Something is eating a huge amount of cabbage in one night. They are under fine mesh and I check every evening and morning. Attached photo is one night damage of a cabbage which was perfect the evening before. The are no animal droppings or slime etc. on the cabbage.

I don't think it's a pest but the condition known as "splitting cabbage head": despite the name it usually looks like something took a big bite out of it and this is definetely the case.

While this is a condition associated with fertilization late in the growing season and/or heavy rains after a spell of drought, they aren't the main causes, which are most likely genetic as the worst affected cabbages are invariably early cultivars of English/Central European origins.

Apart from keeping a close eye on fertilization there isn't really much that can be done bar picking modern cultivars known to be resistant like Stonehead.

Thank you, I am sure you are correct.

I had no idea about this condition and have even set up a "wildcam" to catch the culprit.

I live in The Netherlands and these cabbages are "spitskool" which have a cone shaped head.

Now I am concerned about how to stop the remaining cabbages from splitting, I am guessing that a small amount of watering every day is the best approach, do you agree?

Either that or cut them early when they begin to harden. Never grew Spitskool but the the Wakefields are notorious for "Busting" as are many early varieties. Gave rise to to the antique saying when a person interrupted a conversation with a loud inappropriate comment " another cabbage head busted"

MWA123987 said:Thank you, I am sure you are correct.

I had no idea about this condition and have even set up a "wildcam" to catch the culprit.

I live in The Netherlands and these cabbages are "spitskool" which have a cone shaped head.

Now I am concerned about how to stop the remaining cabbages from splitting, I am guessing that a small amount of watering every day is the best approach, do you agree?

It doesn't need to happen: as is always the case with these genetic issues they affect only part of the crop. Just continue watering as per schedule: it seems to me they are large enough not to need any extra fertilization now.
Spitskool haven't got any more problems than other oxheart cabbages: they were originally selected as an early crop for Northern Europe so they don't like much dry Summers and heat waves, but not more than other similar cultivars.