> What is the opinion though on Bordeaux and Burgundy spray, does the
> copper stay residual in the plant and it's fruits?
>
> Karen

Yes, I sometimes think about this myself as I grow a lot of fruit and
find I have to spray (with Bordeaux) for pear and apple scab, although
I keep it to the bare minimum depending on the weather. Organic
guidelines do allow the 'qualified' use of Copper treatments, but I'm
not sure what that means. A brief surf through HDRA.org.uk turned up
this 'qualified' recommendation:

http://www.hdra.org.uk/guidelines/pd_management.htm

but also listed copper elsewhere among undesirable metals which can
build up in the soil.

Re. potatos, I don't think you'll have any problems if you choose any
of the newer blight-resistant varieties or early (new) ones (e.g.
Swift, Sante).

Tomatos are more of a problem, but I still wouldn't bother spraying as
blight usually strikes when the trusses are full of green tomatos, so
you'd have so spray the actual fruit (I think organic guidelines only
allow for foliar use; this must be one of the 'qualifications').

All the best,
Elizabeth