Complimentary Commercial Content Cassie Krejci is right. There are a lot of py-words out there to break down: pyrethrum, pyrethrins, permethrin, pyrethroids. She shares the differences and helps clear up possible confusion. Source: MGK.com. Link.  Pyrethrins are broad spectrum and kill a wide variety of insects, while pyrethroids tend to have longer residual effects and … [Read more...]