In order to prevent and/or reduce the infection in the nursery, greenhouse and nursery trials were carried out to evaluate effects of Trichoderma harzianum (Rootshield ®) treatments towards host-plant morpho-physiological characteristics and Phaeomoniella chlamydospora artificially inoculated on potted cuttings, as well as evaluating long-distance activity against Botrytis cinerea. The study was performed in a commercial nursery where plants were grown under organic management. Results greatly depended on the Trichoderma stage of application. Treatment at rooting appeared to be the most effective whilst callusing box application and combination of treatments gave controversial results. Treatment at rooting provided an increase of quantitative-qualitative characteristics of root system, an increasing of the percentage of certifiable vines. Moreover a statistically lower necrotic area caused by Botrytis cinerea inoculated on leaves collected from treated plants and a reduction in necrosis development of P. chlamydospora inoculated cuttings were also assessed. This necrosis reduction was statistically higher at 15 months from the inoculation. Finally, an increase of losses of treated plants at the end of growing season was assessed. On the whole, the application of Trichoderma at appropriate stage of the production of propagation material seemed to produce positive effects on vegetative conditions and increase the tolerance to stress–related diseases, like forms of esca infections occurring at nursery levels.