I am helping my neighbor she 80 yrs old and she had replace 3 of the 5 Thuja occidentalis Emerald from mites and this year again the mites are getting to it. I have sprayed Malathion Plus from ortho and it has not slow them down. I have spryed every 15 days, now I am pouring it on the roots of the plant. I have cut off the branches that are yellow and it looks like hell now. She looking at me with evil eyes now!

If I can't save this should I remove the soil around the plant and dispose it all?

Any ideas plz

bob