Agrika: Jurnal Ilmu-Ilmu Pertanian , Volume 13, Nomor 2, November 2019 90 EFEKTIVITAS FUNGISIDA BAHAN AKTIF MANKOZEB UNTUK MENGENDALIKAN HAWAR DAUN KENTANG (Phytopthora infestans) DI SUMBER BRANTAS DAN NONGKOJAJAR Riza Ulil Fitria 1) dan Diding Rachmawati 1) 1) Balai Pengkajian Teknologi Pertanian Jawa Timur, Malang Email: riza_bptp@yahoo.com ABSTRAK Tujuan penelitian untuk mengetahui tingkat efektivitas fungisida berbahan aktif mankozeb 80% terhadap serangan patogen Phythopthora infestans pada kentang. Penelitian dilaksanakan di Desa Sumberbrantas, Kota Batu pada Oktober-Desember 2017 dan di Nongkojajar Kabupaten Pasuruan pada Februari- April 2018. Penelitian menggunakan Rancangan Acak Kelompok dengan 5 ulangan. Perlakuan terdiri dari a). Mankozeb 80% 4g/l; b). Mankozeb 80% 3g/l; c). Mankozeb 80% 2 g/l; d). Mankozeb 80% konsentrasi 1 g/l; dan e). Kontrol (tanpa perlakuan). Hasil penelitian menunjukkan bahwa di lokasi Sumberbrantas- Batu, Mankozeb 80% 3 g/l dan 4 g/l efektif terhadap penyakit hawar daun kentang (P. insfestans) pada tanaman kentang dengan kemampuan menekan serangan masing-masing sebesar 66, 58% dan 77,99%, dengan produksi kentang berturut-turut 6,9 ton/ha dan 7,9 ton/ha. Di lokasi Nongkojajar-Pasuruan, fungisida mankozeb 80% 4 g/l, 3 g/l dan 2 g/l mampu menekan serangan berturut- turut sebesar 61,65% , 45,68% dan 42.18% terhadap penyakit hawar daun kentang P. infestans, dan produksi kentang berturut-turut 6,03 ton/ha, 5,13 ton/ha, dan 5,49 ton/ha. Kata kunci: efektivitas; fungisida; hawar daun; kentang; Phythopthora insfestans ABSTRACT This research is to find out the effectiveness of 80% mankozeb active ingredient on the attack of pathogen Phythopthora infestans on potatoes. This research was conducted at village of Sumberbrantas, Batu on October-December 2017 and at Nongkojajar Pasuruan Regency on February-April 2018. The study used Randomized Block Design with 5 replications. The treatments consisted of a). Mankozeb 80% 4g/l; b). Mankozeb 80% 3g/l; c). Mankozeb 80% 2 g/l;d). Mankozeb 80% 1 g/l; and e. Control (without Mankozeb). The results showed that at Sumberbrantas-Batu, Mankozeb 80% 3 g/l and 4 g/l were effective against potato leaf blight (P. insfestans) on potato plants with the ability to suppress attacks respectively 66.58% and 77.99 % , and potato production respectively 6.9 tons/ha and 7.9 tons/ ha. At Nongkojajar-Pasuruan, the mankozeb 80% 4 g/l, 3 g/l and 2 g/l were able to suppress attacks successively at 61.65%, 45.68% and 42.18% against P. infestans potato leaf blight,and the production were 6.03 tons/ha, 5.13 tons/ha, and 5.49 tons/ha. Keywords: effectiveness; fungicide; leaf blight; Phythopthora insfestas; potato