Artykuły w czasopismach na temat „Pycnisia”
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Page, Timothy J., Kristina von Rintelen i Jane M. Hughes. "Phylogenetic and biogeographic relationships of subterranean and surface genera of Australian Atyidae (Crustacea : Decapoda : Caridea) inferred with mitochondrial DNA". Invertebrate Systematics 21, nr 2 (2007): 137. http://dx.doi.org/10.1071/is06023.
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The biogeographic and phylogenetic relationships of six of the eight Australian genera of freshwater shrimp from the family Atyidae were investigated using mitochondrial 16S rDNA and cytochrome oxidase I sequences. Previous studies on two of the epigean genera (Caridina, Paratya) indicate that Australian species have strong links to congenerics from outside, with Australian members of Paratya being monophyletic and Caridina polyphyletic. The present study found that the endemic Australian epigean genus Australatya forms a strong clade with Pacific ‘Atya-like’ genera (Atyoida, Atyopsis), and that the endemic Australian epigean genus Caridinides falls within a clade containing Caridina species from the Australian ‘indistincta’ group. The two hypogean genera included in this study (Parisia, Pycnisia) form a strong clade in all analyses, implying an Australian subterranean speciation. The possibility of a relationship between Parisia/Pycnisia and an Australian Caridina species may have implications for the monophyly of the highly disjunct genus Parisia (Australia, Madagascar, Philippines). Parisia may descend from local Caridina species and represent convergent morphologies.
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Bruce, AJ. "Pycnisia raptor, a new genus and species of predatory troglobic shrimp (Crustacea : Decapoda : Atyidae) from northern Australia". Invertebrate Systematics 6, nr 3 (1992): 553. http://dx.doi.org/10.1071/it9920553.
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Pycnisia raptor, gen. et sp. nov., a new predatory troglobic atyid shrimp from a limestone cave near Katherine, Northern Territory, Australia, is described and illustrated. The shrimp is immediately distinguishable from all other atyids by the presence of robust, raptorial ambulatory pereiopods. The troglobic atyid fauna of Australia is reviewed and a key provided for the identification of the six species of four genera presently known.
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Navarro-De-La-Fuente, Laura, Alejandro Salinas-Castro, Antero Ramos i Ángel Trigos. "Chaetocapnodium zapotae sp. nov. on Manilkara zapota in central Mexico". Mycotaxon 137, nr 2 (15.07.2022): 179–87. http://dx.doi.org/10.5248/137.179.
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A new sooty mould, Chaetocapnodium zapotae, was isolated from Manilkara zapota in central Veracruz, Mexico. An analysis of ITS+LSU nuclear rDNA concatenated sequences of our isolate revealed taxonomic identity at the genus level located in the same clade as Chaetocapnodium insulare and Chaetocapnodium placitae. Morphological examination confirmed that the new species differs from C. insulare in the absence of the sexual morph and the absence of setae on the pycnidia. Additional characters distinguishing C. zapotae from C. placitae are its narrower pycnidial size range, wider size ranges for the hyphae and conidia, and the dark brown color of its pycnidia.
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Roquebert, Marie-France, i Edith Bury. "Leptoxyphium : Pycnide ou synnéma?" Canadian Journal of Botany 66, nr 11 (1.11.1988): 2265–72. http://dx.doi.org/10.1139/b88-309.
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Structural and developmental analysis of Leptoxyphium sp. conidiomata shows that these consist of aggregated hyphae that develop a conidiogenous cavity near the apex. They have both pycnidial and synnematal characters. This lack of specific differences between synnemata and pycnidia emphasizes the artificial character of the previously established distinction between Coelomycètes and Hyphomycetes.
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Tennakoon, K. M. S., H. J. Ridgway, M. V. Jaspers i E. E. Jones. "Production of Neofusicoccum species conidia and their pathogenicity on wounded and non-wounded blueberry shoots". New Zealand Plant Protection 70 (24.07.2017): 209–14. http://dx.doi.org/10.30843/nzpp.2017.70.52.
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Pycnidial and conidial production by isolates of the four main Neofusicoccum species associated with blueberry in New Zealand was investigated. Pycnidia developed after 8 days on mycelial-inoculated detached green shoots. Conidial ooze was observed after further incubation for 12 h under high relative humidity at 25˚C. Numbers of oozing pycnidia and conidial numbers were generally low, but were significantly affected by isolate and species. Neofusicoccum ribis and N. parvum produced slightly more pycnidia and conidia compared with N. luteum and N. australe. Inoculation of non-wounded and wounded attached green shoots with either N. ribis or N. australe conidia showed that, 14 days after inoculation, lesions developed in wounded shoots only, with N. ribis (58.8 mm) producing longer lesions than N. australe (29.8 mm). Neofusicoccum ribis and N. australe were re-isolated beyond the lesion, with pathogen progression being significantly greater for wounded (47.1 mm) compared with non-wounded shoots (30.4 mm).
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Sztejnberg, Abraham, Sergio Galper i Norberto Lisker. "Conditions for pycnidial production and spore formation by Ampelomyces quisqualis". Canadian Journal of Microbiology 36, nr 3 (1.03.1990): 193–98. http://dx.doi.org/10.1139/m90-033.
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On Czapek agar medium, the optimum temperature for spore germination and pycnidia formation by Ampelomyces quisqualis was 20 and 25 °C, respectively. Inoculation of Czapek agar medium with a spore concentration of 106 or 107/mL significantly increased pycnidia formation as compared with medium inoculated with 104 or 105 spores/mL. In shaken cultures, spore formation in potato dextrose broth (PDB) was higher than in the broth of bran extract and glycerol, aspargine, Czapek, Joham, and synthetic Mucor media. On PDB, pycnidia were formed in hard black aggregates. Spore production in fermentors was similar to that in shaken cultures. The omission of glucose from PDB caused a great increase in the number of spores formed. Also, PDB prepared with the broth of 100 g (instead of the usual 200 g) peeled potatoes/L was effective in spore formation and maintained spore infectivity as high as in controls. It seems that the broth of boiled potatoes is a simple, efficient, and nonexpensive medium for mass production of infective A. quisqualis spores. Key words: Ampelomyces quisqualis, pycnidial production, spore formation, biological control, powdery mildew.
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O'Connell, M. N., V. Kethees Wararajah, A. F. Fieldsend i F. J. Cullum. "Sources of infection and methods of control of Septoria oenotheraein evening primrose (Oenotheraspp.)". Acta Agronomica Hungarica 53, nr 4 (1.12.2005): 385–91. http://dx.doi.org/10.1556/aagr.53.2005.4.4.
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Septoria oenotheraeWest. can cause severe damage in overwintered crops of evening primrose (Oenothera spp.), including complete crop loss. Damage would be reduced if the sources of infection could be identified and removed. Examination of seed capsules inoculated with S. oenotheraeshowed that 96% of the pycnidia present were on the outside of the capsules, and seeds bearing pycnidia were only rarely found. However, internal infection of seeds from these capsules was demonstrated by both a blotter test and by culturing on agar media. Immersing seeds in 45°C water for 25 minutes destroyed viable fungal propagules located internally in seeds without reducing seed germination. The pathogen was also shown to overwinter in the pycnidial stage on stems left standing in the field. It is concluded that both internal seed-borne infection and overwintered crop debris are potential sources of infection in commercial seed stocks of evening primrose.
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NELSEN, Matthew P., Arne THELL, Steven D. LEAVITT, Celia J. HAMPTON-MILLER i H. Thorsten LUMBSCH. "A reappraisal of Masonhalea (Parmeliaceae, Lecanorales) based on molecular and morphological data". Lichenologist 45, nr 6 (31.10.2013): 729–38. http://dx.doi.org/10.1017/s0024282913000509.
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AbstractPrevious studies have identified a close relationship between the monospecific Masonhalea richardsonii and Tuckermannopsis inermis. However, formal taxonomic changes were postponed until existing sequence data could be confirmed. Here we validate these data and discuss the transfer of T. inermis to Masonhalea (made by Lumbsch et al. in Thell & Moberg 2011), consider the morphological, anatomical and biogeographic similarities and differences between these two taxa. The two Masonhalea species both produce lateral apothecia, marginal pycnidia, a layer of cortical tissue beneath the pycnidial wall and bacillariform conidia.
