keyword(s):  
South African ◽  
Leaf Spot ◽  
First Record ◽  
Crown Rot ◽  
Single Spore ◽  
Centraalbureau Voor ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Shoot Blight ◽  
Twig Blight

In December of 2008, a widespread disease was observed on several blocks of approximately 15,000 plants (6-month to 2-year-old) of mallee honeymyrtle (Melaleuca acuminata F. Muell.). The plants were grown in two nurseries in eastern Sicily where high diffusion of diseases caused by Cylindrocladium pauciramosum and C. scoparium was previously detected. The plants exhibited leaf spots, defoliation, and apical blight of shoots. Crown rot and root rot were not present. Leaf spots were detected on all plants, whereas shoot blight was observed on approximately 3% of the plants. A Cylindrocladium sp. was consistently isolated from the diseased portions of plants onto potato dextrose agar. To determine the species, 20 single-conidia isolates of the fungus obtained from symptomatic tissues from different blocks and nurseries were cultured on carnation leaf agar (CLA) for 7 days at 25°C under 12-h light/dark conditions. Mycelia and spores growing on the carnation leaves were examined with a light microscope and the isolates were identified as C scoparium Morgan (teleomorph Calonectria morganii Crous, Alfenas & M.J. Wingf.) on the basis of their pyriform to broadly ellipsoidal terminal vesicles, conidiophore branching pattern, and conidia (1). In addition, the ability of the isolates to mate with South African and Italian opposite tester strains of C. scoparium (2,4) confirmed the identification of all the isolates. Koch's postulates were fulfilled by inoculating 30 6-month-old plants of mallee honeymyrtle with a spore suspension (105 conidia per ml) of one isolate of the pathogen (DISTEF-MA1) obtained from 14-day-old single-spore colonies grown on CLA at 24°C under fluorescent cool white lights on a 12-h light/dark regimen. Following inoculation, all plants were maintained in plastic bags in a growth chamber at 25 ± 1°C and 90 to 95% relative humidity. The same number of mallee honeymyrtle plants was used as uninoculated controls. Leaf spots, defoliation, and apical shoot blight identical to those observed in the nurseries appeared within 4 to 25 days. No symptoms were detected on the control plants. C. scoparium was reisolated from the artificially infected tissues and was identified as previously described. The isolate used in the pathogenicity proof was deposited at the Fungal Biodiversity Centre, Centraalbureau voor Schimmelcultures (Accession No. CBS 124658). In Italy, C. scoparium was detected for the first time on Pistacia lentiscus in 2005 (3). Another report confirmed the spread of the pathogen in Sicilian ornamental nurseries (4). To our knowledge, this is the first record in the world of C. scoparium causing disease on mallee honeymyrtle. The data demonstrate the high susceptibility of this species to the C. scoparium leaf spot and twig blight especially when environmental conditions (heavy rains and mild temperatures) are conductive to the infections. References: (1) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul MN, 2002. (2) P. W. Crous and M. J. Wingfield. Mycotaxon 51:341, 1994. (3) G. Polizzi et al. Plant Dis. 90:1110, 2006. (4) G. Polizzi et al. Plant Dis. 91:769, 2007.

scholarly journals First Report of Blight on Buxus spp. Caused by Cylindrocladium buxicola in Belgium

Plant Disease ◽  
2003 ◽  
Vol 87 (12) ◽  
pp. 1539-1539 ◽  
Author(s):  
C. Crepel ◽  
S. Inghelbrecht
Keyword(s):  
Control Plant ◽  
First Record ◽  
Leaf Spots ◽  
Laboratory Bench ◽  
Buxus Sempervirens ◽  
Similar Disease ◽  
Stems And Leaves ◽  
Blight Disease ◽  
Stem Lesions ◽  
Made In

