Judul: Disease Incidence and Severity of Coffee Leaf  Rust (Hemileia vastatrix) in Seponti District, Kayong Utara Regency, West Kalimantan
Abstrak: Kopi merupakan salah satu komoditas penting dalam sektor perkebunan di Indonesia. Namun, penyakit karat daun kopi (Hemileia vastatrix) menjadi faktor pembatas penting terhadap produksi kopi. Penelitian ini bertujuan untuk mengkaji insidensi dan keparahan penyakit karat daun kopi di sentra produksi kopi di Kecamatan Seponti, Kabupaten Kayong Utara, Kalimantan Barat. Selain itu, dikaji pula hubungan antara teknik budi daya, kondisi lingkungan, dengan perkembangan penyakit karat daun kopi. Pengamatan dilakukan di 8 lahan pertanaman kopi. Sebanyak 30 sampel tanaman kopi dari setiap lahan percobaan diamati selama penelitian. Periode pengukuran insidensi dan keparahan penyakit yaitu 5 minggu dengan interval 1 minggu. Hasil pengamatan menunjukkan bahwa insidensi dan keparahan penyakit karat daun kopi meningkat seiring waktu. Insidensi penyakit tertinggi terjadi di lahan A sebesar 96% (tanaman berumur 26 tahun) dan insidensi penyakit yang paling rendah terjadi di lahan H sebesar 82,7% (tanaman berumur 18 tahun). Sementara itu, keparahan penyakit karat daun kopi yang paling tinggi terjadi di lahan G sebesar 52,67% (ada tanaman penaung) dan keparahan penyakit karat daun kopi terendah yaitu di lahan D sebesar 38,83% (tanpa tanaman penaung). Faktor lingkungan seperti suhu yaitu berkisar dari 27 – 28,3°C dan kelembapan 80,2 – 84,5%, dan lama penyinaran matahari selama 30,9 – 53,2 jam/minggu dapat menyebabkan peningkatan terhadap perkembangan penyakit karat daun kopi. Selain itu, curah hujan juga dapat meningkatkan perkembangan penyakit karat daun kopi, karena hujan dapat membantu proses penyebaran penyakit karat daun kopi. Curah hujan pada saat pengamatan berkisar dari 19,5 - 77 mm/minggu. Kata kunci: budi daya, curah hujan, penaung, sektor perkebunan, suhu., Coffee is one of the important commodities in the plantation sector of Indonesia. However, coffee leaf rust disease (Hemileia vastatrix) become an important limiting factor to coffee production. This study was aimed to assess the incidence and severity of coffee leaf rust disease in coffee production centers in Seponti District, Kayong Utara Regency, West Kalimantan. Moreover, the relationship among cultivation technique, environmental condition, and development of coffee leaf rust disease were also studied. Observations were undertaken in 8 plots of coffee plantations. A total of 30 samples of coffee plants from each experimental plots observed during the study. Measurement period of disease incidence and severity was 5 weeks with 1 week interval. The results showed that the incidence and severity of coffee leaf rust disease increased over time. The highest incidence of disease was occurred in A plot of 96% (plants aged 26 years) and the lowest incidence of disease was occurred in H plot of 82.7% (plants aged 18 years). Meanwhile, the high severity of coffee leaf rust was occurred in G plot at 52.67% (there are shade plants) and the lowest severity of coffee leaf rust in D plot at 38.83% (without shade plants). Environmental factors such as temperature which range from 27 – 28,3°C, humidity 80,2 – 84,5%, and long irradiation which from 30,9 - 49,1 hours/week can cause an increase in disease progress of coffe leaf rust disease. Moreover, rainfall can also increase in disease progress of coffe leaf rust disease, because rain can can help the spread of coffee leaf rust disease. Rainfall at the
Keyword: cultivation, plantation sector, rainfall, shade, temperature

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: Membran Komposit Kitosan-Natrium Alginat untuk Aplikasi Direct Methanol Fuel Cell
Abstrak: Composite of chitosan and sodium alginate can be utilized as base material of proton exchange membrane (PEM). The composite membranes were produced by various concentrations of chitosan-sodium alginate, namely 3:3, 3:4, 3:5, 3:6, 4:3, 5:3, and 6:3 (% b/v). The composites were characterized by using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), and were tested for the performance as PEM from the proton conductivity obtained by using impedance spectrometer. The FTIR spectrum indicated the NH3C group at 1637.29 cm-1 and symmetrical COO group at 1253.68 cm-1 indicating interactions between chitosan and sodium alginate. SEM micrographs showed that the composite membrane was nonporous. Composite membrane with 3:5 chitosan-sodium alginate composition had the highest proton conductivity, namely 9.594 × 10-7 S/cm. Based on this research results, chitosan-sodium alginate composite membrane can be applied well in direct methanol fuel cell system.
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