scholarly journals First Report of Bud Rot of Canary Island Date Palm Caused by Phytophthora palmivora in Italy

Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 1059-1059
Author(s):  
A. Pane ◽  
C. Allatta ◽  
G. Sammarco ◽  
S. O. Cacciola
Keyword(s):  
Canary Island ◽  
Date Palm ◽  
Brown Rot ◽  
Selective Medium ◽  
Phytophthora Species ◽  
Phytophthora Palmivora ◽  
American Phytopathological Society ◽  
First Report ◽  
Phoenix Canariensis ◽  
Electrophoretic Patterns

Canary Island date palm (Phoenix canariensis hort. ex Chabaud) is planted as an ornamental in Mediterranean climatic regions of the world. From 2004 to 2006, withering of the spear leaf was observed on screenhouse-grown potted plants of this palm in Sicily (Italy). The first symptom was a dark brown rot that extended from the petiole base of the spear to the adjacent youngest leaves and killed the bud. Dissection of plants revealed a foul-smelling internal rot. After the bud died, external older leaves remained green for months. As much as 10% of plants in a single nursery were affected. A Phytophthora species was consistently isolated from symptomatic plants on BNPRAH selective medium (4). Single zoospore isolates were obtained from the colonies. The species isolated was identified as Phytophthora palmivora (E. J. Butler) E. J. Butler on the basis of morphological and cultural characteristics (3). On V8 juice agar, the isolates produced elliptical to ovoid, papillate sporangia (33 to 77 × 22 to 38 μm) with a mean length/breadth ratio of 1.8. Sporangia were caducous with a short pedicel (mean pedicel length = 5 μm) and had a conspicuous basal plug. All isolates were heterothallic and produced amphigynous antheridia, oogonia, and oospores when paired with reference isolates of P. nicotianae and P. palmivora of the A2 mating type. The oogonium wall was smooth. Identification was confirmed by electrophoresis of mycelial proteins in polyacrylamide slab gels (1). The electrophoretic patterns of total mycelial proteins and four isozymes (alkaline phosphatase, esterase, glucose-6-phosphate dehydrogenase, and malate dehydrogenase of the isolates) from Phoenix canariensis were identical to those of P. palmivora reference isolates, including four Italian ones, two from pittosporum and olive, respectively, and two (IMI 390579 and 390580) from Grevillea spp. Phoenix canariensis isolates were clearly distinct from those of other heterothallic papillate species including P. capsici, P. citrophthora, P. katsurae, P. nicotianae, and P. tropicalis. Pathogenicity of one isolate from Phoenix canariensis (IMI 395345) was tested on 10 2-year-old potted Canary Island date palm plants. An aqueous 105 zoospores per ml suspension (200 μl) was pipetted onto unwounded petiole bases of the three youngest central leaves of each plant. Sterile water was pipetted onto 10 control plants. All plants were incubated in 100% humidity at 24°C for 48 h and maintained in a greenhouse at 20 to 28°C. Within 3 weeks after inoculation, inoculated plants developed symptoms identical to those observed on plants with natural infections. Control plants remained healthy. P. palmivora was reisolated from symptomatic plants. Phytophthora bud rot is a common palm disease worldwide and Phoenix canariensis is reported as a host (2). To our knowledge, this is the first report of Phytophthora bud rot on Phoenix canariensis in Italy. References: (1) S. O. Cacciola et al. EPPO Bull. 20:47, 1990. (2) M. L. Elliot et al., eds. Compendium of Ornamental Palm Diseases and Disorders. The American Phytopathological Society, St. Paul, MN, 2004. (3) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (4) H. Masago et al. Phytopathology, 67:425, 1977.

