Effectiveness of Clove, Neem and Reutealis Trisperma Oils, and Ageratum Conyzoides Extract on Coffee Leaf Rust Disease (Hemileia vastatrix)

Abstract
Description
Leaf rust disease (Hemileia vastatrix) is commonly controlled using synthetic fungicides.  Plant oils and extracts are expected to reduce the pathogen. The research aimed to determine the effectiveness of clove, Reutealis trisperma, and neem oils, and Ageratum conyzoides extract against H. vastatrix. The study was conducted in the laboratory and greenhouse of the Indonesian Industrial and Beverage Crops Research Institute and smallholder coffee plantation in Garut, West Java, from January to December 2018. The A. conyzoides were extracted in the laboratories.  Plant oils and extract's effectiveness was tested in vitro against the germination of urediniospore and in a greenhouse to inhibit disease development. The in vitro experiment were evaluated the eight concentrations of extract and oil were:  0 (steril water), 250, 500, 1000,  1500, 3000, and 5000 ppm. Whereas, in the greenhouse experiments used three concentrations of 1000, 2500, and 5000 ppm of the extract and oil, and 2000 ppm of Mankozeb (positive control). The greenhouse test was carried out on Arabica coffee plants, completely randomized design and five replications.  The number of spots, disease intensity, and plant growth were examined periodically. The results showed that all of the the extract and oil inhibited the urediniospores germination, and the most effective concentrations were 500 ppm, 3000 ppm, and 5000 ppm. A. conyzoides extract, and clove oil effectively suppressed the infection of H. vastatrix by 75.99% and 64.00%, respectively, and comparable to the synthetic fungicide (68.00%).
Penyakit karat daun (Hemileia vastatrix) umumnya dikendalikan menggunakan fungisisida sistetik. Minyak dan ekstrak tanaman diharapkan dapat mengurangi patogen. Tujuan penelitian adalah untuk mengetahui efektivitas minyak cengkeh, kemiri sunan, nimba dan ekstrak babadotan terhadap penyakit karat daun (H. vastatrix). Penelitian dilakukan di laboratorium dan rumah kaca  Balai Penelitian Tanaman Industri dan Penyegar serta kebun petani kopi di Garut, Jawa Barat dari bulan Januari sampai Desember 2018.  Uji efektivitas minyak dan ekstrak tanaman dilakukan in vitro dan rumah kaca. Uji in vitro dilakukan untuk melihat daya hambat minyak dan ekstrak terhadap perkecambahan urediniospora H. vastatrix. Konsentrasi ekstrak dan minyak yang diuji adalah:  0 (air steril), 250, 500, 1.000, 1.500, 3.000, dan 5.000 ppm. Uji di rumah kaca dilakukan pada benih kopi Arabika menggunakan rancangan acak lengkap dengan 5 ulangan. Perlakuan yang diuji adalah konsentrasi minyak nimba, kemiri sunan, dan ekstrak babadotan (1.000, 2.500 dan 5.000 ppm) dan  Mankozeb (kontrol positif, 2000 ppm). Pengamatan dilakukan terhadap jumlah bercak, intensitas serangan dan pertumbuhan tanaman. Hasil penelitian menunjukkan bahwa konsentrasi terbaik untuk minyak cengkeh,  babadotan, nimba dan kemiri sunan dalam menekan perkecambahan urediniospora adalah 500 ppm, 3000 ppm,  5000 ppm. Ekstrak babadotan dan minyak cengkeh efektif menekan infeksi H. vastatrix sebesar 75,99 % dan 64,00% pada daun kopi, tidak berbeda nyata dengan fungisida  sintetik (68,00%).
Keywords
Botanical fungicides; coffee; leaf rust; urediniospore, , Fungisida nabati; karat daun; kopi; urediniospora,
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