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Pestalotiopsis sydowiana (Bresadola) Sutton

Mycological Papers 80:14, 1961

Basionym: Pestalotia sydowiana Bresadola, Hedwigia 35: 32 (1896)

Synonyms (after Guba 1961, Sutton 1961, Nag Raj 1993):

• Pestalotia rhododendri (D. Sacc.) Guba, Phytopathology 19: 215 (1929) (non Pestalotia rhododendri Westendorp 1858, nom. nud.)
• Pestalotia epigaeae P. Henning, Notizbl. K. Bot. Gard. Mus. Berlin 3: 40 (1900)
• Pestalotia macrotricha Klebahn, Myc. Centralbl. 4: 6 (1914)
• Pestalotia cavendishiae Chardon & Toro, Journal Dept. Agr. Porto Rico 14: 279 (1930)
• Pestalotia guepini Desm. var. rhododendri Cooke, J. E. Vize, Microf. Brit. 509, 512 (1888, nom. nud.)
• Pestalotiopsis sydowiana (Bresadola) Zhu, Ge & Xu (1991, a redundant combination)

Type

According to Sutton (1961), the type material of P. sydowiana from B and BM is very poor, so that Sutton's description is primarily based on the type of P. rhododendri.

Morphology

Description modified after Guba (1961) and Sutton (1961): Acervuli abundant, epiphyllous on dried, dead leaves or sometimes associated with light discoloured areas, sparse or densely gregarious with frequently confluent, black spore masses which are more scattered and discrete towards the edge of the colony; globose-lenticular and irregularly erumpent, surrounded by torn epidermis, 100-400 µm diam., seated in ash-gray or brownish spots with reddish margins. Conidiophores arise from the upper cells of the stroma, erect, hyaline, obpyriform, 1-3 µm diameter, about 10 µm long, conidiogenesis at the apex, aseptate with normally 1 (-3) proliferation (after liberation of the conidium, the conidiophore proliferates through the apex to form another conidium). Conidia clavate to fusiform, straight, rarely curved, equilateral, 5-celled, smooth-walled, 23.0-29.0 x 8.0-9.5 (-11) µm, mean 25.0 x 9.0 µm. Apical and basal cells hyaline; apical hyaline cells long and broad cylindric; the basal hyaline cells broad-conic. Median three cells colored, guttulate, together 16-20 µm (mean 18 µm) long, slightly or hardly constricted at the septa, the lowest colored cell is light brown, the upper two cells darker brown (fuliginous or umber). The septum separating the two superior cells is very dark brown to almost black. Median cells in total 17-20 µm (mean 18 µm) long. Apical appendages (2-) 3 (-4), divergent or recurved, hyaline, cylindrical with obtuse apices, 18-40 µm long (mean 22 µm). Basal appendage hyaline, straight or slightly curved, 3-6 µm long (mean 4 µm).

The species was not studied by Nag Raj (1993), who refers to Sutton and Guba.

Illustrations

• Guba 1961: 199, Fig. 67.

Biology

The fungus, although regularly occurring as a pathogen of hardy ornamentals, mostly Ericaceae, seems to have a wide host spectrum. On artifical inoculation, it acts as a fruit-rot agent of apples (Wollenweber & Hochapfel, Z. Pflanzenkrankheiten 46: 401

Sutton 1961, confirms for the P. sydowiana that only the lowermost of the three median cells (which is the lightest of the three) is capable of germinating.

Similar species

Pestalotiopsis malicola is a pathogen of Rhododendron and other ornamentals known from Japan; the median three colored cells are together only 13-16 µm long.

Material studied

BBA XXXXX

BBA 72157

a) on the host (moist chamber incubation)

Acervuli on Erica spec. 150-350 µm diameter. Spores 5-celled, median 3 cells always darker, median cells versicolor: usually top 2 cells darker than lower cell, of the top two sometimes topmost and sometimes median cell darkest. All cells smooth-walled. Conidial length (21-) 26.1 (-30.9) (n=12, min/mean/max.); total length of colored three median cells: (12.5-) 15.3 (-18.1) (n=32, min/mean/max.).

