Judul: Pengaruh Provenan Sengon Terhadap Perkembangan Larva Boktor (Xystrocera Festiva Thoms) Dalam Makanan Buatan (Artificial Diet)
Abstrak: Problem which is most commonly encountered in the management of sengon plantation forest, at present was the attack by stem borer insect Xystrocera festiva Thoms, a pest which is more often referred to as boktor, uter-uter, wowolan, and engkes-engkes. Up to now, the effective and efficient specific control for boktor pest, has not been discovered yet. One method which had ever been practiced was slicing the sengon bark and discarding the boktor larvae existing inside the tree. However, this practice will damage the physiological process of sengon trees, and this will in turn reduce the quality and price of sengon wood. One of the cause which makes the control of boktor has not been fully successful is the lack of knowledge concerning this insect, particularly in its larval stadium (the damaging phase), when this insect larvae live under the bark, which makes the study of biology and physiology of the insect difficult. For overcoming this phenomenon, a laboratory research was conducted where the boktor insects were reproduced and observed while being raised using artificial diet. This research was useful for obtaining information on the behavior and life cycle of boktor. The objectives of this research were learning the effects of provenance, tree health condition (sick or healthy condition of trees) and artificial diet on the growth of boktor larvae, and seeking the appropriate composition of artificial diet for boktor larvae. Materials used in this research were sengon wood powder from Kediri and Subang provenance with two kinds of tree condition (sick and healthy trees) while each of them had undergone freeze drying process, yeast extract, streptomycin, sucrose, agar, aquadest, vitamin C, vitamin B, benzoate, NaCl, dolomite, olive oil, and small sized boktor larvae (1.4 – 2.4 cm). The parameters observed and measured were larvae weight, weight of consumed food by the boktor larvae, larvae length, and diameter of boktor larvae head. Observation and measurements were conducted each week for 8 weeks, while conducting also food change. Results of analysis of variance showed that the provenance factor exhibited the greatest and significant effect on larvae growth (larvae length, diameter of larvae head) and amount of food consumed by the boktor larvae. On the other hand, factor of tree condition did not create significant effect on all parameters for 7 weeks. Factor of tree condition was seen to have effect on week 8. Patterns of average growth of larvae weight and length, for all treatments showed significant decrease in week-5 and 6. This phenomenon occurred because at week 5 and 6, many larvae underwent ecdysis (molting). Results of Duncan test showed that Subang provenance gave the best effect. The best growth of boktor larvae, namely those of Subang provenance had larvae length increment of 2.53 mm and larvae head diameter increment of 0.166 mm. Feeding behavior of boktor larvae during the laboratory research, using artificial diet, was similar with that in the field. Keywords: sengon, artificial diet, boktor
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Judul: Perkembangan Larva Boktor (Xystrocera festiva Pascoe) di dalam Artificial Diet.
Abstrak: Salah satu upaya yang dapat dilakukan untuk mengatasi kebutuhan kayu yaitu dengan membangun Hutan Tanaman Industri (HTI). Kegiatan tersebut dapat dilaksanakan dengan menanam jenis tanaman yang cepat tumbuh. Salah satu jenis yang memenuhi syarat tersebut yaitu tanaman sengon. Namun masalah hama boktor (Xystrocera festiva Pascoe) merupakan kendala yang cukup penting dalam pengusahaan tanaman sengon. Hal tersebut memerlukan penanganan pengendalian hama yang efektif dan efesien. Belum efesiennya pengendalian hama boktor karena kurangnya pengetahuan tentang serangga boktor, khususnya dari segi fisiologi dan biologi. Salah satu alternatif yang dapat dilakukan yaitu dengan cara memelihara larva boktor di laboratorium dalam makan buatan (artificial diet). Tujuan penelitian ini untuk menjelaskan pengaruh provenan sengon (Kediri dan Solomon) dan pengaruh kondisi pohon (sehat dan sakit) terhadap perkembangan larva boktor. Manfaat dari penelitian ini adalah dapat mempelajari dan memperoleh informasi tentang pola perkembangan larva boktor. Bahan yang digunakan dalam penelitian ini adalah serbuk kulit dan batang sengon yang terdiri dari provenan Salomon kondisi sakit dan sehat, provenan Kediri kondisi sakit dan sehat (masing-masing telah diproses secara freeze dry), yeast extract, streptomycin, sukrosa, agar, aquades, ascorbic acid (vitamin C), Na benzoat dan larva berukuran kecil (panjang 1,5-2,5 cm). Parameter yang diamati yaitu berat larva, panjang larva, diameter kepala larva, dan berat makanan yang dikonsumsi oleh larva boktor. Pengukuran dan penggantian makanan dilakukan setiap dua minggu sekali.
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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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