Einfluss von Fruchtfolge, Stallmistdüngung undSenfzwischenfrucht auf das Brandsporenpotenzial vonSteinbrand- (Tilletia caries) und Zwergsteinbrandsporen(T. controversa) im Boden

Common and dwarf bunt of wheat are important diseases in ecological farming. High infection levels lead to an increase of the spore potential in soil. 3 and 4 years randomized crop rotation field trials are performed at 3 sites with 4 replicates on naturally infested fields with either T. controversa or T. caries spores with crop rotation links commonly used in organic farming to determine whether it is possible to decrease the spore potential in soil. The influence of stable manure on bunt spores is tested. Brassica species setting free thiocyanate and isothiocyanate compounds after mulching are cultivated to examine the possibility to reduce the spore potential in soil. Soil samples are taken yearly from each plot and common and dwarf bunt spore potential is determined. In the crop rotation without perennial grass clover or fallow a higher reduction of bunt spores potential in soil was found. The plots treated with stable manure exhibit a significant reduction of spore numbers over the common bunt sites. No significant difference could be observed between the plots cultivated with mustard and those without intermediate crop.