Apical appendages 2, 3, or rarely 4; 14-36 µm long; tips not spatulate. Basal appendage present and endogenous, or absent.

BBA 72158

On Calluna vulgaris, Elsass (France); received as strain "Gshm F 103" on PDA from the Forschungsanstalt Geisenheim.

Annotated List of References

Morphology

• Allescher, A. 1903. Kryptogamenflora von Deutschland, Österreich und der Schweiz, Band 7: p. 691

  "4573. Pestalotiopsis sydowiana Bresad. in Hedw. 1896, p. (32). Sacc. et Sydow, Syll. XIV. p. 1027. -- Sporenlager auf der Blattoberseite, punktförmig, schwarz, hervorbrechend, dicht zerstreut, in einem aschgrauen, eckig-buchtigen, roth begrenzten Flecken nistend; Sporen spindelig, 24-26 µ lang, 3 µ dick, mit vier Querwänden, bei denselben kaum eingeschnürt; die mittleren Zellen dunkel-olivenfarbig, die Endzellen hyalin; am Scheitel mit drei geraden oder bogig zurückgekrümmten 24-38 µ langen Borsten; Stiel kurz, hyalin, 5-7 µ lang, 1 µ dick. An lebenden Blättern von Gaultheria procumbens im botanischen Garten zu Berlin (Sydow). Der Pilz scheint der Pestalotia longiseta am nächsten zu stehen."

• Brandenburger, W. 1985. Parasitische Pilze an Gefäßpflanzen in Europa, Gustav Fischer Verlag, p. 469.

  "Flecken aschgrau oder bräunlich, mit rötlichem Rand; Acervuli, oberseits 100-400 µm Durchmesser; Konidien keulenförmig, 5zellig, 23-29 x 8-11 µm, Scheitelzelle hyalin, mit (2-)3(-4), 18-30 µm langen Anhängseln, Basalzelle mit einem, 3-6 µm langen Anhängsel."

• Guba, E. F. 1961. Monograph of Pestalotia and Monochaetia. Harvard University Press. Cambridge Massachusetts USA.

  "Acervuli globose-lenticular, epiphyllous, sparse or densely gregarious, erumpent, surrounded by torn epidermis, 150-300 µm in diameter, seated in ash-gray or brownish spots with reddish margins. Conidia 5-celled, equilateral, fusiform, tapering to both ends, 23-29 x 8-9.5 µm, intermediate colored cells guttulate, 16-19 µm long, slightly or hardly constricted at the septa, the lowest colored cell olivaceous, the upper two darker or umber; apical hyaline cells long and broad cylindric; the basal hyaline cells broad-conic; setulae 3, rarely 4, divergent or recurved, flexuous, 23-40 µm long, pedicels 6-12 µm long. -- On living leaves of Gaultheria procumbens L., Bot. Gard. Berlin, Germany, 1894-95, P. Sydow in Sydow, Mycotheca Marchica No. 4372 (type of P. sydowiana Bres.)"

• Sutton, Brian C. 1961. Mycological Papers, No. 80, Coelomycetes, Part A: Developmental Studies in Pestalotiopsis, Part B: Five Species of Pestalotiopsis.

