Quote:
Originally Posted by DKelly
Made from a flower (Chrysanthemum cinerariaefolium), pyrethrum is one of the safest ways to kill whiteflies. While bieng very safe for humans it is highly toxic to bee's and fish so do not spray your fish with it.
http://en.wikipedia.org/wiki/Pyrethrin
It also helps biocontrol by providing them a non-moving target...hint hint.
but alas it is probably made by some giant evil corporation who's CEO believes in world domination or something like that. |
Whiteflies have evolved resistance to pyrethrins, even including most of the newer synthetics.
I get whitefly infestations when I take tomato cuttings and grow them under lights in the winter. That tells me that I must have whiteflies out in the garden, but something must be keeping them under control outdoors. In agricultural areas, I wonder if spraying may be making whitefly problems worse by eliminating their natural predators.
Indoors, I find that what works is a product called Nylar. It's a juvenile hormone mimic, which means it prevents the larvae from growing into adults. It's highly toxic to aquatic insects, so it probably wouldn't be a good choice for use outdoors in places like Florida or Hawaii.
http://sitem.herts.ac.uk/aeru/ppdb/en/Reports/574.htm