Biological Control of Plant Disease Caused by Bacteria

Bacterial diseases in plants are difficult to control. The emphasis is on preventing the spread of the bacteria rather than curing the diseased plant. Integrated management measures for bacterial plant pathogens should be applied for successfull control. Biological control is one of the control measures viz. through the use of microorganisms to suppress the growth and development of bacterial plant pathogen and ultimately reduce the possibility of disease onset. The study of biological control of bacterial plant pathogen was just began compared with of fungal plant pathogen. The ecological nature of diverse bacterial plant pathogens has led scientists to apply different approach in the investigation of its biological control. The complex process of entrance to its host plant for certain soil-borne bacterial plant pathogens need special techniques and combination of more than one biological control agent. Problem and progress in controlling bacterial plant pathogens biologically will be discussed in more detail in the paper and some commercial products of biological control agents (biopesticides) will be introduced. Penyakit tumbuhan karena bakteri sulit dikendalikan. Penekanan pengendalian adalah pada pencegahan penyebaran bakteri patogen dan bukan pada penyembuhan tanaman yang sudah sakit. Untuk suksesnya pengendalian bakteri patogen tumbuhan diperlukan cara pengelolaan yang terpadu. Pengendalian secara biologi merupakan salah satu cara pengendalian dengan menggunakan mikroorganisme untuk menekan pertumbuhan dan perkembangan bakteri patogen tumbuhan dengan tujuan akhir menurunkan kemungkinan timbulnya penyakit. Sifat ekologi bakteri patogen tumbuhan yang berbeda-beda mengharuskan pendekatan yang berbeda pula dalam pengendaliannya secara biologi. Masalah dan perkembangan dalam pengendalian bakteri patogen tumbuhan secara biologi didiskusikan secara detail dalam makalah ini

Biological Control of Bacterial Wilt in South East Asia

Bacterial wilt disease caused by Ralstonia solanacearum destroys many crops of different plant families in South East Asia despite many researches about the disease, and the availability of developed control method in other parts of the world. There is no chemical available for the bacterial wilt pathogen and biological control is then chosen as an alternative to save the crops. Most of the biological control studies were based on antagonism between biological control agent and the pathogen. The biological control agents were intended to reduce the initial inoculum of the pathogen. The effort to minimize the initial inoculum of the pathogen by baiting with the use of hypersensitive host-plant was only reliable when conducted in the greenhouse experiments. Various microorganisms have been searched as possible biological control agents, for instance avirulent form of the pathogen, soil or rhizosphere bacteria (Bacillus spp. and fluorescent pseudomonads), actinomycetes (Streptomyces spp.), yeast (Pichia uillermondii, Candida ethanolica), and a consortium of microorganisms known as effective microorganisms (EM). None of these biological control agents has been used in field application and they need further investigation in order to effectively control bacterial wilt. Opportunities and challenges in developing biological control to combat bacterial wilt are discussed in the paper.Penyakit layu bakteri yang disebabkan oleh Ralstonia solanacearum menghancurkan banyak tanaman dalam famili yang berbeda di Asia Tenggara meskipun telah banyak penelitian tentang metode pengendaliannya. Penyakit ini sulit dikendalikan karena banyaknya variabilitas patogen dan belum tersedianya sumber ketahanan yang mapan. Di samping itu, sampai saat ini belum ada bahan kimia yang tersedia untuk patogen layu bakteri ini sehingga pengendalian biologi kemudian dipilih sebagai cara alternatif untuk menyelamatkan tanaman. Sebagian besar penelitian pengendalian biologi didasarkan pada antagonisme antara agen pengendalian biologi dan patogen. Agen pengendalian biologi tersebut dimaksudkan untuk mengurangi inokulum awal patogen. Upaya untuk meminimalkan inokulum awal patogen dengan umpan dengan menggunakan tanaman inang sangat rentan hanya dapat diandalkan ketika dilakukan dalam percobaan rumah kaca. Berbagai mikroorganisme telah diteliti kemungkinannya sebagai agensia pengendalian biologi seperti bentuk avirulen dari patogen, bakteri tanah atau bakteri rizosfer (Bacillus spp. dan pseudomonad fluorescen), actinomycetes (Streptomyces spp.), khamir (Pichia guillermondii, Candida ethanolica), dan konsorsium mikroorganisme yang dikenal sebagai EM (Effective Microorganisms). Meskipun demikian tidak satupun agensia pengendalian biologi ini sampai pada taraf aplikasi lapangan sehingga diperlukan penelitian lebih lanjut. Peluang dan tantangan dalam mengembangkan pengendalian biologi untuk memerangi penyakit layu bakteri dibahas pada tulisan ini

Daya Tahan Hidup Pseudomonad Fluoresen Di Dalam Matriks Organik Pilen Tembakau Survival of Fluorescent Pseudomonad in Organic Matrix of Coated Tobacco-seed

