Judul: Pengelolaan Penyakit di Pembibitan Sengon Paraserianthes falcataria (L.) Nielsen
Abstrak: Disease management is the important aspect in determining the success of P. falcataria nursery. In the other hand, the information on disease management and technology to control disease P. falcataria nursery was limited. This study was conducted to disease inventory, to obtain information on technique for controlling disease in nursery of P. falcataria and to test of several control techniques. The study was conducted by observing, interviewing, testing several techniques of disease control, and laboratory examination. Disease control techniques consist of : tested two species of Trichoderma spp. to control damping-off disease, seed treatment on one and six months P. falcataria seedling to control the antrachnose disease. The pest and disease was founded at P. falcataria nursery which owned by CV. PMA (Parama Mulya Abadi) Desa Logending, Kec. Ayah, Kab. Kebumen is leaf-folder caterpillar, mealbug, and antrachnose disease. The Important disease in nurseries owned by CV. PMA was anthracnose caused by Colletothtrichum gloeosporioides. The tested of several techniques in P. falcataria nursery showed that the used of two species Trichoderma spp. was not effective to suppress antrachnose disease. Combination of micro fertilizer, yeast antagonists, and sanitation treatment were effective in suppressing the severity of antrachnose disease on one and six month old P. falcataria seedlings. The high intensity of antrachnose disease in nursery caused by several factors; weak of organisation fuction, unprecise used of technologies, high rainfall density, high moisture, and lack of valified human resources
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Judul: Nursery and Palm Oil Plant Pest Management in Putra Grup Agrobisnis Nursery, Pematangsiantar, Sumatera Utara.
Abstrak: Kelapa sawit (Elaeis guinensis Jacq.) merupakan komoditas pertanian yang memiliki peranan penting dan menjadi salah satu komoditas pertanian yang berkontribusi pada kenaikan Produk Domestik Bruto (PDB) Indonesia melalui kegiatan ekspor. Fase pembibitan memegang peranan penting sebagai penentu kemampuan bibit untuk tumbuh sesuai dengan kriteria pertumbuhan yang baik atau tidak. Pengamatan lapangan ini bertujuan memperoleh informasi teknis budidaya pada pembibitan kelapa sawit, melakukakan inventarisasi hama dan penyakit utama di pembibitan kelapa sawit, serta memperoleh informasi teknik pengendalian penyakit di pembibitan kelapa sawit. Pengamatan lapangan ini dilakukan dengan mengumpulkan informasi mengenai profil perusahaan dan teknis pembibitan, pengukuran pertumbuhan vegetatif tanaman serta pengamatan terhadap kemunculan organisme pengganggu tanaman di pembibitan kelapa sawit serta menganalisis dan mendeskripsikan hasil pengamatan dan wawancara. Berdasarkan pengamatan lapangan, PGA Nursery menerapkan sistem pembibitan dua tahap yaitu (pre-nursery dan main-nursery). Kegiatan di nursery meliputi pembuatan bedengan, pengisian babybag dan largebag, pendirian naungan, membuat lubang tanam, seleksi kecambah, pindah tanam penyiraman, pemupukan, pengendalian organisme pengganggu tanaman (OPT), dan pengendalian gulma. Bercak daun dan antraknosa merupakan penyakit yang paling sering ditemukan, sementara kerusakan tanaman yang umumnya diakibatkan serangan hama penyebab kerusakan pada daun dengan tipe alat mulut menggigit mengunyah. Pengelolaan OPT meliputi tindakan penanganan OPT saat kecambah (seleksi kecambah bebas penyakit), tindakan penanganan OPT bibit di pre-nursery (pemberian naungan 60%, pengendalian gulma, pengendalian OPT melalui penyemprotan pestisida), serta tindakan penanganan OPT bibit di main-nursery (pengendalian gulma, sanitasi tanaman terserang OPT, dan penyemprotan pestisida).
Keyword: antraknosa, bercak daun, kecambah, main-nursery, pre-nursery

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.
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