My cukes have done really well this year and produced like crazy until recently. I went on vacation for a few weeks and had a neighbor watering, but that's all she did. When I returned I found these little fluffy white bugs all over my cukes. I got rid of some of them, but they kept multiplying. They are gone now, but what are they? Are they friend or foe?

Now, my cukes have what looks like sawdust (likely eggs) all over them and the leaves are looking dirty and very unhappy. I've gotten about 6 cukes since the end of July beginning of August. Now nothing except little cukes that yellow after a few days. Any ideas?

This picture shows a caterpillar, fluffy white bugs, and the sawdust looking eggs.