About 18 months ago we plante a couple of hundred natives in a windbreak in
apaddock. They've all done very well but there is a pest on two of these
shrubs that has captured my interest.

The two shrubs/trees are a type of hakea and the pest is obviously putting
out some form of exudate attractive to ants as there are ants very active on
the plants. The pest is like a minute snail of about 2 mm maximum size. On
the stem they look like tiny white circular blobs with a tiny black dot on
the outermost part of the shell. It's only when you rub them off and look
at them very closely that it's possible to see that they are small snail
like things. I say snail like because the shell is quite hard and the
opening that is where the pest attached to the tree looks like a miniature
snail opening.

These snail like things don't seem to move, but seem to be attached fairly
firmly to the shrubs on the stems but not on the leaves. I'm wondering it
these things could be some form of scale?????

Does anyone have any idea what these things might be please?