I have been fighting aphids for the past few months. I already had twenty large hydroplants die becuase of aphids and knats. I have not personally come across anyone who has had it as bad as I have. The research I have done suggest Botaniguard and liquid Pyrethrin. I got Botaniquard and ran it through my hydro system. Hundreds of bugs washed out into my reservoir, but my plants wouldn't come out of it. The dead aphids and knats, along with their larvae rotted my roots out. I got rid of all infected plants and started growing in soil again, thinking that the problem would go away. Well they're back!!! I have found liquid pyretrins, but the companies I have talked to cannot give me any info. on using it as a root drench. I need help bad!!!!!!! I cannot afford to lose an entire crop again. Somebody pleae help!!!!!!!!