Judul: Sebaran Kelompok Telur Penggerek Batang Padi Kuning dan Parasitoidnya pada Pertanaman Padi di Kabupaten Indramayu
Abstrak: Tanaman padi merupakan salah satu komoditas tanaman pangan utama di Indonesia. Salah satu kendala yang menjadi faktor penghambat dalam upaya peningkatan produktivitas padi adalah kehilangan hasil yang disebabkan oleh serangan hama penggerek batang padi kuning (Scirpophaga incertulas) yang dapat menyerang tanaman padi pada fase vegetatif dan generatif. Penelitian ini bertujuan mengetahui sebaran kelompok telur penggerek batang padi kuning dan parasitoidnya pada pertanaman padi di Kecamatan Losarang, Terisi, dan Cikedung, Kabupaten Indramayu, Jawa Barat. Penelitian yang dilaksanakan pada bulan Desember 2021 hingga Februari 2022 meliputi pengumpulan kelompok telur di persemaian, wawancara dengan petani dan pemilik kios pestisida untuk mengetahui hubungan antara distribusi kelompok telur dengan intensitas penggunaan pestisida. Hasil penelitian menunjukkan bahwa sebaran kelompok telur di tiga kecamatan tidak berbeda nyata. Jumlah kelompok telur paling banyak didapatkan di Kecamatan Losarang, sementara itu parasitoid terbanyak ditemukan di Kecamatan Cikedung. Parasitoid yang ditemukan di tiga kecamatan yaitu Telenomus dignoides (Hymenoptera: Scelionidae), Telenomus dignus, Telenomus remus, Telenomus rowani, Trichogramma japonicum (Hymenoptera: Trichogrammatidae), dan ditemukan satu hiperparasitoid Cotesia sp. (Hymenoptera: Braconidae). Hasil penelitian ini diharapkan dapat berkontribusi dalam implementasi PHT di Indonesia., Rice plant is one of the main food crop commodities in Indonesia. One of the obstacles in increasing rice productivity is the attack of the yellow rice stem borer (Scirpophaga incertulas). This pest can attack rice plants on the vegetative and the generative phases causing loss of yield. This study aimed to determine the distribution of egg groups of the yellow rice stem borer and their parasitoids on rice in the districts of Losarang, Terisi, and Cikedung, Indramayu Regency, West Java. The study was conducted from December 2021 to February 2022. This study included collecting egg groups in nurseries and interviewing farmers and pesticide kiosk owners to determine the relationship between egg group distribution and the intensity of pesticide use. The results showed that the distribution of egg groups in the three sub-districts was not significantly different. The highest number of egg groups was in Losarang district, while the highest number of parasitoids was found in Cikedung district. The parasitoid species found in three sub-districts were Telenomus dignoides (Hymenoptera: Scelionidae), T. dignus, T. remus, T. rowani, Trichogramma japonicum (Hymenoptera: Trichogrammatidae), and one hyperparasitoid was found Cotesia sp. (Hymenoptera: Braconidae). This research results are expected to contribute in the implementation of IPM in Indonesia.
Keyword: generative phase, hyperparasitoid, kiosk, pesticides, vegetative phase

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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