Need a nuke for Boisduval scale.

[BrassavolaStars]

Hello all,

Boisduval scale is destroying my collection. After months of just trying to power wash and neem oil them off, they just keep getting worse and worse. I'll spray them off plants only to find them covered in the stuff just a few days later.

I have had rare and expensive plants end up turning almost completely yellow from being eaten. I assume this means they have been killed. They only seem to attack the cattleyas and a few select dendrobiums.
I need something I can drench on the whole collection that will eliminate them.

What is my best choice?

Thank you.