New species of Mycosphaerella causing leaf spot on Eucalyptus globulus in Spain
B. de Blas A , E. Iturritxa A and J. J. Diez B CA NEIKER. Granja Modelo – Arkaute. Apdo. 46. 01080 Vitoria-Gasteiz, Spain.
B Forest Entomology and Pathology Laboratory, Plant Production and Forest Resources Department, University of Valladolid, 34071 Palencia, Spain.
C Corresponding author. Email: jdcasero@pvs.uva.es
Australasian Plant Disease Notes 4(1) 59-59 https://doi.org/10.1071/DN09024
Submitted: 8 May 2009 Accepted: 20 May 2009 Published: 10 June 2009
Mycosphaerella spp. are known to cause serious leaf diseases in Eucalyptus forests and they are widespread throughout the world (Corlett and McGregor 1991). More than 60 species of Mycosphaerella have been described in association with diseases of Eucalyptus forests (Crous 1998).
A leaf spot disease caused by Mycosphaerella spp. was first recorded on Eucalyptus globulus Labill in the Basque Country, in the north of Spain, at the end of 2004. The disease was detected in five out of a total of 19 plots, showing a visible percentage of defoliation of the crown area. Affected trees showed lesions that varied in shape from angular to circular.
Mycosphaerella species were identified by studying the morphology of leaf lesions, pseudothecial density, size, shape and germination patterns of ascospores. Necrotic tissues from the leaves, bearing pseudothecia, were cut and adhered to the under-surface of Petri plate lids for deposition of ascospores onto a 2% malt extract agar surface. The plates were incubated at an ambient temperature and were examined under a microscope (40×) to observe germination patterns. More than one species of Mycosphaerella were detected on a single leaf and even fruiting in the same lesion. The perfect state of M. cryptica (Cooke) Hansf., M. ellipsoidea Crous & M.J. Wingf., M. endophytica Crous & Smith., M. flexuosa Crous & M.J. Wingf. M. gracilis Crous & Alfenas, M. lateralis Crous & M.J. Wingf., M. marksii Carnegie & Keane, M. molleriana (Thüm.), M. nubilosa (Cooke) Hansf., M. parkii Crous et al. and M. walkeri R.F. Park & Keane were identified from these samples.
Crous et al. (2004) and Otero et al. (2006) reported several species of Mycosphaerella on E. globulus and E. nitens in north-western Spain (Galicia): M. aurantia A. Maxwell, M. communis Crous & J.P. Mansilla, M. lateralis, M. madeirae Crous & Denman, M. marksii, M. molleriana, M. nubilosa, M. parva R.F. Park & P. Keane, M. readeriellophora Crous & J.P. Mansilla, M. toledana Crous & Bills, and M. vespa Carnegie & Keane. Our work provides the first report of M. cryptica, M. ellipsoidea, M. endophytica, M. flexuosa, M. gracilis, M. parkii, and M. walkeri on Eucalyptus in Spain.
Seven new species of Mycosphaerella from leaf spot on Eucalyptus globulus were first reported in Spain.
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