Judul: Pests and Diseases of Lucky Bamboo (Dracaena sanderiana Sander ex Mast.) (Asparagales: Asparagaceae) in Sukabumi Regency
Abstrak: Bambu hoki merupakan tanaman hias dalam ruangan yang memiliki nilai ekonomi tergolong prospektif. Informasi mengenai hama dan penyakit bambu hoki di Indonesia belum banyak dilaporkan. Penelitian bertujuan memperoleh informasi mengenai hama dan penyakit serta insidensi dan keparahan penyakit penting pada tanaman hias bambu hoki di Kabupaten Sukabumi. Penelitian dilaksanakan pada bulan Februari hingga April 2022 di Desa Sudajaya Girang dan Klinik Tanaman IPB. Penelitian ini meliputi survei penentuan lokasi, wawancara kepada enam petani, pengamatan hama dan penyakit dengan diagonal sampling sebanyak 200 tanaman contoh, hama dan penyakit yang ditemukan kemudian diidentifikasi, laludihitung insidensi dan keparahan penyakit serta persentase dan intensitas serangan hama. Budi daya bambu hoki meliputi pengolahan tanah, penanaman, pemeliharaan tanaman, pemanenan, dan pengelolaan pascapanen. Hama pada bambu hoki yaitu keong semak (Bradybaena similaris), ulat penggulung daun (Bibasis sp.), dan kutu putih (Pseudococcus longispinus). Penyakit pada bambu hoki yaitu antraknosa (Colletotrichum sp.), busuk batang (Fusarium sp.), bercak daun Alternaria (Alternaria alternata), dan karat alga (Cephaleuros sp. dan Phycopeltis arundinacea). Insidensi dan keparahan penyakit antraknosa tertinggi berada di lahan B dengan rata-rata 64,2 dan 16,3%., Lucky bamboo is an indoor ornamental plant with a prospective economic value. Information about pests and diseases of lucky bamboo in Indonesia has not been widely reported. The objective of the research was to obtain information on pests and diseases and the incidence and severity of important diseases in ornamental plant lucky bamboo in Sukabumi Regency. The research was carried out from February to April 2022 at Sudajaya Girang Village and Plant Clinic IPB. The research includes a survey of location determination, interviews with six farmers, observation of pests and diseases by diagonal sampling with 200 plant samples, pests and diseases found and identified, then calculated the incidence and severity of disease as well as the percentage and intensity of pest attacks. Cultivation of lucky bamboo includes tillage, planting, plant maintenance, harvesting, and post-harvest management. Pests on lucky bamboo are Asian trampsnail (Bradybaena similaris), leaf roller (Bibasis sp.), and mealybug (Pseudococcus longispinus). Diseases on lucky bamboo are anthracnose (Colletotrichum sp.), stem rot (Fusarium sp.), Alternaria leaf spot (Alternaria alternata), and algal rust (Cephaleuros sp. and Phycopeltis arundinacea). The highest incidence and severity of anthracnose was in field B with an average of 64,2 and 16,3%.
Keyword: Colletotrichum sp., Fusarium sp., insidensi, keparahan, tanaman hias

Judul: Inventory of Ornamental Plant Diseases in Sukamantri Village, Tamansari District, Bogor Regency, West Java
Abstrak: Tanaman hias merupakan salah satu komoditas hortikultura yang memiliki nilai ekonomi dan estetika yang tinggi. Di Indonesia, penelitian hama dan penyakit pada tanaman hias relatif terbatas. Penelitian ini bertujuan untuk menginventarisasi penyakit tanaman hias di Desa Sukamantri, Kecamatan Tamansari, Kabupaten Bogor, Jawa Barat. Penelitian meliputi wawancara, pengambilan sampel, deteksi dan identifikasi penyakit, pengamatan penyakit, serta analisis data. Wawancara dilakukan dengan menggunakan kuesioner terstruktur kepada 20 petani tanaman hias. Sampel diambil dari 13 jenis tanaman hias. Pengamatan dilakukan terhadap tanaman yang bergejala penyakit dan spora fungi patogen diidentifikasi secara mikroskopik. Pengamatan penyakit dilakukan sebanyak empat kali pada 50 tanaman setiap jenisnya. Analisis data pengamatan penyakit dilakukan menggunakan Microsoft Excel 2010. Hasil penelitian menunjukkan bahwa mayoritas petani tanaman hias di Sukamantri berumur 41 – 50 tahun, tingkat pendidikan sekolah menengah atas, pengalaman bertani 2 – 10 tahun, dan penyewa lahan. Sebanyak sembilan fungi yang berasosiasi dan menyebabkan penyakit pada tanaman hias yaitu bercak daun Bipolaris (Bipolaris sp.), busuk daun (Colletotrichum sp.), busuk pucuk (Phytophthora sp.), hawar daun Fusarium (Fusarium sp.), hawar daun Pestalotia (Pestalotia sp.), bercak daun Cercospora (Cercospora sp.), karat daun Phakopsora (Phakopsora sp.), mati pucuk (Botryodiplodia sp.), dan karat daun Puccinia (Puccinia sp.). Karat daun Puccinia adalah penyakit yang paling dominan dengan tingkat insidensi penyakit tertinggi.
Keyword: farmer, fungi, Puccinia leaf rust

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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