In the fall of 2000, a new blight disease was observed on Buxus spp. in private gardens in Belgium. Since then, more and similar disease samples from other Belgian sites, nurseries, and several garden centers have been received, indicating that this disease is spreading. Similar observations have been made in the U.K. and France, where the disease is widespread and losses are sometimes dramatic (1). Diseased plants have dark brown-to-black leaf spots and streaky, black stem lesions which lead, in some cases, to complete defoliation. On some infected plants new leaves grew in defoliated areas, hiding the original blight symptoms. Infection was mainly observed on Buxus sempervirens cv. Suffruticosa, but B. sempervirens cv. Latifolia raculata, B. microphylla cv. Compacta, and B. microphylla var. japonica cv. Faulkner were also infected. In the U.K., infections have additionally been reported on varieties of B. sempervirens, B. sinica, and B. microphylla (1). On the basis of observed symptoms and comparison of the symptoms with descriptions by Henricot and Culham (2), we identified that this new form of Buxus blight in Belgium is caused by Cylindrocladium buxicola. Sporulating cultures on potato dextrose agar (PDA) had macroconidiophores with stipe extensions terminating in broadly ellipsoidal vesicles with pointed or papillate apices (6.5 to 11 μm in diameter) and a penicillate arrangement of fertile branches each terminating in two to five phialides. Phialides produced clusters of cylindrical conidia (42 to 68 × 4 to 6 μm) that were rounded at both ends and had a single septum. Pathogenicity of the isolate was demonstrated by inoculation of healthy stems and leaves of four 3-year-old plants of B. sempervirens cv. Suffruticosa. On each plant, agar pieces of 1-week-old cultures grown on PDA were placed on five stems and five leaves that had been wounded with a sterile scalpel, then sealed with Parafilm. As a control, five wounded stems and leaves from another B. sempervirens cv. Suffruticosa plant were inoculated with sterile agar plugs. Inoculated plants were incubated in humid chambers (approximately 95% relative humidity) on the laboratory bench. Two weeks after inoculation, no symptoms were visible on the control plant. The inoculated plants showed symptoms as previously described, and C. buxicola was successfully reisolated from diseased tissue completing Koch's postulates. To our knowledge, this is the first record of C. buxicola on Buxus spp. in Belgium. References: (1) B. Henricot et al. Plant Pathol. 49:805, 2000. (2) B. Henricot and A. Culham. Mycologia 94(6):980, 2002.

scholarly journals First Record of Bacterial Crown Rot of Papaya (Carica papaya) Caused by an Erwinia papayae-Like Bacterium in the Kingdom of Tonga

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 70-70 ◽  
Author(s):  
R. A. Fullerton ◽  
L. Taufa ◽  
J. L. Vanneste ◽  
J. Yu ◽  
D. A. Cornish ◽  
...  
Keyword(s):  
16S Rdna ◽  
Soft Rot ◽  
First Record ◽  
Hypersensitive Reaction ◽  
Negative Control ◽  
Crown Rot ◽  
Green Water ◽  
Blue Pigment ◽  
Stem Tissue ◽  
Stem Lesions

