Of the new products that have shown promising
results against grapevine downy mildew on seedlings
under controlled conditions, none has shown high
efficacy against the disease under natural conditions.
All of the products tested showed slight effects, but
the protection against the disease was insufficient
compared to standard treatments. The way of a
product from the lab to the field is hard, only very
few reach the level of field testing.
Under Swiss conditions a replacement of copper
seems to be possible with clay-mineral products,
however, these products have other possible disadvantages.
Within the framework of the EU-project “Replacement
of copper fungicides in organic production
of grapevine and apple in Europe” a new series of
promising products will be tested under controlled
conditions. From further indoor screening experiments
done in winter 2005/6, five products were
recommended for field screening in the season
2006. From all of these experiments we hope to find
at least one or two products or strategies that show
good protection in field screenings, so that they can
be tested on a larger scale in on-farm-trials in the
season 2007.