The mycorrhizal symbiosis plays a major role in plant nutrient acquisition, pathogen control and soil stabilisation in land use systems with a low input of external resources. The use of inocula of mycorrhizal fungi for the development of sustainable agricultural production systems in Europe is still scarce. Since it was found that even in organically managed soils and particularly in substrates mycorrhizas can be limited, a set of recently introduced commercial inocula and 10 pre-selected strains of mycorrhizal fungi were multiplied and screened under farm conditions. Poinsettia, Pelargonium, leak and strawberry were used as test plants, which were inoculated in the seeding or potting substrates. There was a strong interaction between mycorrhizal fungi strains and crop. Mycorrhiza effects were found to be most pronounced in early seedling stages and, therefore, this phase of development should be investigated more intensively applying a combination of selected mycorrhizal fungal strains
