I'm sure it'll kill most stuff since it's basically coating everything in oil and essentially suffocating them. Most insects sorta "breathe through their shells" so the oil coating stops their ability to breathe. But it's also then gonna coat the roots. With coco it might be fine since you'll kinda wash it off soon, but I'd be hesitant with soil. No proof but just feels like oil wouldn't be great for them. DE also attacks the bugs through the shells but cuts the shell up so that the bugs can't heal from it and die