Samenbürtige Erreger in Saat- und Erntegut von Erbsen und Fababohnen auf Ökobetrieben

Summary

A total of 39 organic faba bean and 59 pea seed lots obtained during 2009-2011 from 32 organic farms throughout Germany were assessed for seed-borne fungi. Seed samples collected from the harvested fields grown from these seed lots were also assessed. The focus in the pathogen identification was on the ascochyta blight complex pathogens Ascochyta pisi, Mycosphaerella pinodes and Phoma medicaginis in pea and A. fabae and P. medicaginis in faba bean and on Fusarium spp.
Fusarium spp. were found only rarely on peas with 40 of the seed samples and 44 of the harvested samples free of Fusarium spp. and the maximum infestation rate of 12 % in one harvested sample. Eighteen of the sown and 40 of the harvested lots had infestation rates of > 10 % with the Ascochyta complex pathogens. Several seed samples had infection levels over 50 %.
Only 9 out of 39 faba bean seed lots and 4 out of the 36 harvested samples were free of Ascochyta blight and Fusarium spp. pathogens. Ten and 20 % of the sown and harvested seed samples had infection levels > 10 % with a given pathogen. In most cases, the faba bean seeds were infected with one pathogen only, however, mixed infections occurred.
Overall, highly infested seed lots resulted in highly infested harvest lots. However, harvests were often also infested when they originated from clean seed thus pointing to the importance of local soil borne and air borne infections.