"Chris Hogg" wrote in message
...

On Mon, 29 May 2017 20:25:02 +0100, "Bertie Doe"
wrote:
I notice that Bligh****ch is sponsored by 'Belchim Crop Protection'. I'll
give them a buzz tomorrow but I'll bet they only supply farmers OR the
minimum order for Brand X is 50 gallons :-) The question is - what has
replaced Bordeaux?

Bordeaux mixture is a copper-lime fungicide, as you probably know.
Bayer did 'fruit and vegetable disease control' fungicide, in sachets,
that was based on copper oxychloride, but I see that's been withdrawn
now, although still available on Ebay, apparently
http://tinyurl.com/yd7jsyj8

There is this, which is in effect Bordeaux mixture but not named as
such and is a two-pack system that you mix yourself, which I suppose
gets round the regulations http://tinyurl.com/y9mnbw4q Makes 4 litres,
but for £3.55 + £1.33 postage that seems expensive to me.

It might be cheaper to buy your own hydrated lime and copper sulphate
in bulk and mix as needed. http://tinyurl.com/yc6vw4rf and get
hydrated lime from a builders merchant (most 'lime' sold in garden
centres is actually ground limestone, which won't behave like lime
when combined with copper sulphate, although is ok for adding to
soil). Instructions for making it, here http://tinyurl.com/kkbpqfq
with the caveat that she says slaked lime is calcium oxide, which is
wrong. Slaked lime is calcium hydroxide, and is the same as hydrated
lime. Calcium oxide is just lime.

Many thanks Chris, much appreciated. I note that the "copper sulphate and
lime mix, was developed in the Bordeaux region of France" - so there's the
connection.

Don't know about your ph in SW Cornwall but here in SE the soil is fairly
acid, so may benefit all veg with a dose of lime.

If my remaining BM is effective, I may well try the DIY route. Thanks again.

On 30/05/2017 08:16, Chris Hogg wrote:
On Tue, 30 May 2017 07:28:13 +0100, "Bertie Doe"
wrote:

Many thanks Chris, much appreciated. I note that the "copper sulphate and
lime mix, was developed in the Bordeaux region of France" - so there's the
connection.

There was also a Burgundy mix, copper sulphate neutralised with
caustic soda. Both were developed to combat fungal attack on grape
vines, but they were applied very generously, and over many decades
resulted in a build-up of copper in the soil. I'm not sure whether
that's the principal reason for all the various copper fungicides
being banned, but it was contributory. Cheshunt compound is copper
sulphate neutralised with ammonium carbonate.

Used sparingly I doubt it is that much of a problem. Used regularly on
the same crop in the same dry ground it gradually builds up which is
what caused them problems in France. I suspect plants tolerate copper
quite well so it is more a problem of contaminating groundwater.

All the copper based fungicides work by inhibiting certain enzymes that
are present in damping off, mildews and blight fungi.

--
Regards,
Martin Brown