"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.
|

"The least toxic material that can be sprayed for
white flies is INSECTICIDAL SOAP. This material works
several ways. First, it prevents adults from flying
so they are not able to migrate to neighboring plants.
Secondly, it stops the colonies from laying more eggs.
Thirdly, it will suffocate some members of the colony
immediately decreasing activity following treatments.

Since it's so safe, you can spray any plant - including
fruits and vegetables - without any hazard to people or
pets that may be eating the harvest. However, treatments
won't last long and should be done at least once a
week when activity is present - sometimes more."

Source:
http://www.bugspray.com/article/whiteflies.html

--
TQ