Are you getting female flowers- with the baby squash behind the flower? It's not uncommon for the first flowers to be all male(no baby squash). If you do have female flowers, then pollination is the issue. Maybe all of the rain and high humidity is affecting natural pollination. You migh try hand pollinating. There are many posts describing the process, if you're not familiar.
Good Luck!
Susan

I'll do a little homework about pollination. I'm not afraid to admit that part of gardening is over my head, but not at all afraid to learn.

One question, how do you tell a male flower from a female flower? (Yes, I feel like I just set myself up for a bad punch line :-)

Thank you.

Hi wv2ga. I'll leave the bad punch line to the quick, clever members :) Here's a link to a dandy thread on hand pollination, complete with helpful pics. Note how the female flowers have a tiny squash behind the blossom? The male flowers don't have that, erm, pregnant look to them :) Good luck!

Here is a link that might be useful: Hand pollination of Squash

You might have killed the bees with the sevin dust.
Next time plant "Elite" hybrid zucchini, you will have more than you and your neighbors can eat.