First Report of Petiole (Rachis) Blight of Washingtonia filifera Caused by Phoma glomerata in Greece

In July 2007, a severe petiole (rachis) blight disease was observed on several California fan palms (Washingtonia filifera) in the vicinity of Heraklion (Crete), Greece. Typical symptoms included discolored (brown to reddish-brown), reversed V-shaped lesions on the petiole bases of the oldest (lowest) leaves, and elongated yellow to dark-brown stripes along the petiole. The lesions progressively expanded and penetrated the petioles, resulting in gradual discoloration (from tan to brown-black) of the internal petiole tissues, including the vascular tissue. The bases of infected petioles occasionally became fragile and burst open, while the corresponding leaf blades were characterized initially by yellowing and one-sided or uneven wilt and, later, desiccation and death with the entire leaves curving downwards. The disease gradually moved upward to younger leaves, severely debilitating but rarely killing the infected trees. A filamentous fungus was consistently isolated onto potato dextrose agar (PDA) plates from sections of diseased petioles, forming dense, dark green colonies with abundant light to dark brown, subglobose pycnidia (diameter ranging between 36.4 to 177.4 μm, and averaging 99.4 μm, n = 50) on the agar surface or immersed in the medium. Chlamydospores and numerous dictyochlamydospores were also observed, with the latter being initially light to dark brown and later becoming black. The numerous conidia were hyaline, ovoid to ellipsoid, and single-celled. Their dimensions were 5.3 to 7.3 × 2.4 to 4.9 μm, averaging 6.5 × 3.2 μm (n = 100). The ITS1-5.8S-ITS2 region, together with parts of the flanking 18S and 28S rRNA genes (3), were amplified with PCR from total DNA extracted from two representative isolates, and sequenced (GenBank Accession Nos. KC802086 to KC802087). Using BLASTn, both sequences were 100% identical to Phoma glomerata ITS sequences (FJ427018, FJ427011, AF126816). Based on morphological and molecular analyses, the pathogen was identified as Phoma glomerata (Corda) Wollenw. & Hochapfel, also known as Peyronellaea glomerata (Corda) Goid. ex Togliani or Coniothyrium glomeratum Corda (1,2). To prove pathogenicity and fulfill Koch's postulates, petioles of the older leaves of eight W. filifera 2-year-old seedlings were wounded with a sterile scalpel (shallow cuts 0.5 to 1.0 cm wide, made parallel to the surface), inoculated with agar discs from a 2-week-old PDA culture of the fungus, and sealed with Parafilm. For controls, sterile PDA plugs were placed on the artificial wounds of five more seedlings. All plants were maintained in the greenhouse at 15 ± 5°C, with 90% humidity. Petiole blight and leaf necrosis symptoms—identical to those observed in the infected plants—were evident 5 weeks post-inoculation, and P. glomerata was consistently reisolated from all inoculated plants. No symptoms were observed on control plants. This is the first report of petiole blight of a palm species caused by P. glomerata in Greece. Due to the extensive use of palms as ornamentals in Greece, the occurrence of P. glomerata can potentially cause economic loss to the local ornamental industry. References: (1) M. M. Aveskamp et al. Stud. Mycol. 65:1, 2010. (2) R. M. Hosford, Jr. Phytopathology 65:1236, 1975. (3) M. P. Pantou et al. Mycol. Res. 109:889, 2005.

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First Report of Palm Rot of Phoenix spp. Caused by Neodeightonia phoenicum in Greece

Plant Disease ◽

10.1094/pdis-08-12-0727-pdn ◽

2013 ◽

Vol 97 (2) ◽

pp. 286-286 ◽

Cited By ~ 5

Author(s):

E. K. Ligoxigakis ◽

E. A. Markakis ◽

I. A. Papaioannou ◽

M. A. Typas

Keyword(s):

