Is anyone here convinced that spays work against blight?

[Barry]

I watch blight forecast websites and am clear when blight conditions are around in my area. I did spray against blight IN ANTICIPATION of such an attack and thought I had managed to ward it off. Potatoes on surrounding plots went under, but mine survived. No similar blight conditions have presented themselves for about 20 days, but even my spuds and tomatoes are now affected. I have sprayed both crops, since not all members APPEAR to be affected, although in the case of potatoes it is often too late anyway; the disease is often in place even though you cannot see it. I know farms spray regularly every two weeks, which I simply won't do. All that copper or tin!!
Are any of you convinced that you have managed to ward off blight all together by spraying, using either Bordeaux Mixture or Dithane? I am beginning to be extremely dubious as to the effectiveness of either of these two chemicals!
Also, by pulling off infected leaves, do you think you can prolong the growing life of the potatoes?
By spraying tomato plants even when they show slight signs of blight can you really extend growing life?
I am looking for real evidence here. I know what everybody says, but is this really the case?
I think only regular spraying in high doses throughout the blight season has any affect at all. Anybody disagree?

[richard p]

hi barry you're right, you have to spray before any sign of blight appears and repeat at the specified intervals for the spray to be effective

[Primrose]

I'm not convinced about spraying, although I've tried it in the past, without a great deal of success. The whole point about growing my own is knowing that I'm eating foods which haven't been tainted by chemicals and I really wonder about the toxic effects of eating food which has been either recently or consistently sprayed with various concoctions. Even if you thoroughly wash the vegetables before cooking and eating I'm sure some of the stuff has been absorbed.

[Bren]

My father and all our neighbours used to spray the potato crops, living close to the sea the potatoes were prone to blight, damp conditions they only sprayed once it was a blue coloured liquid, don't know what it was called, We grew enough of spuds to last us most of the year, mind you I am going back a long time ago more years than I care to remember.

Bren

[King Carrot]

someone mentioned "bluestone & washing soda" in relation to blight spraying here, before the era of newer chemicals - I suppose they remember the 40's.

anyone know what the bluestone would be?

[GIULIA]

Bluestone is copper sulphate, one of the ingredients in Bordeaux mixture.