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