Symptoms resembling papaya bacterial crown rot (1,3) attributed to Erwinia papayae were first observed on ‘Waimanalo’ and ‘Solo Sunrise’ papaya on the island of Tongatapu, Kingdom of Tonga in July 2009. Spreading, dark green, water-soaked lesions formed on juvenile stem tissue and developed into a foul-smelling, wet rot that destroyed large sections of the stem. Coalescing, brown, angular, marginal, and intercostal lesions killed large areas of the lamina. Elongated lesions on petioles resulted in breakage and leaf death. Symptoms on stems typically moved toward the crown with the growing point being killed or the whole crown breaking off at a canker below. Isolations at 28°C on King's medium B (KB) yielded slow-growing, raised, white, mucoid colonies that produced a conspicuous, nondiffusable blue pigment in the medium. Two-day-old suspensions (1 × 108 CFU/ml) of two cultures were injected into juvenile stem tissue, petioles, and laminae of four healthy papaya seedlings of ‘Solo Sunrise’ with a sterile 1-ml insulin syringe. Sterile water was used as a negative control. Typical water-soaked lesions appeared at all bacterial inoculation sites on all plants within 5 days but not on controls. Pigment-producing colonies similar to those used for inoculation were reisolated from four different stem lesions. Bacteria isolated from diseased tissues were gram negative, facultative anaerobes, oxidase negative, nonfluorescent on KB, induced a hypersensitive reaction on tobacco leaves, but could not cause soft rot on potato slices. Those characteristics, combined with blue pigment production, are consistent with the bacterium E. papayae. A partial sequence of the 16S rDNA gene of ~804 bp was amplified from four Tongan isolates (ICMP18248–18251) using primers 27f and 1492r (4). Sequences of these strains were 100% identical to each other (GenBank Nos. HQ286366–HQ286369), 99 and 98% identical to the 16SrDNA sequences of E. mallotivora strains LMG2708 (Z96084.1) and DSM4565 (AJ233414.1) respectively, and 97% identical to the 16SrDNA sequence of E. papayae strain NCPPB 4294 (AY131237.1). E. mallotivora and E. papayae cause different diseases, a leaf spot on Mallotus japonicus (2) and bacterial canker on papaya, respectively. They are closely related and in the laboratory are distinguished by only very few biochemical characteristics (1). E. papayae produces a blue pigment on KB and can utilize arabinose but not mannitol. E. mallotivora does not produce a blue pigment and can utilize mannitol but not arabinose. The four Tongan strains produced a blue pigment and could utilize mannitol and arabinose. Symptoms caused by the strains isolated from Tonga are typical of those caused by E. papayae and the strains identified share most of the characteristics of E. papayae. Because the Tongan strains were able to utilize mannitol as well as arabinose and their 16S rDNA was only 97% similar to E. papayae, these strains are referred to as an E. papayae-like bacterium. The taxonomic position of these isolates will be resolved with techniques such as Multilocus Sequence Typing analysis. To our knowledge, this is the first report of this highly destructive papaya disease in the Kingdom of Tonga and of a pathogen closely related to E. papaya in the country. References: (1) L. Gardan et al. Int. J. Syst. Bacteriol. 54:107, 2004. (2) M. Goto. Int. J. Syst. Bacteriol. 26:467, 1976. (3) N. H. Maktar et al. New Dis. Rep. 17:4, 2008. (4) F. Martin-Laurent et al. Appl. Environ. Microbiol. 67:2354, 2001.

scholarly journals First Report of Damping-Off and Leaf Spot Caused by Cylindrocladium scoparium on Different Accessions of Bottlebrush Cuttings in Italy

Plant Disease ◽  
2007 ◽  
Vol 91 (6) ◽  
pp. 769-769 ◽  
Author(s):  
G. Polizzi ◽  
A. Vitale ◽  
D. Aiello ◽  
M. A. Dimartino ◽  
G. Parlavecchio
Keyword(s):  
South African ◽  
Root Rot ◽  
Severe Disease ◽  
Damping Off ◽  
Single Spore ◽  
Centraalbureau Voor ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Collar And Root Rot

In May of 2006, approximately 10,000 cuttings of bottlebrushes (Callistemon cvs. Laevis, Hannah Ray, Kings Park Special, Masotti Mini Red, and Rose Opal with either C. viminalis (Soland. ex Gaertn.) Cheel. [excluded] or C. citrinus (Curtis) Skeels as one parent) grown in a nursery in eastern Sicily (Italy) exhibited severe disease symptoms including damping-off, leaf spots, and collar and root rot. Initially, the infections were detected on approximately 30% of the cuttings, but by late September 2006, 70% of the plants had symptoms. A Cylindrocladium sp. was consistently isolated from the diseased portions of plants onto potato dextrose agar. To determine the species, single-conidial isolates of the fungus were cultured on carnation leaf agar (CLA) for 7 days at 25°C with 12 h of light/dark conditions. Only the mycelia and spores growing on the carnation leaves were examined with a light microscope, and the isolates were identified as Cylindrocladium scoparium Morgan (teleomorph Calonectria morganii Crous, Alfenas & M.J. Wingf.) on the basis of their pyriform to broadly ellipsoidal terminal vesicles, conidiophore branching pattern, and conidia (1). In addition, the ability of the colonies to mate with South African tester strains of C. scoparium (2,3) confirmed the identification. Koch's postulates were fulfilled by inoculating 10 cuttings for each bottlebrush accession with a spore suspension (105 conidia per ml) of one isolate of the pathogen (DISTEF-GCs7) obtained from 14-day-old single-spore colonies grown on CLA at 24°C under fluorescent cool white lights with 12 h of light/dark. Following inoculation, all plants were maintained in plastic bags in a growth chamber at 25 ± 1°C and 90 to 95% relative humidity. The same number of cuttings was used as a control. Damping-off, crown root rot, and leaf spots symptoms identical to those observed in the nursery appeared within 5 to 20 days. No symptoms were detected on the control plants. C. scoparium was reisolated from the artificially infected tissues. The isolate, used in the pathogenicity proof, was deposited at the Fungal Biodiversity Centre, Centraalbureau voor Schimmelcultures (Accession No. CBS 120930). The presence of C. scoparium was detected for the first time in Italy on mastic tree in 2005 (3). To our knowledge, this is the first report of C. scoparium on bottlebrush in Italy and it represents the first information about the susceptibility of these Callistemon cultivar accessions to the fungus and confirms the spread of the pathogen in Sicilian ornamental nurseries. References: (1) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul MN, 2002. (2) P. W. Crous and M. J. Wingfield. Mycotaxon 51:341, 1994. (3) G. Polizzi et al. Plant Dis. 90:1110, 2006.