scholarly journals First Report of Thielaviopsis Trunk Rot of Date Palm in Italy

Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 972-972 ◽  
Author(s):  
G. Polizzi ◽  
I. Castello ◽  
A. Vitale ◽  
V. Catara ◽  
V. Tamburino
Keyword(s):  
Cross Sections ◽  
Date Palm ◽  
Brown Rot ◽  
First Record ◽  
Geotrichum Candidum ◽  
Internal Tissue ◽  
American Phytopathological Society ◽  
Date Palms ◽  
First Report ◽  
Large Sections

As an alternative to Canary Island date palm (Phoenix canariensis Chabaud), date palm (P. dactylifera L.) is being planted in Sicilian landscapes. In January 2006, severe symptoms of trunk rot were noticed on 10 7- to 8-m high mature date palms in the central square of Aci Bonaccorsi (Catania) in eastern Sicily. In June 2004, these palms were transplanted directly from Egypt. In 4 of 13 planted date palms, the canopy suddenly fell off the trunk. The canopy of all palms appeared normal and healthy with no stem bleeding observed before trunk collapse. Cross sections of affected date palms revealed a brown rot of nonlignified or lightly lignified tissues along with a strong odor of fermented fruit (amyl acetate) associated with the presence of Geotrichum candidum Link ex Pers. Brown rot was not detected in three of the date palms examined. Symptoms were not detected on lignified and external fibers. Internal tissue adjacent to the rotted areas was placed on carrot agar amended with 500 μl of streptomycin sulfate and acidified (lactic acid; pH = 3.6) potato dextrose agar. Large sections (10 to 18 cm) of affected palm tissues were maintained in a moist chamber for 8 days. Microscopic examinations of five single-conidia isolates on media and sporulation from affected tissues yielded Thielaviopsis paradoxa De Seyn. (Höhn) (1). Endoconidia measuring 3 to 5.5 × 7 to 11 μm were cylindrical to somewhat oval when mature, hyaline to mid brown and smooth walled. Endoconiodophores were usually straight, colorless to pale brown, as much as 150 μm long, with a terminal spore-bearing cell through which spores are born. Chlamydospores were smooth, thick walled, brown, in chains, and were 7.5 to 13 μm width × 10 to 18 μm length (values referred to 50 examined chlamydospores). T. paradoxa is a pathogen that can infect any part of a palm and its pathogenicity to date palm is well documented (3). T. paradoxa is endemic in northern Italy (Ligurian Riviera) on P. canariensis where it causes a disease known as bud rot (2). To our knowledge, this is the first record of trunk rot caused by T. paradoxa on date palm in Italy and is the first report of the fungus in Sicily. It is recommended to avoid the foreign trade of mature date palms from known infected areas because of the symptomless infections by this pathogen. References: (1) A. R. Chase and T. K. Broschat, eds. Diseases and Disorders of Ornamental Palms. The American Phytopathological Society, St. Paul, MN, 1991. (2) A. Garibaldi et al., eds. Malattie Delle Piante Ornamentali. Calderini Edagricole, Bologna, Italy, 2000. (3) P. Suleman et al. Plant Dis. 85:80, 2001.

scholarly journals First Report of Armillaria mellea on a Fern from Italy

Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 592-592 ◽  
Author(s):  
S. Grasso ◽  
A. Pane ◽  
S. O. Cacciola
Keyword(s):  
Pure Culture ◽  
Late Summer ◽  
The United States ◽  
Selective Medium ◽  
Mount Etna ◽  
Washington Dc ◽  
First Report ◽  
Reference Isolate ◽  
Ornamental Foliage Plants ◽  
Electrophoretic Patterns

