AusBonsai

I hoe you can help me.
I found this pest on my Taiwanese maple, one week ago, I removed all for the tree and then use confidor. However after 4 days new pest were present and also my japanese and trident maple were involved. In a short time all the leaves of two branches are fallen.
I think are scale, but not sure. I have attached two photos.
Can you please suggest the best treatment.

Thank you

Maples don't usually suffer from scale - more likely to affect figs. Usually the scale will be on the branches where there is more sap. You will also usually see ants farming the scale as well. Can't see any on there - did the leaves drop due to something else ?