Judul: Biologi myzus persicae sulzer ( Homotera : Aphididae ) pada tanaman kubis dan parasitoidnya Aphidius sp. ( Hymenoptera : Braconidae )
Abstrak: Penelitian dilaksanakan di laboratorium Taksonomi, Jurusan Hama dan Penyakit Tumbuhan, Institut Pertanian Bogor. Penelitian bertujuan untuk mengetahui siklus hidup dan keperidian M. persicae pada tanaman kubis serta pertumbuhan populasi pada tanaman kubis dan sawi tanah. Selain itu diamati juga siklus hidup parasitoid Aphidius sp. pada berbagai stadia instar M. persicae. Hasil penelitian laboratorium menunjukkan bahwa rata- rata siklus hidup M. persicae adalah 8.40 hari. Rata-rata stadium nimfa pertama, kedua, ketiga dan keempat masing-masing adalah 1.75, 1.60, 1.80 dan 2.15 hari. Rata-rata masa pra kelahiran adalah 1.10 hari. Lama hidup imago rata-rata 11.35 hari. Dalam satu siklus hidup M. persicae mengalami ganti kulit sebanyak empat kali. Banyaknya nimfa yang dilahirkan oleh setiap individu rata-rata adalah 13.20 ekor. Perbedaan jenis tanaman, mempengaruhi pertumbuhan populasi M. persicae. Pada tanaman kubis pertumbuhan populasi M. persicae lebih tinggi daripada tanaman sawi tanah. Hasil pengamatan di laboratorium menunjukkan bahwa rata-rata masa perkembangan parasitoid Aphidius sp. dari telur sampai terjadi mumi pada nimfa I, II, III dan IV masing-masing adalah 8.86, 7.71, 6.20 dan 5.92 hari.
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Judul: Host Plants, Pamitoids and Hyperparasitoids of Green Peach Aphid, Myzus persicae (Sulzer) (Hornoptem: Aphididae) in the neighburhood of Bogor and Cimjur (West Java)., Tumbuhan inang, parasitoid dan hiperparasitoid kutudaun Myzus persicae (Sulzer) (Homoptera: Aphididae) di sekitar Bogor dan Cianjur, Jawa Barat
Abstrak: The green peach aphid Wtls persicae (Sulzer) is truly a cosmopolitan species, very poIyphagous, reproduces parthenogenetically in the tropics, and has a short life cycle. It is a common pest of many cultivated piants and act as vectors of many plant viruses. The predators, parasitoids and pathogens are the important natural enemies of green peach aphid and other aphids. In general this r e m h investigates the natural host plants, parasitoids, and hyperparasitoids of green peach aphid in the neighbourhood of Bogor and Cianjur (West Java). The special purpose of this resarch is to study the diversity of the host plants, the parasitoids, and hyperparasitoids of the aphid and their vertical distributions in the areas. Besides, the influence of the diversity of host crop plants and the application of insecticide on the aphid parasitoids and hrperparasitoids were also studied. Labot~torye xperiments were conducted to investigate the potential of parasitoids as agent of biological control. The results showed that the aphids' host plant diversity is high, and that plant species which are taxonomically related are potential hosts of the aphld. Dominant host plants belong to families Solanaceae and Brassicaceae. There were six species of parasitoids attacking the aphid, i,e. : Aphidius rosae Halida y, Aphidius delicat ers Baker, Aphiditrs sp., Diaeretiella rape (M' intosh) (Aphidiidae), Aphelinus asychis (Walker), and Apkelinus sp. (Aphelinidae). Four species of hyperpamitoids found attacking those parasitoids, i-e.: Aphtdencyrtus sp., Coagerus sp., Ooemyrtus sp. (Emyrtidae), and Charips sp. (Chanpidae). Population abundance and d~stributiono f the parasitoids of the aphid were influenced by the crops plant species, population density and distribution of the aphid, season, and application of insecticide. The species vertical distribution of the aphids' parasitoids and h yperparasi toids differ and apparently are influenced by the occurrence of the aphids' host plant and elevation above sea level. Laboratory experiment showed that the parasitoids D. rape, could suppressed the aphids' population to 62,7%, and the other pamitoid, Aphelinm sp. to 59,4%. The last mentioned parasitoids killed its host by host feeding, besides parasitization. The use of those parasitoids in applied biological control programs is recommended, however more researches are still needed, especially in aspects of field biaecology, mass rearing and release technologies., Kutudaun Myzus persicae (Sulzer) merupakan species yang kosmopolit, polifag, di daerah tropis berkembangbiak partogenetik dan siklus hidupnya pendek serta dapat berperan sebagai hama dan vektor penyakit virus tanaman. Predator, parasitoid dan patogen merupakan musuh alami penting kutudaun.
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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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