What you want is called Spinosad. It's marketed under other names, but it will deal with them immediately and decisively. Can be hard to find, when I needed it there was a local grow shop aimed at weed growers that sold it in small bottles, only a small amount added to your watering can is needed.

Kills every stage of life, which is the downfall of many bug killers - gets the adults but not the eggs. This stuff is a thrip nuclear option.