Plant Production ◽

Rrna Genes ◽

Its2 Region ◽

Post Inoculation ◽

28S Rrna ◽

Leaf Base ◽

First Report ◽

Initial Symptoms ◽

Terminal Bud ◽

Palm Species

In July 2007, a severe rot was observed on Phoenix dactylifera and P. canariensis palms in the vicinity of Heraklion (Crete), Greece. Initial symptoms were pale, elongated spots that gradually turned to dark brown streaks extending along the leaf base and rachis. In early stages, the upper parts of the leaves usually remained unaffected. Eventually decay and premature death of leaves occurred, followed by terminal bud necrosis. Shoot blights and stalk rots were also observed. A filamentous fungus was consistently isolated onto potato dextrose agar (PDA) from leaf base necrotic lesions. Immersed pycnidial conidiomata on pine needles in culture were multiloculate and dark brown to black. Pycnidial paraphyses were absent. Conidiogenous cells were hyaline, cylindrical, and swollen at base. Conidia were thick-walled, ovoid to ellipsoid, with rounded apex and base; initially hyaline and aseptate, 15.2 ± 0.4 × 11.7 ± 0.3 μm, later becoming dark brown and 1-septate, 21.3 ± 0.4 × 11.8 ± 0.3 μm, with a striate appearance. Total DNA was extracted and used for PCR amplification and sequencing of the ITS1-5.8S-ITS2 region, together with parts of the flanking 18S and 28S rRNA genes (1). The sequence (GenBank Accession No. JX456475) was found 99% identical to Neodeightonia phoenicum ITS sequences (GenBank Accession Nos. EU673338 to EU673340), and was clustered together as a single group with the above sequences with good support by phylogenetic analysis that included representatives of other Neodeightonia species and several other Botryosphaeriaceae members. Based on the morphological, molecular, and phylogenetic analyses, the pathogen was identified as N. phoenicum A. J. L. Phillips & Crous (2) (syn. Diplodia phoenicum (Saccardo) H. S. Fawcett & Klotz), formerly also known as Macrophoma phoenicum Saccardo and Strionemadiplodia phoenicum (Saccardo) Zambettakis. To prove pathogenicity, the petioles of the older leaves of seven 2-year-old seedlings of each of three palms, P. canariensis, P. theophrasti, and Washingtonia filifera were wounded with a sterile scalpel (shallow cuts 0.5 to 1.0 cm wide, made parallel to the surface) and inoculated with agar discs from a 1-week-old PDA culture of the fungus. For controls, PDA discs without fungal mycelium were placed on the wounds of four seedlings of each host. Petiole rot, blight, and leaf necrosis were evident on all inoculated plants 6 weeks post inoculation and the pathogen was consistently reisolated from all three inoculated palm species, whereas no symptoms were observed on control plants. N. phoenicum has repeatedly and globally been reported on P. dactylifera (3). To the best of our knowledge, this is the first report of the occurrence of N. phoenicum infecting Phoenix species in Greece. Palms are extensively used as ornamental trees throughout Greece. A potential spread of palm rot caused by N. phoenicum might have a substantial economic impact and should be urgently addressed through appropriate disease management programs. References: (1) M. P. Pantou et al. Mycol. Res. 109:889, 2005. (2) A. J. L. Phillips et al. Persoonia 21:29, 2008. (3) A. Zaid et al. Chapter XII in: Date palm cultivation, FAO Plant Production and Protection Paper 156 Rev. 1, 2002.

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First Report of Leaf Spot of Phoenix theophrasti Caused by Paraconiothyrium variabile in Greece

Plant Disease ◽

10.1094/pdis-01-13-0114-pdn ◽

2013 ◽

Vol 97 (9) ◽

pp. 1250-1250

Author(s):

E. K. Ligoxigakis ◽

I. A. Papaioannou ◽

E. A. Markakis ◽

M. A. Typas

Keyword(s):

