Murcha por Ceratocystis em eucalipto: avalia？？o de resistência e análise epidemiológica

the cultivation of eucalyptus is one of the most important in brazil, constituting a source of renewable energy and wood, supporting important agro-industrial processes for production of pulp, paper and essences. eucalyptus, like other plant species is infected by various pathogens, especially fungi, from nursery to adult trees. in this work, was studied de causative agent of ceratocystis wilt. the fungus ceratocystis fimbriata ellis. et halsted is a typical xylem pathogen, which the marker symptom is observable in the cross sections of woody organs in the form of dark radial striations, from core to the outer periphery of the wood or from the periphery to the core. these streaks in the wood are visible when an affected branch is cut across because pathogen causes the disintegration of the vascular system. it is a fungus of fast spreading and that affects plants in various stages of development and because of this is difficult to control. the objectives of this work were verify the clonal susceptibility to the pathogen for aid breeding programs to obtain resistant materials and study epidemiological model for determination of disease progress on the field. for this, stecklings of operational clones were used for inoculation to evaluate the resistance. epidemiological assessment of spatial distribution was made according to field surveys with plots previously installed. different resistance levels were found in the studied materials, since high resistance until high susceptibility. in the field, the disease showed a clustered distribution, with tendency to aggregation of foci and vertical distribution (in the plant line).