Biological seed treatment of cereals with fresh and long-term stored formulations of Clonostachys rosea: Biocontrol efficacy against Fusarium culmorum

In six field experiments, seed treatment with Clonostachys rosea (IK726) si gnificantly reduced disease caused by Fusarium culmorum. IK726 was active a gainst the pathogen at average soil temperatures at sowing ranging from 6.2 to 12 degrees C. Both in the field experiments and in growth chamber exper iments conducted in sand, dried and stored conidia of IK726 controlled F. c ulmorum as effectively as freshly harvested conidia. A high correlation was found between disease index ratings from field experiments and from corres ponding growth chamber sand tests. Amendment with the stickers Pelgel or Se piret did not influence control activity. The effective dosages of IK726 (c fu/seed) were estimated in bioassays and were very similar for freshly harv ested conidia and for dried conidia. With a density of > 5x10(3) conidia pe r seed more than 80% disease control was repeatedly obtained with both type s of conidia.