Cardoon pests

My cardoons are infested with tiny black beetle-like insects. I’ve cut off the infested leaves but the insects are all over stems and flower buds.

Q: My cardoons are infested with tiny black beetle-like insects. I’ve cut off the infested leaves but the insects are all over stems and flower buds.

A: These are black aphids, and after reading your letter, I nipped out to check my own cardoon and discover that it has a similar problem.
I could treat it with an insecticide, but I think I’ll leave the robust and rugged cardoon to cope. The aphids will feed the tits and warblers in the garden.
If you want to spray, use a contact insecticide such as bifenthrin. Rubbing the stems helps to squash the aphids, too.