This week I've seen two aphids on the pumpkin. Little green sucking bugs that suck. I'm not great with insecticides, so I'm not going to write much about them here. Must of what I've used have come from recommendations on bigpumpkins.com. I've been fortunate in that I haven't seen much bug or disease pressure over the years, but I have been hit from time to time. Because of that I would say I've used a relatively mild rotation of products. I like bees, but I hate losing plants to disease spread by bugs. So, I think there can be a somewhat happy minimum that you can use to minimize environmental impact.
You can go the organic route or the pesticide route and there are pluses and minuses for both. What I have been doing the last few days is at first I put down a contactant. Then a couple of days later I put down a systemic. And since then I've been spraying the leaves to wash off and hopefully kill the buggers with a mildly strong spray of water.