I should add they also eat my broccoli, but not the other types of kale nor swiss chard.

Not an ant problem.......ants don't eat plants :-) That looks like caterpilalr damage or the larval stage of some sort of moth or butterfly that has been munching away. You should inspect the foliage carefully (don't forget the underside) late in the day (dusk) to see what might be lurking but the damage looks older and I'd suspect the critter is long gone now.

Hi Gardengal, thanks for the insight.

I have found green caterpillars in other types of kale when harvesting them. Oddly enough, they don't seem to eat the ones I find them hiding in!

The damage is new, they eat all new sprouts, almost always :(.


Any treatment recommendations?

The brown edges of the eaten portions indicate the damage is not recent....at least on the plants showing in the photos. As to treatments, hunt 'em down, pick 'em off and destroy!! Otherwise a row cover used when the plants are first planted will keep the flying insects from laying the eggs that will become the caterpillars.

Well, this grows harvest ready every 2 weeks, so that is as old as the damage is, maximum. but anything I could maybe spray at the bottom to now prevent more future damage? neem oil? organic preferred...

I grow my kale under mesh cover and they are pristine. I've used bt in the past but you have to wait for it to work and you are still stuck with some unsightly chewed foliage.

Well, the idea with Bt is to use it as a preventative. I spray it on my collards every few weeks since they were planted out, and they are unchewed. In earlier seasons, before I used it, they looked like the kale shown here.

Unless there is something different about your Bt, dan, it is not a preventative. It only works on caterpillars when ingested. But the row cover or mesh cloth IS a preventative in that it prevents the moths from laying the eggs that will become the caterpillars.

The point is to kill the caterpillars when they first get to my plants. Not after they've been chewing on them for a while. That is, if you put Bt on after you see a lot of holes in your leaves, it's not going to make those holes go away. If you put it on as a preventative, you aren't stuck with some unsightly chewed foliage. It doesn't prevent the caterpillars from coming, but it sure prevents them from doing a lot of chewing.

They have to chew to ingest the substance.......... :-)

Found the culprits!

That would do it!! :-)

Big ants!