ABSTRACT
A number of extensive reviews on methodology and experimental results concerning side effects of pesticides on the soil microflora have been published. This chapter discusses different approaches to side effect testing, illustrated by results from a Danish study on ergosterol biosynthesis inhibitor side effects on soil mycoflora under field conditions. It also discusses the suitability of different tests to determine side effects of fungicides on soil mycoflora with special attention to soil-borne pathogens. The soil dilution plate technique was used to favor spore producers in an attempt to assess the effect of propiconazole on fungi with "r-traits". It has been reported that benzimidazoles and dicarboximides may affect the production of fungal metabolites without necessarily affecting growth. The relative increase in some of the primary saprotrophic species of Fusarium may be related to the biological activity of their secondary metabolites in combination with a reduced competition from other primary saprotrophs, like Cladosporium and Ulocladium, which are more sensitive to propiconazole.
