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: Parasitization Levels and Species of Egg Parasitoid on Yellow Rice Stem Borer (Scirpophaga incertulas) at Paddy Field, Karawang District
Abstrak: Produksi padi di Indonesia masih mengalami penurunan signifikan yang disebabkan oleh organisme pengganggu tanaman (OPT), salah satunya adalah penggerek batang padi kuning (PBPK), Scirpophaga incertulas. Pengendalian hama tersebut yang umum dilakukan oleh petani adalah penggunaan insektisida. Aplikasi insektisida apabila dilakukan dengan tidak bijaksana akan berdampak negatif. Oleh karena itu, perlu dilakukan pengendalian hama yang ramah lingkungan sesuai konsep pengendalian hama terpadu (PHT) seperti aplikasi feromon sintetik. Penelitian ini bertujuan mengetahui tingkat parasitasi dan spesies parasitoid telur S. incertulas pada pertanaman padi yang mendapat perlakuan feromon sintetik (Z11-Hexadecenal 33%). Penelitian ini dilakukan di pertanaman padi milik petani di Desa Sukaraja, Kecamatan Rawamerta, dan Desa Sindangmukti, Kecamatan Kutawaluya, Kabupaten Karawang, Jawa Barat mulai dari Februari sampai Juni 2020. Penelitian dilakukan pada lahan 80 ha yang dibagi menjadi beberapa petak lahan. Percobaan dilakukan menggunakan rancangan acak kelompok (RAK) dengan 4 perlakuan dan 5 ulangan. Perlakuan yang digunakan yaitu perlakuan kontrol (pertanaman padi tanpa feromon) dan perlakuan feromon dengan dosis 10 dispenser/ha, 20 dispenser/ha, dan 30 dispenser/ha. Pengambilan kelompok telur dilakukan setiap 2 minggu sebanyak 4 kali. Peubah yang diamati yaitu kemunculan larva PBPK dan imago parasitoid, serta tingkat parasitisasinya. Hasil penelitian ini menunjukkan bahwa penggunaan feromon sintetik dapat memengaruhi tingkat parasitasi kelompok telur pada pengamatan 10 MST dan tingkat parasitasi butir telur pada pengamatan 6 MST, tetapi tidak memengaruhi terhadap jumlah larva PBPK yang menetas, imago parasitoid yang muncul, dan spesies parasitoid yang ditemukan., The rice production in Indonesia have significant declined due to plant pests and diseases, one of them is yellow rice stem borer (PBPK) Scirpophaga incertulas. Insecticide applications have been commonly used by farmers for controlling this pest. Unwise application of insecticides will have a negative impact. Therefore, integrated pest management (IPM) needs to be carrierd out and one of strategy is synthetic pheromone application. This research aims to determine the type of egg parasitoids and its parasitization level of S. incertulas in paddy field applied by synthetic pheromones (Z11-Hexadecenal 33%). This research was carried out in farmers' rice fields at Sukaraja Village, Rawamerta District, and Sindangmukti Village, Kutawaluya District, Karawang Regency, West Java from February to June 2020. The research was carried out on 80 Ha of land which was divided into several plots of land. The experiment was conducted using a randomized group (RBD) with 4 treatments and 5 replications. The treatments used were control treatment (rice cultivation without using pheromone) and treatment of rice planting with 10 dispenser/ha, 20 dispenser/ha, and 30 dispenser/ha. Eggs were sampled biweekly for 4 times with variables were observed of the appearance of PBPK larvae, parasitoid imago, and parasitization levels. The results of this study indicated that the use of synthetic pheromones affected the parasitization levels of egg group at 10 MST and parasitization levels of egg at 6 MST, but does not affected the number of hatched PBPK larvae, emerge parasitoids adults, and parasitoid species found.
Keyword: egg parasitoids, paddy, Scirpophaga incertulas, synthetic pheromones

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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