Judul: Major Pests and Diseases of Orchid (Dendrobium sp.) in Nugroho Orchid Garden, South Tangerang City, Banten Province
Abstrak: Anggrek (Dendrobium sp.) merupakan salah satu komoditas tanaman hias yang banyak dibudidayakan dan bernilai ekonomi tinggi. Serangan hama dan penyakit merupakan salah satu kendala yang dihadapi dalam proses budidaya anggrek dendrobium. Penelitian bertujuan mengamati, menentukan intensitas serangan dan mengidentifikasi hama dan penyakit tanaman anggrek di Kebun Anggrek Nugroho, Tangerang Selatan. Pengamatan hama dan penyakit dilakukan setiap minggu selama dua bulan pada lima varietas anggrek yaitu Sakda Beauty, Liberty White, Ckaii Waiane, Airway Blue, dan Sminn Red. Informasi terkait budi daya digali melalui wawancara dengan pengelola kebun. Identifikasi hama dan penyakit dilakukan dengan membandingkan gejala yang teramati di lapangan dengan referensi dari literatur. Hama utama yang ditemukan pada pertanaman ialah tungau pipih merah anggrek (Tenuipalpus sp.), sedangkan untuk penyakit utama adalah bercak daun cercospora oleh Cercospora sp, dan penyakit mosaik oleh Cymbidium mosaic virus. Insidensi serangan tungau pipih merah berkisar 0-100%, penyakit mosaik berkisar antara 0-80%, dan bercak daun cercospora berkisar antara 0-72%. Intensitas keparahan tungau pipih merah berkisar antara 0-60%. Skor keparahan mosaik berkisar antara 0-1,32, sedangkan untuk bercak daun cercospora berkisar antara 0-1,56. Faktor yang memengaruhi intensitas hama dan penyakit adalah frekuensi penyiraman yang tinggi, frekuensi dan dosis pemumpukan yang tinggi, serta pencampuran dua jenis insektisida dengan cara kerja yang sama. Hama lain yang ditemukan di kebun adalah kutu tempurung, sedangkan penyakit lain ditemukan bercak daun phyllosticta, antraknosa, dan busuk lunak dengan insidensi cukup rendah. Rekomendasi pengelolaan yang dianjurkan untuk Kebun Anggrek Nugroho adalah pemberian dosis pupuk, frekuensi penyiraman, dan penggunaan insektisida yang sesuai, serta penggunaan pestisida hayati yang ramah lingkungan., Orchid (Dendrobium sp.) is one of the ornamental plants which are widely cultivated and have high economic value. Pests and diseases are one of the constraints on Dendrobium sp. cultivation. The study aimed to observe, determine the intensity and identify the insect pests and pathogens of orchid plants in the Nugroho Orchid Garden, South Tangerang. The pests and pathogens observations were carried out every week regularly for two months on five orchid varieties, i.e. Sakda Beauty, Liberty White, Ckaii Waiane, Airway Blue, and Sminn Red. The cultivation data was collected by interviewing the garden’s manager. Identification of pests and diseases was conducted by comparing the visual symptoms found in the garden with the appropriate literature references. The major pest of Dendrobium sp. is red flat mites (Tenuipalpus sp), while the major disease is cercospora leaf spot caused by Cercospora sp. and mosaic caused by Cymbidium mosaic virus. The incidence of red flat mites ranges from 0-100%, with the intensity ranging from 0- 60%, while the incidence of CymMV ranges from 0-80%, and cercospora leaf spot range from 0-72%, depending on the varieties. The severity score of the mosaic diseases ranged from 0-1.32, and the cercospora leaf spot ranged from 0-1.56. The soft scales, phyllosticta leaf spot, anthracnose, and soft rot also found with low incidence. The factors that affect pest and disease intensity, such as high frequency of watering, overdose application of fertilizer, and mixture application of pesticide with similar mode of action. The recommendation for appropriate management of pests and diseases at Nugroho Orchids’ Garden is water, fertilizer, and
Keyword: cultivation, control, dendrobium, leaf spot, mite, virus

Judul: Risk production dendrobium orchid on dede anggrek sub-district cibitung bekasi
Abstrak: Dede Anggrek adalah salah satu usaha budidaya agribisnis yang memproduksi anggrek Dendrobium. Fluktuasi produktivitas sering kali terjadi pada kegiatan produksi anggrek Dendrobium di setiap periode produksinya. Penelitian ini dilakukan untuk mengetahui sumber risiko yang dihadapi untuk kemudian dihitung probabilitas dan dampak risikonya, sehingga dapat diketahui strategi penanganan yang sesuai. Sumber risiko yang dihadapi meliputi kesalahan SDM, media tanam, kualitas bibit, iklim, serta hama dan penyakit. Probabilitas kemungkinan terjadinya risiko tertinggi bersumber dari hama dan penyakit yaitu sebesar 59.09%. Sedangkan dampak risiko yang mungkin terjadi juga bersumber dari hama dan penyakit yaitu sebesar Rp 879 799,- . Strategi penanganan risiko secara preventif dapat dilakukan untuk semua sumber risiko produksi. Sedangkan strategi penanganan secara mitigasi dapat dilakukan untuk sumber risiko produksi hama dan penyakit., Dede Anggrek is one of the agribusiness cultivation business that producing Dendrobium. Fluctuating of productivity almost done in production activities in each period of production. The research was conducted to determine the source of risk and then to calculated the probability and the impact of the risk, so that to know the appropriate strategy. The sources of risk are errors of human resources, growing media, quality of seed, climate, and also pests and diseases. The highest probability of risk is because pests and diseases in the amount of 59.09 %. The highest impact of risk is also because pests and diseases in the amount of Rp 879 799,-. Preventive risk management strategy can be performed for all sources of production risk. Whereas, mitigation risk management strategy can be performed for the sources of production risk of pests and diseases.
Keyword: Dendrobium, produksi, risiko

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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