Judul: Serangga Hama dan Artropoda Lain pada Pertanaman Cabai Rawit (Capsicum frutescens L.) di Desa Margoluwih, Kecamatan Seyegan, Kabupaten Sleman.
Abstrak: Cabai rawit merupakan salah satu komoditas hortikultura penting di Indonesia. Dalam budi daya tanaman cabai petani umumnya menggunakan teknik-teknik konvensional meskipun teknik tersebut dapat menimbulkan dampak buruk pada populasi hama dan ekosistemnya. Penelitian ini bertujuan mengetahui perkembangan populasi hama cabai rawit dan melihat kelimpahan artropoda tanah pada lahan tanaman cabai yang dibudi dayakan secara konvensional di Sleman Yogyakarta. Lahan tanaman cabai dibagi menjadi lima petak pengamatan yang masing-masing berukuran 5 m x 20 m. Pengamatan hama secara langsung dilakukan terhadap 20 tanaman contoh pada tiap petak pengamatan yang diambil dengan metode dua diagonal. Tanaman cabai rawit diamati dari umur 3 MST (minggu setelah tanam) hingga 15 MST dengan interval pengamatan 7 hari. Pada fase vegetatif (3-5 MST), pengamatan dilakukan terhadap seluruh bagian tanaman cabai, sedangkan memasuki fase generatif pengamatan dilakukan terhadap semua pucuk tanaman cabai hingga 5 daun ke bawah. Kelimpahan artropoda diamati menggunakan perangkap pitfall. Hasil penelitian menunjukkan bahwa populasi hama lebih variatif ketika tanaman memasuki fase generatif dibandingkan dengan fase vegetatif. Spesies serangga hama yang paling mendominasi pada penelitian ini ialah kutu daun sebanyak 23.175 individu, Bemisia tabaci 1.761 individu, dan Spodoptera litura 201 individu. Artropoda lain yang mendominasi pada penelitian ini tergabung dalam kelompok famili Formicidae sebanyak 979 individu. Kata kunci: artropoda, budi daya, cabai rawit, serangga hama, Cayenne pepper is one of the important horticultural commodities in Indonesia. In chili cultivation, the majority of farmers still use conventional techniques that have a negative impact on the pest populations and their ecosystems. This study aims to determine the population development of cayenne pepper insect pests and the abundance of soil arthropods on cayenne pepper field cultivated conventionally in Sleman, Yogyakarta. A cayenne pepper field was divided into five plots of 5 m x 20 m each. Observations of insect pests were carried out directly on 20 sample plants in each observation plot taken with two diagonal method. Cayenne pepper was observed from the age of 3 WAP (weeks after planting) to 15 WAP with an observation interval of 7 days. All parts of the sample plants were observed when cayenne pepper was in vegetative phase (3-5 WAP), and all shoots with 5 top leaves were observed when the plants in the generative phase. Arthropod abundance was observed using pitfall traps. The results showed that the pest population was more varied when the plant entered the generative phase compared to the vegetative phase. The most dominant insect pest species in this study were aphids as many as 23175 individuals, Bemisia tabaci 1761 individuals, and Spodoptera litura 201 individuals. Ants (Hymenoptera: Formicidae) (as many as 979 individuals) were the most abundant arthropods trapped in pitfall traps set in cayenne pepper field. Keywords: arthropods, cayenne pepper, cultivation, insect pests
Keyword: arthropods, cayenne pepper, cultivation, insect pests

Judul: Keanekaragaman Serangga (Khususnya Parasitoid) Pada Pertanaman Cabai (Capsicum Annuum L.) Di Desa Taman Sari, Kecamatan Taman Sari, Kabupaten Bogor
Abstrak: Cabai (Capsicum annuum L.) merupakan salah satu komoditas sayuran asli Indonesia yang memiliki nilai ekonomi yang tinggi. Salah satu permasalahan yang sering terjadi ialah keberadaan hama dan penyakit. Pengetahuan mengenai hama dan musuh alami di lapangan sangat dibutuhkan untuk mengetahui cara pengendalian yang tepat. Penelitian ini bertujuan untuk mengetahui keanekaragaman serangga (khususnya parasitoid) pada pertanaman cabai di Desa Taman Sari, Kecamatan Taman Sari, Kabupaten Bogor. Pengamatan dan pengambilan sampel dilakukan di dalam pertanaman dan di sekeliling pertanaman. Pengambilan serangga dilakukan dengan menggunakan jaring serangga, selanjutnya dilakukan sortasi dengan menggunakan separator. Serangga hasil koleksi diidentifikasi hingga tingkat famili. Jumlah serangga yang berhasil dikoleksi sebanyak 1690 individu yang terdiri atas 8 ordo. Sebanyak 279 individu parasitoid berhasil dikoleksi, terdiri atas 15 famili, 11 famili di dalam pertanaman dan 15 famili di sekeliling pertanaman. Keanekaragaman serangga tertinggi ditemukan pada sekeliling pertanaman.
Keyword: Hymenoptera, jaring serangga, kelimpahan, koleksi, separator

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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