Leaf Spot ◽

Rrna Genes ◽

Leaf Spot Disease ◽

28S Rrna ◽

Conidial Suspension ◽

First Report ◽

Spot Disease ◽

Initial Symptoms ◽

Palm Species ◽

Paraconiothyrium Variabile

In the spring of 2011, a severe leaf spot disease of Phoenix theophrasti was observed in the vicinity of Heraklion (Crete), Greece. Initial symptoms were small, round-ovoid spots of varying shades of brown on the leaves, later being transformed into oblong streaks (average dimensions 7.3 ± 1.0 × 3.3 ± 0.5 mm), surrounded by dark brown rings. As the disease progressed, the expanding streaks often coalesced to form enlarged necrotic lesions. Similar symptoms were also detected on petioles and leaf bases. Extended spotting and blighting occasionally resulted in leaf death. A filamentous fungus was consistently isolated onto potato dextrose agar plates from the periphery of the characteristic lesions, with cultures invariably producing brick to cinnamon colonies with sparse aerial mycelium, subglobose and dark brown superficial pycnidial conidiomata on pine needles, 1- to 3-celled hyaline conidiophores, and hyaline, subcylindrical to ellipsoidal, 1-celled, smooth- and thin-walled conidia, with average dimensions of 3.5 ± 0.6 × 1.7 ± 0.4 μm (n = 100). Total DNA of two isolates was extracted and used for PCR amplification and sequencing of the ITS1-5.8S-ITS2 region, together with parts of the flanking 18S and 28S rRNA genes (4). Both sequences (GenBank Accession Nos. JX456476 and JX456477) were 100% identical to deposited Paraconiothyrium variabile ITS sequences (EU295640 to 48, JN983440 and 41, and JF934920), and were clustered together as a single group with these sequences with good support by phylogenetic analysis that included representatives of the relative P. brasiliense and P. africanum species. Based on the morphological, molecular, and phylogenetic analyses, the pathogen was identified as P. variabile Riccioni, Damm, Verkley & Crous (2). To prove pathogenicity, 10 P. theophrasti 2-year-old seedlings were sprayed with a conidial suspension of the fungus (107 conidia ml–1, 10 ml per plant), while five additional control plants were treated with sterile distilled water. All plants were maintained in the greenhouse at 15 ± 5°C, with 90% humidity. Characteristic leaf spots were evident 4 weeks post inoculation on the older leaves, and P. variabile was consistently reisolated from all inoculated plants. No symptoms were observed on control plants. Paraconiothyrium variabile has been isolated from various woody host plants such as Prunus persica, P. salicina, and Malus sp. in South Africa (1,2), Actinidia chinensis and A. deliciosa in Italy (2), Laurus nobilis in Turkey (2), and Salix matsudana in China (3). To our knowledge, this is the first report of P. variabile naturally infecting and causing a leaf spot disease on a palm species. Palms are extensively used as ornamentals throughout Greece and the occurrence of P. variabile can potentially result in economic loss to the local ornamental industry. References: (1) M. Cloete et al. Phytopathol. Mediterr. 50:S176, 2011. (2) U. Damm et al. Persoonia 20:9, 2008. (3) H. Gao et al. Afr. J. Biotechnol. 10:4166, 2011. (4) M. P. Pantou et al. Mycol. Res. 109:889, 2005.

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First Report of Rhizoctonia solani AG-2-2 IIIB Causing Foliar Blight on Bletilla striata in China

Plant Disease ◽

10.1094/pdis-02-21-0270-pdn ◽

2021 ◽

Author(s):

Hao Zhou ◽

Shuang-Feng Yang ◽

Shao-Mei Wang ◽

Ke Yao ◽

Xiao-Yu Ye ◽

...

Keyword(s):

Rhizoctonia Solani ◽

Its Sequences ◽

Nucleotide Sequence Analysis ◽

Peat Moss ◽

Its2 Region ◽

Post Inoculation ◽

Bletilla Striata ◽

First Report ◽

Foliar Blight ◽

Initial Symptoms

Bletilla striata (Thunb.) Rchb. f. (Orchidaceae), a perennial plant, is a traditional Chinese herb (known as baiji) used to treat hemorrhage, scalding injuries, gastric ulcers, pulmonary diseases, and inflammation (Zu et al. 2019). In May 2019, foliar blight symptoms were observed on approximately 25% of B. striata (cv. Guiji No.1) plants in three plantations (∼4.5 hectares in total) in Ziyuan County, Guangxi Province, China. Initial symptoms were light brown, irregular, water-soaked spots on the plant leaves. Several spots often merged, forming large, irregular, lesions that extended onto the stem after a week and led to leaf abscission, and even plant death. To determine the causal agent, 5-mm squares cut from the margin of 6 infected leaves were surface disinfected in 1% sodium hypochlorite solution for 2 min, rinsed three times with sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 28°C (12-h light-dark cycle) for 3 days. The emerging hyphal tip of a single mycelium was transferred to PDA to obtain pure cultures of the isolates. Twenty isolates were obtained, and 10 isolates (50%) were initially white before turning light brown (∼4 days). Septate hyphae were 4.29 to 10.75 μm (average 6.42 μm) in diameter and branched at right angles with a constriction at the origin of the branch point. Staining with 1% safranin O and 3% KOH solution (Bandoni 1979) revealed multinucleated cells (3 to 9 nuclei per cell, n = 142). This morphology was typical of Rhizoctonia solani Kühn (Meyer et al. 1990). For species confirmation by molecular identification, three isolates (BJ101.6, BJ101.11, and BJ102.2) were cultured on PDA for 4 days, then DNA was extracted from the mycelium using the CTAB method (Guo et al. 2000), and the ribosomal ITS1-5.8S-ITS2 region was amplified by PCR using the universal fungal primers ITS1 and ITS4 (White et al. 1990). Internal transcribed spacer (ITS) sequences of strains BJ101.6, BJ101.11, and BJ102 (deposited in GenBank under accession nos MT406271, MT892815, and MT892814, respectively) had over 99% similarity with those of R. solani AG-2-2 IIIB in GenBank (accession nos JX913810 and AB054858) (Carling et al. 2002; Hong et al. 2012). Phylogenetic analysis using ITS sequences showed that the isolates clustered monophyletically with strains of R. solani AG-2-2 IIIB. The AG of the isolates was confirmed by their ability to grow well on PDA at 35°C, which separates AG-2-2 IIIB from AG-2-2 IV (Inokuti et al. 2019). Based on morphological characteristics and nucleotide sequence analysis, the isolates were identified as R. solani AG-2-2 IIIB. Pathogenicity was tested using 1.5-year-old B. striata (cv. Guiji No.1) plants grown in a perlite and peat moss mixture (1:3) in 7-cm pots. Healthy leaves on plants were inoculated with an aqueous suspension (approximately 1 × 105 hyphal fragments/mL, 100 μL) prepared from cultures of strains BJ101.6, BJ101.11, and BJ102.2, each isolate was inoculated onto three plants; three other plants with sterile water served as controls. All plants were enclosed in transparent plastic bags and incubated in a greenhouse at 28°C for 14 days (12-h photoperiod). Three days post-inoculation, leaves exposed to the mycelial fragments had symptoms similar to those originally observed in the field. No symptoms were detected on control plants. Experiments were replicated three times with similar results. To fulfill Koch’s postulates, R. solani AG-2-2 IIIB was re-isolated on PDA from symptomatic leaves and confirmed by sequencing, whereas no fungus was isolated from the control plants. To our knowledge, this is the first report of R. solani AG-2-2 IIIB causing foliar blight on B. striata in China, and these findings will be useful for further control strategies and research.

