Efficacy of Trichoderma spp. Collected from Chiang Mai Province for Controlling <I>Sclerotium rolfsii</I>

Abstract

One hundred and fifty-six isolates of Trichoderma spp. were collected from mushroom spawn, farm lands from all districts in Chiang Mai and commercial biological product by dilution plate method. Based on growth rate (mean ± SD) on PDA medium, the fungal isolates could be separated into 3 groups which were high 32.30 ± 1.62, moderate 27.17 ± 2.32 and low 19.48 ± 0.56 mm per day. The result indicated the average sporulation value of all these 3 groups which were 13.04 ± 2.52 x 10¹⁰, 7.37 ± 1.28 x 10¹⁰ and 3.22 ± 1.22 x 10¹⁰ spores/ml. Afterwards, screening of fungi were evaluated for antagonistic activity to Sclerotium rolfsi, the cusual gent of damping-off, by dual culture technique. Percentage of growth inhibition of S. rolfsi by Trichoderma spp. isolates T15, T42, T75 and TM10 were 71.67, 54.93, 60.79 and 25.42%, respectively. The results of greenhouse experiment indicated that Trichoderma spp., isolate T15 and T75 showed a high ability of inhibitory effects on plant pathogen that percentages of disease incidences were 25.00% for both of the isolates and 48.75% for the T42 isolate. TM10 isolate had low ability to inhibit pathogen that the incidence rates for disease were 72.50 %.