Did u try the nicotine? You could try to set up a control pot to test concentration levels effects on the bugs and the plant. Theres an inexpensive high quality Omax 2500x microscope on amazon, i got it to diagnose a parasite some of my fish had that i couldnt get rid of, it works very well. That might be a crazy thing to do, but you seem like the kind of guy that might get into an ambitious bug killer project. Sorry i cant help out more, i dont know as much about killing bugs as i do their forms and behavior
Sent from my SM-G930V using Tapatalk