Effects of beetroot vinasse on ascospore formation and infestation of Venturia inaequalis in organic apple orchards

摘要

In earlier works, the effect of beetroot vinasse on leaf decomposition and ascospore formation was examined over several years in standardized mesh cage trials with Jonagold leaves. As published in ecofruit proceedings 2014, vinasse applied once during leaf fall in autumn leads to fastened leaf decomposition and in addition to an obvious] reduction of ripe ascospores on remaining leaf material. Ascospore formation in these trials was examined twice during ascospore season with waterbath method according to Kollar (2000). To verify the good results received by waterbath method, the ascospore discharge of vinasse-treated and untreated leaves was continuously recorded using a Mycotrap spore trap during the ascospore seasons 2014 and 2015. To measure the effect of an additional vinasse treatment on resulting apple scab infestation in the field, multiple large scaled trials were additionally conducted in several ecologically managed orchards in Lake Constance area with the cultivar Jonagold. With regardto the long-distance distribution of ascospores, orchards were divided large-scale into plots with and without additional vinasse treatment. Potential effects of the vinasse treatment were recorded by measuring the amount of remaining leaf material in spring and the infestation of apple scab on leaves and fruit. In the mesh cage trial vinasse-treaded leaves discharged an obviously reduced amount of ascospores at every single infection period during the whole primary scab season compared to the untreated leaves. Furthermore, a positive effect of vinasse treatment on leaf decomposition and apple scab infestation on leaves and fruit was observed in every field trial.