Judul: Tingkat infeksi Neozygites fumosa (Speare) Remaudie’re & Keller (Zygomycetes : Entomophthorales) pada kutuputih pe-paya, Paracoccus marginatus Williams & Granara de Willink dan kutuputih singkong, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) pada tanaman singkong di Wilayah Bogor
Abstrak: Cassava (Manihot esculenta CRANTZ) is one of the most important carbohydrate sources after rice and corn. The papaya mealybug, Paracoccus marginatus and the cassava mealybug, Phenacoccus manihoti have been considered as serious pests on cassava plants. The one of their natural enemy is entomophthoralean fungus. This fungus has been found infect mealybug P. marginatus in Bogor, West Java, Indonesia. However, there is no any report of this fungus infected on P. manihoti in Indonesia. The objective of this research was to explore entomophthoralean fungus on both P. marginatus and P. manihoti. The research was conducted at Sukaraja Kaum Village, and Kebon Awi Village, from March 2012 to June 2012. The mealybugs were sampled from three blocks for each plant. Each block selected 10 plant samples with cross method. The insect populations were counted from 3 parts of leaf (up-center-down). The insect samples were put on 30 ml vials of 70% alcohol. Microscope squash method was made for both mealybugs with a lactophenol-cotton blue. Populations of both species mealybug showed significantly different. Population and infections level on P. marginatus significantly different, while the population of P. manihoti not significantly different and infection levels of fungi significantly different in the two villages observation. Entomophthorales fungi species that infects both mealybug is N. fumosa. Primary conidia, secondary conidia, hyphal bodies, and saprofitic fungi were found infect on both of mealybug.
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Judul: Keanekaragaman Kutu Putih (Hemiptera:  Pseudococcidae) dan Cendawan Entomophthorales pada Berbagai Tanaman di  Kabupaten Bogor
Abstrak: Hama dan penyakit tanaman merupakan salah satu faktor penyebab menurunnya produktivitas tanaman budi daya. Hama kutu putih merupakan serangga yang umum ditemukan pada tanaman budi daya. Serangga ini bersifat polifag yang memiliki inang dari berbagai famili tanaman. Kutu putih umumnya ditemukan secara berkelompok pada bagian tanaman yang terserang dan menghisap cairan tanaman. Cendawan Entomophthorales merupakan salah satu musuh alami kutu putih. Gejala lanjut dari kutu putih yang terinfeksi cendawan Entomophthorales yaitu tubuh kutu putih berwarna abu-abu atau hitam. Tujuan dari penelitian ini adalah untuk mengetahui keanekaragaman kutu putih dan asosiasinya dengan cendawan Entomophthorales pada berbagai tanaman inang. Kutu putih dikoleksi dari tanaman alpukat, biriba, bisbul, jambu kristal, jeruk nipis, nanas, pakcoy, pisang, dan singkong. Kutu putih yang ditemukan sebanyak tujuh spesies, yaitu Dysmicoccus brevipes, Dysmicoccus lepelleyi, Exallomochlus hispidus, Ferrisia virgata, Nipaecoccus sp., Paracoccus marginatus, dan Rastrococcus marginatus. Hanya satu spesies kutu putih yang terinfeksi cendawan Entomophthorales yaitu P. marginatus yang ditemukan pada tanaman pepaya dan singkong. Fase cendawan pada kedua tanaman inang yang ditemukan pada P. marginatus adalah hyphal bodies., Plant pests and diseases are one factor cause decrease in the productivity of cultivated plants. The mealybug pests are common insect pest found on cultivated plants. These insects are polyphagous and have hosts from various plant groups. Mealybugs are generally found in clusters on infested plant parts and suck plant fluids. The entomophthoralean fungus is one of the natural enemies of mealybugs. Mealybugs with gray or black bodies are signs of advanced Entomophthoralean fungal infection. The objective of these research is to determine diversity of mealybugs and it is associated with their entomophthoralean fungus on various cultivated plants. Mealybugs were collected from avocado, biriba, bisbul, crystal guava, lime, pineapple, pakcoy, banana and cassava plants. There are seven species of Mealybugs found during this research: Dysmicoccus brevipes, D. lepelleyi, Exallomochlus hispidus, Ferrisia virgata, Nipaecoccus sp., Paracoccus marginatus, and Rastrococcus spinosus. Only one of mealybugs infected by entomophthoralean fungus is P. marginatus on papaya and cassava plants. Fungal phase on both hosts which found on to be infective P. marginatus is the hyphal body.
Keyword: hyphal bodies, P. marginatus, polyphages

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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