Summer oil (or more correctly, summer weight oil) is just a highly refined petroleum product but not as heavy or unctuous as regular hort or dormant oil. For an edible crop I'd stay with a plant based hort oil rather than a petroleum product. I'd opt for the neem or insecticidal soap first since you have it on hand.. And you wll get rid af a large percentage just by blasting with a strong stream of water.....that may be all you need.

If you pinch out the top foliage it helps. The aphids like the tenderest leaves best. Blasting with the hose also works quite well. Or just hold your nerve and await the ladybugs. I've never sprayed my favas with anything.

Aphids have become quite a problem in the central valley of California! I have friends that farm large fields of Melons and they use a systemic that I don't have access to. Organic means by using lady bugs works but the cost of buying them and or waiting for them to arrive isn't worth it to me. I have a buddy that makes a living selling lady bugs. The problem is keeping the gallon of lady bugs in your garden. I will use a systemic next year. iT'S to close to harvest time now so I have already mixed up some neem and soap. I just wanted clarification on the " Summer Oil " Thanks

Just an FYI but neem, insecticidal soap and even horticultural oils are all considered approved organic controls.......very few systemics are. Personally, I'd want no systemics in my homegrown edibles!!

Seconding the "water blast" solution as well. Black aphids were a daily issue on my favas in Berkeley CA. But about 10 days of blasting cleared them out. Perhaps that's their repro cycle?