Most of your pests fly in, and can be kept out with row covers, either floating or supported. Al

I'll second row covers. I also like imidacloprid and beta-cyflurin depending on what I need to do, but I'm guessing that's not the answer you want to hear.

I appreciate the info--I've looked at row covers in some of the gardening catalogs, but never used them. I noticed there are different weights. what's the best to use? supplier? any tricks to putting them on? Would something like this work http://parkseed.com/parks-plant-protector-6-feet-wide-30-feet-long/p/09240/?

I realize my answer only applies to crawling insects; in the spring my seedlings can get wiped out by crawling insects. This last spring I placed each flat on a brick that had duct tape dangling all the way around the 4 edges. The bugs got trapped in the sticky tape and never made it to the seedlings. Of course the sticky part is facing towards the ground.
If available stack two bricks under the flat to raise the tape high off the ground. I just planted 4 flats and will do the brick/tape trick tomorrow.
For a lot of flats there are a lot of ways to raise the flats as a group (I use plastic grids/grills) then only put the bricks with tape under the entire system at 4 or 6 points.
That doesn't address your flying insect issue. I started spraying this year for the first time for the ones that fly. I mainly do flowers.
Bob

why don't you look into kaolin spray ?
It's primarily an organic physical barrier insects do not like
I used it last year, looks like plants full of snow, however not harmful at all...