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First Report of Potato Blackleg Disease Caused by Pectobacterium atrosepticum in Guangdong China

Plant Disease ◽

10.1094/pdis-03-13-0275-pdn ◽

2013 ◽

Vol 97 (12) ◽

pp. 1652-1652

Author(s):

X. M. She ◽

Z. F. He ◽

Y. F. Tang ◽

Z. G. Du ◽

G. B. Lan

Keyword(s):

16S Rdna ◽

Vascular Tissue ◽

Guangdong Province ◽

Bacterial Suspension ◽

Post Inoculation ◽

Blackleg Disease ◽

Potato Blackleg ◽

Pectobacterium Atrosepticum ◽

First Report ◽

Potato Plants

Potato (Solanum tuberosum L.) is an important crop in China. In 2013, diseased potatoes exhibiting blackleg and soft rot symptoms were found in the winter potato growing areas of Huizhou city, Guangdong Province, China, with an incidence of approximately 20%. Initially, the stem bases of infected plants blackened and this symptom spread upward. Later, foliage of the diseased plants became yellow and the stem rotted with vascular discoloration. Twenty diseased plants with typical black leg symptoms were collected from a 10-ha potato field with approximately 60,000 potato plants per hectare. A bacterium with small, irregular, round, fluidal, white colonies was isolated from the vascular tissue of all diseased plants on nutrient agar at 26°C for 2 days. Ten strains were randomly selected for pathogenicity assays. Potato plants (cv. Favorita) at the five- to six-leaf stage were inoculated by injecting their stems with 1 ml of each strain in a bacterial suspension (3 × 108 CFU/ml). The inoculated potato plants were incubated at 16 to 21°C and 65 to 85% humidity, and exhibited the same symptoms as the diseased potato plants in the field by 3 to 5 days post inoculation (dpi). The bacterium was reisolated from the diseased tissue (stem) of the inoculated potato plants and produced characteristic pits on crystal violet pectate medium (1). The bacterium utilized a-methyl glucoside, glucose, lactose, maltose, cellobiose, raffinose, melibiose, and citrate, but not d-arabitol, sorbitol, or malonate. The bacteria also gave a positive reaction for catalase and production of reducing substances from sucrose, but gave a negative reaction for oxidase, production of phosphatase, and indole. Using the universal bacterial 16S rDNA primer set, 27f/1541R (4), 1,400-bp fragments were amplified from the 10 strains. The sequences of the 10 fragments (GenBank Accessions KC695819 to KC695828) were identical and had 100% sequence identity with 16S rDNA of Pectobacterium atrosepticum CFBP 1526 (JN600332). Further, the 438-bp and 690-bp fragments were respectively amplified from all 10 strains with the P. atrosepticum-specific primers Y45/Y46 (3) and ECA1f/ECA2r (2). To our knowledge, this is the first report of potato blackleg disease caused by P. atrosepticum (formerly named as Erwinia carotovora subsp. atroseptica) in Guangdong Province, China. References: (1) D. Cupples et al. Phytopathology 64:468, 1974. (2) S. H. De Boer et al. Phytopathology 85:854, 1995. (3) D. Frenchon et al. Potato Research 41:63, 1995. (4) M. Horita et al. J. Gen. Plant Pathol. 70:278, 2004.

