Bt is for caterpillars.

Those are aphids. To be more precise, cabbage aphids. Lots and lots of cabbage aphids.

Very common to have so many, probably because they tend to blend in with the leaf coloration.

Here's a freebie: Red cabbage tends to have fewer problems than green.

Squish 'em; hose 'em off; hit with insecticidal soap diluted according to label directions. Repeat as needed every several days.

"Lots and lots of cabbage aphids."

...and lots more inside the center.

I do have some Safer soap spray (purchased to deal with last week's tree hopper attack) and will use it on the rest of the cabbage plants in the morning .

Thank you again for your help.

Athenian: To help conserve your soap and to make control more effective, it's suggested to hit with a water nozzle a few times about 3-4 days apart BEFORE the soap application(s).. Make sure you do the undersides of the leaves also.

This helps bring the populations down so when you do "soap," it's even more effective.

Kevin

Insecticidal Soaps have no residual affect so it must be sprayed on the target insect. Keep in mind also that the Insecticidal Soaps can be detrimental to predators of these Aphids

Here is a link that might be useful: Cabbage Aphids

"it's suggested to hit with a water nozzle a few times about 3-4 days apart BEFORE the soap application(s).. Make sure you do the undersides of the leaves also."

Okay, that's what I'll do. I did wash them down thoroughly yesterday; making sure to hit the center of each plant hard. After reading up on these, I'm thinking it was a mistake to plant cabbage in the row next to my turnip greens. I'll start keeping the greens washed down too.

...and some of my friends wonder what I could be doing when I spend the first hour or so of every day in the garden.

Athena

It's a great way to start the day, isn't it? :-)