At 4 weeks in flower, your options are limited. Neem is one, and it's safe, but smelly. I would not use anything that is not rated for use up to the day of harvest on your budded plants.
Here's the MSDS for Azatrol:
PAN Product Info for Azatrol ec insecticide
Lots of unknowns there, and I would NOT use it on a budded cannabis plant, if at all.
You can try SMC leaf wash, which is not as smelly as neem oil, but works similarly. Or use a pyrethrin bomb- Doktor Doom brand is what the grow shops stock generally. Use it right away, because you want to allow ~3 weeks after application before harvest. A combination of a bomb NOW and neem or SMC (coriander) to keep the population from getting back to infestation levels, would be a good bet.
Last, you can increase the air movement and physically remove what mites you can, or add ladybugs.
I use a combo of SMC and ladybugs to keep mite levels down on my plants successfully. If the population gets out of control, the plants in VEG ONLY are treated with a harsher chemical, like Avid. But I'd never use it more than 4-6 weeks before harvest!