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Root-Knot Nematodes in Golf Course Greens of the Western United States

Plant Disease ◽

10.1094/pdis-09-11-0808 ◽

2012 ◽

Vol 96 (5) ◽

pp. 635-647 ◽

Cited By ~ 32

Author(s):

Michael A. McClure ◽

Claudia Nischwitz ◽

Andrea M. Skantar ◽

Mark E. Schmitt ◽

Sergei A. Subbotin

Keyword(s):

United States ◽

Western Hemisphere ◽

Western United States ◽

16S Rrna Genes ◽

Rrna Genes ◽

Golf Course ◽

28S Rrna ◽

Golf Courses ◽

Root Knot Nematodes ◽

First Report

A survey of 238 golf courses in 10 states of the western United States found root-knot nematodes (Meloidogyne spp.) in 60% of the putting greens sampled. Sequence and phylogenetic analyses of 18S rRNA, D2-D3 of 28S rRNA, internal transcribed spacer-rRNA, and mitochondrial DNA gene sequences were used to identify specimens from 110 golf courses. The most common species, Meloidogyne naasi, was found in 58 golf courses distributed from Southern California to Washington in the coastal or cooler areas of those states. In the warmer regions of the Southwest, M. marylandi was recovered from 38 golf courses and M. graminis from 11 golf courses. This constitutes the first report of M. marylandi in Arizona, California, Hawaii, Nevada, and Utah, and the first report of M. graminis in Arizona, Hawaii, and Nevada. Two golf courses in Washington were infested with M. minor, the first record of this nematode in the Western Hemisphere. Columbia root-knot nematode, M. chitwoodi, was found in a single golf course in California. Polymerase chain reaction restriction fragment length polymorphism of the intergenic region between the cytochrome oxidase and 16S rRNA genes in the mitochondrial genome with restriction enzyme SspI was able to distinguish populations of M. graminis from M. marylandi, providing a fast and inexpensive method for future diagnosis of these nematodes from turf.

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First Report of Ilyonectria robusta Causing Rusty Root of Asian Ginseng in China

Plant Disease ◽

10.1094/pdis-06-14-0663-pdn ◽

2015 ◽

Vol 99 (1) ◽

pp. 156-156 ◽

Cited By ~ 6

Author(s):

X. H. Lu ◽

X. L. Jiao ◽

A. J. Chen ◽

Y. Luo ◽

W. W. Gao

Keyword(s):

Dna Sequence ◽

Histone H3 ◽

Morphological Characters ◽

Perennial Herb ◽

Its2 Region ◽

Post Inoculation ◽

Single Spore ◽

First Report ◽

Irregular Shapes ◽

Histone H3 Gene

Asian ginseng (Panax ginseng) is an economically important perennial herb, mainly cultivated in Jilin Province, China. In September 2013, Asian ginseng plants in Jilin showed rusty root symptoms. Typical symptoms included rusty superficial lesions of irregular shapes and margins. Ten symptomatic roots were collected from each of five fields for investigation. To isolate the pathogen, root epidermal tissues with typical lesions were excised, surface-sterilized, and placed on potato dextrose agar (PDA) amended with 50 μg/ml tetracycline. After incubation at 20 ± 1°C in the dark for a week, 18 single-spore isolates out of 50 samples were obtained and identified as Ilyonectria robusta (A.A. Hildebr.) A. Cabral & Crous based on morphological characters and DNA sequence analysis (1). After incubating 7 days on PDA in the dark at 20°C, colonies were cottony to felty in texture and orange white to brownish grey in color with average diameters of 60 ± 3 mm. Isolates were cultured on synthetic nutrient-poor agar for conidial measurements. Macroconidia formed on simple conidiophores predominately, with mostly one and occasionally up to three septa, and were cylindrical with both ends broadly rounded. Macroconidia varied in size depending on the number of cells as follows: one-septate, 7.0 ± 0.6 × 27.7 ± 2.7 μm; two-septate, 7.3 ± 0.7 × 33.3 ± 2.1 μm; three-septate, 7.4 ± 0.6 × 33.4 ± 2.2 μm. Microconidia that formed on complex conidiophores were ellipsoid to ovoid and ranged in size from aseptate 3.7 ± 0.5 × 8.7 ± 1.1 μm to one-septate 5.0 ± 0.6 × 13.1 ± 1.6 μm. Brown chlamydospores were abundantly produced on PDA, globose to subglobose in shape, and in size of 10.9 ± 1.3 × 11.8 ± 1.5 μm (n ≥ 30 observations per structure for each measurement). The isolates were further classified by amplifying and sequencing the ITS1-5.8S rRNA-ITS2 region and histone H3 gene with primer pairs ITS5 and ITS4 (4), and H3-1a and H3-1b (3), respectively. Sequences of the two loci (GenBank Accession Nos. KM015300 and KM015299) showed 100% identity among the three examined isolates and the published I. robusta isolates (JF735268 and JF735517). To confirm the pathogenicity, bare roots of 3-year-old Asian ginseng were inoculated with mycelial plugs of three isolates of I. robusta selected randomly. Four roots were inoculated as replicates for each isolate with pathogen-free agar plugs as a control. One week post-inoculation in the dark at 20 ± 1°C, all the inoculated ginseng roots showed light-brown to dark-brown lesions. I. robusta was recovered from symptomatic roots and confirmed by analyzing the DNA sequence of the histone H3 gene. The inoculation experiment was repeated, and both trials showed the same results. The ginseng tissue under the control agar plugs remained symptomless, and no fungi were isolated. To our knowledge, this is the first report of I. robusta causing rusty root of P. ginseng in China (1,2,5). References: (1) A. Cabral et al. Mycol. Prog. 11:655, 2012. (2) I. Erper et al. Eur. J. Plant Pathol. 136:291, 2013. (3) N. L. Glass et al. Appl. Environ. Microbiol. 61:1323, 1995. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (5) X. Lu et al. Plant Dis. 98:1580, 2014.