Strain Pf-20 of Pseudomonas putida and pseudomonad fluoresent isolate Pf- 33 are the biological control agents of tobacco bacterial wilt caused by Ralstonia solanacearum. The method of delivery of the biological control, however, is inefficient and laborious due to the need a lot of bacterial suspension for ipping the seedlings before transplanting. The use of cattle manure as a main substance for coating of tobacco seed was reported here. The cattle manure was sieved to 0.09 mm then mixed with 0.1% CMC and suspension of Pf-20 and Pf-33. Prior coating, the seeds were surface sterilized with 1% sodium hypochloride for 30 seconds then air dried. The sterilized seeds were coated with the matrix until the size is 1.5- 2.00 mm. The results indicated that fluorescent pseudomonad could survive longer in the coated seed when strain Pf-20 of P. putida and fluorescent pseudomonad isolate Pf-33 were used together in one formulation. Fluorescent pseudomonad could survive in the coated seed for 4 weeks. Seed germination, however, was not affected by coating with the materials stated above

Deteksi Bakteri Patogen Terbawa Benih Akor (Acacia Auriculiformis a. Cunn. Ex Benth.)

Detection of seed-borne pathogenic bacteria of northern black wattle (Acacia auriculiformis A. Cunn. ex enth.). Intensive research of seed-borne pathogen of A. mangium and A. crassicarpa which have been established in industrial timber estate (HTI) was undertaken in Indonesia, while plantings development of northern black wattle have recently been established in the 1990s. Very limited information available on northern black wattle diseases especially seed-borne diseases. The objectives of this study were to identify seed-borne pathogenic bacteria of northern black wattle and the effects on seed germination. Methods for the isolation of bacteria were by seed soaking, seed griding, blotter test, growing-on test on paper and soil. Identification of bacteria by PCR used 63F/1387R primer. The results showed that seed-borne bacteria of northern black wattle were Paenochrobactrum sp., Ralstonia sp., Burkholderia cepacia complex, Pseudomonas stutzeri, Acinetobacter sp., Alcaligenes faecalis, Salmonella bongori, Escherichia hermannii while pathogenic bacteria cause seedling leafspot were Micrococcus luteus and Burkholderia cepacia complex. Burkholderia cepacia complex, A. faecalis, Acinetobater sp., P. stutzeri, S. bongori and Ralstonia sp. reduced seed germination and increased rotten seed, suggested that they were the pathogenic bacteria of northern black wattle seed. Ralstonia sp. significantly increased the percentage of rotten seed and decreased shoot length and root length. P. stutzeri and S. bongori significantly inhibited the root growth. Paenochrobactrum sp. and E. hermannii were assumed as pathogen with weak virulence due to seed germination, the percentage of rotten seed and vigour index were relatively similar to untreated seed

Penapisan PGPF untuk Pengendalian Penyakit Busuk Lunak Lidah Buaya (Aloe Vera) di Tanah Gambut

Aloe (Aloe vera) planted in West Borneo peat soil is well known as having the best product quality in Indonesia. Soft rot disease is one of the constraints of Aloe cultivation on peat soil. Many methods have no significant result for controlling this disease. This research objectives are to obtain Plant Growth Promoting Fungi (PGPF) for controlling Aloe bacterial soft rot in peat soil. The research was conducted in Clinical Laboratory of Plant Pathology and glass house of Faculty of Agriculture, Gadjah Mada University, Yogyakarta from October 2008 to September 2009. The methods included fungal isolation from peat land, hypovirulent and PGPF ability test, and biological control test in the glass house. Among 42 peat soil fungi tested, 28 isolates were hypovirulent and only 2 isolates i.e. SNTH001 (Penicillium sp.) and SNTH003 (Aspergillus sp.) showed the PGPF ability. Glass house trial showed that single application of SNTH001 and SNTH003 isolates were able to increase the growth of Aloe. In the biological control of Aloe soft rot disease test showed that the lowest intensity (25%) might be obtained by using SNTH001 isolate. Lidah buaya (Aloe vera) asal tanah gambut Kalimantan Barat dikenal mempunyai kualitas terbaik di Indonesia. Penyakit busuk lunak yang disebabkan oleh bakterimerupakan salah satu kendala dalam pengembangan tanaman lidah buaya dilahan gambut dan beberapa cara pengendalian yang telah dilakukan belum memberikan hasil nyata. Penelitian ini bertujuan untuk mencari jamur asal tanah gambut yang mampu berperan sebagai Pemacu Pertumbuhan Tanaman untuk pengendalian penyakit busuk lunak di tanah gambut. Penelitian telah dilakukan di Laboratorium Ilmu Penyakit Tumbuhan Klinik dan Rumah Kaca Fakultas Pertanian UGM Yogyakarta dari bulan Oktober 2008 sampai September 2009, meliputi isolasi jamur dari tanah gambut, uji hipovirulensi dan uji kemampuan sebagai PGPF serta uji pengendalian hayati penyakit busuk lunak lidah buaya di rumah kaca. Dari 42 isolat jamurtanah yang diuji, diperoleh 28 isolat hipovirulen dan setelah diuji kemampuan sebagai PGPF didapatkan dua isolat yang mampu berperan sebagai PGPF, yaitu isolat SNTH003 (Aspergillus sp.) dan SNTH001 (Penicillium sp.). Pemberian kedua isolattersebutsecara tunggalmampumeningkatkan pertumbuhan lidah buaya lebih baik dibandingkan kontrol. Dalam uji pengendalian penyakit, pemberian dua isolat ini mampu mengurangi intensitas penyakit.Intensitas penyakit terendah diperoleh dari pemberian isolat SNTH001 (Penicillium sp.) yaitu sebesar 25%

