1. Department of Plant Pathology, Swedish University of Agricultural Sciences, P.O. Box 7044, S-750 07 UPPSALA, Sweden
2. Danish Institute of Plant and Soil Science, Department of Plant Pathology and Pest Management, Lottenborgvej 2, DK-2800 Lyngby, Denmark
3. Nestlé R&D Center Bjuv AB, P.O. Box 520, S-267 25 BJUV, Sweden