ISOLASI DAN UJI ANTAGONIS BAKTERI ASAL TANDAN KOSONG SAWIT YANG DIAPLIKASIKAN PADA AREAL TANAMAN KARET TERHADAP PENYAKIT JAMUR AKAR PUTIH (R. microporus)

Abstract

Uji antagonis terhadap jamur R. microporus telah dilakukan pada delapan isolat bakteri di laboratorium proteksi Balai Penelitian Sungei Putih. Isolat-isolat tersebut diisolasi dari permukaan TKKS yang diaplikasikan pada areal perkebunan karet. Media nutrient agar (NA) digunakan dalam isolasi dan pemurnian bakteri. Uji antagonis dilakukan secara in vitro dengan metode Dual Culture dan diamati pada 2,4,6, dan 8 hari setelah inokulasi (HSI). Hasil penelitian menunjukkan bahwa delapan isolat bakteri memiliki karakter morfologi (warna, bentuk, tepian dan elevasi) serta kemampuan penghambatan jamur R. microporus yang berbeda. Penghambatan oleh bakteri mulai terlihat pada 2 HSI terutama pada isolat B2, B3, B4, dan B7. Persentase penghambatan masing-masing isolate tersebut adalah 30%, 60%, 65% dan 69%. Hingga 8 HSI, isolat B2, B3, B4, B6, B7 dan B8 mampu menghambat perkembangan jamur R. microporus ≥ 80%. Isolat B3 dan B4 memiliki kemampuan antagonisme yang paling baik dengan persentase penghambatan ≥ 95%. Sedangkan isolat B1 dan B5 hanya dapat menghambat perkembangan jamur R. microporus ≤ 50%.  Eksistensi bakteri-bakteri antagonis inilah yang kemungkinan besar menyebabkan TKKS tidak menjadi inang penyakit jamur akar putih (R. microporus) ketika diaplikasikan di lapangan.

The antagonistic assay of eight isolates of bacteria against R. microporus fungi has been conducted in the Plant Protection Laboratory of Sungei Putih Research Centre. The isolates of bacteria were isolated by the surface of oil palm empty fruit bunches (TKKS) applied in the rubber field. Nutrient agar (NA) was employed in the isolation and purification of bacteria. The antagonistic assay was carried out in vitro using the dual culture method. The observation was performed on 2, 4, 6, and 8 days after incubation (HSI). The result indicated that the eight isolates have varied morphological characters (including color, shape, edge, and elevation) and their inhibition ability of R. microporus fungi as well. The initial inhibition by the isolates of bacteria was started since 2 HSI particularly in the isolates B2, B3, B4, and B7.  The inhibition percentage of those isolates were 30%, 60%, 65% dan 69% respectively. Until 8 HSI, the isolates B2, B3, B4, B6, B7 and B8 were still inhibiting the growth of R. microporus fungi > 80%. The isolates B3 and B4 showed the best performance in the inhibition of fungi with inhibition percentage > 95%. Whereas, the ability of inhibition of the isolate B1and B5 were very low as < 50%. The existence of such antagonistic bacteria perhaps led to TKKS was not role as the host of white root disease while applied in the rubber field.