I believe that in organic growing the far most important thing is to provide good natural conditions for the grapevine growth, and make use of cultural practices which ensure good natural vine resistance.
Several different natural preparations can be used in organic winegrowing, for example: extracts of parasitic fungi, bacteria-based preparations, oil preparation, and preparations and or tee of herbs - Achillea, chamomile, valerian, oak bark and dandelion, extracts from algae and clay minerals, compost water, etc. Some suggestions:

• Against downy mildew: plant tonic based on clay sulfate and selected plant extracts.
• Against powdery mildew: extract of parasitic fungi (Ampelomyces quisqualis).
• Against mites: rapeseed oil
• Preparations for strengthening of vine resistance: cereal ferment (asset-building plants with minerals, vitamins, amino acids and lactic acid bacteria), and algae extracts.