| dc.description.abstract | The objective of the research is determine the approved degree of two Eucalyptus spp clons that is : Eucalyptus grandis x Eucalyptus pellita dan Eucalyptus grandis x Eucalyptus urophylla and also to identify the Mycosphaerella spp virulence in two class ages of the Eucalyptus plants ( two and three month ) . The research was done with the intake sample of Eucalyptus seed plants from the PT . TPL Tbk Nursery , Toba Samosir Region , Porsea , North Sumatera . The research method used the fungi isolation tecnic with the brush method and be reinoculated to the fresh Eucalyptus leaf seed plant in two ages is two and three month , and then be calculated the attack intensity and wide attack . The observasif do for a four week and every week we must look the disease plant . The result showed that there were Mycosphaerella spp is the kind of pathogen that attacked the Eucalyptus spp plants in the plants leaf with the attacked mode . The very hole up plant type to the pathogen cause in leaf spot disease is the Eucalyptus plant that were seen and low of attack intensity that happened is 4,71 % in the four week but the highest pathogen virulence cause the leaf spot affected by Mycosphaerella spp to the Eucalyptus plant that was seen from the attack intensity is 11,01 % in the fourth week . | en_US |