Integrated management of fungal pathogens of yam (<i>Dioscorea alata</i> L.) using Trichoderma species

Abstract

Plant pathogens are the major constraints that decrease the productivity and post-harvest deterioration of yam crop. Among the plant pathogens, fungal pathogens are major agents responsible for the infection of yam crop. Therefore, the present study was carried out to manage fungal pathogens of yam (Dioscorea alata L.) crop using Trichoderma spp., fungicides and their combination for integrated disease management. In vitro evaluation of dual culture test of AUT1 (Trichoderma harzianum) and AUT2 (Trichoderma viride) obtained from Addis Ababa University against AUF1 (Fusarium isolate 1), AUA1 and AUA2 (Alternaria isolate 1 and 2) and AUV1 and AUV2 (Verticillium isolate 1 and 2) revealed that both biocontrol agents showed 60.42% to 76.95% and 68.82% to 75.75% of mycelial growth inhibition, respectively. From in vitro evaluation of fungicides (curzate, 43.95% WP and sancozeb, 80% WP) tested at concentrations of 100, 200, 400, 600, 800 and 1000 ppm based on inhibitory concentration against fungal pathogens of yam. Sancozeb was more effective than curzate in terms of percent mycelial growth inhibition of fungal pathogens. For this study the minimum concentration of fungicide, 600 ppm (curzate) and 400 ppm (sancozeb) were recommended. From the study of combined efficacy of Trichoderma species with fungicides, the highest percent of inhibition of mycelial growth of fungal pathogens was 85.6%, 79.7%, 87.5%, 89.3% and 80.2% when AUT2 was combined with sancozeb at 400 ppm for AUF1, AUA1, AUA2, AUV1 and AUV2, respectively. The results showed that combination and integration of AUT1 and AUT2 with chemical fungicides (curzate and sancozeb) at lower concentrations may offer a promising management strategy of fungal pathogens of yam compared to fungicides and Trichoderma species separately.

Keywords/phrases: Fungicides, Integrated fungal pathogen management, In vitro, Trichoderma species