Abstract. Numerous experiments demonstrating potential biocontrol effects on soilborne diseases have been reported in the scientific literature. However, from the lists of approved and registered biocontrol agents, it is striking how few have been commercialised and are used in practise for plant disease control. The main hindrances are often claimed to be legislative aspects and the costs involved in the registration. Although this is in many respects true, there is a range of both biological and technical problems which must be considered when developing an effective biocontrol agent for commercial use. Among the success stories for control of seed- and soilborne diseases are fungal biocontrol agents based on Trichoderma harzianum, Clonostachys rosea and Conithyrium minitans, and bacterial biocontrol agents based on strains of Agrobacterium, Pseudomonas and Streptomyces.We have developed C. rosea strain ‘IK726’, which has proved to be an effective antagonist in several crops against seed- and soilborne diseases. Although a biocontrol agent based on C. rosea ‘IK726’ is not yet commercialised, this paper will be used to address some of the biological and technical aspects that must be dealt with in such a development

Keywords