Judul: Mapping The Distribution of Coffee Leaf Rust Disease (Hemileia vastatrix) and It's Controls in Indonesia
Abstrak: Tanaman kopi (Coffea sp.) merupakan komoditas perkebunan ekspor terbesar keempat di Indonesia, bahkan Indonesia telah menjadi produsen kopi terbesar keempat di dunia. Sejak abad ke-16 kopi telah ditanam di Indonesia dan terus mengalami perkembangan hingga saat ini. Namun kopi di Indonesia terserang penyakit karat daun yang dapat menyebabkan kerusakan 20-70% dan belum dapat teratasi dengan sempurna hingga saat ini. Berbagai pengendalian telah dilakukan seperti penggunaan klon tahan, penyemprotan dengan pestisida kimiawi maupun nabati, kultur teknis. Berbagai pengendalian tersebut belum maksimal dan memberi dampak yang berbeda di setiap daerah maupun setiap musim/iklimnya. Penelitian ini bertujuan memetakan persebaran dan perkembangan penyakit karat daun pada kopi serta pengendalian yang pernah dilakukan di Indonesia. Penelitian dilakukan dengan mengumpulkan data produksi kopi, luas lahan, luas serangan penyakit karat daun kopi, kondisi iklim dan pengendalian yang dilakukan di Indonesia. Penelitian ini diharapkan dapat menjadi pertimbangan pengendalian karat daun kopi yang efektif di Indonesia, sehingga dapat meningkatkan produktivitas kopi Indonesia dengan maksimal. Penyakit karat daun kopi telah menyebar hampir di seluruh wilayah Indonesia dengan kejadian tertinggi di sentra produksi kopi jenis Arabika, dan pengendalian yang telah dilakukan belum efektif., The coffee plant (Coffea sp.) is the fourth largest export plantation commodity in Indonesia, and makes Indonesia become the fourth largest coffee producer in the world. Since the 16th century, coffee has been grown in Indonesia and it has been developed until now. Unfortunately, there is one of coffee’s disease which cause 20-70% damage, namely coffee leaf rust which caused by Hemileia vastatrix and never completely resolved until now. Various controls such as technical culture, the use of resistant clones, biological controls, biological fungicides, and the application of fungicides have been carried out, but have not been maximized and have different impacts in each region and each season/climate’s condition. This study aims to map the distribution and development of the coffee leaf rust and to learn the controls that have been carried out in Indonesia. The literature review was conducted by collecting data of coffee production, coffee’s land area, area of coffee leaf rusts attack ,climate conditions and controls have been carried out in Indonesia. This literature review is expected to be a consideration for effective coffee leaf rust control in Indonesia, so that can maximize the productivity of Indonesia’s coffee. Coffee leaf rust has been spread in all region in Indonesia, which Arabica coffee’s production center became the highest incidence rate and the controls’d been done in Indonesia are not yet effective.
Keyword: Arabica, fungicides, climate, technical culture

Judul: Disease Incidence and Disease Severity of Coffee Leaf  Rust (Hemileia vastatrix) in Sangir District, South Solok Regency, West Sumatra  Province
Abstrak: Kopi merupakan salah satu komoditas perkebunan Indonesia yang banyak diproduksi dan diekspor. Salah satu penyakit penting yang menginfeksi tanaman kopi adalah penyakit karat daun kopi yang disebabkan oleh cendawan Hemileia vastatrix. Cendawan ini menginfeksi daun tanaman kopi sehingga fotosintesis tanaman dapat terganggu. Penelitian ini bertujuan mengetahui insidensi dan keparahan penyakit karat daun kopi pada tanaman kopi arabika di Kecamatan Sangir, Kabupaten Solok Selatan, Provinsi Sumatra Barat. Data mengenai penyakit, kondisi lahan, dan karakteristik petani, dikumpulkan dari 6 (enam) lahan pengamatan yang diberi nama: lahan A, B, C, D, E, dan F dengan cara menghitung skor insidensi dan skor keparahan penyakit serta wawancara petani. Sampel tanaman di masing-masing lahan (50 tanaman) dipilih menggunakan sistem diagonal. Data yang diperoleh ditabulasikan menggunakan aplikasi Microsoft Excel dan dianalisis dengan publikasi yang berasal dari buku, jurnal, dan buletin. Berdasarkan data yang telah diperoleh, pada minggu pertama pengamatan insidensi penyakit di lahan B, E, dan F sudah mencapai 100% sementara di lahan A, C, dan D masing-masing sebesar 40%, 88%, dan 52%. Insidensi penyakit pada minggu ke-5 pengamatan di lahan A, C, dan D masing- masing sebesar 78%, 90%, dan 78%. Persentase keparahan penyakit tertinggi pada minggu ke-5 pengamatan mencapai 72.89% pada lahan E sementara keparahan terendah mencapai 23.78% pada lahan A. Tidak ada pengendalian khusus yang dilakukan petani pada wilayah ini., Coffee is one of the Indonesia's plantation commodities which is widely produced and exported. One of the important diseases which is able to reduce the production is coffee leaf rust disease caused by the fungus Hemileia vastatrix. This fungus infects the leaves of the coffee plant so that the plant's photosynthesis can be disrupted. This study aims to determine the disease incidence and the disease severity of coffee leaf rust disease in arabica coffee plants in Sangir District, South Solok Regency, West Sumatera. Data of the disease, field condition, and farmers characteristics were collected from 6 observation plots which selected based on the possibility access, namely A, B, C, D, E, and F by calculating the disease incidence and disease severity scores and farmers interview. Sample plants in each plots (50 plants) were selected using diagonal system. Collected data were tabulated using the Microsoft Excel and be analyzed with published data from the books, journals, and newsletters. Based on the collected data, disease incidence at the 1st week on B, E, and F plots were already 100%, while on A, C, and D plots were up to 40, 88, and 52%, respectively. Disease incidence at the 5th week of observation on A, C, and D plots were up to 78, 90, and 78%, respectively. The highest percentage of disease severity at the 5th week of observation was up to 72.89% on E plot, while the lowest was up to 23.78% on A plot. There were no specific controls conducted by the farmers in this area.
Keyword: Coffeae arabica, C. robusta, Fungi, Integrated Pest Management

Judul: Sintesis BaTiO3 dari Campuran Ba(OH)2 dan TiO2 dengan Tambahan PbO
Abstrak: Piezoelectric material can generate electric field in response to applied mechanical stress. Conversely, they can stretch and contract in response to an electric field. This material can be used for many applications such as transducer, microphone, ultrasound, and pressure gauge. Barium titanate is a ferroelectric material with piezoelectric properties that can be synthesized easily. The aim of this study is to synthesis barium titanate from mixture of Ba(OH)2 and TiO2, also observe its optimum temperature and the effect of PbO addition. The method of synthesis was solid-state reaction and sol-gel method, then the products were characterized with x-ray diffraction (XRD). Based on XRD analysis, the optimum temperature for both methods was 800°C. Addition of PbO to BaTiO3 in the solid-state reaction formed a compound with formula of Ba1-xPbxTiO3. The addition has changed diffraction pattern peak at 2θ and strengthened its tetragonal structure. The best result was obtained at x of 0.5 which will form a compound of Ba0.5Pb0.5TiO3.
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