Plant Pathology (2010) 59, 411 Doi: 10.1111/j.1365-3059.2009.02162.x Chalara fraxinea associated with dieback of narrow-leafed ash (Fraxinus angustifolia) T. Kirisits a *, M. Matlakova a , S. Mottinger-Kroupa a , E. Halmschlager a and F. Lakatos b a Institute of Forest Entomology, Forest Pathology and Forest Protection (IFFF), Department of Forest and Soil Sciences, University of Natural Resources and Applied Life Sciences, Vienna (BOKU), Hasenauerstrasse 38, A-1190 Vienna, Austria; and b Institute of Silviculture and Forest Protection, University of West Hungary, Sopron, Ady E. str. 5, H-9400 Sopron, Hungary Narrow-leafed ash, Fraxinus angustifolia is an ecologically and economi- cally important tree species in floodplain forests in southern Europe and some parts of central Europe. In recent years, afforestations of this species along the river March near Hohenau ⁄ March in eastern Austria (province Lower Austria) have been severely affected by dieback and tree mortality. Symptoms included shoot and twig dieback, necrotic lesions and cankers in the bark as well as discolouration of the wood. In 2008 Chalara fraxi- nea, the anamorphic stage of Hymenoscyphus albidus (Kowalski & Hold- enrieder, 2009) was consistently isolated from small necrotic lesions on shoots of diseased F. angustifolia saplings in this area and from diseased seedlings from a nursery near Kapuva ´r in northwest Hungary. In spring 2009 the fungus was also commonly detected on affected narrow-leafed ash seedlings in a nursery in Lower Austria. Colonies on malt extract agar (MEA) were cottony, white, orange- brown or fulvous brown, with grey sectors in areas associated with phi- alophore production. Pseudoparenchymatous stromata formed occasion- ally after prolonged incubation. Micromorphological characteristics of two Austrian isolates (CBS Accession Nos. 123139, 123140) were as fol- lows: phialides 16Æ3 (13Æ7–18Æ3) lm · 4Æ7 (3Æ9–6Æ1) lm at the base and 2Æ6 (2Æ2–3Æ0) lm at the collarette; conidia 3Æ3 (2Æ7–3Æ9) · 2Æ2 (1Æ5– 2Æ7) lm; first-formed conidia 6Æ3 (5Æ5–7Æ7) · 2Æ2 (1Æ8–2Æ8) lm. In May 2008, 20 potted, two-year-old F. angustifolia seedlings were wound-inoculated with C. fraxinea isolate CBS 123140. Inoculum con- sisted of autoclaved F. excelsior phloem (approximately 10 · 4 · 2–3 mm) that had been placed for 15 days on C. fraxinea cultures on MEA. Within three months 55% of the plants showed wilting of leaves and dieback. Necrotic phloem lesions (mean length = 7Æ7 cm) and wood discolour- ation developed on all seedlings inoculated with C. fraxinea, but none on any of the 20 control seedlings. The fungus was re-isolated from 60% of the C. fraxinea -inoculated seedlings but not obtained from any of the con- trol plants. This is the first definitive report of C. fraxinea from a host other than F. excelsior. On the latter ash species this fungus has been causing severe dieback in Europe (Kowalski, 2006; Halmschlager & Kirisits, 2008; Szabo ´ , 2009). The detection of C. fraxinea in forest nurseries may suggest that diseased plants for planting are an important pathway for accelerating the spread of this emerging pathogen. Acknowledgements We thank the BMLFUW (‘Lebensministerium’), the governments of Lower Austria, Carinthia, Salzburg, Burgenland, Upper Austria and Styria as well as the O ¨ BfAG for funding. References Halmschlager E, Kirisits T, 2008. First record of the ash dieback pathogen Chalara fraxinea on Fraxinus excelsior in Austria. Plant Pathology 57, 1177. Kowalski T, 2006. Chalara fraxinea sp. nov. associated with dieback