SUMMARY
Wilt vessels disease in oil palm plants is caused by Fusarium oxysporum f.sp. This disease is very harmful because of its ability to kill the infected oil palm plant in less than a year. Endophytic bacteria are likely to be biological controllers for the disease because of their ability to produce bioactive antifungal compounds. Isolation of endophytic bacteria from oil palm plant and activity test of their active compounds against F. oxysporum f.sp. in vitro had been done. Antagonistic test of endophytic bacterial isolates against F. oxysporum f.sp. was carried out using a double culture method. The potential endophytic bacterial isolates were extracted using ethyl acetate solvent for their active compounds, which were then tested for its activity in inhibiting the growth of F. oxysporum f.sp. The results showed that the active compound extract of B11 endophytic bacteria with the incubation time of 24 and 54 hours gave the growth inhibition of F. oxysporum f.sp. at the level of 29.23% and 43.85%, respectively. Penyakit layu pembuluh pada tanaman kelapa sawit disebabkan oleh Fusarium oxysporum f.sp. Penyakit ini menjadi penyebab kematian tanaman kelapa sawit yang telah terinfeksi dalam waktu kurang dari setahun. Bakteri endofit asal tanaman kelapa sawit dimungkinkan menjadi pengendali hayati bagi penyakit ini karena kemampuan bakteri tersebut memproduksi senyawa bioaktif yang bersifat antifungi. Isolasi bakteri endofit dari tanaman kelapa sawit dan uji aktivitas senyawa aktifnya terhadap F. oxysporum f.sp. secara in vitro telah dilakukan. Uji antagonis isolat bakteri endofit terhadap jamur patogen F. oxysporum f.sp. menggunakan metode kultur ganda. Isolat bakteri endofit potensial diekstrak senyawa aktifnya dengan menggunakan pelarut etil asetat, kemudian senyawa aktif ini diuji aktivitasnya dalam menghambat pertumbuhan jamur patogen F. oxysporum f.sp. Hasil penelitian menunjukkan bahwa ekstrak senyawa aktif bakteri endofit B11 dengan waktu inkubasi 24 dan 54 jam memberikan daya hambat terhadap F. oxysporum f.sp. sebesar masing-masing 29,23% dan 43,85%.