Mycosphaerellaceae and Teratosphaeriaceae associated with Eucalyptus leaf diseases and stem cankers in Uruguay By C. A. Pe ´rez 1,2,5 , M. J. Wingfield 3 , N. A. Altier 4 and R. A. Blanchette 1 1 Department of Plant Pathology, University of Minnesota, 495 Borlaug Hall, 1991 Upper Buford Circle, St Paul, MN 55108, USA; 2 Departamento de Proteccio ´ n Vegetal, Universidad de la Repu ´ blica, Ruta 3, km 363, Paysandu ´ , Uruguay; 3 Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa; 4 Instituto Nacional de Investigacio ´ n Agropecuaria (INIA), Ruta 48, km 10, Canelones, Uruguay; 5 E-mail: caperez@fagro.edu.uy (for correspondence) Summary Mycosphaerella leaf diseases represent one of the most important impediments to Eucalyptus plantation forestry. Yet they have been afforded little attention in Uruguay where these trees are an important resource for a growing pulp industry. The objective of this study was to identify species of Mycosphaerellaceae and Teratosphaeriaceae resulting from surveys in all major Eucalyptus growing areas of the country. Species identification was based on morphological characteristics and DNA sequence comparisons for the Internal Transcribed Spacer (ITS) region of the rDNA operon. A total of ten Mycosphaerellaceae and Teratosphaeriaceae were found associated with leaf spots and stem cankers on Eucalyptus. Of these, Mycosphaerella aurantia, M. heimii, M. lateralis, M. scytalidii, Pseudocercos- pora norchiensis, Teratosphaeria ohnowa and T. pluritubularis are newly recorded in Uruguay. This is also the first report of M. aurantia occurring outside of Australia, and the first record of P. norchiensis and T. pluritubularis in South America. New hosts were identified for Kirramyces gauchensis, M. aurantia, M. marksii, M. lateralis, M. scytalidii, P. norchiensis, T. molleriana, T. ohnowa and T. pluritubularis. Interestingly K. gauchensis, which has been known only as a stem pathogen, was isolated from leaf spots on E. maidenii and E. tereticornis. The large number of Mycosphaerellaceae and Teratosphaeriaceae occurring in Uruguay is disturbing and raises concerns regarding the introduction of new pathogens that could threaten not only Eucalyptus plantations but also native forests. 1 Introduction Eucalyptus is one of the most important hardwood crops in the world, planted primarily for pulp and timber production (Turnbull 2000). The success of Eucalyptus plantations in areas outside Australia, where most species are native, has been attributed to many factors including the absence of pests and pathogens that affect these trees in their areas of origin (Burgess and Wingfield 2002; Wingfield et al. 2001). A diverse group of fungi threatens Eucalyptus production worldwide and amongst these, Mycosphaerella leaf diseases (MLD) are considered particularly important (Park et al. 2000; Summerell et al. 2006). To date, more than 90 species of Mycosphaerellaceae and Teratosphaeriaceae residing in Mycosphaerella, Teratosphaeria, and several anamorph genera where the teleomorph is unknown (Crous et al. 2007a) have been recorded on Eucalyptus (Burgess et al. 2007; Cortinas et al. 2006b; Crous et al. 2004a, 2006; Hunter et al. 2006). This group of fungi may cause leaf spots, leaf blotch, and stem cankers and various species have the capacity to reduce tree growth (Park et al. 2000). Carnegie et al. (1994) found a negative correlation between tree height and diameter and severity of MLD in Eucalyptus globulus plantations and Carnegie et al. (1998) reported that even a 10% infection resulted in a 17% reduction in height of E. globulus in plantations. Other For. Path. 39 (2009) 349–360 doi: 10.1111/j.1439-0329.2009.00598.x Ó 2009 Blackwell Verlag GmbH Received: 8.9.2008; accepted: 3.2.2009; editor: S. Woodward www3.interscience.wiley.com