<![CDATA[The Sclerotium Rot Disease is highly destructive to the scallions cultivation in the peat soil. The antagonistic fungi isolated from the rhizosphere and the endophytes of healthy plants, have been proven to be able to reduce Sclerotium rolfsii. The aim of this study was to evaluate the characteristics of antagonistic fungi from rhizosphere and endophytes of Scallions to S. rolfsii in-vitro in the laboratory. The purpose of this study was also to perform the suppression test on the intensity of Sclerotium rolfsiiRot Disease in planta in the peat media in the screen house. This research it was shown that genus Fusarium, Penicillium, Aspergillusas antagonistic fungi, were identified from the endophytes, meanwhile genus Trichoderma, Penicillium dan Aspergillus sp. were identified from the rhizosphere. Trichoderma Rz-1 and Trichoderma Rz-3 isolated from the rhizosphere was shown to have the highest antagonistic activity by 94,4 %, followed by Aspergillus Ed-2, which was isolated from the endophytes by 83,8%. In planta on peat media, Trichoderma Rz-1 was capable to demonstrate 82,19% of antagonistic effect and it could suppress Sclerotium Rot Diseasehence it produced the fresh weight of the plant highest to 19gcluster-1.  Taken together, the result of this study showed that Trichoderma Rz-1 isolated from rhizosphere has been proven to be the most beneficial to reduce the Sclerotium rolfsii on Scallions as a biological control agent, especially in peat soils. Keywords: biocontrol, rhizosphere,endophyte, scallions, Sclerotium rolfsii]]>
