Judul: Serangan Hama Uret di Perkebunan Tebu Jengkol Kabupaten Kediri
Abstrak: Sugarcane is one of the major estate commodities as source of white sugar. Among constraints limit the sugarcane culture is damage by grubs that could reduce 45% - 60% sugar production. The objective of this research is to study the damage caused by whitegrub and their natural enemies in Jengkol plantation, owned by Pesantren Baru Sugar Factory PTPN X Plosoklaten, District Kediri, East Java Province. The research has been conducted from July 2014 until August 2014. Observation of the grub infestation has been carried out in 23 fields covering 4.10 to 12.95 Ha each field. Using diagonal method, five plots in each field and five subplots in each plot were determined to be sampled. In each subplot digging was done to check the presence of insect pest. The collected insect then reared and observed in the laboratory. The result showed that all insect samples were in the larval stage, consisted of two species i.e. Lepidiota stigma (Coleoptera: Scarabeideae) and Euchlora viridis (Coleoptera: Scarabeideae). Of the collected samples, 95.23 % were dominated by E. viridis. The plant damage were not in correlation with the clone of sugarcane. The infestation of white grubs on sugarcane in Jengkol estate was estimated low, ranged between 0.01% – 10.6%. In this estate neither parasitoids nor entomopathogenic fungi were found. Presumably the intensive use of chemical insecticides limited the pest population and caused the absence of parasitoid and entomopathogenic fungi.
Keyword: Bogor Agricultural University (IPB), parasitoid, clone, Euchlora viridis, Lepidiota stigma

Judul: Hama-Hama pada Tanaman Tebu (Saccharum officinarum) di PG Madukismo PT Madubaru Yogyakarta
Abstrak: Tebu (Saccharum officinarum) merupakan salah satu komoditas perkebunan unggulan yang mempunyai peranan penting sebagai bahan baku produksi gula. Budi daya tebu tidak lepas dari serangan organisme pengganggu tanaman (OPT), terutama hama. Informasi mengenai hama spesifik lokasi penting diketahui sebagai rujukan dalam melakukan pengendalian di lokasi tersebut. Penelitian ini bertujuan mengetahui berbagai jenis hama pada tanaman tebu dan intensitas serangan hama utama di PG Madukismo, PT Madubaru, Yogyakarta. Penelitian diawali dengan menentukan tanaman contoh menggunakan metode diagonal. Pengamatan hama dilakukan dalam interval waktu dua minggu sebanyak empat kali meliputi koleksi, identifikasi hama, pencatatan gejala kerusakan yang ditimbulkan, dan menghitung intensitas serangan hama. Tahap identifikasi dilakukan di Laboratorium Invertebrata Hama, Departemen Hama dan Penyakit Tanaman, Fakultas Pertanian, Universitas Gadjah Mada dan Laboratorium Biosistematika Serangga, Departemen Proteksi Tanaman, Fakultas Pertanian, Institut Pertanian Bogor. Hama yang ditemukan menyerang tanaman tebu selama pengamatan, yaitu Lepidiota stigma (Coleoptera: Scarabaeidae), Euchlora viridis (Coleoptera: Scarabaeidae), Chilo sacchariphagus (Lepidoptera: Crambidae), Scirpophaga excerptalis (Lepidoptera: Crambidae), Rattus argentiventer (Rodentia: Muridae), Saccharicoccus sacchari (Hemiptera: Pseudococcidae), Pyrilla perpusilla (Hemiptera: Fulgoridae), dan Valanga nigricornis (Orthoptera: Acrididae). Uret (Lepidiota stigma dan Euchlora viridis) adalah hama yang paling dominan dengan intensitas serangan tertinggi.
Keyword: attack intensity, Lepidiota stigma, Rattus argentiventer

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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