Judul: Population Dynamics of the Rice Stem Borer in Kiarasari Village, Subang District
Abstrak: The rice stem borer is one of the most important rice pests in Indonesia. Three species of rice stem borer are found in Subang Regency, including the yellow rice stem borer (Scirpophaga incertulas), the striped rice stem borer (Chilo suppressalis), and the pink rice stem borer (Sesamia inferens). This study aims to determine the population dynamics of rice stem borer species in Kiarasari Village, Compreng District, Subang Regency. Rice stem borers were collected using an Insect Light traps 0.4 watt LED trap lamp, then counted and identified to determine the species. The research was conducted from January to October 2022. Lightrap was placed in three parts of the rice fields based on the compass point, west, east and north. The dominant rice stem borer was the yellow rice stem borer (92.2%). Other types of rice stem borer are pink rice stem borer (4.4%) and striped rice stem borer (3.5%). There was a difference in the average number of rice stem borer adults caught in each wind direction. The number of catches of the yellow rice stem borer was higher when the lamp traps were placed in the north, west and east directions compared to the striped rice stem borer and the pink rice stem borer. The development of rice stem borer populations can be affected by wind speed, temperature, and humidity., Penggerek batang padi merupakan salah satu hama tanaman padi yang penting di Indonesia. Penggerek batang padi yang ditemukan di Kabupaten Subang ada tiga jenis yaitu penggerek batang padi kuning (Scirpophaga incertulas), penggerek batang padi bergaris (Chilo suppressalis), dan penggerek batang padi merah muda (Sesamia inferens). Penelitian ini bertujuan untuk mengetahui dinamika populasi spesies penggerek batang padi di Desa Kiarasari, Kecamatan Compreng, Kabupaten Subang. Penggerek batang padi dikumpulkan dengan lampu perangkap LED Insect Lightrap 0,4 watt, kemudian dihitung dan diidentifikasi untuk menentukan spesiesnya. Penelitian dilakukan pada bulan Januari hingga Oktober 2022. Lightrap ditempatkan di tiga bagian pesawahan berdasarkan arah mata angin, yaitu barat, timur, dan utara. Penggerek batang padi yang dominan adalah penggerek batang padi kuning (92,2%). Jenis penggerek batang padi lainnya adalah penggerek batang padi merah jambu (4,4%) dan penggerek batang padi bergaris (3,5%). Terdapat perbedaan rata-rata jumlah imago penggerek batang padi yang tertangkap pada setiap arah mata angin. Jumlah tangkapan penggerek batang padi kuning lebih banyak tertangkap pada semua penempatan lampu perangkap dibandingkan dengan penggerek batang padi bergaris dan penggerek batang padi merah jambu. Kecepatan angin, suhu, dan kelembapan udara dapat berpengaruh terhadap perkembangan populasi penggerek batang padi.
Keyword: Padi, Penggerek Batang Padi, Perangkap Cahaya, Arah Mata Angin

Judul: The Rice Stem Borers in the Rice Field at Karawang
Abstrak: Penggerek batang padi (PBP) merupakan salah satu hama penting pada tanaman padi. Kerusakan dari semua spesies penggerek menimbulkan gejala yang sama, pada fase vegetatif disebut sundep (deadheart) dengan gejala titik tumbuh tanaman muda mati, dan pada fase generatif beluk (whitehead) malai mati dengan bulir hampa yang terlihat berwarna putih. Penggunaan feromon YSB-MDP merupakan teknologi pengendalian yang dapat menekan populasi penggerek batang padi kuning dan didesain menjadi produk yang ramah lingkungan. Penelitian ini bertujuan untuk melihat spesies PBP pada lahan yang mendapat perlakuan pemasangan feromon YSB-MDP. Posisi feromon YSB-MDP pada tiang pemancang menghadap ke utara yang dipasang pada awal musim tanam dengan jarak masing- masing plot yang berbeda. Petak perlakuan seluas 4 ha diaplikasikan dengan dispenser YSB-MDP dengan masing-masing 10 dispenser/ha, 20 dispenser/ha, 30 dispenser/ha, dan tanpa dispenser. Pengamatan spesies penggerek batang padi dilakukan dengan memotong anakan padi yang terdapat gejala dan membedah batang padi yang bergejala. Pengamatan dilakukan sebanyak 4 kali, yaitu 2 kali pada fase vegetatif dan 2 kali pada fase generatif. Hasil pengamatan menunjukkan bahwa terdapat 3 spesies penggerek batang padi di lahan, yaitu penggerek batang padi kuning (Scirpophaga incertulas), penggerek batang padi merah jambu (Sesamia inferens), dan penggerek batang padi bergaris (Chilo suppressalis). Penggerek batang padi yang dominan menyerang tanaman padi adalah penggerek batang padi kuning, S. incertulas. Feromon YSB-MDP dapat menekan populasi larva S. incertulas di lahan pertanaman padi dari awal pertanaman., Rice stem borers are one of the important crop pests, especially in rice plants. The damage of these stem borers can cause the same symptoms. The symptom on vegetative phase is called deadheart where the center tiller of plants dried or even died, whereas on generative phase is called whitehead where the panicle is dead resulting in the unfilled grain with white in color. YSB-MDP dispensers has been considered as a new environmentally friendly technology that can reduce the population of rice stem borers. This study aims to observe the rice stem borer species diversity on the field applied with YSB-MDP dispensers. The YSB-MDP dispensers were installed at the early planting season facing the north direction within several ranges different for each plot. The number of dispensers placed were 10/ha, 20/ha, 30/ha, and no dispensers as a check plot. Observation the rice stem borer species was carried out by cutting the tillers infested by stem borers. Observations were made for 4 times, 2 times in the vegetative phase and 2 times in the generative phase. The observations showed that there were 3 species of rice stem borers in the land, namely the yellow rice stem borer (Scirpophaga incertulas), pink rice stem borer (Sesamia inferens), and striped rice stem borer (Chilo suppressalis). The rice stem borer which predominantly attacks rice plants was S. incertulas.
Keyword: deadheart, rice stem borer, whitehead

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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