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Li, J. Y., G. Strobe, W. M. Hess i E. Ford. "An Endophytic Fungus from Cephalotaxus: Phoma SP. which Produces Anti-Fungal Substances". Microscopy and Microanalysis 3, S2 (sierpień 1997): 105–6. http://dx.doi.org/10.1017/s1431927600007418.
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Various species of endophytic fungi produce a variety of potentially useful new Pharmaceuticals in host tissue of different plants. As an example, the anti-cancer drug, taxol is produced by several species of fungi isolated from various host species.A Phoma was isolated from the inner bark of Cephalotaxus fortunei growing near Hangzhou, China. After 7-10 days of incubation at 23C cultures were hyphal tipped and transferred to PDA and gamma-irradiated carnation leaves. Cultures which produced bioactive substances were studied further. This Phoma sp. is particularly active against Pythium ultimum. Another endophytic Phoma sp. isolated from Taxus wallachiana also makes antimetabolite compounds. Presumably these endophytic Phoma spp. exist in a symbiotic relationship with various tree species contributing substances that inhibit or destroy invading pathogenic fungi and bacteria.The fungus produces globose dark brown, thin-walled pycnidia which are semi-immersed in carnation leaf pieces (Fig. 1). Cream-colored conidia (Fig. 2), which average 4.5-5 × 1.75-3 μm are produced in pycnidia with a single ostiole normally obscured by a gelatinous mass (Fig. 3), which is characteristically not evident on old pycnidia (Fig. 4). Conidia are formed enteroblastically from discrete phialidic conidiogonous cells attached directly to the pycnidial wall. Sclerotia (ca. 1.5-2 mm) are also produced on PDA.
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Lorenc, František, i Adam Véle. "Sphaeropsis sapinea (Fr.) Dyko & B. Sutton in Pinus sylvestris L. stands affected by long-term drought". Central European Forestry Journal 68, nr 4 (21.10.2022): 214–23. http://dx.doi.org/10.2478/forj-2022-0010.
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Abstract In this study, the fruit bodies (pycnidial) colonization and spore presence of Sphaeropsis sapinea (Fr.) Dyko & B. Sutton on Scots pine (Pinus sylvestris L.) trees in stands affected by long-term drought in the Czech Republic were evaluated. A total of 520 cones at four sites were evaluated every 1.5 months from June 2019 to December 2020. The pycnidia of S. sapinea in relation to colonization by subcortical insects in inner bark and wood, and wood-decaying fungi a total of 340 trunks at 17 sites during the autumn of 2020 were also evaluated. Pycnidial colonization of S. sapinea on cones was significantly higher at the site with the highest air humidity and significantly lower in the sampling periods of June 2019, August 2019, and November 2019, which were characterized by low precipitation levels. S. sapinea spore presence on cones was significantly higher at sites in Bohemia compared to those in Moravia, in sites with higher air humidity, and in three consecutive sampling periods in March 2020–June 2020. Pycnidial colonization of S. sapinea on trunks was significantly positively dependent on the colonization of subcortical insects in both inner bark and wood, but not with the colonization of wood-decaying fungi. The results of this study show a positive relationship between high humidity and colonization by subcortical insects in inner bark and wood with S. sapinea on Scots pine.
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Ormeno-Nunez, J., R. D. Reeleder i A. K. Watson. "A new species of Phomopsis recovered from field bindweed (Convolvulus arvensis)". Canadian Journal of Botany 66, nr 11 (1.11.1988): 2228–33. http://dx.doi.org/10.1139/b88-305.
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Isolates of a Phomopsis recovered from diseased foliage of Convolvulus arvensis L. were morphologically distinct from other species of Phomopsis. Alpha-conidia were oblong to fusiform-ellipsoid, usually blunt at both ends with two guttules, and were distinctly larger than alpha-conidia of previously reported species. Beta-conidia were found only in culture. Stromata developed as small, superficial masses of aggregated mycelium, later becoming pulvinate, and were dark brown to black. Stromata were scattered throughout the colony, rarely aggregated. Pycnidia were uniostiolate or multiostiolate, usually arising from the stromata bodies, and pycnidial beaks were prominent. Leaf spot and anthracnose symptoms were reproduced on inoculated bindweed plants. The binomial Phomopsis convolvulus is proposed for this taxon.
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Athira, K., N. Ragupathi i T. Raguchander. "Morphological characterization of Ampelomyces spp., a hyperparasite of Bhendi (Abelmoschus esculentus (L.) Moench) powdery mildew". Journal of Applied and Natural Science 9, nr 4 (1.12.2017): 1954–57. http://dx.doi.org/10.31018/jans.v9i4.1471.
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Ampelomyces is a naturally occurring hyperparasite on powdery mildews. Survey was conducted in major bhendi (Abelmoschus esculentus (L.) Moench) growing districts of Tamil Nadu during June 2014 to assess the incidence of powdery mildew and to collect different isolates of Ampelomyces spp. The results of the survey revealed that the disease incidence ranged from 15.54 to 63.45 %. Ten isolates of Ampelomyces spp. were collect-ed from surveyed areas of powdery mildew. Isolation of Ampelomyces spp. was done from powdery mildew infected bhendi leaf parasitized by Ampelomyces spp. using tissue segment method. All the isolates were identified by their morphological characters. The colour of the colonies in various medium was brownish black to greenish white. Most of the isolates showed radial and fluffy growth pattern with raised growth. The pycnidia of different isolates of Ampelomyces varied in their shape and were mostly ovoid, ellipsoid, cylindrical, pyriform to globose in shape. The size of pycnidia varied from 29.2-72.5×22.4-43.1 μm. The number of pycnidia was found to be more in isolates viz., TNAU-AQ101 and TNAU-AQ103. Pycnidiospores are hyaline, unicellular and guttulate in shape. The pycnidial production was higher in TNAU-AQ101 and TNAU-AQ103. Application of agrochemicals is one of the oldest and most effective methods to manage powdery mildew disease. However, incessant use of these agrochemicals has many demerits such as development of resistance to pathogens, residual toxicity and environmental pollution. Hence, search for an alternative means for disease management is envisaged. The genus Ampelomyces are the major antagonists as an alternative of Erysiphales fungi being a significant group of phytopathogens.
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Islam, MM, M. Asaduzzaman, ME Hoque i MB Meah. "Morphological Characterization of Isolates of Phomopsis vexans of Bangladesh". Journal of Science Foundation 8, nr 1-2 (17.04.2013): 123–30. http://dx.doi.org/10.3329/jsf.v8i1-2.14635.
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Forty four isolates of Phomopsis vexans from different eggplant cultivars collected from core eggplant growing regions of Bangladesh which were characterized using mycological characteristics. Variation exists among the isolates of Phomopsis vexans of Bangladesh covering two types of farm having two ecosystems and the isolates were grouped into five distinct groups based on their cultural properties. The highest sized ? conidia were observed in group -1 and the lowest size in-group -2. The highest sized ? conidia were recorded in group -5 and the lowest in-group 2. The highest pycnidial size noted in-group -3 and the smallest sized pycnidia were recorded in group 1. DOI: http://dx.doi.org/10.3329/jsf.v8i1-2.14635 J. Sci. Foundation, 8(1&2): 123-130, June-December 2010
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Pnini-Cohen, S., A. Zilberstein, S. Schuster, A. Sharon i Z. Eyal. "Elucidation of Septoria tritici × Wheat Interactions Using GUS-Expressing Isolates". Phytopathology® 90, nr 3 (marzec 2000): 297–304. http://dx.doi.org/10.1094/phyto.2000.90.3.297.