Several perennial species of rhizomatous herbaceous ferns are cultivated as ornamental foliage plants. During late summer 1999, in a garden at the foot of Mount Etna, eastern Sicily (Italy), we noted a fern hedge showing patches of withered or stunted plants. The fern was identified as Cyrtomium falcatum (L.f.) C. Presl. (=Polystichum falcatum (L.f.) Diels), a house holly fern or Japanese holly fern, which is an ornamental fern native to East and South Asia. Other woody plants in the immediate vicinity had died over the last few years, including apricot and cedar trees whose stumps had not been removed. A close examination of uprooted ferns revealed the presence of creamy white fan-shaped mycelial mats with an odor typical of Armillaria species that were intermixed with the felt-like tangle formed by the rhizomes and roots of the ferns. In autumn, clumps of honey mushrooms with an annulus grew around patches of the withered fern hedge and in other parts of the same garden. The spore print of the basidiocarp was light cream. Basidiospores (8 to 9 × 5 to 6.5 µm) examined under a microscope were hyaline and apiculate. The fungus was isolated in pure culture from infected rhizomes with the selective medium of Kulman and Hendrix (3). In pure culture on 2% malt agar, the fungus formed ribbon-shaped, contorted, fast-growing rhizomorphs that branched profusely. Mycelial proteins of the isolate were analyzed by both polyacrylamide slab gel and starch gel electrophoreses, as described by Bragaloni et al. (1). The electrophoretic patterns of five isozymes (esterase, glutamic oxalacetic transaminase, phospho-glucomutase, alcohol dehydrogenase, and polygalacturonase) of the isolate from fern were identical to those of the reference isolate of A. mellea (Vahl:Fr.) Kumm. from grapevine. Conversely, the patterns were clearly distinct from those of reference isolates from other species, including A. ostoyae (Romagnesi) Herink, A. bulbosa (Barla) Kile et Watling, and A. cepistipes Velenovsky. Thus, on the basis of cultural, morphological, and biochemical characteristics, the species infecting the fern was identified as A. mellea. This pathogen, very common and widespread on wooded or previously wooded sites, has an extremely wide host range, encompassing both woody and herbaceous plants (2,4). However, this is the first report of A. mellea on a fern in Italy. References: (1) M. Bragaloni and N. Anselmi. Eur. J. For. Pathol. 27:147, 1997. (2) D. F. Farr et al. 1989. Fungi on Plants and Plants Products in the United States. The American Phytopathological Society, St. Paul, MN. (3) E. G. Kulman and F. F. Hendrix. Phytopathology 52:1310, 1962. (4) C. G. Shaw and G. A. Kile. 1991 Armillaria root disease. Agric. Handb. No 691. U.S. Department of Agriculture Forest Service, Washington, DC.

scholarly journals The contribution of the Canary Island date palm (Phoenix canariensis) to the winter diet of frugivores in novel ecosystems

2019 ◽  
Vol 5 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Dirk HR Spennemann
Keyword(s):  
Urban Areas ◽  
Canary Island ◽  
Food Source ◽  
Date Palm ◽  
Food Sources ◽  
Novel Ecosystems ◽  
Date Palms ◽  
Phoenix Canariensis ◽  
Winter Diet ◽  
Native Foods

Abstract With the increasing expansion in urban areas, many species have adapted to utilising horticulturally used plants as alternate or augmentary food sources, in particular, during winter – when native foods are largely absent. Ornamental palms, particularly Canary Island Date Palms, fruit continuously during most of the year and thus provide a stable food supply. Based on observational, metric and bio-chemical data, this paper examines the role Canary Island Date Palms can and do play in the nutrition of frugivorous animals, in particular, for birds. It demonstrates that with its nearly year-round provisioning of drupes, the palm plays a major role as a ‘staple’ and backup food source for several species.

scholarly journals First Report of Phytophthora ramorum on Viburnum bodnantense in Belgium

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 203-203 ◽  
Author(s):  
D. De Merlier ◽  
A. Chandelier ◽  
M. Cavelier
Keyword(s):  
The Netherlands ◽  
Plant Protection ◽  
Morphological Characteristics ◽  
Pcr Primers ◽  
Selective Medium ◽  
Phytophthora Species ◽  
Phytophthora Ramorum ◽  
Pathogenicity Test ◽  
First Report ◽  
Root Necrosis

