On Mon, 13 Apr 2009 02:18:08 GMT, Jonno
wrote:

snip

We tend to use manual methods on the catapillars (pull off and jump on
them), failing that one Pyrethrum seems to do it very effectively.

The manual method only works on one or two plants though - hopeless on
multiples.

The "aphids" I reckon would be the caterpillar eggs hatching...
No problems growing any if a regular "warmer days" spraying of Dipel is
done, or whenever you see any white cabbage moths flying around. Theyre
the menace.
BTW you will usually not see them till its too late, so spraying, while
it may seem to be distatefull is the only way

Umm, I assure you, these are aphids, not catapillars. The ones on the
brassicas / corn are blue/green to black, on the corn they are even
farmed by ants.

Happy to post photographs of them on the corn - it is awful. If I had
the time, they would get a ruddy good application of soapy water.

LindaB