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Isolate ISR398 of Septoria tritici (which produces none to few pycnidia on the wheat cv. Seri 82 and high coverage on cv. Shafir) and isolate ISR8036 (which is virulent on both cultivars) were genetically cotrans-formed using the selectable marker gene hph, which confers resistance to hygromycin B (hygB), and the reporter gene uidA, encoding β-glucuronidase (GUS). Most of the genetically transformed isolates (98.8%) produced similar pycnidial coverage on seedlings of ‘Seri 82’ and ‘Shafir’ as the two wild-type isolates. Southern analysis of 25 randomly selected hygBRGUS+ transformants probed with the uidA sequence revealed multiple insertion sites. GUS activity was determined fluorimetrically by measuring the conversion of 4-methylumbelliferyl β-D-glucuronide (MUG) to 4-methylumbelliferone (MU). The high GUS-expressing transformants 398D97 and 8036E27 were used to elucidate fungal development within inoculated leaf tissue by using GUS activity to estimate the fungal proteins content in planta. Increase in fungal biomass was recorded in ‘Shafir’ inoculated with the GUS-expressing transformants 398D97 and 8036E27 following a 12-day latent period. A 15-day latent period was recorded in ‘Seri 82’ inoculated with 8036E27, whereas an 18-day latent period was recorded on ‘Seri 82’ inoculated with 398D97 and the two mixtures 398D97 + ISR8036 and ISR398 + 8036E27. The rate of fungal development and the estimated level of fungal proteins at the pycnidia maturation stage was high in leaves of ‘Shafir’ and moderate to low on ‘Seri 82’, even in cases in which no significant differences were recorded in pycnidial coverage. An endogenous capacity to hydrolyze β-1,4-D-glucuronidase was recorded in leaves inoculated with wild-type isolates. The latent periods in MU production of the uidA-expressing transformants mimicked those recorded for the wild-type isolates. However, at all stages, the levels of MU produced in wheat inoculated with wild-type isolates were markedly lower than those produced by GUS-expressing transformants. The mode of interaction (compatible or incompatible) determined the onset of the induction, rate, and level of enzyme production.
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Rai, Barun, Sekhar Bandyopadhyay, Avisak Thapa, Adeetya Rai i Deewakar Baral. "Morphological and cultural characterization of Phyllosticta zingiberi (Ramkr.) causing leaf spot disease of ginger". Journal of Applied and Natural Science 9, nr 3 (1.09.2017): 1662–65. http://dx.doi.org/10.31018/jans.v9i3.1418.
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Isolation of ginger (Zingiber officinale) leaf spot pathogen form the UBKV farm field was done in the laboratory. The isolated pathogen was identified as Phyllosticta zingiberi on the basis of morphological characters as documented in taxonomic keys. The microscopic observation revealed that the pycnidia were globose to subglobose with dark brown colour measuring 124.16 μm × 2.35 μm in average. The pycnidio spores were hyaline, oval to bullet shaped, monoguttulate measuring 4.02 μm × 2.35 μm in average. Among the different media tested for growth highest growth was recorded in Oat meal agar (26.44 cm2) followed by malt extract agar (24.04 cm2) which was statistically at par. The temperature of 25˚C favoured maximum growth (24.20 cm2). However, higher sporulation was observed in 30˚C. Among the different carbon source tested, mannitol supported the highest growth of the pathogen (27.67 cm2).
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Arciuolo, Roberta, Marco Camardo Leggieri, Giorgio Chiusa, Giuseppe Castello, Giuseppe Genova, Nicola Spigolon i Paola Battilani. "Ecology of Diaporthe eres, the causal agent of hazelnut defects". PLOS ONE 16, nr 3 (10.03.2021): e0247563. http://dx.doi.org/10.1371/journal.pone.0247563.
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Diaporthe eres has been recently reported as the causal agent of hazelnut defects, with characteristic brown spots on the kernels surface and internal fruit discoloration. Knowledge regarding the ecology of this fungus is poor but, is critical to support a rationale and effective hazelnut crop protection strategy. Therefore, a study was performed to describe and model the effect of different abiotic factors such as temperature (T, 5–35°C, step 5°C) and water activity (aw 0.83–0.99, step 0.03) regimes on D. eres mycelial growth, pycnidial conidiomata development and asexual spore production during a 60-day incubation period. Alpha conidia germination was tested in the same T range and at different relative humidities (RH = 94, 97 and 100%) over 48 h incubation period. Fungal growth was observed from the first visual observation; regarding pycnidia and cirrhi, their development started after 8 and 19 days of incubation, respectively and increased over time. The optimum T for growth was 20–25°C and for pycnidia and cirrhi development was 30°C; aw ≥ 0.98 was optimal for the tested steps of the fungal cycle. The best condition for conidial germination of D. eres was at 25°C with RH = 100%. Quantitative data obtained were fitted using non- linear regression functions (Bete, logistic and polynomial), which provided a very good fit of the biological process (R2 = 0.793–0.987). These functions could be the basis for the development of a predictive model for the infection of D. eres of hazelnuts.
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Stanosz, G. R., i G. W. Moorman. "Branch Dieback of Savin Juniper in Pennsylvania Caused by Diplodia mutila". Plant Disease 81, nr 1 (styczeń 1997): 111. http://dx.doi.org/10.1094/pdis.1997.81.1.111a.
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Branch dieback of savin juniper (Juniperus sabina L.) was observed on a tree in Dauphin County, PA, in May 1996. The symptomatic tree was in an ornamental planting that had been established approximately 10 years previously. Branches were cankered and girdled, causing yellowing and death of foliage beyond the cankers. Black pycnidia occurred in necrotic bark of cankers. Dark, two-celled conidia obtained from these pycnidia produced pure cultures of Diplodia mutila (Fr.:Fr.) Mont., the anamorph of Botryosphaeria stevensii Shoemaker. The fungus was identified based on pycnidial, conidial, and cultural characteristics, and comparison with known isolates provided by N. A. Tisserat (2). Pathogenicity of a single conidial isolate from Pennsylvania was tested in a greenhouse by wounding and inoculating twigs of potted eastern red cedar (Juniperus virginiana L.) with water agar plugs colonized by mycelium. Cankers formed and enlarged to girdle and kill the inoculated shoots, from which the pathogen was reisolated. No symptoms developed on, nor was the pathogen isolated from, control twigs. B. stevensii has been reported more frequently on angiosperms, such as apple (Malus Mill.) and oak (Quercus L.), than on gymnosperms. However, a canker disease caused by B. stevensii previously has been reported to affect J. scopulorum Sarg. and J. virginiana in Kansas, Missouri, and Iowa (1,2). References: (1) P. H. Flynn and M. L. Gleason. Plant Dis. 77:210, 1993. (2) N. A. Tisserat et al. Plant Dis. 72:699, 1988.
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Hollingsworth, C. R., i F. A. Gray. "First Report of Brown Root Rot on Alfalfa Caused by Phoma sclerotioides in the Continental United States". Plant Disease 83, nr 11 (listopad 1999): 1071. http://dx.doi.org/10.1094/pdis.1999.83.11.1071a.
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Phoma sclerotioides G. Preuss ex Sacc. (previously named Plenodomus meliloti Dearn. & G.B. Sanford) is associated with root rot and extensive winterkill of leguminous forage crops, such as clover (Trifolium and Melilotus spp.), sainfoin (Onobrychis viciifolia), and alfalfa (Medicago sativa). Winterkill and root rot of irrigated alfalfa were observed for the first time in a field of cv. Multiplier in western Wyoming during the spring of 1996. Dark brown to black, sunken, rotting lesions were noted on upper secondary roots and taproots of dead and living diseased plants. Superficial and embedded beaked pycnidia and pycnosclerotia were observed near root lesions. A Phoma sp. isolated from a diseased plant in Farson, WY, was maintained on potato dextrose and half-strength V8-juice agars. Beaked pycnidia, typical of P. sclerotioides, were observed in culture when grown at 10°C for 2 months. A pathogenicity test was performed on cv. Multiplier. Two barley seeds colonized by a Phoma sp. derived from a Wyoming isolate were positioned on taproots of healthy, greenhouse-grown, 5-month-old plants ≈2.5 cm below the crown and were covered with a small piece of sterile cotton. Three replicate samples (24 plants inoculated and 24 plants uninoculated per replicate) were winter-hardened for 4 weeks (15.6°C/10°C, day/night, for 2 weeks, followed by 10°C/7.2°C, day/night, for 2 weeks) and placed outside during January 1998 in Laramie, WY, for a 4-month winter exposure period. Plants were rated for disease during June 1998. A disease severity rating of 1 to 5 was assigned to each experimental unit, where 1 = no disease and 5 = dead plant. The percentage of diseased plants at each severity rating for all inoculated plants was 1 = 19%, 2 = 33%, 3 = 31%, 4 = 13%, and 5 = 4%. Mycelium typical of P. sclerotioides was found on 99% of inoculated plant roots whether or not they had pycnidia. Pycnidia were found on the lower stems and petioles of some inoculated plants. Three percent of control plants also developed brown root rot (BRR) symptoms (taproot lesions or discoloration) by June 1998. The percentage of diseased plants at each severity rating for all uninoculated plants was 1 = 96%, 2 = 4%, and 3 through 5 = 0%. Aboveground propagule placement likely contributed to the spread of BRR by raindrop splash and wind-driven plant debris to adjacent alfalfa. Most inoculated plants had immature pycnidia or protopycnidia (94%), whereas 6.9% of the plants also had fully mature, beaked pycnidia. Pure fungal cultures were obtained from several diseased roots and compared with the original Wyoming Phoma sp. culture and a Canada isolate of P. sclerotioides (ATCC no. 56515) (2): colony, pycnidial, and conidial morphologies were identical, completing Koch's postulates. This is the first report of BRR on alfalfa in the continental United States. References: (1) J. G. N. Davidson. 1990. Brown root rot. Pages 29–31 in: Compendium of Alfalfa Disease. 2nd ed. The American Phytopathological Society, St. Paul, MN. (2) C. R. Hollingsworth et al. Phytopathology 88(suppl.):S39, 1999.
