I would only wish russets on my worst enemy.The Avid should work just fine. As long as you follow the directions properly.
I prefer FORBID 4F myself.
One and done stuff. The active ingredient is also used in hand lotions and some shampoo's. It acts on the bug's ability to absorb lipid fats.
Each of them ONLY need to be applied lightly on the top surface of the leaves. No having to spray the bottom of the leaves.
Now then. IF you ever get Russet mites (the BORG). Use each on a 5 day rotation of 2 applications each - alternating every other spraying.
Wait a week and see how your doing. You must knock Russet mites down quickly or the plant can/will get genetic damage.
Many simply chuck and start over. Russet's suck....
I heard they were introduced intentionally.