Acer palmatum 'Shishi gashira'

Japanese Maple

Question from Tracy Granger

Hi,
My Japanese Maple has Horse chestnut scale and Aphids.
I have sprayed and done everything but they keep returning.

But what is slightly worrying is that I think the tree might be dying. the ends on some branches are turning grey w/ nothing growing. I try to cut them back when they appear. See pics.

Thanks so much

Tracy