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Galper, S., A. Sztejnberg i N. Lisker. "Scanning electron microscopy of the ontogeny of Ampelomyces quisqualis pycnidia". Canadian Journal of Microbiology 31, nr 10 (1.10.1985): 961–64. http://dx.doi.org/10.1139/m85-181.
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Observations on Ampelomyces quisqualis disclosed that the pycnidium may originate either from one cell of a single pycnidiospore, or from one hyphal cell. In the first case the pycnidiospore becomes two celled and swollen and a profuse germination of one of the two swollen spore cells can be observed. Later, the short hyphae branches, interweave, and anastomose to form a compact network around the mother spore, the pycnidium primordium. Similarly, we observed profuse branching in a single hyphal cell. The newly formed branches interweave and anastomose to form a compact network which gives rise to the pycnidium primordium. Hyphal rings were also observed throughout this study, but no pycnidia arose from these structures. During the vegetative growth of the fungus, hyphal anastomosis seems to be a frequent pattern. It seems that the pycnidial ontogeny of A. quisqualis does not conform to any known developmental type.
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Muntañola-Cvetković, M., Jelena Vukojević i M. Mihaljčević. "Pathohistology of sunflower stems attacked by Diaporthe helianthi". Canadian Journal of Botany 67, nr 4 (1.04.1989): 1119–25. http://dx.doi.org/10.1139/b89-146.
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Nearly 7000 histological preparations of sunflower plant parts attacked by the holomorph Diaporthe helianthi – Phomopsis helianthi Munt.-Cvet., Mihaljčević et Petrov have been examined since 1980. After foliar infection the hyphae progress through the vascular system and then spread to invade other tissues. Hyphal masses that form in the host cortex represent pycnidial primordia. When fully differentiated the pycnidia expand towards the host periphery and rupture the epidermis. The stem cankers with the conidiomata of the fungus represent an advanced stage of pathogenesis. The nuclear phase change of the fungus occurs in the host pericycle, beneath the endodermis. Ascogonia can be observed beginning in the autumn; their development into protoperithecia and perithecia takes place slowly and unevenly during the subsequent months. Perithecial maturation in spring, when ascospores are abundantly released, must coincide with the onset of host vegetation to satisfy the nutritional needs of the anamorphic, parasitic phase of the fungus. Exceptions to this general scheme have been observed, with ascospore maturation occurring during the winter months.
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Madar, Z., Z. Solel i M. Kimchi. "First Report of Cytospora Canker Caused by Cytospora chrysosperma on White Poplar in Israel". Plant Disease 88, nr 2 (luty 2004): 220. http://dx.doi.org/10.1094/pdis.2004.88.2.220c.
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A new disease, causing death of mature white poplar trees (Populus alba L.), was observed in Hulla Valley in northern Israel in the summer of 2002. The affected branches turned yellowish brown, and the inner bark turned black. The bark dried out and separated from the underlying wood. Later, copious, dark pycnidia developed on the dead bark. The pycnidia had a diameter of 650 µm (n = 50), ranging 600 to 800 µm. Under moist conditions, spore masses oozed out in long, reddish brown, coiled tendrils. The spores were hyaline, one-celled, and slightly curved, 1.1 × 5.5 µm (5.0 to 6.0 µm) (n = 100), and somewhat smaller than those reported by Schreiner (1). A herbarium specimen was deposited at the U.S. National Fungus Collections (BPI 843390). Isolations made from affected branches yielded colonies of Cytospora chrysosperma (Pers.:Fr.)Fr. with a whitish orange mycelium that turned dark green 11 days later. Its growth rate on potato dextrose agar at 25°C was 7.1 mm per day. Exposure to daylight induced pycnidial development after 3 to 4 weeks. Inoculation of eight 1-year-old seedlings of white poplar and willow (Salix acmophylla Boiss) proved the pathogenicity of several isolates of C. chrysosperma. The average canker length at 28 days after inoculation was 28.0 and 14.5 cm on white poplar and willow, respectively, indicating the higher susceptibility of P. alba. No cankers developed on the control seedlings. Reisolations from inoculated plants yielded C. chrysosperma. To our knowledge, this is the first report of Cytospora canker on white poplar in Israel. Reference: (1) E. J. Schreiner. Am. J. Bot.18:1, 1931.
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Onesti, G., E. González-Domínguez i V. Rossi. "Production of Pycnidia and Conidia by Guignardia bidwellii, the Causal Agent of Grape Black Rot, as Affected by Temperature and Humidity". Phytopathology® 107, nr 2 (luty 2017): 173–83. http://dx.doi.org/10.1094/phyto-07-16-0255-r.
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Black rot, caused by the fungus Guignardia bidwellii, is a polycyclic disease affecting grape leaves and berries. In environmentally controlled experiments and in a 3-year field study, the effects of temperature and relative humidity (RH) were assessed on the following growth parameters of G. bidwellii: (i) formation of pycnidia and cirri in grape leaf lesions, (ii) production and germination of conidia, and (iii) length of the period between lesion appearance and pycnidia production. Pycnidia were produced between 5 and 35°C and at 90 to 100% RH but more pycnidia were produced between 20 and 30°C. No pycnidia were produced at RH < 90%. The first pycnidia were produced in approximately 2 days after lesion appearance at ≥20°C and in 8 days at 5°C; pycnidia continued to be produced on the same lesion for 5 to 16 days after lesion appearance, depending on the temperature. Models were developed to describe the effect of temperature and RH on pycnidia production, accounting for 95 and 97% of variability, respectively. Cirri were extruded only between 15 and 35°C and mainly at 100% RH. Field experiments confirmed that pycnidia are produced for several days on a leaf lesion and that the length of the period between lesion appearance and pycnidia production depends on temperature. Overall, the findings showed that production of conidia requires high humidity; under field conditions, some hours at high humidity, which usually occur at nighttime, rather than constant high humidity may be sufficient.
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Stewart, Ethan L., i Bruce A. McDonald. "Measuring Quantitative Virulence in the Wheat Pathogen Zymoseptoria tritici Using High-Throughput Automated Image Analysis". Phytopathology® 104, nr 9 (wrzesień 2014): 985–92. http://dx.doi.org/10.1094/phyto-11-13-0328-r.
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Zymoseptoria tritici, causal agent of Septoria tritici blotch on wheat, produces pycnidia in chlorotic and necrotic lesions on infected leaves. A high-throughput phenotyping method was developed based on automated digital image analysis that accurately measures the percentage of leaf area covered by lesions (PLACL) as well as pycnidia size and number. A seedling inoculation assay was conducted using 361 Z. tritici isolates originating from a controlled cross and two different winter wheat cultivars. Pycnidia size and density were found to be quantitative traits that showed a continuous distribution in the progeny. There was a weak correlation between pycnidia density and size (r = −0.27) and between pycnidia density and PLACL (r = 0.37). There were significant differences in PLACL and pycnidia density on resistant and susceptible cultivars. In all, >20% of the offspring exhibited significantly different pycnidia density on the two cultivars, consistent with host specialization. Automated image analysis provided greater accuracy and precision compared with traditional visual estimates of virulence. These results show that digital image analysis provides a powerful tool for measuring differences in quantitative virulence among strains of Z. tritici.
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Lalancette, N., i D. M. Robison. "Seasonal Availability of Inoculum for Constriction Canker of Peach in New Jersey". Phytopathology® 91, nr 11 (listopad 2001): 1109–15. http://dx.doi.org/10.1094/phyto.2001.91.11.1109.