scholarly journals First Report of Leaf Spot Caused by Cylindrocladium pauciramosum on Dwarf Willow Myrtle in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (2) ◽  
pp. 274-274 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
G. Parlavecchio ◽  
A. Vitale ◽  
F. Nigro
Keyword(s):  
Leaf Spot ◽  
Morphological Characteristics ◽  
Intergenic Spacer ◽  
First Record ◽  
Morphological Characters ◽  
Leaf Spot Disease ◽  
Centraalbureau Voor ◽  
Potted Plants ◽  
Leaf Spots ◽  
Plant Pathol

Dwarf willow myrtle (Agonis flexuosa (Willd.) Sweet) cv. Nana, an evergreen ornamental shrub belonging to the Myrtaceae, is grown in Italy as an ornamental potted plant. In November 2008, a widespread new leaf spot disease was noticed on ~80% of 5,000 6-month-old potted plants. Plants were obtained from cuttings and produced by a commercial nursery in Catania Province. Symptomatic leaves showed minute, reddish brown spots that enlarged (3 to 5 mm in diameter) and then darkened, presenting a necrotic center defined by a dark purple halo. Leaf spots were surface disinfested with 0.8% NaOCl and plated on potato dextrose agar. Twenty isolates of the fungus that was consistently isolated from the spots were selected and cultured for 8 days at 25°C on carnation leaf agar (CLA). Macroconidiophores consisted of a stipe, a penicillate arrangement of fertile branches, and stipe extension terminating in an obpyriform to ellipsoidal vesicle (6 to 10 μm in diameter). Cylindrical conidia were rounded at both ends, straight, one-septate, and ranged from 44 to 60 × 4 to 5 μm. The fungus was tentatively identified as Cylindrocladium pauciramosum based on these morphological characteristics (2). All single-conidium isolates were mated with tester strains of Calonectria pauciramosa C. L. Schoch & Crous, telomorph of C. pauciramosum, on CLA and produced fertile perithecia (4). Perithecia were solitary or in groups, orange to red-brown, subglobose to ovoid, and ranged from 280 to 400 μm long × 180 to 290 μm in diameter. Further confirmation of species was obtained by amplification and sequencing of the intergenic spacer (IGS) region of rDNA, using M13 Forward (-20) and M13 Reverse primers. On the basis of the complete IGS sequence, two primer sets (218F/218R and 106F/106R) were designed and successfully used in a nested-PCR protocol for the detection of C. pauciramosum from tissues of infected plants (3). On the basis of the combination of morphological characters, mating type, and molecular data, the isolates were identified as C. pauciramosum C.L. Schoch & Crous. One representative isolate (DISTEF-Af1) was deposited at Centraalbureau voor Schimmelcultures open fungi collection (Fungal Biodiversity Centre, Utrecht, the Netherlands; CBS 124659). Pathogenicity tests were performed by adding sterile water to CLA cultures of C. pauciramosum from a single-conidium isolate (DISTEF-Af1) and spraying the resulting spore suspension (105 conidia per ml) on the leaf surface of 20 6-month-old A. flexuosa cv. Nana potted plants. The same number of plants served as noninoculated controls. Following inoculation, plants were kept in plastic bags in a growth chamber at 25 ± 1°C. All inoculated plants developed circular, brown leaf spots identical to those observed in the nursery 5 to 7 days after inoculation. Control plants remained symptomless. C. pauciramosum was always reisolated from the infected plants and identified as previously described. Leaf spotting in seedlings of A. flexuosa was previously associated with infections by C. scoparium in Australia (1). To our knowledge, this is the first record in the world of leaf spots caused by C. pauciramosum on A. flexuosa. References: (1) A. L. Bertus. Agric. Gaz. N. S. W. 87:22, 1976. (2) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul MN, 2002. (3) F. Nigro et al. J. Plant Pathol. 88:S22, 2006. (4) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105:407, 1999.