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First Report of Downy Mildew on Delphinium Caused by Peronospora ficariae in California

Plant Disease ◽

10.1094/pdis.2003.87.12.1540b ◽

2003 ◽

Vol 87 (12) ◽

pp. 1540-1540 ◽

Cited By ~ 2

Author(s):

S. A. Tjosvold ◽

S. T. Koike

Keyword(s):

Downy Mildew ◽

Economic Loss ◽

Central Vein ◽

Cut Flower ◽

First Report ◽

Initial Symptoms ◽

Adjacent Field ◽

Dark Green ◽

Production Areas ◽

Blue Butterfly

Along California's central coast, delphinium (Delphinium species and cultivars) is grown as a cut flower and potted plant. In the spring of 2003, severe downy mildew was observed on various delphinium crops in Santa Cruz County. The disease was detected on cut flower Delphinium ‘Volkerfrieden’ in a greenhouse and adjacent field production areas. At a different nursery, outdoor, containerized D. grandiflorum ‘Blue Butterfly’ and Delphinium elatum (Pacific Hybrids) were also infected. Initial symptoms on leaves consisted of light green patches. These areas quickly turned dark green to blackish green and often were delimited by the central vein of the leaf. Purple-gray sporulation of the pathogen could be seen primarily on the abaxial leaf surfaces. Symptoms were most severe on older foliage. As disease progressed, the lower leaves withered and dried up, giving the plant a blighted appearance. Disease was most severe on D. grandiflorum ‘Blue Butterfly’, in which the disease affected the entire planting and blighted all foliage with the exception of the youngest leaves on the plant's central leader. For this cultivar, the diseased nursery stock had to be discarded, resulting in significant economic loss. Sporangiophores branched dichotomously, with branches ending in slender, slightly curved tips. Sporangia were slightly purplish, ellipsoid to ovoid, and measured 27 to 36 × 19 to 22 μm. Inside the tissue of older symptomatic leaves, extensive numbers of oogonia and oospores were observed. Oospores were globoid, amber to light brown, verruculose, and measured 25 to 27 μm in diameter. The pathogen was identified as Peronospora ficariae (1). Pathogenicity was demonstrated by spraying sporangial suspensions (1.0 × 104 sporangia per ml) onto the leaves of healthy, potted Delphinium elatum (Pacific Hybrids), incubating the plants in a dew chamber at 18°C for 48 h, and then maintaining them in a greenhouse (22 to 24°C). After 10 to 12 days, inoculated plants developed downy mildew symptoms, and the same pathogen sporulated sparsely on the host. If these plants were again placed in the dew chamber for an additional 24 h, leaf lesions sporulated profusely in the following 48 h. Control plants treated with water did not develop any symptoms or signs of downy mildew. To our knowledge, this is the first report of downy mildew caused by P. ficariae on cultivars of delphinium in California. Reference: (1) G. Hall. Mycopathologia 126:51, 1994.