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The seasonal sporulation ability of Phomopsis amygdali was evaluated over a 2-year period by sampling twig cankers from commercial ‘Encore’ and ‘Jerseyglo’ peach orchards. Canker size, pycnidia per canker, percent pycnidia forming cirri, and spore production were evaluated once each month from January 1997 through December 1998. Average canker size and number of pycnidia per canker, which followed a sinusoidal pattern of change, were at lowest values in spring and at maximum values in fall. In 1997, the ability of pycnidia to sporulate (produce cirri) increased significantly from a minimum during winter to a maximum during summer. In contrast, pycnidia sporulation in 1998 increased slowly throughout the year with a maximum in the fall. Inoculum potential, measured as number of spores per canker, peaked between June and August and was lowest in winter. Although pycnidia numbers in 1997 were about 50% of that observed in 1998, approximately twice as many conidia per canker were produced in 1997; consequently, the number of conidia produced per canker was equivalent in both years. These results indicated that P. amygdali acts as an r strategist by maintaining abundant pycnidia and sporulation capability throughout much of the year. Therefore, infection is most likely not limited by the availability of inoculum.
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Kema, G. H. J., i J. G. Annone. "In vitro production of pycnidia by Septoria tritici". Netherlands Journal of Plant Pathology 97, nr 2 (marzec 1991): 65–72. http://dx.doi.org/10.1007/bf01974270.
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Amponsah, N. T., E. E. Jones, H. J. Ridgway i M. V. Jaspers. "Production of Botryosphaeria species conidia using grapevine green shoots". New Zealand Plant Protection 61 (1.08.2008): 301–5. http://dx.doi.org/10.30843/nzpp.2008.61.6840.
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Methods for producing large numbers of conidia were developed to allow investigation of the pathogenicity of five Botryosphaeria species (B lutea B australis B obtusa B parva and B stevensii) previously isolated from symptomatic grapevines Pycnidium formation of all five species was low on five mycological media tested Further any pycnidia produced on the media contained few conidia An alternative method was developed whereby grapevine green shoots were infected with Botryosphaeria species the lesions air dried and then induced to sporulate under moist conditions Botryosphaeria australis B lutea and B stevensii produced abundant pycnidia oozing conidia within 36 h The air dried stem pieces could still produce pycnidia that oozed conidia after 3 months of storage at room temperature Botryosphaeria parva produced few pycnidia that did not release any conidia Botryosphaeria obtusa lesions were small and restricted to the inoculation point with only a few pycnidia and conidia being produced
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Stajić, Mirjana, Jelena Vukojević i Sonja Duletić-Laušević. "DEVELOPMENT OF REPRODUCTIVE STRUCTURES OF Phomopsis helianthi Munt.-Cvet. et al. AND Phoma macdonaldii Boerema ON SUNFLOWER SEEDS / DESARROLLO DE ORGANOS REPRODUCTIVOS DE Phomopsis helianthi Munt.-Cvet. et al. Y Phoma macdonaldii Boerema EN LAS SEMILLAS DE GIRASOL / DÉVELOPPEMENT DES ORGANES REPRODUCTEURS DU Phomopsis helianthi Munt.-Cvet. et al. ET DE Phoma macdonaldii Boerema SUR LES ACHÈNES DE TOURNESOL". HELIA 24, nr 34 (lipiec 2001): 83–94. http://dx.doi.org/10.1515/helia.2001.24.34.83.
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SUMMARY We investigated possibilities for the formation of reproductive structures of important sunflower pathogens, Phomopsis helianthi and Phoma macdonaldii, on the husk and kernels of naturally infected and inoculated seeds. Pycnidia were typically formed at the wider part of the husk in all sunflower lines and hybrids infected by P.helianthi and/or P.macdonaldii, partly immersed in the epidermis. The pycnidia of P.macdonaldii were larger than the pycnidia of P.helianthi. The kernels infected by P.helianthi showed slight structural changes in comparison with the non-infected achenes. An exception were the seeds of a line which, on infection by P.helianthi, showed a complete disintegration of the central part of the cotyledon while numerous pycnidia formed in the outer layers of the parenchyma. Seeds of lines infected by P.macdonaldii were considerably damaged. The cotyledonary tissue was disintegrated and pycnidia arranged in rows formed in the outer layers of the parenchyma.
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Stenroos, Soili. "Configuration and location of pycnidia in the lichen genus Cladonia section Perviae". Nova Hedwigia 66, nr 3-4 (19.05.1998): 457–62. http://dx.doi.org/10.1127/nova.hedwigia/66/1998/457.
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Monte, E., P. M. Martin i I. García-Acha. "Pycnidial development in Phoma betae". Mycological Research 92, nr 3 (kwiecień 1989): 369–72. http://dx.doi.org/10.1016/s0953-7562(89)80082-6.
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Janex-Favre, M. C., A. Parguey-Leduc i F. Jailloux. "The ontogeny of pycnidia of Guignardia bidwellii in culture". Mycological Research 97, nr 11 (listopad 1993): 1333–39. http://dx.doi.org/10.1016/s0953-7562(09)80166-4.
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Sérusiaux, E., B. J. Coppins, P. Diederich i C. Scheidegger. "Fellhanera gyrophorica, a new European species with conspicuous pycnidia". Lichenologist 33, nr 4 (lipiec 2001): 285–89. http://dx.doi.org/10.1006/lich.2001.0328.
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AbstractFellhanera gyrophorica Sérus., Coppins, Diederich & Scheidegger is described as new from Europe Austria, Lithuania, Luxembourg, Poland, Switzerland and Ukraine. It is a sterile corticolous species with conspicuous and sometimes shortly stalked pycnidia whose outer walls produce gyrophoric acid. Its position in the genus Fellhanera (Pilocarpaceae) is tentative and further studies may necessitate its transfer to another genus.
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Xiao, C. L., Y. K. Kim i R. J. Boal. "Sources and Availability of Inoculum and Seasonal Survival of Sphaeropsis pyriputrescens in Apple Orchards". Plant Disease 98, nr 8 (sierpień 2014): 1043–49. http://dx.doi.org/10.1094/pdis-12-13-1218-re.
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Sphaeropsis pyriputrescens is the cause of Sphaeropsis rot, a recently reported postharvest fruit rot disease of apple. Infection of apple fruit by the fungus is believed to occur in the orchard, and symptoms develop during storage or in the market. S. pyriputrescens also is the cause of a twig dieback and canker disease of apple and crabapple trees. To determine sources of pathogen inoculum in the orchard, twigs with dieback and canker symptoms, dead fruit spurs, dead bark, and fruit mummies on the trees were collected and examined for the presence of pycnidia of S. pyriputrescens. To monitor inoculum availability during the growing season from early May to early November, dead fruit spurs or twigs from Fuji trees, and twigs with dieback from crabapple trees (as a source of pollen for apple production) in a Fuji orchard as well as dead fruit spurs and dead bark from Red Delicious trees in a Red Delicious orchard were sampled periodically and examined for the presence and viability of pycnidia of S. pyriputrescens. To determine seasonal survival and production of pycnidia of the fungus on twigs, apple twigs were inoculated in early December, sampled periodically for up to 12 months after inoculation, examined for the presence of pycnidia, and subjected to isolation of the fungus from diseased tissues to determine its survival. Pycnidia of S. pyriputrescens were observed on diseased twigs, dead fruit spurs and bark, and mummified fruit on both apple and crabapple trees, suggesting that these tissues were the sources of inoculum for fruit infection in the orchard. With the combined observations from two orchards during three growing seasons, viable pycnidia of the fungus were present throughout the year and observed in 50 to 100% of the Fuji trees, >90% of crabapple trees, and 0 to 50% of the Red Delicious trees. S. pyriputrescens was recovered from diseased tissues of inoculated twigs at all sampling times up to 12 months after inoculation. The results suggest that S. pyriputrescens can survive as mycelium in diseased twigs in north-central Washington State and that availability of viable S. pyriputrescens pycnidia is unlikely a limiting factor for infection of apple fruit in the orchard leading to Sphaeropsis rot during storage.
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Fernando, W. G. D., K. Ghanbarnia i M. Salati. "First Report on the Presence of Phoma Blackleg Pathogenicity Group 1 (Leptosphaeria biglobosa) on Brassica napus (Canola/Rapeseed) in Iran". Plant Disease 91, nr 4 (kwiecień 2007): 465. http://dx.doi.org/10.1094/pdis-91-4-0465a.
