Potensi Isolat Ko-kultur Bacillus siamensis LDR, Bacillus SP. TKA6A, dan Stenotrophomonas maltophilia G17 dalam Menghambat Fungi Fitopatogen Ganoderma boninense = Potency of Co-culture Isolates of Bacillus siamensis LDR, Bacillus sp. TKA6A, and Stenotrophomonas maltophilia G17 in Inhibiting the Growth of the Fungal Phytophatogen, Ganoderma boninense