No it's all the same stuff Sheila.
Just that in crystal form or as powder you would have to mix it yourself.
As regards the blight .
There is nothing that you can use that will kill the blight that is already infecting a part of a plant. All any of the sprays do is give uninfected parts
of the plant a layer of protection as spores from the fungus fall on to it.
So it calls for thorough and regular sprays to protect in heavy infestations.
A real devil.
For a stronger ...non organic spray....use something containing the chemical chlorothalonil.