For organic wine farmers the only permitted products are copper and sulphur, it is often said. That is not quite correct, since in organic farming you are allowed to use other products – if they are “natural”.
Here’s a summary of diseases and treatments for organic wine growing (based on an article from La Vigne):
- Mildiou (downy mildew): copper is used preventively, currently maximised at 6 kg/ha (possible reduction to 4 kg/ha in view). Having a well aerated vine is important.
- Oidium (powdery mildew): spraying with sulphur preventively. There are trials with some alternative products based on e.g. citrus fruit peels, milk or fenugreek (fenugrec, bockhornsklover) with varying success
- Botryts (rot): Prevention by avoiding excessive humidity in the vine is most important. Inconclusive trial with e.g. Bacillus Subtilis, talcum or clay powders have been done.
- Insects: the insect that spreads flavesence doree can since 2009 be fought with “Pyrevert”, a product made from Dalmatian Pyrethrum. This replaced a product called Rotenon which was not very effective. Against the grape worm trials are done with an extract of bacteria (e.g. Bacillus Thuringensis).
