Mycosphaerella species associated with leaf disease of Eucalyptus globulus in Ethiopia

Abstract

Eucalyptus spp. are among the most widely planted exotic trees in Ethiopia. Several damaging leaf pathogens are known from Eucalyptus spp. worldwide. Of these, Mycosphaerella spp. are among the most important, causing the disease known as Mycosphaerella leaf disease (MLD). Characteristic symptoms of MLD include leaf spot, premature defoliation, shoot and twig dieback. Recent disease surveys conducted in Ethiopian Eucalyptus plantations have revealed disease symptoms similar to those caused by Mycosphaerella spp. These symptoms were restricted to E. globulus trees growing in several localities in south, south western and western Ethiopia. The aim of this study was to identify the fungi associated with this disease. This was achieved by examining ascospore germination patterns, anamorph associations and sequence data from the Internal Transcribed Spacer (ITS) region of the rRNA operon, for representative isolates. Several different ascospore germination patterns were observed, suggesting that more than one species of Mycosphaerella is responsible for MLD on E. globulus in Ethiopia. Analysis of sequence data showed that three Mycosphaerella spp., M. marksii, M. nubilosa and M. parva were present. This is the first report of these three species from Ethiopia and represents a valuable basis on which to build further studies in the region.

Teratosphaeria nubilosa, a serious leaf disease pathogen of Eucalyptus spp. in native and introduced areas

“…Recent surveys in other African countries have also resulted in the confirmation of T. nubilosa . Teratosphaeria nubilosa has been identified from south, south‐western and western Ethiopia, causing severe defoliation on E. globulus (Gezahgne et al ., 2006). Eucalyptus plantations in Kenya, Tanzania and Zambia have also been affected by T. nubilosa , where it has been identified causing defoliation of E. globulus (Crous et al ., 2004a; Hunter et al ., 2008).…”

Mycosphaerella and Teratosphaeria diseases of Eucalyptus; easily confused and with serious consequences

“…Several Mycosphaerella and Teratosphaeria species have been identified in South Africa and can now be found in Kwa-Zulu Natal, Eastern Cape, Mpumalanga and the Limpopo provinces (Crous and Wingfield 1996;Crous 1998;Crous et al 2004;Hunter et al 2004a;. Surveys conducted in other African countries, including Madagascar, Malawi, Mozambique, Tanzania, Kenya, Ethiopia and Zambia, have also revealed species of Mycosphaerella and Teratosphaeria in Eucalyptus plantations (Crous and Swart 1995;Crous 1998;Crous et al 2004;Roux et al 2005;Hunter et al 2008;Gezahgne et al 2006). In South Africa, E. nitens is the main species affected by leaf diseases caused by Teratosphaeria spp., which is different to other African countries where E. globulus is the most susceptible species.…”

Teratosphaeria pseudonubilosa sp. nov., a serious Eucalyptus leaf pathogen in the Teratosphaeria nubilosa species complex

“…For phylogenetic analyses, 21 isolates were selected to represent the global intraspecific diversity previously described for T. nubilosa (Chungu et al 2010;Crous et al 2004;Gezahgne et al 2006;Hunter et al 2009) and the three native population groups identified based on microsatellite marker analyses (Pérez et al 2012). Phylogenetic analyses included the exepitype specimen of T. nubilosa, isolate CMW 3282 (= CPC 937, = CBS 116005) from Victoria, Australia, designated by Crous et al (2004).…”

“…All DNA sequences used in this study were used in previous phylogenetic analyses (Chungu et al 2010;Crous et al 2004;Gezahgne et al 2006;Hunter et al 2009;Pérez et al 2009aPérez et al , b, 2010Pérez et al , 2012 and were downloaded from GenBank (http://www. ncbi.nlm.nih.gov; Table 1).…”

“…Although native to Australia, this pathogen has been introduced into many countries along with its hosts (Dick 1982;Gezahgne et al 2006;Hunter et al 2009;Mohammed et al 2003;Pérez et al 2009aPérez et al , 2012.…”