238 ISSN: 0215-7950 *Alamat penulis korespondensi: Fakultas Pertanian Universitas Nusa Cendana. Jalan Adisucipto Penfui, Kupang, NTT, Indonesia. 85001 Tel: (0380) 881580. Surel: asimamora@staf.undana.ac.id Volume 19, Nomor 6, November 2023 Halaman 238–245 DOI: 10.14692/jfi.19.6.238–245 Patogenisitas Botryodiplodia theobromae pada Batang Cendana dan Penghambatannya secara in Vitro oleh Trichoderma spp. Pathogenicity of Botryodiplodia theobromae on Sandalwood Stems and Its in Vitro Inhibition by Trichoderma spp. Sane Wolagole, Agnes Virginia Simamora*, Mayavira Veronica Hahuly Program Studi Agroteknologi, Fakultas Pertanian Universitas Nusa Cendana, Kupang. Jalan Adisucipto Penfui, Kupang, 85001 (diterima Agustus 2023, disetujui November 2023) ABSTRAK Penelitian dilaksanakan untuk menentukan patogenisitas Botryodiplodia theobromae dalam menginfeksi batang cendana dan menguji kemampuan 10 isolat Trichoderma spp. dalam menghambat pertumbuhan dua isolat B. theobromae secara in vitro. Uji patogenisitas dilakukan dengan menginokulasi potongan isolat B. theobromae pada batang cendana. Uji antagonis dilakukan menggunakan metode kultur ganda dengan 10 isolat Trichoderma spp. dan dua isolat B. Theobromae sebagai kombinasi perlakuan. Hasil uji patogenisitas membuktikan bahwa B. theobromae menyebabkan gejala penyakit dimulai pada hari ke 30 setelah inokulasi. Hasil uji antagonis menunjukkan bahwa isolat-isolat Trichoderma spp. mampu menghambat pertumbuhan dua isolat B. theobromae melalui antibiosis dan kompetisi. Penghambatan terbaik terhadap B. theobromae Bt01 dicapai oleh T. viride TVJKS (53.20%), sedangkan penghambatan terbaik terhadap B. theobromae Bt02 dicapai oleh T. hamatum THAK (53.26%). Kata kunci: antibiosis, kompetisi, metode kultur ganda, uji antagonis, uji patogenisitas ABSTRACT Research was carried out to determine the pathogenicity of Botryodiplodia theobromae in infecting sandalwood stems, and to test the ability of 10 isolates of Trichoderma spp. in inhibiting in vitro growth of two isolates of B. theobromae. The pathogenicity test was carried out by inoculating B. theobromae isolates on sandalwood stems. The antagonist test was conducted using the dual culture method with 10 isolates of Trichoderma spp. and two isolates of B. theobromae as combination treatment. The pathogenicity test proved that B. theobromae caused disease symptoms starting on the day 30 th after inoculation. Antagonist test showed that isolates of Trichoderma spp. were able to inhibit the growth of two isolates of B. theobromae through antibiosis and competition activities. The best inhibition against B. theobromae Bt01 was achieved by T. viride TVJKS (53.20%), while the best inhibition against B. theobromae Bt02 was achieved by T. hamatum THAK (53.26%). Keywords: antagonist test, antibiosis, competition, dual culture methode, pathogenicity test