scholarly journals First Report of Crown Rot Caused by Cylindrocladium pauciramosum on Scarlet Honey Myrtle in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1217-1217 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
I. Castello ◽  
G. Parlavecchio ◽  
A. Vitale ◽  
...  
Keyword(s):  
Plant Root ◽  
Intergenic Spacer ◽  
Soil Surface ◽  
First Record ◽  
Morphological Characters ◽  
Molecular Data ◽  
Crown Rot ◽  
Centraalbureau Voor ◽  
Potted Plants ◽  
Plant Pathol

Scarlet honey myrtle (Melaleuca fulgens R. Br.), native to Australia, is an evergreen colorful shrub (Myrtaceae) and grown in Italy as an ornamental plant. During November 2008, a widespread disease was noticed on ~90% of 3,000 6-month-old M. fulgens cv. Red potted plants. Plants were obtained from cuttings and produced by a commercial nursery in Catania Province. Symptomatic plants showed a crown rot and longitudinal sections of tissues revealed a brown discoloration of the basal stem. As a consequence, leaves gradually became necrotic and abscised, followed by death of the entire plant. Root rots and leaf spots were not observed. M. gibbosa, M. ericifolia, M. thymifolia, and M. elliptica, cultivated in the same nursery, did not show disease symptoms. A Cylindrocladium sp. was consistently isolated from the crown and basal stem of symptomatic plants on potato dextrose agar (1). Ten Cylindrocladium isolates obtained from infected basal stems and crowns were selected and cultured for 8 days at 25°C on carnation leaf agar (CLA). Macroconidiophores consisted of a stipe, a penicillate arrangement, and a stipe extension terminating in an obpyriform to ellipsoidal vesicle (6 to 10 μm in diameter). Cylindrical conidia were rounded at both ends, straight, 1-septate, and 42 to 60 × 4 to 5 μm. All single-conidial isolates were mated with opposite tester strains of C. pauciramosum on CLA and produced fertile perithecia (3). Perithecia were solitary or in groups, orange to red-brown, subglobose to ovoid, and 270 to 400 μm high × 180 to 290 μm in diameter. Further confirmation of species was obtained by amplification and sequencing of the intergenic spacer (IGS) region of rDNA with the M13 forward (-20) and M13 reverse primers. On the basis of the complete IGS sequence, two primer sets (218F/218R and 106F/106R) were designed and successfully used in a nested-PCR protocol for the detection of C. pauciramosum from tissues of infected plants (2). On the basis of morphological characters, mating type, and molecular data, the isolates were identified as C. pauciramosum C.L. Schoch & Crous. One representative isolate (DISTEF-MFR2; CBS 124657) was deposited at Centraalbureau voor Schimmelcultures open fungi collection (Fungal Biodiversity Centre, Utrecht, the Netherlands). Pathogenicity tests were performed by adding sterile water to CLA cultures of C. pauciramosum from a single-conidial isolate and incorporating the resulting spore suspension (105 conidia per ml) on the soil surface of 20 3-month-old M. fulgens cv. Red potted plants. The same number of plants served as uninoculated controls. Following inoculation, plants were well irrigated and maintained in a growth chamber at 25 ± 1°C and 90 to 95% relative humidity. All inoculated plants developed crown rot symptoms identical to those observed in the nursery 2 months after inoculation. Control plants remained symptomless. C. pauciramosum was always reisolated from the infected plants and identified as previously described. C. pauciramosum was previously detected in Italy as being responsible for a leaf spot on M. hypericifolia (3). To our knowledge, this is the first record in the world of crown rot of scarlet honey myrtle caused by C. pauciramosum. References: (1) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul MN, 2002. (2) F. Nigro et al. J. Plant Pathol. 88:S22, 2006. (3) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105:407, 1999.

