I'd try growing them first and see if it's a problem. If so, grow the affected veggies in a different part of the garden next year and try row covers then. However, you have to remove the covers in any case once the plants flower in order to allow pollination, so they're not a guaranteed preventive.

Generally, I think you're better off growing things that don't have established pests, and following growing practices that won't invite them in. Chief among these are good drainage, full sun, well-dug beds (for drainage and root room), soil composition (especially amending with compost), not crowding your plants too much (for root room, sun penetration, and air circulation), and weeding.

Thanks NY Gardener. I'm doing SOOO much reading that I'm getting "pest hypochondriosis". It's the first really large garden (1200 sq. ft. total expanded onto previous lawn areas) and I'm expanding to crops I've never had before:brocolli, squash,peas. I think both of those things help me because as you noted, I haven't had any established pests before other than japanese beetles attacking my peonies 1/4 acre away on the other side of the house..
And as for your other suggestions- I'm on it. I did come across some literature which suggested good soil and monitoring goes a long way to preventing disease and pests so I'll be vigilant.
Thanks again.
s.

Just wanted to say, your bee farm 3 miles away isn't the only reason not to use Sevin on your garden. You'd prevent your own plants from being pollinated. In general with small gardens it isn't usually necessary to use chemical controls, and herbicides and insecticides will often harm beneficial organisms.