LAUSR

Abstract Growth of young fruit trees replanted into old orchard soil is often poor relative to growth in soil that has not previously been planted with fruit trees. There is evidence that a consortium of deleterious soil biota, commonly referred to as the replant disease complex, are responsible for this poor early growth. We used a bioassay, comparing cherry plant growth in sterilized and non-sterilized subsamples of soil, to assess the net effect of soil biota from 18 orchards in the Okanagan Valley of British Columbia, Canada with differing histories of fruit tree production (previously cropped ‘old’ orchards, and not previously cropped ‘young’ orchards). Generally, shoot height increment was larger in non-sterile soil from young orchards than from old orchards (two-factor ANOVA; P