METODOLOGIA DE AVALIAÇÃO DA AGRESSIVIDADE DE ISOLADOS DE Sphaeropsis sapinea A Pinus taeda

Sphaeropsis sapinea is known as an important pathogen of  Pinus , causing tip blight and death of trees in commercial plantings. In Brazil, the first report of this disease was done in the 1940s, during introduction of  Pinus radiata  in Sao Paulo State, when these plantations were destroyed by  S sapinea . In order to select material resistant to such disease in Brazil,a methodology was developed to evaluate aggressiveness in  S. sapinea  isolates on apple fruits and  Pinus taeda . Three environments (greenhouse with different regimes of irrigation), two inoculation methods (with and without injury) and three methods of re-isolation of fungus (PDA medium, moist chamber in plastic bags and moist gerbox) had been tested. Results pointed to significant differences  (p < 0,05)  on aggressiveness in apple fruit and  P. taeda  seedlings. The better method to re-isolate was moist chamber in plastic bags and the better environment to incubate inoculated seedlings was greenhouse with two diary aspersion of four minutes. Other result was that injury is necessary for a good inoculation of  S. sapinea . The characterization results have presented significant differences in relation to aggressiveness and genetic diversity of the pathogen in all tested hosts.