[andreadon]

i didn't take a picture because i don't have a camera anymore. 

baiscally, they were little clusters of tiny yellow blobs - they looked like seeds.
i am assuming they're eggs of some kind, and they didn't want to be rubbed off.
not every leaf affected- prob 1 in 8?- and the clusters were about 1/4" inch in diameter.

any ideas?

[scabs]

Cabbage White perhaps?

[Salmo]

If they are yellow/cream coloured and under a lens they are ribbed they are the eggs of large white cabbage butterflies. If you wait a day or two they will hatch into catterpillars which will spread out and devour your whole crop in a few days. Scrape off the eggs with you thumbnail when you see them. Any you miss you can squidge later.

[andreadon]

 
i got all i could see, but i'll go back later and have another probe.

thanks!