Judul: Analysis of Attack Rate of Yellow Rice  Stem Borer (Scirpophaga incertulas) Based on Climate in Majalengka Regency
Abstrak: Kabupaten Majalengka merupakan salah satu penghasil produksi padi terbesar di Jawa Barat dengan produksi 534.520,2 ton pada tahun 2021. Meningkatnya kebutuhan beras di Indonesia dapat diatasi dengan meningkatkan produksi padi. Hama S. incertulas yang menyebabkan penyakit pada tanaman padi bahkan dapat menyebabkan kematian pada tanaman muda. Peningkatan luas serangan hama tersebut dapat dipengaruhi oleh beberapa parameter iklim seperti suhu, kelembapan, curah hujan dan kecepatan angin. Penelitian ini bertujuan untuk mengetahui pengaruh kondisi iklim terhadap serangan OPT di daerah penelitian dan mengetahui nilai Ecoclimatic Indeks (EI) daerah penelitian dengan menggunakan model Climex 4.0. Analisis ini menggunakan hasil regresi dengan aplikasi Minitab dan nilai indeks ekoklimatologi yang diperoleh dengan menggunakan aplikasi Climex. Hasil analisis regresi menunjukkan nilai R² antara luas serangan hama dengan parameter iklim sebesar 24,49% berdasarkan parameter iklim selama sepuluh tahun. Hasil indeks ekoklimat (EI) memiliki nilai 51 yang termasuk dalam kategori sesuai dengan deskripsi hama penggerek batang padi kuning di wilayah tersebut. Oleh karena itu, dapat disimpulkan bahwa populasi hama dan tingkat serangan hama dapat dipengaruhi oleh kondisi iklim di Kabupaten Majalengka., Majalengka Regency is one of the largest producers of rice production in West Java with a production of 534,520.2 tons in 2021. The increasing need for rice in Indonesia can be overcome by increasing rice production. S. incertulas pests that cause disease in rice plants can even cause death in young plants. The increase in the area of pest attack can be influenced by several climatic parameters such as temperature, humidity, rainfall and wind speed. This study aims to determine the effect of climatic conditions on pest attacks in the study area and determine the value of the Ecoclimatology Index (EI) of the study area using the Climex 4.0 model. This analysis uses regression results with the Minitab application and the ecoclimatic index value obtained using the Climex application. The results of the regression analysis showed the R² value between the extent of pest attack and climatic parameters of 24.49% based on climatic parameters for ten years. The results of the ecoclimatic index (EI) have a value of 51 which is included in the category in accordance with the description of the yellow rice stem borer pest in the region. Therefore, we can conclude that the pest population and the level of pest attack can be influenced by the climatic conditions of Majalengka Regency.
Keyword: attack area, compare location, ecoclimatic index, regression analysis

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.
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