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Canola/rapeseed (Brassica napus L.) is a new crop in Iran, grown since 1996. In 2006, 180,000 ha were planted. During the same year, leaf and upper stem lesions (3) were observed on cv. Hyola 401 at rosette and flowering stages in the Gorgan Province in northern Iran. Field disease incidence ranged from 1 to 40%. Several isolates from stem lesions were sent to the Department of Plant Science, Blackleg Research Lab, University of Manitoba, Canada from the Agricultural and Natural Resources Research Center of Golestan Province of Iran for pathogenicity group identification. The blackleg pathogen is divided into several pathogenicity groups on the basis of phenotypic interaction (IP) of isolates on differential cvs. Westar, Glacier, and Quinta. Isolates PG2, PG3, PG4, and PGT are highly virulent, but PG1, which recently has been named Leptosphaeria biglobosa (2), is weakly virulent. Colonies of the blackleg pathogen were reisolated from their original medium, potato dextrose agar, and grown onV8 agar medium and incubated under light for 2 weeks. Pure cultures of the pathogen were then characterized by colony morphology, pycnidia, and measurement and microscopic observation of pycnidio-spores. Fungal colonies formed with concentric rings containing pycnidia with pink ooze on V8 agar. Pycnidia were globose and as much as 200 μ 200 μm. They had a prominent beak on the ascomata that was enlarged, cylindrical, central, terete, erect, and 150 to 200 × 100 μm. Pycnidiospores were cylindrical, straight, 4 to 5 × 2 μm, and hyaline (2). To identify the pathogenicity group of the Iranian isolates, pycnidiospores were harvested from single-spore cultures after 14 days of incubation under continuous cool-white fluorescent light (1). One-week-old cotyledons from the differential cvs. Westar, Glacier, and Quinta were inoculated with pycnidiospore suspension concentration of 2 × 107 spores per ml of the four Iranian isolates. Each cotyledon lobe was punctured with forceps and inoculated with a 10-μl droplet of spore suspension. Disease evaluations were made 10 to 14 days after inoculation using a 0 to 9 rating scale. Inoculations were repeated twice with identical results yielding only the PG1 type reaction. To our knowledge, this is the first report of the presence of L. biglobosa (PG1; B-type) on canola in Iran. Differential testing fulfilled Koch's postulates. L. biglobosa seems to be less damaging compared with L. maculans, but severe phoma stem lesion epidemics have been associated with the L. biglobosa in Poland (3). The importance of this weakly virulent pathogen, whenever the relative humidity increases, has been demonstrated in greenhouse conditions (A. El-Hadrami, W. G. D. Fernando, and F. Daayf, unpublished data). Since the relative humidity in northern Iran is high, an epidemic may occur if appropriate management practices are not utilized to minimize inoculum levels. References: (1) W. G. D. Fernando and Y. Chen. Plant Dis. 87:1268, 2003. (2) R. A. Shoemaker and H. Brun. Can. J. Bot. 79:412, 2003. (3) J. S.West et al. Plant Pathol. 48:161, 2001.
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Huhndorf, Sabine M., i Dean A. Glawe. "Pycnidial Development from Ascospores ofFenestella Princeps". Mycologia 82, nr 5 (wrzesień 1990): 541–48. http://dx.doi.org/10.1080/00275514.1990.12025926.
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CZARNOTA, Paweł, i Brian J. COPPINS. "A new Bacidia with long-necked pycnidia from Central Europe". Lichenologist 38, nr 5 (22.08.2006): 407–10. http://dx.doi.org/10.1017/s0024282906005986.
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Bacidia pycnidiata sp. nov. (Ramalinaceae) is described from Poland and the Czech Republic. It is the first species within Bacidia s. lat., referable to the Bacidina group, known to have sessile, long-necked, lageniform pycnidia bearing straight macroconidia. It has been found growing on saxicolous as well as on corticolous bryophytes and directly on bark of deciduous trees within young, hardly changed woodlands or in the vicinity of human settlements.
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Ekundayo, C. A. "Sodium inhibition of formation of pycnidia of Lasiodiplodia theobromae PAT". Zeitschrift für allgemeine Mikrobiologie 15, nr 1 (24.01.2007): 63–65. http://dx.doi.org/10.1002/jobm.19750150111.
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Choi, Kihyuck, i Stephen M. Marek. "Unique gene Pmhyp controlling melanization of pycnidia in Phoma medicaginis". Fungal Genetics and Biology 125 (kwiecień 2019): 53–59. http://dx.doi.org/10.1016/j.fgb.2019.01.007.
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Ma, J., C. B. Hill i G. L. Hartman. "Production of Macrophomina phaseolina Conidia by Multiple Soybean Isolates in Culture". Plant Disease 94, nr 9 (wrzesień 2010): 1088–92. http://dx.doi.org/10.1094/pdis-94-9-1088.
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Macrophomina phaseolina is the cause of charcoal rot of soybean (Glycine max). Resistance to M. phaseolina in commercial soybean cultivars is not common but is needed in locations where the disease is chronic and severe. The objective of this study was to develop a reliable method to produce sufficient M. phaseolina conidia that can be used to inoculate soybean plants in a high-throughput resistance-screening program. Production of pycnidia is not common on most culture media, such as potato dextrose agar, but can be produced on media containing plant parts or oilseed extracts. Seven semi-defined media were tested to induce pycnidia production. Results indicated that the number of pycnidia that were produced by eight M. phaseolina isolates was dependent on induction medium; however, peanut butter extract-saturated filter paper placed over soynut butter extract agar (PESEA) allowed for greater pycnidia and conidia production than the other media tested. Production of pycnidia on PESEA ranged from 269 to 1,082 per plate. There were no differences among isolates in germination of conidia produced on PESEA, which averaged 83 ± 2% germination. A conidial suspension from one M. phaseolina isolate produced on PESEA and inoculated onto soybean radicles significantly distinguished (P < 0.01) ‘DT97-4290’, a soybean genotype with partial resistance to charcoal rot, from a susceptible genotype, ‘LS98-0358’. Results of this study indicated that multiple isolates of M. phaseolina from soybean produced sufficient amounts of conidia on PESEA to use as inoculum. This conidia inoculum production method will facilitate soybean charcoal rot resistance screening evaluation with different soybean isolates.
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Wiseman, M. S., Y. K. Kim, F. M. Dugan, J. D. Rogers i C. L. Xiao. "A New Postharvest Fruit Rot in Apple and Pear Caused by Phacidium lacerum". Plant Disease 100, nr 1 (styczeń 2016): 32–39. http://dx.doi.org/10.1094/pdis-02-15-0158-re.
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During surveys for postharvest diseases of apple and pear, an unknown postharvest fruit rot was observed in Washington State. The disease appeared to originate from infection of the stem and calyx tissue of the fruit or wounds on the fruit. An unknown pycnidial fungus was consistently isolated from the decayed fruit. Isolates from apple and pear were characterized and identified by molecular phylogenetic analysis and morphology. Pathogenicity of representative isolates on apple and pear fruit was tested under laboratory or field conditions. A BLAST search in GenBank showed that isolates differed from Phacidium lacerum and its synonym, Ceuthospora pinastri, by only 0 to 4 bp in sequences within part of the combined large ribosomal subunit + internal transcribed spacer + small ribosomal subunit regions. The phylogenetic analysis confirmed the taxonomic placement of the unknown fungus in the genus Phacidium, with the highest match being C. pinastri (formerly anamorphic P. lacerum) and with closely related taxa from GenBank forming congeneric clades. The fungus grew at 0 to 30°C and formed unilocular to multilocular pycnidial conidiomata on artificial media after approximately 5 to 7 days at room temperature. On potato dextrose agar incubated for a 12-h photoperiod, semi-immersed globose to subglobose pycnidial conidiomata were 250 to 1,000 μm in diameter (mean = 350), with 1 to 3 nonpapillate to slightly papillate ostioles and a buff conidial matrix. Conidia produced on phialides were 8 to 13 by 1.5 to 2.5 μm, hyaline, aseptate, cylindrical, with an abruptly tapered, typically slightly protuberant base, 2 to 3 guttules, and sometimes with a mucilaginous, flexuous, unbranched appendage which is attached to the apex of the conidium and disappears with age. Conidiogenous cells were flask shaped and 6 to 15 ×1.5 to 3 μm. Colony characteristics included felt-like aerial white mycelium, gray olivaceous at the center becoming greenish to colorless toward the margin, in concentric rings, with pycnidia forming in 5 to 7 days originating from the center of the plate. Morphological characteristics of the fungus had the greatest conformity with the description for C. pinastri. Based on molecular and morphological data, the fungus is identified as P. lacerum. ‘Fuji’ apple fruit and ‘d’Anjou’ pear fruit that were wounded, inoculated with representative isolates, and incubated at 0°C yielded the same symptoms as seen on decayed fruit collected from commercial fruit packinghouses. Stem-end rot, calyx-end rot, and wound-associated rot developed on fruit inoculated in the orchard after 3 months of cold storage. The fungus was reisolated from the diseased fruit. This is the first report of a fruit rot in apple and pear caused by P. lacerum. We propose Phacidium rot as the name of this disease.
