Posted: 24/05/2014 at 11:01
Anyone wonder why marigolds work to deter whitefly?
They contain pyrethrum, which is extracted & used as a commercial spray. When you rub the leaves of marigolds between your fingers, they exude a very pungent smell.....this is the smell of pyrethrum.
Btw, while marigolds will deter whitefly, it won't kill the ones you already have. Hence I recommend those yellow sticky strips.