Pease pay attention:
To effectively kill scale, the water where the juniper will be submerged needs to be mixed with some kind of oil, like Need Oil.
Which is bad news, as junipers and pines don't like to be covered in oil.
This is a real warning; following this "technique" I have killed a very special (and big) cork bark black pine.
Yes, I got rid of the scale.
But the tree didn't survive the treatment. First sun out the needles got droopy, yellow and died.