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: Biologi larva boktor (Xystrocera festiva Pascoe) dalam makanan buatan (Artificial diet) dengan bahan dasar serbuk kayu sengon (Paraserianthes falcataria)
Abstrak: The constraints faced in the development of sengon plantation forest is that i he sengon trees are planted in monoculture condition, they are very susceptible t -oktor (Xystrocera festiva) pest attack. During larvae stadium, boktor pest, in s r h for food, will bore sengon tree stem. This boktor larvae activity causes age on sengon trees, and even could cause death of the sengon plants. Various e • rts to control this pest have been conducted, although the results are still not e ective yet. This phenomenon was related with lack of knowledge concerning goktor larvae, because activities of this larvae occured in the inside parts of s gon trees, which made them difficult to be observed directly in the field. erefore, observation in the laboratory will help providing information on the biol gy of boktor pest, which comprise growth, life cycle, and feeding behavior. Artificial diet is an artificial food consisting of natural ingredients and chemicals with certain amount of dosage as a substitute for host plant for boktor larvae, to allow easy observation in laboratory. Materials used in this research was sengon wood powder comprising those of ijanjarnegara provenance in sick condition, Banjamegara provenance in healtpy condition, Solomon provenance in sick condition, Solomon provenance in healt y condition (each of them has undergone process of freeze dry), yeast extr ct, streptomycin, sucrose, agar, aquadest, ascorbic acid (vitamin C), benzoate, vitamin B, NaCl, dolomite, olive oil and small size boktor larvae (1.5 - 2.3 cm). The observed variables were weight of larvae, length of larvae, diameter of larvae head, and weight of food consumed by the boktor larvae. Measurement and replacement of food was conducted each week for a period of 8 weeks. Results of analysis of variance showed that factor which gave the largest contribution in creating significant effect on larvae growth (larvae weight, larvae lengili, larvae head diameter) and amount of food consumed by boktor larvae, was provenance factor. On the other hand, factor of condition (sick or healthy cond"tion of the trees which provide the wood powder) did not give significant effe on all observed variables during 6 weeks period. Factor of condition exe ed its effect, only during week-7 and week-8. Graph pattern of average gro h of larvae weight and length showed that during week -5, larvae from all treatments, on the average, underwent significant decrease in length and weight. This was because during the week -5, many of the larvae underwent molting. Results of Duncan test showed that provenance which exerted the greatest effect was Solomon provenance. The best growth of boktor larvae was in Solomon provenance with larvae weight increment of 72 mg, larvae length increment of 4.47 pun, and larvae head increment of 0.67 mm. During 8 weeks observation in laboratory, feeding behavior of boktor larvae in artificial diet was similar with fi ing behavior of boktor larvae in trees in the field .
Keyword: sengon, artificial diet, boktor

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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