Judul: Identifikasi Kutudaun (Hemiptera: Aphididae) pada Tanaman Buah di Bogor
Abstrak: Aphids (Hemiptera: Aphididae) is a group of insect pests that have a very wide host range. Almost all plants are the host of aphids. Aphids can reduce the quality and quantity of fruit. This research aimed to know the species diversity of aphids on fruit crops in Bogor. The method used in this research is by collecting aphids and ants on 13 districts in Bogor. Sample of aphids were put in plastic bag then labelled by the location and the name of host plants. Samples then were taken to the laboratory and the number of individuals and the number of winged and wingless aphids in the colony were counted. Aphid specimens in the microscope slides were used for identification to species level using published keys based on morphological characters. Identification of aphids were using these keys: Aphids on the World’s Trees, Aphids of the World Crop, and Aphids on the World’s Herbaceous Plants and Shrubs. There were seven aphid species identified, they were Aphis gossypii Glover, Aphis spiraecola Patch, Brachycaudus helichrysi (Kaltenbach), Pentalonia nigronervosa Coquerel, Toxoptera aurantii (Boyer de Fonscolombe), Toxoptera citricidus (Kirkaldy), and Toxoptera odinae (van der Goot). T. aurantii was the most abundant aphid species found in the area. The plant family of Myrtaceae was the most host frequently attacked by aphids. The ants found in the aphid colonies were Dolichoderus sp. and Technomyrmex sp. Based on the morphological character, a pictorial and dichotomous keys of aphids associated with fruit crops were constructed
Keyword: Bogor Agricultural University (IPB), identification., hemiptera, fruit, Aphididae, Aphids

Judul: Identifikasi Spesies, Karakteristik Koloni dan Kunci Identifikasi Kutudaun (Hemiptera: Aphididae) pada Tanaman Hias di Daerah Bogor dan Cianjur
Abstrak: Kutudaun merupakan kelompok serangga hama yang memiliki kisaran inang yang sangat luas. Hampir seluruh tanaman hias merupakan inang dari kutudaun. Kerugian yang ditimbulkan oleh kutudaun sebagai hama berkisar antara 6-25%, sedangkan sebagai vektor virus tanaman dapat mencapai lebih dari 80%. Informasi mengenai taksonomi dan karakteristik koloni kutudaun pada tanaman hias di Indonesia masih sangat terbatas. Penelitian ini bertujuan untuk mengetahui jenis dan karakteristik kutudaun pada tanaman hias di Bogor dan Cianjur. Pada pengamatan terhadap koloni, jumlah kutudaun bersayap dan tidak bersayap dihitung dan jenis semut yang berasosiasi pada koloni diidentifikasi. Kutudaun yang ditemukan dibuat preparat slide dan diidentifikasi. Gambar karakter morfologi kutudaun yang ditemukan digunakan untuk membuat kunci identifikasi berdasarkan gambar (pictorial key). Sebanyak 10 spesies kutudaun ditemukan pada 29 spesies tanaman hias di Bogor dan Cianjur yaitu Aphis gossypii, Astegopteryx nipae, Aulacorthum solani, Greenidea psidii, Indomegoura indica, Macrosiphum euphorbiae, Myzus persicae, Neomyzus circumflexus, Toxoptera aurantii dan T. odinae. Tiga spesies diantaranya belum pernah dilaporkan pada tanaman hias di Indonesia, yaitu I. indica, M. euphorbiae dan N. circumflexus. Sebagian besar kutudaun yang ditemukan merupakan kutudaun tidak bersayap. A. gossypii adalah spesies kutudaun yang paling sering ditemukan pada tanaman hias. Famili Acanthaceae merupakan tanaman inang yang paling banyak terserang kutudaun. Jenis semut yang ditemukan berasosiasi dengan kutudaun pada tanaman hias adalah Dolichoderus thoracicus, Lepisiota sp., Myrmicaria sp. dan Pheidole sp.. Kunci identifikasi berdasarkan gambar dari 10 kutudaun yang ditemukan pada tanaman hias di Bogor dan Cianjur telah dibuat dan dapat digunakan oleh siapapun yang memerlukan.
Keyword: kutudaun, tanaman hias, identifikasi morfologi, kunci identifikasi

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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