PERSISTENCE OF TRICHODERMA ASPERELLUM POPULATION IN STRAWBERRY SOILLESS CULTURE GROWING SYSTEMS

Biological control of soil-borne fungal pathogens with the antagonist fungus Trichoderma asperellum (T-34)^® is important for the suppression of root diseases in strawberry soilless culture. The aim of this study was to measure the long-term survival of Trichoderma asperellum (T-34) ^® inoculum in substrate as well as the protective effect of this antagonist fungi against strawberry diseases caused by Phytophthora cactorum and Verticillium dahliae. The experiment was carried out under a methacrylate greenhouse. A randomized complete block design with two replicates was performed. ‘Camarosa’ cultivar (cv.) plug plants were planted at the beginning of October for two consecutive growing seasons (2005/2006 and 2006/2007) with a plant density of 11 pl/m2. Closed soilless growing systems with and without slow sand filtration for disinfestations of the recirculated nutrient solution, were evaluated. Perlite inoculated with Trichoderma asperellum (T-34) ^® was used at the begining of the trials as substrate. The last twelve plants of each subplot/row were inoculated with Phytophthora cactorum or Verticillium dahliae. The results showed that Trichoderma is present after inoculation in new and re-used substrate. Results also showed the possibility of using Trichoderma to protect strawberry roots against Phytophthora cactorum but not against Verticillium dahliae.