  "Acervuli abundant, epiphyllous on dried, dead leaves or sometimes associated with light discoloured areas, densely gregarious with frequently confluent, black spore masses which are more scattered and discrete towards the edge of the colony; globose-lenticular and irregularly erumpent, 100-400 µm diam. Conidiophores arise from the upper cells of the stroma, erect, hyaline, obpyriform, 1-3 µm diameter, about 10 µm long, aseptate with up to 3 but normally 1 proliferation. Conidia are formed singly at the apex of the conidiophore which after liberation of the conidium, proliferates through the apex to form another conidium. Conidia clavate, straight, rarely curved, smooth-walled, 5-celled, 23-29 µm(mean 25 µm) long x 8.0-11.0 µm (mean 9.0 µm) wide. Apical and basal cells are hyaline, whilst the 2 superior median coloured cells are dark brown (fuliginous or umber) and the inferior is light brown. The septum separating the two superior cells is very dark brown to almost black. Median cells 17-20 µm (mean 18 µm) long. Apical appendages 2-4, mostly 3, hyaline, cylindrical with obtuse apices, 18-39 µm (mean 22 µm) in length. Basal appendage hyaline, straight or slightly curved, 3-6 µm (mean 4 µm) in length. On dead leaves of Rhododendron hybridum and R. ponticum, Italy, and living leaves of Gaultheria procumbens, Germany. Isolated from Erica caffra, Great Britain."

Phylogenetics

• Jeewon, R., Liew, E. C. Y. Simpson, J. A. Hodgkiss, I. J. & Hyde K. D. 2003. Phylogenetic significance of morphological characters in the taxonomy of Pestalotiopsis species. Molecular Phylogenetics and Evolution 27: 372-383. (doi)

  Based on strains having been previously identified as P. sydowiana and P. rhododendri - which were found to have separate sequences -, they accept both species, but without detailed discussion or reasoning.

• Jeewon, R., Liew, E. C. Y. & Hyde K. D. 2004. Phylogenetic evaluation of species nomenclature of Pestalotiopsis in relation to host association. Fungal Diversity 17: 39-55. [1]

  A strain of P. sydowiana is included, but no mentioning of P. rhododendri.

Biology and Control

• Hopkins, K. E. & McQuilken, M. P. 2000. Characteristics of Pestalotiopsis associated with hardy ornamental plants in the UK. European Journal of Plant Pathology 106: 77–85. (http://www.springerlink.com/index/KJ228340Q3P7P104.pdf)

  The authors studied the pathogenicity of 18 isolates of Pestalotiopsis sydowiana and demonstrated that the isolates were not host-specific and able to infect a wide range of hardy ornamentals.

• McQuilken, M. P. & Hopkins, K. E. 2001. Sources, survival and management of Pestalotiopsis sydowiana on Calluna vulgaris nurseries. Crop Protection 20 (7): 591-597.

• McQuilken, M. P., Litterick, A. M. & Hopkins, K. E. 1997. Evaluation of fungicides against Pestalotiopsis sydowiana on Calluna vulgaris and Rhododendron. Tests of Agrochemicals and Cultivars (18): 20-21.

  (not seen)

• McQuilken, M. P. & Hopkins, K. E. 2004. Biology and integrated control of Pestalotiopsis on container-grown ericaceous crops. Pest Management Science 60 (2): 135-142, (doi)

  They confirm the lack of host specificity for P. sydowiana; report growth optimum temperature of three selected isolates as 20–25 °C, little or no growth < 5 or > 30 °C; optimum acidity at pH 5.5 (max. pH 2.6-8.6). Several disease management methods (irrigation, flooring/pot disinfection and fungicide application) were studied for potted plants of Calluna vulgaris. In addition to fungicide-treatment (five-spray program of alternating Prochloraz and Carbendazim) watering by sub-irrigation compared with watering from overhead was beneficial, as were single and combined treatments of flooring/pot disinfection (hydrogen peroxide/peracetic acid).

• Remlein-Starosta, Dorota 2004 Pestalotiopsis associated with Erica spp. ornamental plants in nurseries near Poznań - increasing problem, Journal of Plant Protection Research, Vol. 44, No. 4 (2004) (http://journals.indexcopernicus.com/fulltxt.php?ICID=446487)

  The source of newly occurring, increasingly damaging infection of ericaceous ornamental plants was identified as Pestalotiopsis sydowiana, newly noted in Poland.