These photos are of a squash bug and its eggs. These little shits destroyed our entire crop last year. What they do is suck out liquid from the squash's stem and at the same time release a poison that will eventually kill the plant. There is a 10-14 day window between when the eggs are laid and their unfortunate hatch. Last year we didn't know what to look for, but now we do and we are addressing them early. Our approach to containing these things is simple, but kind of labor intensive.
When we direct seeded earlier in the spring, we also planted nasturtiums, because apparently they work as a deterrent. As the photos indicate, so far, not so effing good. We don't have a lot of squash bugs (last year was awful), so maybe there is some proof in the pudding. The meticulous bit of our control mission is to check under the leaves (oh yeah, that's where they do business) twice a week and smash them when we find them. Now granted, we have a decent sized garden, but anything larger than this and I would have to say, "eff this," to the hand to bug combat.
If you're not down with smashing them or pollinating the plants by hand (that's another alternative that requires the use of row covers), the best thing to do is practice preventative maintenance during fall clean up and mulch heavily in the spring. We did both, but our infestation was really bad last year so it may take a while before we can convince them all to pack up and go. If you've got them, good luck.