The potential of antagonists for fungal control

The use of antagonistic microorganisms to control fungal pathogens is very limited because very few of the species which showed potential under experimental conditions were successful in the field. To be commercially useful, organisms must be easy to propagate and introduce into the soil in sufficient numbers to affect the pathogen and the cost must be significantly less than the expected losses that would result from disease caused by the pathogen.Fungi are more able to grow in soils of low moisture content than bacteria and under such conditions bacteria are likely to be poor antagonists. However, in practice the most attractive microbial antagonists for root diseases appear to be bacteria, particularly species of Pseudomonas and Bacillus. Advances in microbial genetics have provided methods whereby it may be possible in the near future to manipulate microorganisms and produce new antagonistic strains for particular purposes. However, the breeding of strains of this nature will require a much better understanding of interactions between microorganisms, plants and the soil than we have at present.