In the past decade, a new Phytophthora species inducing shoot canker on Rhododendron and dieback of Viburnum has been observed in Europe, mainly in Germany and the Netherlands, and California. This new pathogen has been named Phytophthora ramorum (3). In May 2002, a diseased Viburnum plant (Viburnum bodnantense) from the Plant Protection Service (Ministry of Agriculture, Belgium) was submitted to our laboratory for diagnosis. Symptoms included wilting, leaves turning from green to brown, discolored vascular tissues, and root necrosis. The plant came from a Belgian ornamental nursery that obtained supplies of stock plants from the Netherlands. Pieces of necrotic root tissue were excised, surface-disinfected, and transferred aseptically to a Phytophthora selective medium. P. ramorum was identified based on morphological characteristics, including the production of numerous, thin-walled chlamydospores (25 to 70 µm in diameter, average 43 µm) and deciduous, semi-papillate sporangia arranged in clusters. Radial growth after 6 days at 20°C on V8 juice agar was 2.8 mm per day. Random amplified microsatellite markers (RAMS) (2) from the total genomic DNA of the Belgian strain (CBS 110901) were similar to those of P. ramorum reference strains (CBS 101330, CBS 101332, and CBS 101554). Using PCR primers specific for P. ramorum, the identification was confirmed by W. A. Man in't Veld (Plantenziektenkundige Dienst, Wageningen, the Netherlands) (1). A pathogenicity test was carried out on three sterile cuttings of Rhododendron catawbiense (3). Brown lesions were observed on the inoculated cuttings after 6 to 7 days. None of the three uninoculated cuttings showed symptoms of infection. P. ramorum was reisolated from lesion margins on the inoculated cuttings. To our knowledge, this is the first report of the fungus from Belgium. Since our initial observation, we have found P. ramorum in other Belgian nurseries on R. yakusimanum. References: (1) M. Garbelotto et al. US For. Ser. Gen. Tech. Rep. PSW-GRT. 184:765, 2002. (2) J. Hantula et al. Mycol. Res. 101:565, 1997. (3) S. Werres et al. Mycol. Res. 105:1155, 2001.

scholarly journals First Report of Phytophthora hydropathica Causing Wilting and Shoot Dieback on Viburnum in Italy

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1582-1582 ◽  
Author(s):  
S. Vitale ◽  
L. Luongo ◽  
M. Galli ◽  
A. Belisario
Keyword(s):  
Natural Infection ◽  
Morphological Characteristics ◽  
Leaf Tissue ◽  
The United States ◽  
Selective Medium ◽  
Phytophthora Species ◽  
Phytophthora Ramorum ◽  
Width Ratio ◽  
Morphological Identification ◽  
First Report

