What's eating my caulies?

[barrowbob]

I tried some miniature cauliflower in the greenhouse in the hope that it would not be attacked by miscellaneous predators.  They were doing well until about a week ago when a few holes appeared in leaves and despite checking each leaf there's no signs of eggs, caterpillars etc.  Yesterday (and many more ravaged leaves later) I found small, roundish green things at the bottom of the stems and on the surface of the pots.  Can anyone tell me what's producing them, and, more importantly, can I do anything with them??

Tried to post pictures of them but failed miserably.   :'(

[barrowbob]

[wardy]

froghoppers?

[barrowbob]

 :-[  erm, just had a colleague drop in and he had a good look (he doesn't wear glasses and I should).  He pronounced the green things to be caterpillar s**t, opened up some of the leaves and dragged out two large green ones - at least I know what I'm looking for now and I must look for my specs!!   :-[

[titchhagger]

 ::) :-X It's some comfort to hear other gardeners having the same problem as me.  Nearly all my caul's brussels, broc's have been eaten.  My problems is the wife who tells me off if I knock them off and squash them.  If I had my way I would nuke the lot???