I had a whole crop of canteloupe taken out by (I think) the same thing. They were covered in little white and black specks in a matter of days and plants were dead in less than a week. Now I see squiggly lines on the top of the leaves and these white little buggers underneath my zucchini. I thought they were whiteflies, but all the pictures seem like a bigger insect. These are tiny white. Yes, they fly.
picture of leaves from top
I'm not sure what the black and whitre 'specks' are/were, but the squiggly lines are the tunnels made by the leaf-mining larvae of flies in the family Agromyzidae. Although unsightly, they seldom are a serious mortality factor.
