Judul: Potensi Seduhan Vermikompos untuk Pengendalian Penyakit Karat Daun (Puccinia arachidis Speg.) pada Tanaman Kacang Tanah (Arachis hypogaea L.)
Abstrak: One of important disease in groundnuts is leaf rust disease that caused by P. arachidis Speg. The effectiveness of vermicompost tea derived from worm castings was tested against the rust in groundnut leaf. The objective of this research was investigating the potency of vermicompost tea as controlling agent against the rust in groundnut leaf. The test was performed to observe (1) possibility of phytotoxin action in vermicompost tea against the plants, (2) effect of vermicompost tea in germination of P. arachidis uredospores in vitro, (3) ability of vermicompost tea to suppress growth of the rust disease in vivo. Vermicompost tea was tested in two preparations including aerated vermicompost tea and non-aerated vermicompost tea at concentrations 12.5, 25, 50, 75, and 100% respectively. This concentrations were applied both in germination test and the rust growth test. Results showed that aerated vermicompost tea and nonaerated vermicompost tea are not phytotoxin to the tested groundnuts and able to suppress uredospores germination and the rust growth by P. arachidis.
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Judul: Pengaruh Plant Growth Promoting Rhizobacteria (PGPR) dan Pupuk Mikro terhadap Penyakit Karat Puru dan Pertumbuhan Tanaman Sengon (Paraserianthes falcataria) di Lapangan
Abstrak: Albizia is one of the forest tree which was chosen by many farmers to be cultvated as wood source. Gall rust caused by Uromycladium tepperianum is a most devastating disease in albizia plantation in Java. Until now there is no effective control technique to suppress rust gall disease. The treatments was PGPR by the dosage of 1:50 and 1:100 (mixed with synthetic fertilizer), the micro fertilizer, the combination of PGPR and micro fertilizer, and fungcide a.i. mancozeb. The experiment was done by randomized block design by four blocks. The research were caried out in field scale for 11 week. The heigh of the plants, the diameter of trunk, diseases incidence and disease severity were measure. Beside that the AUDPC (Area Under Disease Progress Curve) and the development of the disease were calculated. Based on this research, PGPR 50 and PGPR 100 are proven to be effective in suppressing gall rust and increasing plant growth. But the micro fertilizer (guano) and PGPR + micro fertilizer were not effective in in suppressing gall rust and increasing plant growth
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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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