I can grow early season cabbage without interference, but second crop and onwards the leaves are riddled with small holes about a quarter inch in diameter. The earliest of these come before caterpillars so these are not the culprits. Can anyone help? Thanks.
sounds like cabbage flea beetle to me, I've had this before, in the evening if you brush your hand across the plant, or try to look under the leave you may see the blighters jumping away,
i couldnt find a good picture of the damage they cause but basically the eat lots of little holes in the leaves, here's a link with a bit more info for you