Judul: Screening and Characterization of Bacterial Antagonists as Potential Agents for the Biological Control of the Chrysanthemum White Rust Disease
Abstrak: White rust disease caused by Puccinia horiana (Basidiomycetes: Uredinales) is the major problem on chrysanthemum plantation and caused yield lost until 100%. Biocontrol is an alternative way to control this disease. Therefore, the aims of this study are to obtain antagonist bacterial as biocontrol agents of chrysanthemum white rust disease, to identify the potential isolate and their biocontrol character, charachterized their biocontrol mechanism, and to know the role of their chitinolytic activity on germination of teliospore. The methods used in this study are selection of antagonistic bacteria which are able to control this disease in-vitro, characterized of potential antagonist bacteria with polymerase chain reaction of a 16S rRNA gene and physiology and biochemical character, characterized the mechanism of inhibition teliospore germination, and the role of chitinolytic activity in antagonism activity using transposon mutagenesis. The result showed that out of 29 bacterial isolates, 12 isolates had chitinolityc activity. The twelve isolates were the potential antagonist agents to control teliospore germination with percentage above 90%. Isolate K2 was the most potential antagonist bacteria to control this disease. This isolate could inhibit the germination up to 98% and had the highest chitinolytic activity among the isolates. Based on 16S rRNA gene partial sequences analysis and physiology and biochemical characters, this isolate was identified as Chromobacterium sp. The major mechanism was antibiosis. It is showed from the biocontrol activity which are bacteria’s cell colonization, lytic activity, and disintegrated of protoplasm. This bacteria produced cyanide acid (HCN) and phenazine beside chitinolytic enzyme. Chitinolytic activity was not a single factor in the mechanism of antibiosis but other secondary metabolic compounds produced by this bacteria also come into play. It is showed on the results of mutagenesis that transconjugants which had no chitinolytic activity was still able to inhibit germination of teliospora, whereas transconjugants which still had an activity equal to or smaller than wild type bacteria, the inhibitory were lower. It was indicated that chitinase was not the most important compound that inhibited the germination of teliopsore. There was another compound have the bigger role such as hydrogen cyanide, phenazine, or other substances produced by Chromobacterium sp..
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Judul: The Use of Trichoderma hamatum and Fluorescent Pseudomonad BJ10-86 in Controlling Phytophthora capsici on Chili (Capsicum
Abstrak: Phytophthora capsici is an important plant infecting oomycete with a worldwide/cosmopolitan distribution. The pathogen has a wide host range, especially capsicums and cucurbits, and attacks nearly all plant parts and at all growth stages. Chemical control is proofing no longer effective due to reported pathogen resistance development, not to mention the related environmental concerns and the consumer demands for low, if not zero, use of fungicides. Biological control is a sustainable option. Several biocontol agents have been reported effective against this pathogen. In this research, the biocontrol activities of Trichoderma hamatum and fluorescent pseudomonad BJ10-86 against P. capsici were studied in order to propose an optimization of their application. The objectives of the biological control application were to improve chili pepper seed germination, reduce damping off disease incidence, and improve the growth of the seedlings. The studies were done in vitro as well as seed treatment assays and polybag application experiments. Fluorescent pseudomonad isolate BJ10-86 was subjected to molecular identification by amplifying the 16S rRNA region and sequencing the nucleotides before searching for similar sequences in the BLAST search engine. The isolate was identified as Pseudomonas aeruginosa and deposited in the GenBank under the accession number KM102771 as P. aeruginosa BJ10-86. The in vitro experiments involved plating the micro-organisms in dual and triple culture assays on agar media. The results showed that both biocontrol agents were compatible and increased the inhibition of P. capsici. Chili pepper seeds treated with the biocontrol agents, individually or in combination, were sown in commercial nursery media that had been pre-inoculated with P. capsici zoospores. Results of data collected over a period of 35 days indicated that seed treatment significantly (P=0.008) reduced damping off disease incidence. Combined application of T. hamatum and fluorescent pseudomonad BJ10-86 was the best biocontrol treatment with an area under disease progress curve (AUDPC) of only 36.61 units compared to 92.87 units in the control treatment. This combination was seen to increase biocontrol efficacy to 60.58%. Both organisms evidently had a synergistic interaction. Seed treatment had no effect on seed germination and seedling growth. In further experiments, the objective was to utilize synergism between T. hamatum and fluorescent pseudomonad BJ10-86 in order to reduce root and collar rot caused by P. capsici and promote chili pepper plant growth under field conditions. The treatments involved individual and combined polybag application of the biocontrol agents as conidial and bacterial cell suspension as soil drench. These were either administered 14 days before transplanting or during the transplanting day. The results indicated that fluorescent pseudomonad BJ10-86 increased the chili pepper plant height and number of leaves. Combined T. hamatum and fluorescent pseudomonad BJ10-86 had synergistic effects against root and collar rot disease incidence through delaying the disease onset. For better effects, these combined application of biocontrol agents should be at least 14 days before transplanting. Based on these findings, it is proposed that chili pepper seeds should be treated with a combination of both organisms. These organisms are effective at concentrations of 2×108 CFU ml-1 and 9.4×105 spores ml-1 for P. aeruginosa BJ10-86 and T. hamatum respectively.
