Judul: Keefektifan Trichoderma harzianum dan Media Pupuk Kandang dalam Mengendalikan Busuk Pangkal Batang Fusarium oxysporum Tanaman Bawang Daun
Abstrak: Stem rot disease (Fusarium oxysporum) is an important disease of welsh onion. T. harzianum can suppress this disease (F. oxysporum) effectively. Manure contains rich of organic compounds which can increase antagonistic activity of T. harzianum and can induce plant resistance. This study is to evaluate potential uses of T. harzianum and manure formulation to suppress the growth of F. oxysporum. Factor of this study are combination of T. harzianum with chick manure (PAT), T. harzianum with cow manure (PST), T. harzianum with sheep manure (PDT), T. harzianum with rabbit manure (PKT), T. harzianum (T), fungicide (F), control (K), on yield using a complete block randomized design with five replications. In addition, this study also done in vitro test between T. harzianum with F. oxysporum, in laboratory using a complete rondomized design with three replication and isolation microbe from manure. In vitro test have shown that T. harzianum can suppressed F. oxysporum about 74.36%. Eficacy test have shown that addition chick, sheep, cow, and rabbit manure with T. harzianum not effective to controlling stem rot disease by F. oxysporum. Microbe population in chick manure has found hightly than other manure. Fungi in sheep manure more have variation than other manure.
Keyword: Bogor Agricultural University (IPB), welsh onion., T. harzianum, manure, F. oxysporum

Judul: Keefektifan Trichoderma harzianum dan Trichoderma koningii dalam Pengendalian Penyakit Moler pada Bawang Merah
Abstrak: Penyakit moler yang disebabkan oleh Fusarium oxysporum f.sp. cepae merupakan salah satu faktor pembatas produksi bawang merah. Gejala yang ditunjukkan yaitu daun terpelintir, memanjang abnormal, menguning, layu, serta pembusukan umbi atau perakaran. Upaya pengendalian penyakit moler saat ini masih ditekankan pada teknik pengendalian dengan menggunakan fungisida. Trichoderma harzianum dan Trichoderma koningii perlu diupayakan sebagai alternatif pengendalian hayati. Penelitian ini bertujuan mengetahui keefektifan Trichoderma harzianum dan Trichoderma koningii serta kombinasinya dalam pengendalian penyakit moler pada bawang merah. Pengujian in vitro menunjukkan T. harzianum and T. koningii dapat menghambat pertumbuhan Fusarium oxysporum f.sp. cepae sebesar 67% and 63.6% dalam 6 hari. Mekanisme penghambatan antara cendawan antagonis dan cendawan patogen yaitu kompetisi, antibiosis dan hiperparasitisme. Hasil uji in planta menunjukkan pada 25 hari setelah inokulasi (hsi), perlakuan tunggal T. harzianum, T. koningii dan kombinasinya dapat menekan insidensi penyakit (80% - 90%). Perlakuan kontrol tanpa agens hayati memiliki insidensi penyakit (100%) dan periode inkubasi 9.3 hsi. Perlakuan dengan agens hayati tidak memberikan efek terhadap vigor pertumbuhan tanaman selama 4 minggu masa tanam (MST). Perlakuan tunggal T. harzianum, T. koningii dan kombinasinya menunjukkan potensi yang tinggi sebagai agens hayati dalam pengendalian penyakit moler. Perlakuan tunggal T. harzianum atau T. koningii lebih direkomendasikan sebagai alternatif pengendalian yang efektif dan efisien.
Keyword: Trichoderma spp., Fusarium oxysporum, bawang, antagonisme

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
Keyword: