When carnations were cultivated out of soil using NFT (nutrient film technique) the incidence of Fusarium greatly decreased from the first crop to the third crop when the nutrient was not changed from one production to another. When Fusarium was articially introduced in a disinfected production unit, the incidence of disease was 70% compared to 45% in the control (non disinfected). This demonstrates a gradual and natural build up of microflora antagonistic to Fusarium. When some of these natural antagonists were introduced into the nutrient solution along with the Fusarium pathogen, disease suppression was very effective in contrast to the application of the antagonists onto the surface of the rockwool blocks. Various microorganisms have also been found to suppresss Pythium aphanidermatum. Suppression is caused by fungal parasitism or antibiosis, production of inhibitory chemicals, competition for space and nutrients or the stimulation of increased disease resistance of the plants being grown. Such biological control offers considerable future advantages to soilless cultivation. Helen Armstrong, "Fruit & Veg" vol.1 nr.2 www.HortiWorld.nl