[snow white]

I netted my brassicas against pigeons and butterflies to great success.  But whitefly have ruined the crop.  I did some organic spraying but it is near impossible to do under all the leaves with it as I have so many and it was a little hand pumped bottle.  So I might have to use a chemical spray next year if I want brassicas.  Do any of you spray and what are the results.

[brianc]

The easiest and I find successful method is to spray with soapy water . I use a fine spray container .
You can spray as much as you want it only kills the whitefly.
sometimes after 2 or 3 days I will spray with clean water to wash the dead flies off.
I hope this is of some help ? I have been using this method for many years.
IF you have abit of white residue on the leaves it will wash off when you prepare to cook.

[snow white]

What quantities did you use?

[brianc]

I used 1 or 2 drips per litre but it is not that critical I use a 1 gallon sprayer with a pump up handle on the  top.
You can buy these from most garden centres for afew pounds.
It does control them, I know it sounds time consuming but its not really.
The idea behind this method is that it coats the green fly to break down their coating.
Long live fairy liquid.

[Annen]

I found that washing up liquid worked okay on greenfly but didn't seem so good against white fly.  The whiteflies just go up in a cloud when spraying and resettle after and seem to be unaffected.
Horticultural soap seemed to help a bit.

[moose]

I've used the yellow sticky card traps and found they do work but if you have an infestation of whitefly you have to  frequently replace the cars as it soon gets coated.