"Pam Moore" wrote after...
me:

Bordeaux Mixture (copper sulphate and lime) is a preventative and I use
it
as a matter of course on my outdoor grown Tomatoes to stop THE blight,
applied from about mid August. The books say Early blight isn't a problem
usually but if you want to remove infected bits and spray the rest with
BM
then OK, it does need reapplying after heavy rain. (I Wish!)

I tried Bordeaux mixture last year on my tomatoes, but it was so messy
and coated the fruits in a whitish-blue "frost" and needed thorough
washing. It only kept the blight at bay for a week or so, and then
the whole lot went, as in the last 4 years.
This year they will take their chance.
Famous last words?

I find it keeps it at bay except on the bush type "Roma" which seem very
susceptible, however as you have probably guessed we are in a dry spot so it
doesn't get washed off by rain much.
Try growing a resistant variety like "Ferline" next year, T & M do them.

--
Regards
Bob
in Runnymede, 17miles west of London, UK