Yes I have been rotating Forbid and two others. Each spraying is still a lot of work with multiple brugs (and other deck plants), not to mention expensive. That's why I was hoping to find an effective systemic instead. I just noticed the start of a new infestation breaking out on one of my brugs--which means I need to go spray all of the plants again.

To my knowledge there is no systemic miticide, only the translaminar ones like Forbid , Avid, etc.

I'm really surprised that you can't get them under control with Forbid. I have good luck with it.

Hope you get them under control.

Good luck !

I would urge you to rotate your miticides, as the two spotted mite (spider mite) WILL develop resistance to almost any miticide on the market.
A rotation I use is Avid once, then Floramite once, then Tetra San. Then back to Avid. The Avid and Tetra San are both trans laminar while the Floramite is contact. Three different modes of action. Please note that these materials can be harmful to both you, children and pets.
If you want to use just one material, it is possible to use just one miticide, and have no chance of resistance. Ultra Pure Oil, it is contact, and works by suffocation (the little nippers can not breathe, and suffocate in seconds).
The oil is safe on the foliage, as long as the temp remains below 80 degrees. Not sure of the temperature? Simple, spray the oil, wait 15 minutes, and then wash it off. This material is very safe around pets, us and kids.
I will note that it will damage the flowers however.
I have used the oil extensively on my brugs in the winter inside my home. I put them in the bath tub, spray them thoroughly, and then give them a shower after a half hour. Once they dry off overnight, I put them back in the windows.

If its regular spider mites you can use Bayer 3 in one for roses.

Spider mites are fairly delicate - cooler, wetter conditions will kill them. I keep them under control indoors by misting affected plants with cool water once every day or two (easier if they are on a non-carpeted floor) and use a diverter to stop the heating/AC from hitting them directly. I might drag them out and wash them down if something drastic happens, but if I keep them healthy, mites cannot get much of a foothold as long as I remember to mist them down good.

Kontos is a good systemic miticide to use in your rotation - makes new eggs non-viable ... uses a version of spiromesifen I think.