The genus Viburnum comprises over 150 species of shrubs and small trees such as Laurustinus (Viburnum tinus L.), which is one of the most widely used ornamental plants in private and public gardens. Furthermore, it commonly forms stands of natural woodland in the Mediterranean area. In autumn 2012, a survey was conducted to determine the presence of Phytophthora ramorum on Viburnum in commercial nurseries in the Latium region where wilting, dieback, and death of twigs were observed on 30% of the Laurustinus plants. A Phytophthora species was consistently recovered from soil rich in feeder roots from potted Laurustinus plants showing symptoms. Soil samples were baited with rhododendron leaves. Small pieces of leaf tissue cut from the margin of lesions were plated on P5ARPH selective medium (4). Pure cultures, obtained by single-hypha transfers on potato dextrose agar (PDA), were petaloid. Sporangia formation was induced on pepper seeds (3). Sporangia were almost spherical, ovoid or obpyriform, non-papillate and non-caducous, measuring 36.6 to 71.4 × 33.4 to 48.3 μm (average 53.3 × 37.4 μm) with a length/width ratio of 1.4. Chlamydospores were terminal and 25.2 to 37.9 μm in diameter. Isolates were considered heterothallic because they did not produce gametangia in culture or on the host. All isolates examined had 30 to 35°C as optimum temperatures. Based on these morphological characteristics, the isolates were identified as Phytophthora hydropathica (2). Morphological identification was confirmed by internal transcribed spacer (ITS), and mitochondrial partial cytochrome oxidase subunit 2 (CoxII) with BLAST analysis in the NCBI database revealing 99% identity with ITS and 100% identity with CoxII. The sequences of the three isolates AB234, AB235, and AB236 were deposited in European Nucleotide Archive (ENA) with the accession nos. HG934148, HG934149, and HG934150 for ITS and HG934151, HG934152, and HG934153 for CoxII, respectively. Pathogenicity tests were conducted in the greenhouse on a total of six 1-year-old shoots cut from V. tinus plants with two inoculation points each. Mycelial plugs cut from the margins of actively growing 8-day-old cultures on PDA were inserted through the epidermis into the phloem. Controls were treated as described above except that sterile PDA plugs replaced the inoculum. Shoots were incubated in test tubes with sterile water in the dark at 24 ± 2°C. After 2 weeks, lesions were evident at the inoculation points and symptoms were similar to those caused by natural infection. P. hydropathica was consistently re-isolated from the margin of lesions, while controls remained symptomless. In the United States in 2008, P. hydropathica was described as spreading from irrigation water to Rhododendron catawbiense and Kalmia latifolia (2). This pathogen can also attack several other horticultural crops (1), but to our knowledge, this is the first report of P. hydropathica causing wilting and shoot dieback on V. tinus. References: (1) C. X. Hong et al. Plant Dis. 92:1201, 2008. (2) C. X. Hong et al. Plant Pathol. 59:913, 2010. (3) E. Ilieva et al. Eur. J. Plant Path. 101:623, 1995. (4) S. N. Jeffers and S. B. Martin. Plant Dis. 70:1038, 1986.

Geographic Distribution and Host Range of Lethal Bronzing Associated with Phytoplasma Subgroup 16SrIV-D on Palms in Southern Louisiana

2020 ◽  
Vol 21 (4) ◽  
pp. 350-355
Author(s):  
Mary Helen Ferguson ◽  
Raghuwinder Singh ◽  
Madeline Cook ◽  
Timothy Burks ◽  
Kevin Ong
Keyword(s):  
Host Range ◽  
New Orleans ◽  
Geographic Distribution ◽  
Small Proportion ◽  
Canary Island ◽  
Date Palm ◽  
Date Palms ◽  
Phoenix Canariensis ◽  
Sabal Palmetto ◽  
City Park

Lethal bronzing (LB), also previously known as date palm lethal decline or Texas Phoenix palm decline, associated with phytoplasma subgroup 16SrIV-D, was first identified in Louisiana in December 2013. A survey of palms showed that the disease was not only confined to City Park in New Orleans, where it was first detected, but is present in other parts of Orleans Parish, as well as two adjacent parishes. Canary Island date palms (Phoenix canariensis) tested positive at the highest frequency, and some edible date palms (P. dactylifera) and a small proportion of cabbage palms (Sabal palmetto) tested positive as well. Symptoms do not appear to be a reliable indicator of LB, because a substantial proportion of palms indicated as symptomatic tested negative. Furthermore, not all infected palms showed symptoms. Since the palm survey conducted in 2015 to 2016, LB has positively been identified from silver date palm (P. sylvestris) and Chinese windmill palm (Trachycarpus fortunei) in three additional parishes in Louisiana.

