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: Infestation Level of the Yellow Rice Stem Borer, (Scirpophaga incertulas) and its Parasitizing Level of Egg Parasitoid in Pacet  Subdistrict, Bandung Regency
Abstrak: Produksi padi di Indonesia setiap tahun mengalami penurunan yang salah satunya diakibatkan oleh organisme pengganggu tanaman (OPT). Penggerek batang padi merupakan salah satu OPT yang seringkali menyebabkan penurunan hasil terutama di Provinsi Jawa Barat. Aplikasi insektisida merupakan salah satu upaya yang seringkali dilakukan oleh petani. Akan tetapi, penggunaan insektisida secara berlebihan dapat menimbulkan berbagai efek negatif baik terhadap lingkungan maupun konsumen. Oleh karena itu, diperlukan penerapan konsep pengendalian hama secara terpadu (PHT). Salah satu upaya tersebut adalah dengan pemanfaatan musuh alami, yaitu parasitoid telur. Keberadaan hama maupun musuh alami sangat terpengaruh oleh lingkungan salah satunya ketinggian. Oleh karena itu penelitian dilaksanakan dengan tujuan memperoleh informasi mengenai intensitas serangan dan penyebaran populasi masing-masing parasitoid telur pada ketinggian 800 m dpl dan >1000 m dpl. Pengamatan dilakukan di Desa Pangauban dengan ketinggian 1087 m dpl dan Desa Tanjungwangi dengan ketinggian 866 m dpl, yang terletak di Kecamatan Pacet, Kabupaten Bandung. Ditentukan lahan pengamatan dari masing-masing lokasi, terdiri atas lahan pengambilan sampel kelompok telur dan lahan pengamatan kerusakan tanaman oleh penggerek batang padi kuning (PBPK). Setiap lokasi pengamatan ditentukan 5 petak yang memiliki ukuran 5 m 5 m dengan metode diagonal satu arah. Pengamatan dilakukan secara langsung dengan menghitung intensitas serangan pada 10 rumpun di masing-masing petak sebanyak 4 kali masa pengamatan. Kemudian dilakukan pengambilan kelompok telur setiap 2 minggu sekalisebanyak 4 kali pada lahan seluas 2 ha yang dibagi menjadi 4 bagian. Hasil penelitian ini menunjukkan bahwa faktor lingkungan serta cara budi daya dapat memengaruhi intensitas serangan penggerek pada pengamatan 4 dan 6 minggu setelah tanam (MST). Faktor lingkungan juga memengaruhi spesies parasitoid yang ditemukan selama penelitian., Rice production in Indonesia has decreased every year, one of which is due to the presence of plant pest organisms (PPO). Rice stem borer is one of the pests that often causes a decrease in yield, especially in West Java Province. The application of insecticides is one of the efforts that are often carried out by farmers. However, excessive use of insecticides can cause various negative effects on both the environment and consumers. Therefore, it is necessary to apply the concept of integrated pest management (IPM). One of these efforts is the use of natural enemies, namely egg parasitoids. The presence of pests and natural enemies is greatly affected by the environment, one of which is altitude. Therefore, the research was carried out to obtain information about the intensity of attack and population distribution of each egg parasitoid at an altitude of 800 m asl and > 1000 m asl. Observations were made in Pangauban Village with an altitude of 1087 m asl and Tanjungwangi Village with an altitude of 866 m asl, which are located in Pacet District, Bandung Regency. The observation area was determined from each location, consisting of an egg group sampling area and observation area for plant damage by the yellow rice stem borer (YRSB). Each observation location was determined by 5 plots with a size of 5 m × 5 m using the one-way diagonal method. Observations were made directly by calculating the intensity of the attack on 10 clumps in each
Keyword: altitude, infestation levels, egg parasitoids, paddy

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.
Keyword: