PENGENDALIAN PENYAKIT LAYU BAKTERI NILAM MENGGUNAKAN PSEUDOMONAD FLUORESEN

ABSTRAK Penelitian pengendalian penyakit layu bakteri nilam (Ralstonia solanacearum) menggunakan pseudomonad fluoresen di kebun petani nilam Desa Situak Pasaman Barat, Sumatera Barat telah dilakukan pada bulan Oktober 2003 sampai dengan Juni 2004. Penelitian ini bertujuan untuk mendapatkan pseudomonad fluoresen yang berpotensi untuk mengendalikan penyakit layu bakteri, dan meningkatkan pertumbuhan dan produksi nilam. Isolat pseudomonad fluoresen Pf 63, Pf 90, Pf 91, Pf 147, dan Pf 180 sebagai perlakuan diisolasi dari rizosfer nilam sehat, dan diseleksi  berdasarkan  kemampuan  antagonistik  terhadap  R. solanacearum secara in vitro di Laboratorium Bakteriologi Tumbuhan Fakultas Pertanian UGM. Isolat pseudomonad fluoresen tersebut diintroduksikan ke nilam dan diadaptasikan selama 1 minggu sebelum ditanam. Tanaman yang telah diperlakukan dengan isolat pseudomonad fluoresen ditanam pada kebun yang telah terinfeksi dengan patogen pada bulan Oktober 2003. Percobaan disusun dalam rancangan acak kelompok (RAK) dengan 6 ulangan. Parameter pengamatan adalah masa inkubasi, intensitas penyakit, pertumbuhan tanaman dan produksi minyak nilam. Hasil penelitian menunjukkan bahwa isolat pseudomonad fluoresen dapat mengendalikan penyakit layu bakteri dengan perpanjangan masa inkubasi 6-52 hari dan penekanan intensitas penyakit 31,11 – 50,56%. Disamping itu isolat pseudomonad fluoresen dapat mempengaruhi peningkatan pertumbuhan tanaman yaitu tinggi tanaman (6,7 – 26,3 cm), jumlah daun (4,6 – 30,1 daun/tanaman) dan berat kering daun (24,5 – 154,3 g/tanaman), dan produksi minyak nilam terutama jumlah minyak (4,8 – 22,3 ml/tanaman). Hasil percobaan ini menunjukkan bahwa isolat Pf 91 mempunyai kemampuan antagonistik tertinggi dalam mengen- dalikan penyakit layu bakteri di lapangan. Kata kunci : Nilam, Pogostemon cablin Benth, penyakit layu, bakteri, pengendalian hayati, pseudomonad fluoresen ABSTRACT Controlling bacterial wilt disease on patchouli plant with fluorescent pseudomonad The study of controlling bacterial wilt disease on patchouli plant (Ralstonia solanacearum) with fluorescent pseudomonad was carried out in a farmer’s field in Situak Village West Pasaman, West Sumatera from October 2003 to June 2004. The aims of the study were to find out the effectiveness of fluorescent pseudomonad for controlling bacterial wilt disease, increasing plant growth and production. Isolates of fluorescent pseudomonad Pf 63, Pf 90, Pf 91, Pf 147 and Pf 180 as treatments were isolated from the rhizosphere of healthy patchouli plant, and selected based on antagonistic activity on R. solanacearum in vitro at the Laboratory of Plant Bacteriology, Faculty of Agriculture, UGM. The isolates were inoculated on patchouli plant and adapted for one week before planting. The plants treated with fluorescent pseudomonad isolates were planted in the field infected with pathogen on October 2003. The experiment was arranged in a randomized block design (RBD) with six replications. The assessment parameters were incubation period, disease intensity, plant growth and production of patchouli plants. The results showed that fluorescent pseudomonad isolates could control the bacterial wilt disease and delay the incubation period 6-52 days and decrease the disease intensity 31,11–50,56%. In addition fluorescent pseudomonad isolates could affect the increase of plant growth, i.e. plant height ( 6,7 – 26,3 cm ), leaf numbers (4,6 – 30,1 leaves/plant) and dry weight of leaves (24,5 – 154,3 g/plant), and plant production, especially oil content (4,8 – 22,3 ml/plant). The results of the experiment showed that Pf 91 isolate had the highest antagonistic activity on controlling the bacterial wilt disease on field. Key words : Patchouli, Pogostemon cablin Benth, wilt disease, bacterial, biological control, fluorescent pseudomonad