183 ISSN: 0215-7950 Volume 14, Nomor 5, September 2018 Halaman 183–188 DOI: 10.14692/jf.14.5.183 *Alamat penulis korespondensi: Jurusan Hama Penyakit Tanaman, Fakultas Pertanian, Universitas Gadjah Mada. Jalan Flora 1 Bulaksumur Yogyakarta 55281. Tel: 0274-523926, Faks: 0274-523926, Surel: sulandari77@yahoo.com KOMUNIKASI SINGKAT Keefektifan Bakteri Rizosfer Streptomyces sp. untuk Menekan Pepper yellow leaf curl virus Pada Tanaman Cabai Besar di Lapangan Efectiveness of Rhizobacteria Streptomyces sp. to Suppress Pepper yellow leaf curl virus on Chili in the Field Riska Awalia Putri, Sri Sulandari*, Triwidodo Arwiyanto Universitas Gadjah mada, Yogyakarta 55281 ABSTRAK Penyakit daun keriting kuning cabai yang disebabkan Pepper yellow leaf curl virus (PYLCV) merupakan salah satu kendala produksi cabai di Indonesia. Salah satu metode untuk mengendalikan penyakit ini ialah menggunakan plant growth promoting rhizobacteria (PGPR). Penelitian bertujuan menguji keefektifan Streptomyces spp. untuk menekan penyakit daun keriting kuning pada tanaman cabai besar varietas Twist di Pakem, Sleman, Yogyakarta. Sebanyak 10 mL Streptomyces sp. dengan konsentrasi 10 8 cfu mL -1 diaplikasikan ke dalam lubang tanam sebelum pindah tanam. Selama pertumbuhan tanaman diamati beberapa parameter, yaitu insidensi dan keparahan penyakit, dan peubah agronomi tanaman. Hasil penelitian menunjukkan bahwa Streptomyces spp. mampu menurunkan insidensi dan keparahan penyakit berturut-turut sebesar 38% dan 57% pada 11 minggu setelah tanam dibandingkan dengan tanpa perlakuan. Perlakuan Streptomyces sp. menyebabkan pertumbuhan tanaman yang lebih baik berdasarkan pengamatan terhadap tinggi tanaman, diameter batang, panjang dan volume akar, jumlah cabang produktif, jumlah dan bobot total panen, serta kualitas buah diperoleh, walapun tidak berbeda nyata dengan perlakuan kontrol. Kata kunci: insidensi penyakit, keparahan penyakit, penyakit daun keriting kuning cabai, plant growth promoting rhizobacteria ABSTRACT Chili yellow leaf curl disease caused by Pepper yellow leaf curl virus (PYLCV), has been known as an important constrain for chili’s production in Indonesia. Disease control method can be done by utilizing plant growth promoting rhizobacteria (PGPR). The research aimed to evaluate the efectiveness of Streptomyces sp. in suppressing yellow leaf curl disease on chili var. Twist in Pakem, Sleman, Yogyakarta. Streptomyces spp. was applied into planting hole, i.e. 10 mL per plant before transplanting with a concentration of 10 8 CFU mL -1 . Observation during plant growth involved disease incidence and intensity, and also agronomic parameters. The results showed that Streptomyces sp. could suppress signifcantly disease incidence and severity, i.e. up to 38% and 57%, respectively at 11 weeks after planting (WAP) compared to control treatment. Although it did not give signifcant efect with those of control treatment, application of Streptomyces sp. resulted a better plant growth based on observation of plant height, stem diameter, root length and volume, productive branches, number and total weight, and increased the quality of marketable fruits. Key words: disease intensity, disease severity, plant growth promoting rhizobacteria, pepper yellow leaf curl disease