Pics

Man I got those too. I always thought aphids were those bugs that would sit on the stem and suck the plant dry. I thought these bugs were called something else. But I'm still an amateur so I don't know.

These little things just infest the underside of the foliage and make the leaves curl up and eventually die. I bought a bottle of Ortho and that seemed to help. They're not gone yet but I imagine after a couple more applications they'll be gone. I really wanted to stay away from the pesticides but I'm a couch gardener. If it ain't easy, I ain't doing it.

Try using a sprayer with dish soap. YEP!
1/2 tbl. spoon per gallon of water. Just the cheap stuff from the dollar store will do the trick and will not hurt the good bugs or pumpkins. It suffocates soft bodied creatures. Plus you will have clean pumpkins and leaves. You will need to spray about every 5 days(reproduction rate) to get rid of them completely. Do not spray when its real hot(early morning is good) and I don't use Dawn its a little harsh.

Your leaves have really bad aphid infestation. Please do as campv said and their numbers will be greatly reduced.

The soap water solution works awesome for squash bugs too. I use a 1 1/2 gallon pump sprayer. With about 1-2 T of dish or Kirk's Castile soap. I try to spray just directly on bugs though so it is not all over the leaves.