Entwicklung des Befalles mit Weizensteinbrand (Tilletia caries) bei Saatgut in der Biosaatgutanerkennung in Österreich und Qualitätsvergleich zu Nachbausaatgut

Summary

Common Bunt (Tilletia caries) is a mainly seed borne disease and causes high losses in organic wheat and spelt production. Due to the basic role of seed health in disease prevention, seed quality aspects have to be focussed strictly in organic farming.
In the scope of these studies, Tilletia results of 1291 wheat seed lots and 298 spelt wheat lots obtained from officially organic seed production from 2000 to 2012 have been analysed. The data indicated significantly the increasing spread of Tilletia caries in seed production in the last years, nevertheless in 2012 a high rate of more than 90% of the tested lots still corresponds to the requirements for untreated seed according to the Austrian Seed Regulations (threshold level 10 spores/kernel). As the infection level of the used propagation seeds was stable high over the whole period (≤1 spore/kernel), mainly phytosanitary issues (e.g. soil contaminations) seems to be responsible for that development.
Additionally the contamination level of farm saved seed has been analysed. Farm saved seed is contaminated significantly and several times higher than organic certified seed and can be considered therefore as a main agent for uncontrolled and sustainable disease spread.