EKSPLORASI RIZOBAKTERI INDIGENOUS DAN UJI ANTAGONIS TERHADAP PATOGEN Rigidosporus microporus DAN Phellinus noxius PADA TANAMAN KARET (Hevea brasiliensis) SECARA IN VITRO Abstrak. Penelitian bertujuaan untuk mendapatkan isolat rizobakteri yang mampu berperan sebagai agens biokontrol terhadap pengendalian patogen R. microporus dan P. noxius secara in vitro serta sebagai agen rizobakteri pemacu pertumbuhan tanaman (RPPT). Penelitian dilaksanakan di Laboratorium Ilmu dan Teknologi Benih Jurusan Agroteknologi, Fakultas Pertanian, Universitas Syiah Kuala, Darussalam Banda Aceh, mulai Oktober sampai Desember 2017. Penelitian ini menggunakan Rancangan Acak Lengkap non faktorial. Faktor yang diteliti yaitu isolat rizobakteri, taraf yang dicobakan terdiri dari 15 isolat dan dua patogen antagonis R. microporus dan P. noxius, yang diulang sebanyak 3 kali sehingga terdapat 90 unit satuan percobaan. Hasil penelitian menunujukkan isolat rizobakteri mampu menekan pertumbuhan koloni cendawan patogen. Pada patogen uji R. microporus terdapat 3 rizobakteri yang paling baik yaitu isolat DLG5/3 dengan persentase penghambatan 68,33%, DLG4/1 dengan persentase penghambatan 66,66% dan DLG4/7 dengan persentase penghambatan 63,33%. Pada patogen uji P.noxius terdapat dua rizobakteri yang paling baik dalam menghambat pertumbuhan koloni cendawan patogen yaitu isolat DLG5/1 dengan persentase penghambatan 60,33%, dan DKP6/3 dengan persentase penghambatan 52,50%. Pada laju penghambatan isolat rizobakteri yang paling baik pada patogen R. microporus yaitu isolat DLG6/4 dan DKP4/1 dengan nilai rerata laju penghambatan 20,33 mm/hari. Pada patogen P. noxius menunjukan isolat rizobakteri yang paling baik yaitu isolat DLG4/1 dengan nilai laju penghambatan 12,05 mm/hari. Kata kunci : Rizobakteri, Uji Antagonis, R microporus, P noxius, Tanaman Karet. Exploration of Indigenous Rizobacteria and Antagonistic Test against Patogen Rigidoporus microporus And Phellinus noxius In Rubber Plant (Hevea brasiliensis) In Vitro Abstract The research was conducted to obtain rhizobacteria isolates capable of acting as biocontrol agents on pathogen control of R. microporus and P. noxius in vitro and as plant growth promoter rhizobacteria (PGPR). The research was conducted at the Science and Technology of seed Laboratory, Department of Agrotechnology, Faculty of Agriculture, Syiah Kuala University, Darussalam Banda Aceh, starts from October to December 2017. The research using Completely Randomized Design non factorial. Factors researched were rhizobacteria isolates, the experimental stage consisted of 15 isolates and 2 antagonist were R. microporus dan P. noxius, and 3 time repeated until be found 90 units of treatment. The results showed that rhizobacteria isolates capable to inhibith growth of colonies pathogenic. In the pathogen of R. microporus test, there are 3 better rhizobacteria were DLG5/3 isolate with 68.33% inhibition percentage, DLG4/1 with 66.66% inhibition percentage and DLG4/7 with 63,33% inhibition percentage. In the pathogen of P. noxius there are 2 best rhizobacteria inhibiting growth, DLG5/1 isolate with 60.33% inhibition percentage, and DKP6/3 with 52,50% inhibition percentage. In the pathogen of R. microporus test, there are 2 better rhizobacteria were DLG6/4 and DKP4/1 with 20,33 mm/day inhibition percentage. In the pathogen of P. noxius test, the best rhizobacteria were DLG4/1 with 12,05 mm/day inhibition percentage. Keywords: Rhizobacteria, Antagonis Test, R microporus, P noxius, Rubber Plant,