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Khangura, R., i M. Aberra. "Strains of Leptosphaeria maculans with the Capacity to Cause Crown Canker on Brassica carinata are Present in Western Australia". Plant Disease 90, nr 6 (czerwiec 2006): 832. http://dx.doi.org/10.1094/pd-90-0832a.
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Blackleg, caused by Leptosphaeria maculans (Desm.) Ces. et de Not., is the most important disease of canola (Brassica napus L.) in Australia, Europe, Canada, and North America (2). During the early 1990s, new cultivars of canola with resistance to blackleg were released in Australia. Despite good adult-plant resistance, these cultivars still suffered significant yield losses from blackleg under high disease pressure. Potential new sources of blackleg resistance such as B. nigra L., B. carinata L., and Sinapis alba L. are being evaluated. B. carinata is believed to be highly resistant to blackleg by virtue of its B-genome. However, some L. maculans isolates that can attack B. carinata have been reported from Germany (1). During the 2003 growing season, 22 isolates of L. maculans were collected from different canola-growing areas of Western Australia and tested for their reaction on 24 seedlings of each of various Brassica genotypes, including B. carinata, in a controlled environment chamber. Twenty-four seeds per genotype were sown in 100-ml plastic pots (12 seeds per pot) and both cotyledons of 10-day-old seedlings were wound inoculated with a conidial suspension (1 × 107 conidia/ml) of each isolate of L. maculans. Disease assessments were made 2 weeks after inoculation. The majority of isolates induced a noninvasive hypersensitive reaction on B. carinata without pycnidial development. However, four of the isolates caused lesions with abundant pycnidia on B. carinata cotyledons. The lesion size ranged between 3 and 7 mm and appeared similar to that on susceptible B. napus cultivars. B. carinata seedlings were grown for another 8 weeks in a glasshouse, and crown cankers were observed from plants inoculated with three of the four seedling virulent isolates. The severity of crown cankers as percent of stem circumference (percent disease index) ranged between 20 and 54%. Twenty-five stem pieces from mature B. carinata plants infected with one of the three isolates were plated on V8 juice agar and L. maculans was recovered from 70% of pieces. Abundant pycnidia were also observed on these stem pieces. These results have important implications for using B. carinata as a source of blackleg resistance in canola breeding. To our knowledge, this is the first report of L. maculans isolates with the capacity to induce crown cankers on B. carinata in Australia. References: (1) C. Sjöidin and K. Glimelius. J. Phytopathol. 123:322, 1988. (2) J. West et al. Plant Pathol. 51:454, 2002.
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Li, H., K. Sivasithamparam i M. J. Barbetti. "Breakdown of a Brassica rapa subsp. sylvestris Single Dominant Blackleg Resistance Gene in B. napus Rapeseed by Leptosphaeria maculans Field Isolates in Australia". Plant Disease 87, nr 6 (czerwiec 2003): 752. http://dx.doi.org/10.1094/pdis.2003.87.6.752a.
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Blackleg, caused by Leptosphaeria maculans, is a major disease of oilseed rape (Brassica napus) grown in Canada, Europe, and Australia. Cv. Surpass 400 was released in Australia in 2000 as the most resistant cultivar to L. maculans. It carries a single dominant resistance gene from B. rapa subsp. sylvestris. This cultivar usually shows a hypersensitive response to L. maculans characterized by small, dark brown lesions that are necrotic, localized, and without pycnidia on cotyledons, leaves, and stems. However, in 2001 on a Western Australian experimental farm, a small proportion of the lesions on the lower stem and crown region of cv. Surpass 400 were typical of those observed in susceptible cultivars, which were brown, necrotic lesions with a darker margin, but they contained fewer pycnidia. Forty seedlings of cv. Surpass 400 and susceptible cv. Westar were inoculated with pycnidiospore suspensions (106/ml) of each of 18 isolates taken from lesions on cv. Surpass 400. All 18 isolates caused collapse of cotyledons of susceptible cv. Westar. Four of these isolates caused large cotyledon lesions with some pycnidia on cv. Surpass 400. Three of these four isolates were subsequently inoculated onto 60 seedlings per isolate, at each of the four cotyledon lobes of each seedling of the two cultivars. Inoculated plants were assessed for disease severity on cotyledons and transplanted to the field 14 days after inoculation. The cotyledons of inoculated cv. Surpass 400 showed characteristic large, necrotic lesions with pycnidia, while the cotyledons of cv. Westar had collapsed and contained a mass of pycnidia. Blackleg disease severity in the crown region of the stem was assessed at 2 weeks before harvest. Fifty-four percent of the cv. Surpass 400 transplanted inoculated plants subsequently developed susceptible symptoms of crown cankers on stems. These symptoms were deep, girdling, brown lesions on the plant crowns with some pycnidia. One hundred percent of cv. Westar plants were infected and dead at this stage. This confirmed the ability of these field isolates to overcome the single dominant resistance gene present in cv. Surpass 400. To our knowledge, this is the first report of breakdown of a single dominant B. rapa subsp. sylvestris gene based resistance to blackleg in oilseed rape in the field.
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Zhou, You, Guoshu Gong, Yongliang Cui, Daixi Zhang, Xiaoli Chang, Rongping Hu, Na Liu i Xiaofang Sun. "Identification of Botryosphaeriaceae Species Causing Kiwifruit Rot in Sichuan Province, China". Plant Disease 99, nr 5 (maj 2015): 699–708. http://dx.doi.org/10.1094/pdis-07-14-0727-re.
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Species of Botryosphaeriaceae fungi are important plant pathogens causing cankers, blight, and fruit rot in an extremely wide range of host. In recent years, kiwifruit rot has been a serious problem in Sichuan Province, one of the important kiwifruit production areas of China. Botryosphaeria dothidea has previously been associated with kiwifruit rot but little is known regarding whether other Botryosphaeriaceae genera also constitute kiwifruit rot pathogens in China. Accordingly, diseased fruit were collected from six different areas of Sichuan Province. Based on morphological characteristics, pathogenicity testing, and comparisons of DNA sequences of the internal transcribed spacer, transcription elongation factor 1-α, and β-tubulin genes, 135 isolates of Botryosphaeriaceae were identified as B. dothidea, Lasiodiplodia theobromae, and Neofusicoccum parvum. All of these species were found to cause kiwifruit rot. To understand the infection cycle of kiwifruit rot pathogens, these three species were used to inoculate leaves and shoots of kiwifruit. The results showed that these species could cause spots on leaves and lesions on shoots, producing abundant pycnidia on leaves and shoots surfaces. Moreover, B. dothidea conidia and ascospores from overwintered pycnidia and pseudothecia in kiwifruit orchards in April and August could cause fruit rot and spots on leaves of kiwifruit. Therefore, we concluded that overwintered pycnidia and pseudothecia of B. dothidea in kiwifruit orchards are the primary inoculum for kiwifruit rot, with new pycnidia that develop during the growing season serving as a secondary inoculum. This is the first report of N. parvum and L. theobromae causing kiwifruit rot in China and is also the first report that B. dothidea is able to overwinter as pycnidia and pseudothecia in kiwifruit orchards and serve as the primary inoculum for kiwifruit rot.
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Mondal, S. N., J. P. Agostini, L. Zhang i L. W. Timmer. "Factors Affecting Pycnidium Production of Diaporthe citri on Detached Citrus Twigs". Plant Disease 88, nr 4 (kwiecień 2004): 379–82. http://dx.doi.org/10.1094/pdis.2004.88.4.379.
