Evaluation of native Trichoderma isolates for the management of sugarcane smut (Ustilago scitaminea) in sugar plantations of Ethiopia

Biological control of sugarcane smut (Ustilago scitaminea Syd.) using Trichoderma isolates is one of the untapped potentials in Ethiopian sugarcane plantations. To this end, this study was carried out with the objective to identify potential native Trichoderma isolates for the management of sugarcane smut. A total of 120 soil samples were collected from Kesem, Metehara, and Wonji sugarcane plantation fields. Consequently, 21 Trichoderma isolates were recovered from the samples, and in-vitro antagonist study of Trichoderma isolates against U. scitaminea was done using dual culture technique on fresh PDA. Among the native isolates, 12 of them revealed a pathogen suppression potential of >90% at 7 days after inoculation and most of them had higher pathogen suppression than the commercial isolate. However, five of the isolates were selected as potential candidates based on distinct suppression features, growth rate, and antagonistic performance. Identification of the five effective Trichoderma isolates (WI4-27, MKI2-k17, MI3-m33, WI12-25, and MKI3) was done based on macroscopic and microscopic characteristics. Thus, the isolates were identified as T. harzianum, T. asperellum, T. viride, T. viride, and T. harzianum, respectively. Accordingly, these isolates could be used as one component of integrated smut management practices once a study on compatibility with fungicides, in-vivo efficacy test against smut, and substrate selection for mass production of the isolates were commenced.