Botryodiplodia spp. potentially cause dieback disease on jabon (Anthocephalus cadamba (Roxb.) Miq) seedlings. Five isolates of Botryodiplodia spp were inoculated on jabon seedling to find out its virulence levels, mechanism of pathogen attack and mechanism of host plant defense. The virulence levels was estimated by disease severity of host plants; the pathogen attack mechanism was done by measuring pectinase and cellulase enzyme activities; whereas host plant defense mechanism was determined by measuring peroxidase enzyme activity. The virulent isolates caused disease severity > 50%. Botryodiplodia sp. 1, Botryodiplodia sp. 2, and Botryodiplodia sp. 3 showed pectinase activities of 21.311; 18.131; 26.083 U/ml, and cellulase 0.014; 0.015; 0.023 U/ml, respectively. The peroxidase activity of host plants after pathogen inoculated was ranging from 0.0006 to 0.0012 UAE/g. Based on this research, three Botryodiplodia spp. isolates were virulent on jabon seedlings and involved enzymatic strength as attack mechanism, whereas the host plant defense mechanism involved peroxidase activity.