"Peltigera" wrote in
message ...

For the last two years (I'm not bothering this year) all my
brassicas
have been covered in whitefly. I always thought this was a
greenhouse
pest, not outdoors. Does anyone have a basically organic method of
prevention/cure. The whitefly are persisting even after fairly
sharp
frosts.

Consider biological controls. A wasp called Encarsia formosa is
parasitic on white flies. You can also get a beetle, Delphastus
pusillus. I have used Encarsia, but not Delphastus. These predators
are quite specific, so there is no danger to humans, pets or other
beneficial insects. They are easy to use, just release and stand back.
However, they will never completely eliminate the pest. In the case of
whiteflies, that isn't necessary, just reduce the population and your
crop won't be bothered too much. The downside is these are expensive.
I include a link to one company from whom I have bought Encarsia.

Guy Bradley
Chesterfield MO
zone 6

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