Nachweis über die Dauer der Infektionsfähigkeit von Steinbrand- (Tilletia caries) und Zwergsteinbrandsporen (Tilletia controversa) im Boden und Stallmist in Biobetrieben

Summary

This research work is scoping on whether in the case of huge infestation with common and/or dwarf bunt farmers have to stop temporarily wheat cultivation and furthermore how many years wheat should not be grown on these fields. For answering these questions, 3-years randomized crop rotation field trials are performed at 3 sites with 4 replicates on infested fields with crop rotation links commonly used in organic farming to determine whether it is possible to decrease the spore potential in soil. Brassica species setting free isothiocyanate after mulching are cultivated to examine if it is possible to reduce the viability of spores. Additionally, the influence of stable manure on bunt spores it tested.
Soil samples are taken half-yearly from each plot and common and dwarf bunt spore potential is determined under the microscope as well as the germination ability of the spores on agar plates. Variation of the number of spores in stable manure is determined half-yearly during storage.
Physical and chemical facts hamper a really high finding of spores out of soil. Retrieval rates of about 50 % could be achieved at present. After one year storage, spore potential in the stable manure has been decreased by more than 90 %. Optimal germination conditions for common and dwarf bunt spores from bunt balls have been elaborated and established. These conditions are tested at present with spores out of soil.