Keyword: biological control, damping off, collar rot, synergism, growth promotion

Judul: Studi kasus migran pedagang kaki lima di pasar Senen, Jakarta Pusat
Abstrak: Sejak Jakarta menjadi ibukota negara RI, Jakarta tidak pernah sepi dari arus migrasi penduduk. Masuknya para migran ke Jakarta disebabkan karena pertumbuhan fisik yang nyata, yaitu dari pembangunan gedung perkantoran, fasilitas hiburan dan lainnya, memberi daya tarik bagi orang bukan penduduk Jakarta. Termasuk di antara migran adalah kaum golongan kecil yang berasal dari kalangan sirkuit bawah desa. Alasan utama migrasi di sirkuit bawah, yaitu khususnya yang akhirnya bekerja sebagai pedagang kaki lima di Pasar Senen ini pindah ke Jakarta, adalahJakarta menawarkan kesempatan kerja bagi siapa saja yang mau bekerja. Karena di desa tak ada pekerjaan yang dapat menampung golongan muda, kaum migran meninggalkan desa menuju Jakarta. Pola migrasi masuk ke Jakarta tidak dipengaruhi oleh kemungkinan golongan muda mampir di kota-kota kecil sebelum tiba di Jakarta. Keberanian dan tekad bulat meninggalkan desa asal didorong pula oleh sumber cerita tentang Jakarta (saudara/kenalan) yang juga mengalami bahwa setiba di Jakarta mereka akan langsung bekerja. Pendidikan rendah, tidak memiliki ketrampilan, orang petani/buruh tani, merupakan bagian kecil latar tua belakang sosial migran pedagang kaki lima. Memperoleh pekerjaan apa saja asal halal pada mulanya, tempat tinggal dimana saja, modal kecil dan pendapatan harian yang rendah juga mewarnai hidup para migran pedagang kaki lima di Jakarta. Namun sekalipun demikian mereka tetap hidup, bahkan dapat mengirim uang ke desa asal, pulang ke desa minimum setahun sekali dan sedikit-sedikit mampumenabung. Bekerja sebagai pedagang kaki lima sudah ditekuni selama lebih dari lima tahun bahkan ada yang lebih dari tujuh tahun. Inipun dimulai setelah minimum selama dua tahun migran mengerjakan apa saja di Pasar Senen: yang penting dapat uang dan bisa hidup di Jakarta. Bahkan modal membuka usaha kaki lima diperoleh dari selama bekerja mula-mula itu. untuk pengumpulan upah Sekalipun terdapat kenaikan tingkat kehidupan sosial di kota dibandingkan dari desa, kaum migran pedagang lima di Pasar Senen ini tetap berada bawah kota. di kaki bawah sirkuit Ikatan-ikatan baru di kota hampir tidak terjadi kecuali ikatan-ikatan kedaerahan yang terus dipertahankan.
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