As usual with RIU, there is some good and bad info here. But they key is proper identification of the insect, because many available products don't work on
all mites or bugs.
Here is a very helpful web site for various products:
http://thelandscaperstore.com/page/insecticides
But I'll quickly relay my personal experience....I fought the borg for over 2+ years and used just about EVERY available product in my journey. $100's and $100's and $100's of dollars over the years. Finally though, I found Forbid 4F worked most effectively. You can buy a small amount on Ebay for $20 and it's good for around 5-6 does. A dose per gallon is .5ml to 1.2ml and I accidently used 5ml, 5X to 6X too strong. When I realized it, I sprayed down the plants to dilute what was on the leaves. But it totally wiped out any issues and I haven't seen a mite since. It is also absorbed into the leaves and has a 45 day residual effectiveness which is nice so no additional spraying will be necessary.
Also, always water the plants well a few hours before the spraying. This will reduce the amount of miticide absorbed by the leaves and reduce any chances for leaf damage.