Uji Penggabungan Pgpf Dan Pseudomonas Putida Strain Pf-20 Dalam Pengendalian Hayati Penyakit Busuk Lunak Lidah Buaya Di Tanah Gambut

Aloe (Aloe vera L. Webb) planted in West Borneo peat land is well known to have the best product quality in Indonesia. Bacterial soft rot is one of the constraints on aloe cultivation on peat land. Many methods have not given significant result for controlling this disease. The research objectives were to study the application of PGPF and its combination with Pseudomonas putida Pf-20 for controlling aloe bacterial soft rot on peat land. In vitro test showed that two isolates of PGPF tested had different respons when combining with P. putida Pf-20. The bacterial P. putida Pf-20 inhibit the growth of PGPF SNTH003 (Aspergillus sp.) as 20.14% on King\u27s B and 7.48% on PDA, whereas SNTH001 (Penicillium sp.) as 62.4% on King\u27s B dan 34.39% on PDA. Glass house trial showed that root dipping in P. putida Pf-20 suspension could not promote the growth of aloe, but could reduce the disease intensity. The single application of SNTH001 and SNTH003 isolates were able to increase the growth of aloe compare with its combination each of PGPF isolates with P. putida Pf-20. Single application of SNTH003, SNTH001 and P. putida Pf-20 was able to reduce the disease intensity of bacterial soft rot, but the capability decreased when each of PGPF combined with P. putida Pf-20. However combination between SNTH003 and P. putida Pf-20 increased that disease intensity. The lowest disease intensty (25%) obtained by using SNTH001 isolate

Karakteristik Fisiologis Ralstonia Solanacearum Penyebab Penyakit Layu Bakteri Nilam

Physiological characteristics of Ralstonia solanacearumcausing bacterial wilt disease on patchouli plantThe study of characteristics of Ralstonia solanacearum causingbacterial wilt disease on patchouli plant was conducted in the patchouliplant field in Pasaman Barat West Sumatera and bacteriological laboratoryand green house of Agricultural Faculty of Gadjah Mada University,Yogyakarta. The field activity were identification of disease symptom andcollection of infected plant by bacterial disease from the patchouli plantfield that have the height disease intensity (more than 75%) that wasconducted on January 2003. Activity of laboratory and green house wereisolation and assay of bacterial morphology, hypersensitive andpathogenicity test, bacteriological characteristic, fluorescens pigment,antibiotic, biotype and ras pathology were conducted from January toAugust 2003. Results showed that 31 isolates showed hypersensitivereaction on tobacco leaf. Twenty isolates infected patchouly plant withwilt symptoms with incubation period 14.6 – 39.3 days after inoculation.Ns 31 was the most virulent isolate. Analytic results of bacteriologicalcharacteristic showed that the bacterial isolates of Patchouli plant fromWest Pasaman-West Sumatera is Ralstonia solanacearum. Based onbiotype and host range test, this isolates was grouped into biotype III andras one

Sebaran Penyakit Hawar Daun Bakteri Di Beberapa Sentra Produksi Bawang Merah Di Indonesia

Penelitian ini bertujuan mengetahui daerah sebaran penyakit hawar daun bakteri di beberapa sentra pertanaman bawang merah di Indonesia dan kultivar bawang merah yang dapat diinfeksi, serta mengidentifikasi patogen penyebabnya. Penentuan lokasi pengamatan dan pengambilan sampel dilakukan secara stratified purpossive random sampling. Survei dilakukan dengan cara wawancara dan pengamatan di lapangan (observasi) terhadap kultivar bawang dan gejala penyakit yang terinfeksi oleh bakteri patogen. Sampel diidentifikasi melalui pengamatan morfologi koloni, uji postulat Koch, uji reaksi hipersensitif dan pengujian sifat-sifat biokimia dan fisiologi. Hasil penelitian menunjukkan bahwa penyakit hawar daun bakteri telah tersebar secara merata di seluruh daerah pertanaman bawang merah di Indonesia, yang meliputi Kabupaten Cirebon, Tegal, Nganjuk, Bantul, dan Sigi, dengan tingkat serangan mencapai 62,5–100%. Penyakit ini menginfeksi bawang merah kultivar Bima curut, Bauji, Biru-sawah, dan Palasa. Gejala hawar daun bakteri yang dijumpai berupa water soaking, terjadi lekukan daun, pengerutan daun, klorosis, nekrosis, mati pucuk, pertumbuhan kerdil, dan kematian. Isolat bakteri yang ditemukan mempunyai bentuk koloni bulat, cembung, berlendir, dan berwarna kuning. Ciri morfologi koloni, gejala dan karakteristik isolat bakteri mirip dengan sifat-sifat bakteri Xanthomonas axonopodis pv. allii penyebab penyakit hawar daun pada bawang bombay