SUMMARY
Fusarium nivale (Fr.) Ces., an endophytic fungi from Dendrobium crumenatum Sw. (pigeon orchid)showed an antimicroorganism activity against Absidia corymbifera (Cohn) Sacc. & Trotter, causing of human zygomycosis. The aim of this study is to find out the effect of concentration of antimicroorganism agent, fermentation medium, and incubation time to control A. corymbifera by F. nivale; and to make curve of F. nivale growth and curve of its antimicrobial production. Five different concentrations of antimicroorganism agent (0, 75, 150, 225, and 300 ul), four different fermentation media (PotatoDextrose Yeast, Tauge Extract Broth , Kedelai Extract Broth , and Jagung Extract Broth), and eight different incubation times (0, 1, 2, 3, 4, 5, 6, and 7 days) were chosen for this experiment. Parameters of the study were change of filtrate pH, dry weight of mycelial cell of F. nivale, and percentage inhibition of mycelial growth of A. corymbifera. The results indicated that antimicroorganism agent concentration of 150 ul applied and potato dextrose yeast medium were the most effective to inhibit A.corymbifera. The antimicroorganism agent was produced during growth of the fungi. The production of antimicroorganism agent coinced with the decrease in pH from 6.0 to 4.81; and the increase in pH from4,81 to 7.24-8.01. A optimum activity of antimicroorganism agent (31,23) during growth of fungi occurred on the 2th day of incubation. Keywords: A. corymbifera; aktivitas antimikroorganisme; F. nivale; persentase hambatan pertumbuhan miselium A. corymbifera