A COMPARATIVE-STUDY OF FUNGAL POPULATIONS IN HEALTHY AND SYMPTOMATIC TWIGS OF EUCALYPTUS-GRANDIS IN URUGUAY

Seven hundred and eighty two isolates corresponding to 52 fungal taxa have been obtained from 920 segments of healthy and symptomatic twigs of Eucalyptus grandis, incubated on media with water potential -0.138 MPa and -4.19 MPa. Only thirty taxa were isolated at frequencies of 2% and greater. The composition of species isolated from bark of healthy twigs incubated on media with both water potentials was similar, with Aureobasidium pullulans being dominant. Sistrotrema brikmannii was th e main species isolated from xylem of healthy twigs at -0.138 MPa wher eas Pleospora sp, and Sphaeropsis eucalyptus were the dominant species isolated from this material on medium at -4.19 MPa. Fusicoccum eucaly pti and Cytospora chrysosperma were most commonly isolated from bark a nd xylem of symptomatic twigs. Correspondence analysis showed the fung al species associated with each tissue. Summer drought followed by fre quent frost in early autumn may have incited wounds allowing fungal in vasion of the bark of twigs.