POSTERS: New and emerging diseases
Infection by Neopestalotiopsis spp. occurs on unwounded eucalyptus leaves and is favored by long periods of leaf wetness
Renata Belisário - Universidade Federal de Vicosa. Gleiber Furtado- Universidade Federal de Vicosa, Lucas Abreu- Universidade Federal de Vicosa, Carlos Aucique- Embrapa Agroenergia
Brazil is the global leader of forest productivity; however, one of the major challenges to fiber crops is the existence of fungal diseases. In this specific instance, Pestalotiopsis-like fungi were continuously observed in a privately-owned forest nursery in Brazil, reaching epidemic levels with incidence levels greater than 70% in the eucalyptus micropropagation stages. The objectives of the present study were to identify the causal agent associated with leaf spot and dieback on eucalyptus, assess its pathogenicity to different commercial clones, and evaluate which conditions favor infection by the pathogens. Results showed that Neopestalotiopsis protearum and N. rosae caused symptoms on unwounded eucalyptus leaves and disease development was strongly correlated to long leaf wetness periods (? 72 h). All of the commercial clones tested were susceptible to both pathogens and the set of data disputes the assumption that pestalotioid fungi are weak and opportunistic. The data produced in the study implies that single-gene phylogenetic trees constructed from ITS and TEF regions showed unresolved polytomies, while TUB and multi-locus phylogenies provided sufficient resolution tree topologies. This is the first report of different phylogenetic species of Neopestalotiopsis causing dieback, leaf and stem lesions on eucalyptus seedlings. Hence, this study can provide a basis for developing novel management strategies in forest nurseries.