Thrips are small insects that move very fast. You can see them without magnification, but usually you notice the speckled silverish damage on the leaves. Monterey with spinosad works very well in my opinion. Mix as instructed on the bottle, use a pressure sprayer unless you only have a couple small plants then you could just use a hand spray bottle (I strongly recommend a pressure sprayer). Spray 3x 4 to 5 days apart. I've had greAt success with this product. I started a neem oil regime at the beginning of veg, that worked pretty well. After about 7 to 10 days thrips came back so I tried Spinosad and so far I haven't seen hardly any thrips. Spinosad also works on many other leaf suckers. But as always do some reading about it and get other opinions. Good luck. I wouldn't worry about them too much, you can keep them in check.