Studi pengendalian hayati penyakit Lincat Tembakau dengan menggunakan kombinasi Pseudomonad Fluoresen, Bacillus Spp., dan Streptomyces Spp

DJATMIKO, Heru Adi, Promotor Dr.Ir. Triwidodo Arwiyanto, M.Sc

2006 | Disertasi | S3 Ilmu Pertanian

Penyakit “lincat” yang disebabkan oleh Ralstonia solanacearum dan Meloidogyne incognita merupakan salah satu penyakit penting yang timbul pada tembakau di lahan tegal pada ketinggian 800–1100 m dpl. Penyakit ini menyebabkan kematian tembakau lebih dari 50% dan menurunkan produktivitas 60%. Penelitian ini bertujuan untuk: (1) mengkarakterisasi pseudomonad fluoresen asal rizosfer cabai dan kacang tanah, Bacillus spp.asal rizosfer cabai, dan Streptomyces spp. asal rizosfer terung sebagai agensia pengendali hayati, (2) mengetahui kemampuan bakteri antagonis tersebut dalam menekan patogen lincat in vitro dan penyakit lincat selain antibiosis di lapangan, (3) mendapatkan kombinasi antagonis pseudomonad fluoresen, Bacillus spp., dan Streptomyces spp. untuk menekan penyakit lincat di lapangan, (4) mengetahui pengaruh kombinasi pseudomonad fluoresen, Bacillus spp., dan Streptomyces spp. terhadap pertumbuhan dan hasil tembakau temanggung di lapangan. Penelitian terdiri atas delapan tahap, yaitu: (1) karakterisasi antagonis, (2) seleksi kombinasi antagonis di lapangan, (3) pemantapan antagonis di rumah kaca, (4) penekanan patogen lincat in vitro, (5) pengujian kompatibilitas antagonis (6) daya tahan bakteri antagonis dalam pupuk kandang, (7) pengujian mutan antibiosis, dan (8) pengaruh kombinasi antagonis terhadap penekanan penyakit lincat, pertumbuhan dan hasil tembakau temanggung di lapangan. Hasil penelitian menunjukkan bahwa: (1) isolat bakteri asal rizosfer cabai (Pf51), kacang tanah (Pf83), cabai (Ba4, Ba22), dan terung (S4 dan S7) yang dikarakterisasi termasuk dalam pseudomonad fluoresen, Bacillus spp., dan Streptomyces spp. Keenam antagonis tersebut mampu memanfaatkan beberapa senyawa karbon dan nitrogen, mendegradasi makromolekul, mampu tumbuh pada berbagai suhu dan kandungan garam, dan mempunyai kemampuan tumbuh pada medium yang mengandung kitin dan pektin, (2) kombinasi dua dan tiga antagonis mempunyai kemampuan menekan penyakit lincat lebih baik dibandingkan dengan satu antagonis baik dalam seleksi kombinasi antagonis di lapangan dan pemantapan antagonis di rumah kaca, (3) antagonis yang mempunyai kemampuan paling baik dalam menekan patogen lincat adalah S4 (Streptomyces spp.). Keenam antagonis yang diuji mempunyai kemampuan menekan R. solanacearum dengan cara antibiosis, (4) kompatibilitas antarantagonis yang paling baik yaitu Pf51 terhadap Pf83 dan Ba22 atau sebaliknya, (5) keenam antagonis mampu bertahan dalam pupuk kandang selama 4 minggu dan mampu menurunkan populasi total jamur, (6) mutan antibiosis antagonis Bacillus spp.(Ba4ant-) mempunyai kemampuan menekan penyakit lincat tembakau paling baik dengan mekanisme lain selain antibiosis di lapangan. Mutan antibiosis antagonis yang paling baik meningkatkan pertumbuhan dan hasil tembakau masing-masing Pf51ant- dan S4ant-, (7) kombinasi antagonis yang cenderung mempunyai kemampuan paling baik dalam menekan penyakit lincat dan meningkatkan pertumbuhan tembakau di lapangan yaitu Ba22 Pf83 S7., dan (8) kombinasi antagonis Bacillus spp. dan Streptomyces spp. (Ba4 S7) merupakan kombinasi antagonis yang cenderung mempunyai kemampuan paling baik dalam meningkatkan hasil tembakau di lapangan.

“Lincat” disease caused by Ralstonia solanacearum and Meloidogyne incognita is one of the important diseases affecting tobacco in non irrigated upland soils with altitude of 800 to 1100 m above sea level. The disease causes wilting of more than 50% of the plants and decrease productivity of 60%. The objectives of the research were to: (1) partially characterize fluorescent pseudomonad from pepper and peanut rhizosphere, Bacillus spp. from pepper rhizosphere, and Streptomyces spp. from eggplant rhizosphere, (2) study the ability of the antagonistic bacteria in suppressing the pathogens in vitro and the disease by other mechanisms than antibiosis in the field, (3) find out combination between fluorescent pseudomonad, Bacillus spp., and Streptomyces spp. to suppress the disease in the field, (4) study effect of the combinations on growth and yield of temanggung tobacco in the field. The research consisted of eight stages, i.e., (1) characterization of antagonists, (2) selection of antagonistic combination in the field, (3) stabilization of antagonists at the glasshouse, (4) suppression of the pathogens in vitro, (5) testing of antagonist compatibility, (6) survival of antagonistic bacteria in dung manure, (7) testing of antibiosis mutants, and (8) the effect of antagonist combination on the disease suppressions, growth and yield of the tobacco in the field. The result indicated that: (1) bacterial isolates from the rhizosphere of pepper (Pf51), peanut (Pf83), pepper (Ba4, Ba22) and eggplant (S4 and S7) were grouped in fluorescent pseudomonad, Bacillus spp., and Streptomyces spp. The sixth antagonists were able to utilize some carbon and nitrogen compounds, degrade macromolecules, grew at different temperatures and salt contents, and grew at medium with chitin and pectin, (2) combination of two and three antagonists were able to suppress lincat disease better than one antagonist in the field and glasshouse, (3) the antagonist having the best ability in suppressing lincat pathogens was S4 (Streptomyces spp.). The sixth antagonists could suppress R. solanacearum by antibiosis mechanism, (4) the best antagonist compatibility was Pf51 to Pf83 and Ba22 or just the opposite, (5) the sixth antagonists could survive in dung manure for 4 weeks and decrease total population of fungi, (6) mutant antibiosis of Bacillus spp. (Ba4ant-) tending to have suppress lincat disease by other mechanism than antibiosis in the field. The best antibiosis mutant of the antagonist which could increase growth and yield of tobacco was Pf51ant- and S4ant-, respectively, (7) antagonist combinations tending to have the best ability in suppressing the lincat disease and increasing growth of tobacco in the field was Ba22 Pf83 S7., and (8) combination of Bacillus spp. and Streptomyces spp. (Ba4 S7) was the best combination tended to have the best ability in increasing yield of tobacco in the field.

Kata Kunci : Penyakit Lincat Tembakau, Pengendalian Hayati, Pseudomonad Fluoresen