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First Report of Pink Rot of Phoenix and Washingtonia Species Caused by Nalanthamala vermoesenii in Greece

Plant Disease ◽

10.1094/pdis-08-12-0725-pdn ◽

2013 ◽

Vol 97 (2) ◽

pp. 285-285 ◽

Cited By ~ 3

Author(s):

E. K. Ligoxigakis ◽

I. A. Papaioannou ◽

E. A. Markakis ◽

M. A. Typas

Keyword(s):

The United States ◽

Molecular Characteristics ◽

Lesion Length ◽

Post Inoculation ◽

Single Spore ◽

Additional Species ◽

First Report ◽

Pink Rot ◽

Agar Plug ◽

Palm Species

A disease resembling pink rot was first observed on Phoenix dactylifera in Heraklion (Crete, Greece) in the summer of 2007, and was later found to be relatively common in the same district on additional species (P. canariensis, P. theophrasti, Washingtonia filifera, W. robusta). Symptoms included chlorotic and necrotic leaves (dead tips), light-brown spots (1 to 2 mm in diameter) on the leaves and rachis, rot of the rachis, sheath, and trunk, and eventual death of infected plants. A pinkish-orange layer formed both on the surface and within the infected tissues. A hyphomycete was isolated from symptomatic petioles and the pinkish-orange layer of the sheath. Sixteen isolates were examined on potato dextrose agar (PDA). All formed salmon to grayish-red colonies with sparse aerial mycelium, hyaline conidiophores with penicillate branches and terminal phialides, and ovoid, single-celled conidia in long chains. Mean conidial dimensions were 3.5 (± 0.1) × 5.5 (± 0.1) μm (n = 60 each), for 1-week-old cultures of two single-spore isolates recovered from W. filifera. A BLASTn search of GenBank with sequences of rDNA ITS (JX456472 to JX456474) revealed 100% identity of three isolates to that of Nalanthamala vermoesenii (Biourge) Schroers, comb. nov. [syn. Penicillium vermoesenii Biourge; Gliocladium vermoesenii (Biourge) Thom] originating from several palm species in Spain, the Czech Republic, Australia, and the United States (GenBank AY554212 to AY554217). Therefore, our examination of morphological and molecular characteristics suggested that the fungus recovered from symptomatic trees was N. vermoesenii (3,4). Pathogenicity tests were performed on wounds (shallow cuts 0.5 to 1.0 cm wide, made parallel to the surface with a sterile scalpel) of petioles of mature leaves of eight 2-year-old seedlings each of P. canariensis, P. theophrasti, and W. filifera. A 6-mm agar plug from a 1-week-old PDA culture was placed on the artificial wound of each inoculated plant. For non-inoculated controls, sterile PDA plugs were placed on the artificial wounds of four seedlings per host. All plants were maintained in the greenhouse at 16 ± 5°C, with 95% humidity and a 12-h photoperiod. Petiole and stem rot, leaf necrosis, and production of pinkish-orange spore masses appeared at 5 weeks post-inoculation. Average lesion length was 2.75 ± 0.15, 3.28 ± 0.21, and 6.14 ± 0.53 cm for P. canariensis, P. theophrasti, and W. filifera, respectively, suggesting that the latter is more susceptible. The fungus was consistently reisolated from all three inoculated palm species, whereas no symptoms appeared on control plants. To our knowledge, this is the first report of N. vermoesenii infecting palms in Greece. The invasion of the plants by the fungus is probably favored by wounds, such as those caused by pruning or by feeding of the red palm wheevil Rhynchophorus ferrugineus Olivier, which is widespread in Greece (1). References: (1) D. C. Kontodimas et al. Entomol. Hellenica 16:11, 2006. (2) M. P. Pantou et al. Mycol. Res. 109:889, 2005. (3) H.-J. Schroers et al. Mycologia 97:375, 2005. (4) J. Y. Uchida. Page 25 in: Compendium of Ornamental Palm Diseases and Disorders, APS Press, St. Paul, MN, USA, 2004.

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First Report of Diaporthe pseudomangiferae Causing Inflorescence Rot, Rachis Canker, and Flower Abortion of Mango

Plant Disease ◽

10.1094/pdis-12-13-1223-pdn ◽

2014 ◽

Vol 98 (7) ◽

pp. 1004-1004 ◽

Cited By ~ 1

Author(s):

L. M. Serrato-Diaz ◽

L. I. Rivera-Vargas ◽

R. D. French-Monar

Keyword(s):

