Population dynamics of non-pathogenicFusariumand fluorescentPseudomonasstrains in rockwool, a substratum for soilless culture

In soilless cropping systems, soil-borne plant pathogens, especially Fusarium oxysporum, are responsible for severe damage in vegetable and flower cultures. Non-pathogenic Fusarium and fluorescent Pseudomonas are able to control fusarium diseases, thereby increasing the yield. The association of the non-pathogenic Fusarium strain Fo47 and of the fluorescent Pseudomonas strain C7R12 gave a better control of fusarium diseases compared to single inoculations of each antagonistic microorganism. So far, no data have been available on the survival of these two microorganisms in soilless growing substrate. The results of this study indicate that both microorganisms survive well in rockwool when inoculated alone or together as well as in the absence or the presence of plants. Under the present experimental conditions, a single application of the antagonists appears to be enough to get a significant control of fusarium wilts.