[Sharon]

Can anyone tell me what's up with my sprouts please?
It looks like someone has sprinkled soot lightly over the plants and when I cut into a sprout they have brown patches inside.
I can't see any pests only small whitefly but they don't cause much damage so it can't be them.
Has anyone got a clue ? I can't find anything in any of the books Iv'e got.

[DD.]

It is indeed the whitefly. They secret a sap called 'Honeydew" and a sooty mould grows on this.

http://www.rhs.org.uk/Advice/profiles0500/whitefly.asp

[Sharon]

Thanks for that.
I had to search for the whitefly that attacks brassicas.  I had been told that whitefly didn't cause much damage.  I must just be unlucky by the sound of it.
I will have to try and find an organic spray, I think Iv'e seen some at the garden centre.

[DD.]

Sorry, gave you the link to the wrong type of whitefly - try this one.

http://www.rhs.org.uk/advice/profiles1100/cabbage_whitefly.asp

The fly are not so much the problem, but the sooty mould they encourage.