Judul: Distribusi Spasial Serangan dan Biologi Aulacaspis tegalensis Zehntner (Hemiptera: Diaspididae) pada Tanaman Tebu
Abstrak: The decrease of sugar production can be caused by a decrease in productivity of sugarcane, one of which is caused by pests. The sugarcane scale, Aulacaspis tegalensis, is a pest that sucks sucrose liquid stored in parenchyma cells on sugarcane stalk. The aim of this study were to determine the dispersion pattern and to observe the biology of the pest. The study was conducted at Laboratory of Insect Bionomy and Ecology, Department of Plant Protection, Faculty of Agriculture, Bogor Agricultural University and at Laboratory of Entomology, Department of Research and Development of Gunung Madu Plantations (GMP), Lampung from March to October 2014. The insect samples were collected from sugarcane field at GMP and kept in laboratory to observe its biological aspects. Field observation on the insect population was also conducted at sugarcane plantation field of GMP. The result showed that the spatial distribution pattern of A. tegelensis infestation on three varieties of sugarcane with different susceptibility were clumped. A. tegalensis have two instars nymph. The average of nymph stadia was 17.11 ±0.90 days. Pre oviposition and oviposition periods were 5.89 ± 1.12 days and 11.19 ± 6.23 days respectively. The female can lay on average of 210.03 ± 114.29 eggs during their lifetime. Eggs were laid under the female scale. The longevity of adult female was 17.13 days.
Keyword: Bogor Agricultural University (IPB), scale insect sugarcane pest., Saccharum officinarum, Gunung Madu Plantations

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: 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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