Some garden plants are sure to attract lots of pests. But corn, beans, and squash are not among the most heavily attacked in my experience. You probably won't have too much of a pest problem.

The crops with the most pests (in my experience) are brassicas (white butterfly), tomatoes (everything seems to attack tomatoes!), and beets (slugs).

Nasturtiums as a trap crop supposedly can draw away aphids. But remember that nasturtiums attract aphids. So it's a gamble. I guess just don't plant them too close. I've never tried.