scholarly journals Severe Outbreak of Crown Rot and Root Rot Caused by Cylindrocladium pauciramosum on Strawberry Tree in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 842-842 ◽  
Author(s):  
A. Vitale ◽  
D. Aiello ◽  
I. Castello ◽  
M. A. Dimartino ◽  
G. Parlavecchio ◽  
...  
Keyword(s):  
Root Rot ◽  
Soil Surface ◽  
First Record ◽  
Crown Rot ◽  
Limiting Factor ◽  
Centraalbureau Voor ◽  
Potted Plants ◽  
Leaf Spots ◽  
Strawberry Tree ◽  
Crown And Root Rot

From 2006 to 2009, a new disease was noticed in several commercial nurseries in Sicily (Italy) on ~13,000 potted plants of strawberry tree (Arbutus unedo L.) ranging from 3 months to 4 years old. Symptomatic plants showed a crown and root rot and internal brown discoloration of the basal stem. No leaf spots were detected. The percentage of symptomatic plants was variable in the different stocks (1 to 28%). A Cylindrocladium sp. was isolated consistently from symptomatic tissues on potato dextrose agar (PDA). Although many crown rots are caused by Phytophthora or Rhizoctonia spp., plating small pieces of diseased tissue from rotten roots and crowns onto corn meal agar or PDA yielded these pathogens sporadically. Twenty Cylindrocladium isolates obtained from infected basal stems, crowns, and roots were selected and subsequently cultured on carnation leaf agar (CLA). Macroconidiophores consisted of a stipe, a penicillate arrangement of fertile branches, and stipe extension terminating in an obpyriform-to-ellipsoidal vesicle (6 to 10 μm in diameter). Conidia cylindrical, straight, and 1-septate ranged from 40 to 60 × 4 to 5 μm. All single-conidial isolates were mated with tester strains DISTEF-G87 (MAT1-1) and DISTEF-G128 (MAT1-2) of Cylindrocladium pauciramosum (3) on CLA and produced fertile perithecia after 2 months. Perithecia were solitary or in groups, orange to red-brown, subglobose to ovoid, and ranged from 260 to 400 × 180 to 290 μm in diameter. On the basis of the combination of morphological and perithecial characters and mating type the isolates were identified as C. pauciramosum C.L. Schoch & Crous, teleomorph Calonectria pauciramosa C.L. Schoch & Crous (1,4). One representative isolate was deposited at Centraalbureau voor Schimmelcultures (CBS; No. 123918) open fungi collection. Pathogenicity tests were performed by adding sterile water to CLA cultures of C. pauciramosum from a single-conidial isolate and incorporating the resulting spore suspension (105 conidia per ml) on the soil surface of 20 3-month-old strawberry tree potted plants. The same number of plants served as a control. After inoculation, plants were maintained in a growth chamber at 25 ± 1°C and 90 to 95% relative humidity. All inoculated plants developed crown and root rot identical to one observed in the nursery 2 months after inoculation. Control plants remained symptomless. C. pauciramosum was always reisolated from infected plants. This fungus represents a serious threat for ornamental nurseries in Europe. Diseases related to infection of C. pauciramosum are different in relationship to the host tissues and the affected species. On strawberry tree, C. pauciramosum was previously detected in Italy as causal agent of leaf spots (2). To our knowledge, this is the first record of crown and root rot of strawberry tree caused by C. pauciramosum. In contrast with leaf spots, this report could indicate an important limiting factor for cultivation of strawberry tree potted plants in nurseries. The knowledge of the susceptibility of this host to crown and root rot caused by C. pauciramosum can help growers apply specific control strategies in nurseries. References: (1) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. The American Phytopathological Society, St. Paul, MN, 2002. (2) G. Polizzi and V. Catara. Plant Dis. 85:803, 2001. (3) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105:407, 1999. (4) C. L. Schoch et al. Plant Dis. 85:941, 2001.

