Thank you for your question. Yes, these are definitely aphids. (Different species are different colors.) Most of the time, natural predators will catch up to them and take care of them naturally. Plants typically will outgrow the damage later in the season. If you do want to intervene, you can hit them with a strong spray of water, or apply an insecticidal soap. Here is additional information on aphids and how to control them: https://extension.umd.edu/hgic/aphids-trees-and-shrubs

CKC

There was a suggestion on the internet to use banana peels to get rid of aphids.  Does that work?
I did put strips of peels on a few of my milkweed plants however I'm not sure if the decrease in aphid population was due to that or the natural predators.  What do you think???

We do not have any research indicating that banana peels get rid of aphids. It's more likely that the natural predators took care of them. You could look to see if there are any round, tan-colored aphid "mummies" on the plants -- this would be an indicator of that parasitic wasps controlled them. There is information about this, under "biological control," in this article: https://extension.umd.edu/hgic/aphids-trees-and-shrubs

ckc