By Johnjoe
Ireland 
I am growing Rooster potato at my allotment that seems to be going very well. Many moons ago when I was a young lad the local farmers used to spray their potato crop with a substance which left a blue colour on the foliage of the potato. I was wondering was it for blight .
John
On plant
Potato
26 Jun, 2016
Answers
Thank you Owdboggy. It has being mentioned by a member that if one sprays with bread soda it keeps away blight, would you agree?
29 Jun, 2016
New one on me!
1 Jul, 2016
I thought it strange Owdboggy.
1 Jul, 2016
Copper sulphate would do that and yes it was to control Blight. Not sure if you can still buy it. One of the things which went because of EU regulations.
26 Jun, 2016