scholarly journals Cylindrocladium Leaf Spot, Blight, and Crown Rot, New Diseases of Mastic Tree Seedlings Caused by Cylindrocladium scoparium

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1110-1110 ◽  
Author(s):  
G. Polizzi ◽  
A. Vitale ◽  
I. Castello ◽  
J. Z. Groenewald ◽  
P. W. Crous
Keyword(s):  
Root Rot ◽  
Histone H3 ◽  
Mediterranean Area ◽  
First Record ◽  
Crown Rot ◽  
Tree Seedlings ◽  
Single Spore ◽  
Crown And Root Rot ◽  
Stem Lesions ◽  
Β Tubulin

The mastic tree (Pistacia lentiscus L., Anacardiaceae) is an important sclerophyllous evergreen shrub in the Mediterranean area where it is the dominant component of maquis and garrigues, which is vegetation composed of shrubs, or scrub, usually not exceeding 3 m high. In October 2005, new widespread diseases were noticed in a nursery in eastern Sicily (Italy) affecting container-grown, 1-year-old mastic tree seedlings. Symptoms were detected on approximately 40% of the 5,000 plants and consisted of minute, brown spots, stem lesions, blight, and defoliation. Occasionally, symptoms of crown and root rot were observed. A Cylindrocladium sp. was consistently isolated from rotted crown and roots, leaf spots, and stem lesions on potato dextrose agar. Morphological features of the fungus including conidiophores, conidia, and terminal vesicles were studied under a light microscope. Five Cylindrocladium isolates were cultured on carnation leaf agar (CLA) and identified as C. scoparium Morgan (teleomorph Calonectria morganii Crous, Alfenas & M.J. Wingf.) on the basis of their pyriform to broadly ellipsoidal terminal vesicles, conidiophore branching pattern, conidium and perithecial morphology, as well as their ability to mate with tester strains of selected C. scoparium isolates (2,3). Sequences of partial β-tubulin (GenBank Accessions Nos. DQ521599 and DQ521600) and histone H3 genes (GenBank Accessions Nos. DQ521601 and DQ521602) were generated as described previously (1) for two of the isolates (CBS 119669 and CBS 119670, respectively). A BLAST analysis of the β-tubulin sequences revealed 100% similarity with C. morganii (GenBank Accessions Nos. AF210872, AF210874, and AF210875). No histone H3 sequences are currently available in the GenBank database for C. morganii, and the two sequences generated in this study, therefore, represent the first publicly available histone H3 sequences for this species. Koch's postulates were fulfilled by inoculating 20 1-year-old mastic tree seedlings with a spore suspension of the fungus (105 conidia per ml) obtained from 14-day-old single-spore colonies grown on CLA at 24°C under fluorescent cool white lights on a 12-h light/dark regimen. Following inoculation, all plants were maintained in plastic bags in a growth chamber in which the temperature was 25 ± 1°C and relative humidity was 90 to 95%. The same number of seedlings was used as a control. After 5 to 7 days, foliar symptoms resembling those seen in the nursery were detected on inoculated plants. Crown and root rot symptoms appeared on two plants after 1 month. C. scoparium was reisolated from the artificially infected tissues. No symptoms were detected on the control plants. To our knowledge, this is the first record of this disease in mastic tree and the first record of C. scoparium in Italy. This report also represents the first definitive confirmation of C. scoparium in Europe. References: (1) P. W. Crous et al. Stud. Mycol. 50:415–430, 2004. (2) P. W. Crous and M. J. Wingfield. Mycotaxon 51:341, 1994. (3) C. L. Schoch et al. Mycologia 91:286, 1999.

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