Brazil is the leader in the global ranking of forest productivity; however, one of the major challenges to eucalyptus production is the existence of fungal diseases. A severe epidemic caused by pestalotiopsis‐like fungi was observed in a forest nursery in Brazil, causing a huge impact on the eucalyptus micropropagation stages. The aims of the present study were to identify the causal agents associated with pestalotiopsis leaf spot and dieback in eucalyptus, assess their pathogenicity to different commercial clones, and evaluate which conditions favour conidial germination and infection by the pathogens. Multilocus phylogenetic analyses using ITS, TEF and TUB identified the isolates as members of Neopestalotiopsis and segregated them into three species. Isolates from all Neopestalotiopsis spp. caused symptoms on unwounded eucalyptus leaves and disease development was strongly dependent on long leaf wetness periods (≥72 h). All four commercial clones tested were susceptible to the pathogen. These results clearly dispute the commonly held assumption that pestalotioid fungi are weak and opportunistic pathogens. This is the first report of different phylogenetic species of Neopestalotiopsis causing dieback, leaf and stem lesions in eucalyptus cuttings and provides a basis for developing novel disease management strategies in forest nurseries.
Abstract. -In order to contribute to the alignment of the radio and optical reference frames, 50 stars with confirmed radio emission and published radio positions were observed by astrographical means. Additionally, two confirmed radio-stars of fainter magnitude were observed using a CCD direct camera with a long focus, large aperture telescope. The reductions are made relative to four catalogues: the Carlsberg Meridian Catalogue #4, the International Reference Stars Catalogue, the Positions and Proper Motion Catalogue and the Astrographical Catalogue of Reference Stars. The best results were obtained with the CAMC catalogue. The plate error of a radio star position is 0. 07 for both right ascension and declination, rising to 0. 10 − 0. 20 for bright stars. Ten of the program stars are not in the HIPPARCOS Input Catalogue and 12 do not belong to any of the major reference catalogues used. As soon as the HIPPARCOS results become available, its reference stars already measured in the plates will enable us to get positions for those 10 radio stars in the HIPPARCOS system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.