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Melanose, caused by Diaporthe citri, produces black-to-reddish brown lesions on twigs, leaves, and fruit of citrus and reduces the external quality of fruit destined for the fresh market. Inoculum for infection is produced primarily in pycnidia formed on dead twigs, and conidia are dispersed by rainwater. In laboratory studies, the effect of moisture, temperature, twig size, and melanose severity on pycnidium production on detached twigs was investigated. Pycnidium production was greatest when twigs were soaked for 3 to 4 h on alternate days three times per week and the temperature was 28°C. Production was greatest on twigs 3 to 5 mm in diameter and less on thinner or thicker twigs. Pycnidium production was related linearly to melanose severity on the twigs, and almost no pycnidia were produced on asymptomatic twigs. In the field, pycnidium production was greatest on detached, melanose-affected twigs placed in the canopy monthly during January to April than it was on twigs placed in the canopy during other months. The largest number of pycnidia was produced from May to August when fruit is most susceptible. The number of pycnidia produced was related significantly to degree-days above 20°C and weakly related to cumulative rainfall. Knowledge of inoculum production peaks may assist in timing of pruning and fungicide sprays.
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Huhndorf, Sabine M., i A. Glawe. "Pycnidial Development from Ascospores of Fenestella princeps". Mycologia 82, nr 5 (wrzesień 1990): 541. http://dx.doi.org/10.2307/3760042.
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Holdenrieder, Ottmar, i Tadeusz Kowalski. "Pycnidial formation and pathogenicity in Tubakia dryina". Mycological Research 92, nr 2 (marzec 1989): 166–69. http://dx.doi.org/10.1016/s0953-7562(89)80007-3.
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Mondal, S. N., A. Vicent, R. F. Reis i L. W. Timmer. "Saprophytic Colonization of Citrus Twigs by Diaporthe citri and Factors Affecting Pycnidial Production and Conidial Survival". Plant Disease 91, nr 4 (kwiecień 2007): 387–92. http://dx.doi.org/10.1094/pdis-91-4-0387.
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Melanose, caused by Diaporthe citri, produces reddish brown lesions on the fruit, leaves, and twigs of citrus trees, and greatly reduces the marketability of fresh fruit. Most of the inoculum is produced in pycnidia on dead twigs in the tree canopy, which exude large numbers of conidia in slimy masses. In this study, detached twigs inoculated with conidia were readily colonized and produced large numbers of pycnidia within 30 to 40 days when they were soaked 3 to 4 h on alternate days. Conidial production was measured by wetting twigs in a rain tower periodically and collecting the conidia in the runoff water. Production began after 80 days and continued for nearly 300 days. In other experiments, production of mature pycnidia on detached twigs was greatest at 94 to 100% relative humidity (RH) and at 28°C. Low RH and temperature, however, favored survival of conidia in exuded masses on twigs. In the field, colonization of detached twigs by D. citri was high in rainy season, moderate in spring and early fall, and minimal in late fall and winter. Twig colonization was positively related to the number of rain days and average temperature, but not to total rainfall. In another experiment, inoculated twigs placed in the tree canopy developed pycnidia and then produced conidial masses for about 200 days. D. citri is a serious pathogen, but a weak parasite, that survives primarily by colonization and reproduction on dead twigs.
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Zhao, Xinbei, Yunxia Ni, Xintao Liu, Hui Zhao, Jing Wang, Yung-Chun Chen, Weidong Chen i Hongyan Liu. "A Simple and Effective Technique for Production of Pycnidia and Pycnidiospores by Macrophomina phaseolina". Plant Disease 104, nr 4 (kwiecień 2020): 1183–87. http://dx.doi.org/10.1094/pdis-08-19-1795-re.
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Production of pycnidia and pycnidiospores by Macrophomina phaseolina is not often seen in vitro. The objective of this study is to develop a simple and effective technique to obtain pycnidiospores of M. phaseolina isolates in vitro and to evaluate germination rates and pathogenicity of pycnidiospores. We found M. phaseolina isolates can produce pycnidia on oatmeal agar (OMA) under ultraviolet light with 365 nm wavelength (UV). For evaluating the effect of OMA and UV on growth of M. phaseolina, combinations of two agar media and three lighting conditions were tested. The results confirm that all six M. phaseolina isolates produced pycnidia only on OMA under UV. The pycnidiospores produced on OMA under UV had germination rates higher than 90%. In pathogenicity tests, inoculation with the pycnidiospores showed symptoms later than inoculation with hypha-colonized toothpicks. Significant differences in the pathogenicity is detected between isolates Mp2014003 and Mp2014024 when inoculation is done with the pycnidiospores (P < 0.001), but not when hypha-colonized toothpicks are used as inoculum (P = 0.091). This study provides a new method for obtaining pycnidiospores of M. phaseolina for future investigations.
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Morin, Louise, Alan K. Watson i Richard D. Reeleder. "Production of conidia by Phomopsis convolvulus". Canadian Journal of Microbiology 36, nr 2 (1.02.1990): 86–91. http://dx.doi.org/10.1139/m90-017.
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Various solid-substrate fermentation and shake-flask liquid fermentation systems were investigated as spore production methods for Phomopsis convolvulus, a potential bioherbicide. Among them, "pot" barley grains and modified Richard's (V-8) liquid medium produced 5 × 108 conidia/g and 5 × 106 conidia/mL, respectively. Distinct pycnidia, covering the surface of pot barley grains, produced virulent conidia in a water-soluble mucilage approximately 10 days after seeding the substrate with conidia. In complex liquid media, conidia were produced in pycnidia 3 to 4 days after seeding the media with mature pycnidia or conidia. A negative relationship was demonstrated between inoculum density and yield of conidia in modified Richard's (V-8) liquid culture. Omission of V-8 juice or decrease of the carbon to nitrogen ratio in modified Richard's (V-8) medium inhibited sporulation. Conidia lost viability after 30 days when held at −10 °C in a sucrose solution, but conidia stored at −70 °C remained viable and pathogenic for at least 6 months. Key words: Phomopsis convolvulus, bioherbicide, sporulation.
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Baskarathevan, J., M. V. Jaspers, E. E. Jones i H. J. Ridgway. "Evaluation of different storage methods for rapid and costeffective preservation of Botryosphaeria species". New Zealand Plant Protection 62 (1.08.2009): 234–37. http://dx.doi.org/10.30843/nzpp.2009.62.4825.
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Four Botryosphaeria species isolated from grapevine namely Diplodia seriata (teleomorph B obtusa) Diplodia mutila (teleomorph B stevensii) Neofusicoccum parvum (syn B parva) and Neofusicoccum luteum (syn B lutea) were stored using 11 different methods Duplicate isolates were stored for 1 3 and 6 months as myceliumcolonised agar plugs and pycnidia in sterile water mineral oil 20 glycerol or potato dextrose agar (PDA) at room temperature (RT) 4C or 80C The viability of the four Botryosphaeria species was similar (81100) for all storage methods apart from pycnidia on pine needles at RT (68) but their overall growth rates differed between the storage methods (P
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Kouterick, K. B., J. M. Skelly, S. P. Pennypacker i R. M. Cox. "Birch foliar responses to simulated acidic fog and Septoria betulae inoculations". Canadian Journal of Forest Research 31, nr 3 (1.03.2001): 392–400. http://dx.doi.org/10.1139/x00-181.
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The effects of simulated acidic fog and inoculation with Septoria betulae Pass. on foliar symptom development and foliar senescence of Betula papyrifera Marsh. and Betula cordifolia Regel seedlings were investigated in 1997 and 1998 under greenhouse conditions. An interactive role may exist between acidic fog events and S. betulae in causing birch foliar browning, a disease reported over the past decade to occur on mature trees growing adjacent to the Bay of Fundy, Canada. Seedlings received applications of simulated fog adjusted to pH 3.2, 4.2, and 5.6 or a no-fog treatment. Inoculation treatments at each fog pH level were accomplished through spray atomization with S. betulae conidial suspensions and by placing naturally infected birch leaves bearing pycnidia of the fungus on plastic nets suspended above seedlings in enclosed chambers. Percent symptomatic leaf area of seedlings inoculated with S. betulae was nearly double that recorded for non-inoculated seedlings. Foliar browning resembled symptoms observed on mature trees in the field. Foliar symptoms were observed on non-inoculated seedlings, with greater severities associated with seedlings exposed to the most acidic fog treatment. Leaf senescence was also greatest for spray-inoculated leaves that had been exposed to the pH 3.2 fog treatment. Pycnidial development was not influenced by the pH of the fog treatments but was greater in all fog treatments than in no-fog treatments. Although both acidic fog and S. betulae infection are able to cause symptoms independently, the data suggest that an interactive role may exist in causing birch foliar browning. However, to obtain the same severity of foliar browning as observed on natural forest-grown trees in the Bay of Fundy region, S. betulae must be present.