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 Phoenix canariensis: Canary Island Date Palm

EDIS ◽  
2013 ◽  
Vol 2013 (8) ◽  
Author(s):  
Timothy K. Broschat
Keyword(s):  
Canary Islands ◽  
Canary Island ◽  
Date Palm ◽  
Short Root ◽  
Fact Sheet ◽  
Phoenix Canariensis ◽  
Self Cleaning ◽  
Slow Growing ◽  
Basal Foot ◽  
Shaped Pattern

The Canary Island date palm is native to the Canary Islands. Although it can reach heights of 40–50 feet, it is slow growing and requires many years to attain that height. It has 8- to 15-foot-long rigid leaves that contain up to 200 V-shaped leaflets, the basal ones of which are modified into long, sharp spines. Leaves are not self-cleaning and must be manually removed when dead, but the leaf bases eventually rot off, leaving an attractive diamond-shaped pattern of leaf scars on the 2- to 3-foot-diameter trunk. On older specimens, the basal foot or so of the trunk typically is covered with short root initials. This 6-page fact sheet was written by T. K. Broschat, and published by the UF Department of Environmental Horticulture, August 2013. http://edis.ifas.ufl.edu/st439

scholarly journals First Report of Phytophthora palmivora on Coronilla valentina subsp. glauca in Italy

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 327-327
Author(s):  
S. O. Cacciola ◽  
A. Pane ◽  
S. Davino ◽  
F. Raudino
Keyword(s):  
Mating Type ◽  
Irrigation System ◽  
Field Capacity ◽  
Industrial Area ◽  
Selective Medium ◽  
Phytophthora Palmivora ◽  
Dual Culture ◽  
Trickle Irrigation ◽  
First Report ◽  
Pure Cultures

The genus Coronilla L. (family Fabaceae), which includes several species native to central and southern Europe, such as C. varia L. (axseed or crown-vetch), C. emerus (scorpion senna), and C. valentina L., is used in Italy as a landscape shrub or potted ornamental plant. During the summer of 2001, 80% of approximately 10,000 1-year-old plants of C. valentina subsp. glauca (L.) Batt. used to landscape an industrial area in the Caltanissetta Province (Sicily) showed symptoms of dieback associated with basal stem and root rot. Plants had been transplanted from pots in April and watered using a trickle irrigation system. A species of Phytophthora was isolated consistently from rotted roots and basal stems using BNPRAH selective medium (3). Pure cultures of this fungus were obtained by single-hypha transfers. Ten isolates, each originating from a single plant, were identified as P. palmivora (Butler) Butler on the basis of morphological and cultural characters as described by Erwin and Ribeiro (1). On solid media, including potato dextrose agar, cornmeal agar, and V8-juice agar, all the isolates produced elliptical to ovoid, papillate sporangia with a mean length/breadth ratio of 1.8. Sporangia were caducous with a short pedicel (mean pedicel length = 5 µm) and a conspicuous basal plug. Mating type was determined on V8 agar in dual culture with mating type A1 and A2 of reference isolates of P. nicotianae and P. palmivora. All isolates were heterothallic and produced oogonia and oospores only with reference isolates of the A2 mating type. Antheridia were amphigynous. Electrophoresis of mycelial proteins on polyacrylamide slab gel confirmed that all isolates were pure cultures and belonged to the same species. Koch's postulates were fulfilled using 6-month-old C. valentina subsp. glauca plants that were transplanted into pots filled with soil artificially inoculated with chlamydospores (50 chlamydospores per gram of soil) produced in submerged axenic cultures (2). The plants were maintained in a glasshouse at temperatures ranging from 18 to 28°C, and the pots were watered to field capacity once a week. One month after transplanting, 70% of plants showed dieback symptoms, while control plants, which were grown in pots containing noninoculated soil, remained healthy. The pathogen was reisolated from roots and basal stems of symptomatic plants. These results demonstrate that P. palmivora is the causal agent of dieback of C. valentina subsp. glauca plants. High temperatures in summer and waterlogging of soil due to excess irrigation water could have enhanced disease development. To our knowledge, this is the first report of P. palmivora on a species of Coronilla. P. palmivora is an exotic pathogen, but it is becoming widespread in Italy, where it has been reported from various regions on different hosts, including cyclamen, English ivy, palms, Pittosporum, and olive. References: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society. St Paul, MN, 1996. (2) J. Y Kadooka and W. H. Ko. Phytopathology 63:559, 1973. (3) H. Masago et al. Phytopathology 67:425, 1977.

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