that would work, just make sure the leaves are 100% covered, however you want to apply it.
get yourself a magnifying glass or LED 420scope for like $10 on amazon and stay vigilant. You can beat this, it sounds early enough.
Remove the plants temporarily and clean the entire area with water/bleach solution. Then after this grow, clean EVERYTHING with water/bleach solution . Tent, all equipment, clean the room the tent is in, etc basically clean fucking everything. And trash all your ducting, unless you want to throw it in the oven on 150. WAy too hard to clean. Easier to buy new ducting.
I just went through this recently and I went through the whole process. I took everything out of the room, wiped it all down with bleach diluted water, put the carbon scrubber in the oven on 150 for 30 minutes,bought new ducting, sprayed and wiped down the whole tent, etc. Then I caulked up the ceiling since there was a big gap going all the way around and brought everything in the room piece by piece. The room was sanitized.
I'm on a new grow now and they havent been back, I'm on day 60 now.
They are little bastards and can stay dormant for like 6 months, hidden in cracks of your tent, or walls, etc. Once they find a nice environment they rapidly reproduce, it's insane.
Once they're gone, clean up the surrounding area, don't wear shoes in your grow room, don't even wear clothes that you've worn outside if you want to be sure. Change your outfit before entering. Try not to let people see your plants or tent, no friends etc. And make sure your intake has mite-proof screening on it if it's going outside. And be sure to keep things clean. These steps will help prevent bugs and mites from wrecking havoc again.