of ash (Fraxinus excelsior) in Poland. Forest Pathology 36, 264–270. Kowalski T, Holdenrieder O, 2009. The teleomorph of Chalara fraxinea, the causal agent of ash dieback. Forest Pathology 39, in press. Szabo ´ I, 2009. First report of Chalara fraxinea affecting common ash in Hungary. Plant Pathology 58, 797. *E-mail: thomas.kirisits@boku.ac.at. Accepted 12 June 2009 at http://www.bspp.org.uk/ndr where figures relating to this paper can be viewed. Plant Pathology (2010) 59, 411 Doi: 10.1111/j.1365-3059.2009.02165.x Dischloridium gloeosporioides on Annona muricata: a new pathogen in Brazil B. A. Halfeld-Vieira* and K. L. Nechet Embrapa Roraima, BR 174, km 08, CP 133, 69301-970, Boa Vista-RR, Brazil Soursop (Annona muricata), in the family Annonaceae, is a fruit tree indigenous to central and northern South America. In Brazil, it is com- monly cultivated in the north and northeastern states for commercial exploitation of fruits and pulp. Over five million fruits are harvested each year in Brazil. During a survey of plant diseases in October 2007 in Pacaraima (Roraima State), trees of A. muricata were observed exhibiting necrotic dark brown circular leaf spots, 0Æ7–3Æ0 cm wide, frequently with concentric circles. All plants surveyed presented symptoms in high sever- ity. Microscopic examination revealed an association with a fungus that displayed amphigenous fructification, predominantly on the abaxial leaf surface, and stromata 21–83 lm in diameter. Conidia were solitary, short subcylindrical to ellipsoid, 10–21 · 2Æ6–5Æ2 lm, base rounded to sub- truncate, hyaline, smooth, and non-septate. Conidiophores in fascicles were erect, 63–101 · 2Æ6–5Æ2 lm, brown, smooth, 1–5 septate, and unbranched. Conidiogenous cells were monophialidic and inconspicu- ous, 7Æ8–34 · 2Æ6 lm. Based on these features, the lesion-associated fun- gus was identified as Dischloridium gloeosporioides (Schubert & Braun, 2005). A specimen was deposited at the herbarium of the Universidade Federal de Vic ¸osa (VIC 30548). To perform Koch’s postulates, 30-day-old soursop plants cultivated in the greenhouse were sprayed with a conidial suspension (10 3 conidia per mL) until runoff. After inoculation, plants were covered with plastic bags for 48 hours to simulate a dew chamber and kept in a greenhouse. Control plants were sprayed only with water. Two weeks after inoculation, leaf lesions developed only on the inoculated plants from which the pathogen was re-isolated. Previously denominated Cladosporium gloeosporioides, D. gloeospo- rioides has a known restricted distribution being reported only in the Uni- ted States and associated with plants belonging to the genus Hypericum (Saccardo & Sydow, 1899; Schubert & Braun, 2005). It is reported to cause lesions on leaves and stems of H. stans (= Ascyrum stans), H. muti- lum and H. virginicum. Therefore, this is the first report of D. gloeospo- rioides in Brazil. Acknowledgements The first author thanks the Brazilian agency CNPq for a research fellow- ship (proc. 303081 ⁄ 2007-4). References Saccardo PA, Sydow P, 1899. Sylloge Fungorum, Volume 14. Padova, Italy: Pier Andrea Saccardo. Schubert K, Braun U, 2005. Taxonomic revision of the genus Cladosporium s.l. 4. Species reallocated to Asperisporium, Dischloridium, Fusicladium, Passalora, Pseudoasperisporium and Stenella. Fungal Diversity 20, 187–208. *E-mail: halfeld@cpafrr.embrapa.br. Accepted 18 June 2009 at http://www.bspp.org.uk/ndr where figures relating to this paper can be viewed. ª 2010 The Authors 411 Journal compilation ª 2010 BSPP