Septoria eferdingensis Plenk – a new Septoria-species on Aesculus hippocastanum
Septoria eferdingensis Plenk – eine neue Septoria-Art an Aesculus hippocastanum
Journal für Kulturpflanzen, 62 (10). S. 383–385, 2010, ISSN 0027-7479, DOI: 10.5073/JfK.2010.10.04, Verlag Eugen Ulmer KG, Stuttgart
Septoria eferdingensis Plenk, a new species collected on Aesculus hippocastanum L. differs from other species of Septoria on this host in the diameter of the pycnidia, length, width and number of septa of the conidia.
Key words: Septoria eferdingensis Plenk, Aesculus hippocastanum L., symptoms, systematics, new species
Septoria eferdingensis Plenk, eine neue Art an Aesculus hippocastanum L. unterscheidet sich von anderen Arten der Gattung Septoria auf diesem Wirt im Durchmesser der Pyknidien, der Länge, Breite und Anzahl der Septen der Konidien.
Stichwörter: Septoria eferdingensis Plenk, Aesculus hippocastanum L., Symptome, Systematik, neue Art
Infections of Septoria on horse-chestnut have been found at Gstöttenau (a small village near Eferding/Upper-Austria) every year since 1995. From literature we know four different Septoria-species occurring on this common tree, Septoria aesculi, S. aesculina, S. aesculicola and S. hippocastani.
All of these fungi cause small, white or grey leafspots, which are scattered all over the leaf surface (Fig. 1, 2). Typically, they are surrounded by a thin red or dark brown margin. In the centre of these spots the pycnidia can be found, often single, up to three at the most (Fig. 3). The pycnidia are visible with the naked eye and are dark brown or black. Via the ostiolum the typical filiform, hyaline conidia (Fig. 4) are set free. The pycnidia occur on both sides of the leaf.
Fig. 1. Symptoms of Septoria eferdingensis on an upper surface of a leaf of Aesculus hippocastanum.
Fig. 2. Symptoms of Septoria eferdingensis on an upper surface of a leaf of Aesculus hippocastanum (part of a leaf).
Fig. 3. Leaf spot with pycnidium of Septoria eferdingensis.
Fig. 4. Conidia of Septoria eferdingensis, stained with Wittmann’s blue (Wittmann, 1970).
Under the microscope, significant differences in the diameter of the pycnidia, the length and the width and the number of septa of the conidia were found compared to the well known species on horse-chestnut trees.
Astrid Plenk (1998) published the finding and the original diagnosis of this Septoria species. This original diagnosis is invalid, because not written in Latin. Therefore the original diagnosis follows below in Latin and I recommend to name this new fungus Septoria eferdingensis Plenk.
For identification and comparison the following material, mostly borrowed from herbarium collections of the Natural History Museum in Vienna, was examined:
The holotype of Ascochyta aesculi Lib. =[Septoria aesculi (Lib.) Westend.], M.-A. Libert, Pl. Crypt. Arduennae. – Fasc. II, (NR 154); Herbarium mycologicum Romanicum, Septoria aesculi ([Lib.] Westend.) from Bucharest 1926; Pilzherbar Franz Petrak, Septoria aesculi Prov. Kiev 1913.
The holotype of Septoria aesculina Thüm. De Thüm. Mycotheca universalis (NR 2079) Kalksburg/Wien 1879; Kabát et Bubak Fungi imperfecti exsiccati, Septoria aesculina Thüm. (NR 60) Welwarn 1901; J. Smarods Fungi latavici exsiccati (NR 1090) Septoria hippocastani, Riga 1941.
The pycnidia and conidia were measured with by the electronical image analysis system „Kontron Image Analyses“ Model KS 400 Version 1.2 and 2.0.
The main difference between Septoria aesculina, S. hippocastani, S. aesculicola and the new species was the lack of septa in the conidia of the first three species. Furthermore they differ in length and width. According to literature (Rabenhorst, 1901) the conidia of Septoria aesculina are quite short (36-44 µm) but 3,5 – 5 µm wide. Septoria aesculicula is characterised by very short (20-30 µm) and thin – only 1 µm-conidia. Septoria hippocastani has fairly long (55-60 µm) and thin – about 2,5 µm - conidia.
Septoria aesculi is most similar to the new species. According to literature (Kickx, 1867, Fl. I. p.431) the conidia are 50 to 60 µm long, 3 to 3,5 µm thick and have 3-4 septa. In our own measurements the conidia of S. aesculi were found to be 35,57 – 63,71 µm long and 3,13 – 4,57 µm thick. Passerini (Rabenhorst, 1901) says that the conidia are only about 32 µm long. The diameter of the pycnidia of Septoria aesculi ranges from 66 to 168,3 µm.
The diameter of the pycnidia of the new species is 125 – 252 µm. The conidia are 40 – 80 µ long, 1,7 – 2,8 µm wide and have 1 – 4 septa. The width of the pycnidia wall amounts to 10,36 – 17,06 µm (Table 1).
Table 1. Septoria species on Aesculus hippocastanum
Species | Length of Conidia | Width of Conidia | Number of Septa | ||||||
Septoria aesculina | 36 | – | 44 *) | 3,5 | – | 5 *) | 0 *) | ||
36,25 | – | 44,3 x) | 3,4 | – | 4,8 x) | 0 x) | |||
Septoria aesculicola | 20 | – | 30 **) | 1 **) | 0 **) | ||||
Septoria hippocastani | 55 | – | 60 **) | 2,5 **) | 0 **) | ||||
54,6 | – | 61,5 x) | 2,3 | – | 2,6 x) | 0 x) | |||
Septoria aesculi | 50 | – | 60 *) | 3 | – | 3,5 *) | 3 | – | 4 *) |
35,57 | – | 63,71 x) | 3,13 | – | 4,57 x) | 3 | – | 4 x) | |
Septoria eferdingensis | 40 | – | 80 x) | 1,7 | – | 2,8 x) | 1 | – | 4 x) |
*) according to original descriptions | |||||||||
Maculae parvae, orbiculatae incano-albicantes, pycnidia 1-3, epi- et hypophylla, fusco-nigricantia; Pycnidia 125 – 252 µ diam., pariete 10 – 17 µm crasso.
Conidia filiformia, hyalina recta vel curvata, utrimque obtusiuscula, ± attenuata, 1 – 4 septata, 40 – 80 µm × 1,7 – 2,8 µm.
Type: Austria, Gstöttenau/Oberösterreich (Upper Austria). On living leaves of Aesculus hippocastanum L. 17 08 1997. A. Plenk (holotype, hb W)
The type specimen has been deposited at the Department of Botany, Natural History Museum, Vienna.
I would like to thank Univ.-Doz. Dr. H. Riedl (former Natural History Museum, Vienna) for critically reviewing the manuscript and for helpful information on systematics and Latin translations.
Rabenhorst, L., 1901: Kryptogamen-Flora von Deutschland, Österreich und der Schweiz, ed. 2, I/6, 1016 pp. (Septoria on Aesculus pp. 724-725), Leipzig, Verlag von Eduard Kummer 1016 S.
Kickx, J., 1867: Flore cryptogamique des Flandres, I, VIII (p.431). Gand, Librairie de H. Hoste, et Bonn, Librairie d’Adolphe Marcus, S.521.
Plenk, A., 1998: Auftreten einer neuen Septoria-Art an Rosskastanie. Mitt. Biol. Bundesanst. Land- Forstwirtsch. 357, 301.
Wittmann, W., 1970: Ein neues Rezept zur Herstellung mykologischer Präparate. PflSchber., Bd. 41, (5/6/7), p. 91-94.
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