Effectiveness of Trichoderma spp. in biological control agents for Rhizoctonia solani in coffee seedling

anglais. Rhizoctonia solani is the cause of dumping-off disease which destroys great number of coffee seedlings in South Sulawesi, East Java and Central Java. Until now the control of this pathogen is still relied on pesticide application. Trichoderma spp. are considered to be potential antagonistic microorganisms in biological control. A study on the effectiveness of Trichoderma spp. as biological control of Rhizoctonia solani, was carried out in the laboratory and green house of ICCRI (Indonesian Coffee and Cocoa Research Institute). The aim of this study was to find out the effectiveness of Trichoderma harzianum and Trichoderma koningii in controlling the disease by using an appropriate concentration. Laboratory experiment implementing complete randomized design with two treatments and ten replications was aimed to study the antagonistic capability of T. koningii and T. harzianum to the growth of R. solani. Green house experiment was subjected to study the effect of different concentrations and Trichoderma species in suppressing lesion growth caused by R. solani. Using RCBD, this glass house experiment treatments of T. harzianum and T. koningii with concentration of 0; 10 at the power of 6; 10 at the power of 7; 10 at the power of 8; 10 at the power of 9 spores/ml. The results showed that T. koningii and T. harzianum were effective to inhibit the growth of R. solani in the laboratory but T. koningii was more effective than T. harzianum. T. koningii with concentration of 10 at the power of 6 spores/ml was capable to suppress the growth of R. solani disease, in which higher concentration more effective in the capability of suppressing. Concentration of 10 at the power of 8 spores/ml T. harzianum was the most effective

indonésien. Jamur Rhizoctonia solani merupakan penyebab penyakit rebah batang yang banyak merugikan pembibitan kopi di Sulawesi Selatan, Jawa Timur dan Jawa Tengah. Pengendalian penyakit ini masih mengandalkan penggunaan pestisida. Salah satu mikroorganisme antagonis yang berpotensi dalam pengendalian hayati antara lain jamur Trichoderma spp. Penelitian keefektifan jamur Trichoderma harzianum dan Trichoderma koningii sebagai agen pengendali Rhizoctonia solani pada bibit kopi telah dilaksanakan di laboratorium dan rumah kaca Pusat Penelitian Kopi dan Kakao. Percobaan laboratorium untuk mengetahui daya antagonis T. koningii dan T. harzianum terhadap pertumbuhan R. solani menggunakan rancangan acak lengkap dengan dua perlakuan dan sepuluh ulangan. Percobaan di rumah kaca menggunakan rancangan acak kelompok untuk menguji jamur T. harzianum dan T. koningii dengan perlakuan konsentrasi 0, 10 pangkat 6, 10 pangkat 7, 10 pangkat 8, 10 pangkat 9 spora/ml. Hasil penelitian menunjukkan bahwa T. koningii dan T. harzianum efektif menghambat perkembangan R. solani di laboratorium tetapi T. koningii mempunyai kemampuan menghambat lebih baik. T. koningii dengan konsentrasi 10 pangkat 6 spora/ml sudah dapat menekan perkembangan penyakit rebah batang. Makin tinggi konsentrasi makin efektif menekan perkembangan penyakit. Konsentrasi 10 pangkat 8 spora/ml T. harzianum paling efektif menekan penyakit rebah batang