New Results from scab-experiments (treatments on fallen leaves and summer-applications)

Summary

In the leaf-decompositon-trials to reduce the ascospore potential of Venturia inaequalis (2003/2004 and 2004/2005) different agents were tested with regard to direct effects on scab and to increasing the attractivity of the leaves for earthworms. TSB (lab medium with soya extracts) had a heavy direct effect on ascospore potential, but in this formulation it cannot be used in organic fruit-growing. Humofix and Bactofil B didn´t re-duce the potential as strongly as in the trial 2002/2003. A yeast extract and a combination of bean extract with powdered milk increased the attractivity for earthworms. In the trial 2004/2005 the reduction of the asco-spore potential was at best to 60 % of the control (powdered milk+Humofix), respecting the loss by earth-worms yeast extract+malt showed positive effects. In the experiment about applications against scab in summer 2004 the fluid formulation Sommerschwefel was comparable with wetting sulphur, during the stor-age season Frutogard and Agromil+BioPluss retarded best the development of late scab lesions on the ap-ples. Why Agromil+BioPluss caused an increasing of superficial scald in April 2005, cannot be explained at the moment.