Dna Analysis ◽

Mangifera Indica ◽

Germplasm Collection ◽

Its2 Region ◽

Post Inoculation ◽

Tropical Fruit ◽

First Report ◽

Flower Abortion ◽

Wide Range ◽

Β Tubulin

Although mango (Mangifera indica L.) is a very important tropical fruit crop, limited studies have been conducted on fungal pathogens affecting the inflorescences. During a disease survey conducted from 2008 to 2010, 50% of the inflorescences were affected with inflorescence rot, rachis canker, and flower abortion characterized by blackening of plant tissue with soft rot lesions and suken lesions on the rachis, respectively. Symptoms were observed at the Mango Germplasm Collection of the University of Puerto Rico's Experiment Station in Juana Diaz, Puerto Rico. Five diseased pieces of 350 inflorescences from cvs. Haden and Irwin were disinfested with 70% ethanol, followed by 0.5% sodium hypochlorite, rinsed with sterile water, and transferred to acidified potato dextrose agar (APDA). Among several typical or common fungi, three isolates of Diaporthe pseudomangiferae (Dp) R.R. Gomes, C. Glienke & Crous were obtained from symptomatic tissue and identified morphologically using taxonomic keys and DNA sequence comparisons (1,2). On APDA, colonies of Dp initially had white-gray moderate aerial mycelia. Pycnidia were black and superficial on cultures with a central ostiole that exuded beige to light orange conidial droplets. Alpha conidia (n = 50) were aseptate, hyaline, smooth, fusiform, apex rounded and base truncate, averaged 7.34 μm long by 2.60 μm wide. Beta conidia (n = 50) were spindle-shaped, aseptate, hyaline and smooth, averaged 22.03 μm long by 1.53 μm wide. DNA analysis of the ITS1-5.8S-ITS2 region using primers ITS5 and ITS4, and fragments of both β-tubulin and translation elongation factor 1 alpha (EF1-α) genes using primers T1 and Bt2b, and EF1-728F and EF1-986R, respectively, were sequenced and compared using BLASTn with sequences available in the GenBank. Accession numbers of gene sequences of Dp submitted to GenBank were KF616498 to KF616500 for ITS region, KF616501 to KF616503 for β-tubulin, and KF616504 to KF616506 for EF1-α. For all genes used, sequences were 99 to 100% identical to reference isolate CBS 388.89 of Dp in GenBank. For each fungal isolate, pathogenicity tests were conducted on six random healthy non-detached mango inflorescences for both cvs. Haden and Irwin. Inflorescences were inoculated with 5-mm mycelial disks from 8-day-old pure cultures grown on APDA and kept in a humid chamber using plastic bags for 8 days under field conditions. Untreated controls were inoculated with APDA disks only. The test was repeated twice. On cv. Haden, isolates of Dp caused rachis canker (sunken lesion on the rachis) at 8 days post inoculation (dpi). On cv. Irwin, isolates of Dp caused inflorescence rot. Initially, white mycelia was observed on inflorescences but eventually inflorescences turned brown and flower abortion was observed at 8 dpi. Untreated controls did not show any of the above symptoms and no fungi were re-isolated from tissue. From diseased inflorescences, Dp was re-isolated, thus fulfilling Koch's postulates. Diaporthe spp. have been associated with fruit rots, stem cankers, decay, and wilt on a wide range of plant hosts (3,4). Recently, Dp was associated with fruit peel of mango in Mexico and the Dominican Republic (2). To our knowledge, this is the first report of Dp causing inflorescence rot, rachis canker, and flower abortion in mango. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. APS Press. St. Paul, MN, 1998. (2) R. R. Gomes et al. Persoonia. 31:1, 2013. (3) J. M. Santos et al. Persoonia 27:9, 2011. (4) S. M. Thompson et al. Persoonia 27:80, 2011.

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Phylogeny of hymenolepidids (Cestoda: Cyclophyllidea) from mammals: sequences of 18S rRNA and COI genes confirm major clades revealed by the 28S rRNA analyses

Journal of Helminthology ◽

10.1017/s0022149x21000110 ◽

2021 ◽

Vol 95 ◽

Author(s):

B. Neov ◽

G.P. Vasileva ◽

G. Radoslavov ◽

P. Hristov ◽

D.T.J. Littlewood ◽

...

Keyword(s):

Ribosomal Rna ◽

18S Rrna ◽

Phylogenetic Analyses ◽

The Other ◽

Rrna Genes ◽

Host Switching ◽

28S Rrna ◽

Mitochondrial Cytochrome ◽

Rapid Radiation ◽

18S Rrna Genes

Abstract The aim of the study is to test a hypothesis for the phylogenetic relationships among mammalian hymenolepidid tapeworms, based on partial (D1–D3) nuclear 28S ribosomal RNA (rRNA) genes, by estimating new molecular phylogenies for the group based on partial mitochondrial cytochrome c oxidase I (COI) and nuclear 18S rRNA genes, as well as a combined analysis using all three genes. New sequences of COI and 18S rRNA genes were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analyses confirmed the major clades identified by Haukisalmi et al. (Zoologica Scripta 39: 631–641, 2010): Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade. While the Ditestolepis clade is associated with soricids, the structure of the other three clades suggests multiple evolutionary events of host switching between shrews and rodents. Two of the present analyses (18S rRNA and COI genes) show that the basal relationships of the four mammalian clades are branching at the same polytomy with several hymenolepidids from birds (both terrestrial and aquatic). This may indicate a rapid radiation of the group, with multiple events of colonizations of mammalian hosts by avian parasites.

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