Recommended distance for minimum purity among same squash varieties is one-half mile. Anything less requires hand-pollination and measures taken to prevent access to any insects.if you are saving seeds plant the same species around 50 to 100 feet apart, if you aren't ..no problemo
What material do you prefer for the bag?If you want to save seed, bag the female flowers before they open. Find a male flower (without the bulb at its base) and use it to make babies. Then bag the female again. Once the bulb swells and the flower withers away, you can unbag and let it grow to maturity. Just be sure to mark that fruit with a bit of coloured string so you will remember which one you want to have for pure seed.
Did you use powder or liquid?One tip that really helped me out last year - when the squash was about 4" tall I sprayed the plants liberally with Sevin, making sure that the bottoms of the stems were almost white. From that point on I didn't use any insecticide at all, and had minimal squash bug problems until the very tail end of the harvest. Killing those first breeders is like stopping a nuclear reaction, and the amount of total insecticide used is minimal compared to waiting until there is a problem. It takes time for squash to grow, but it also takes time for each breeding cycle of the squash bug. Get the first couple of cycles and then be sure to dispose of the vines at the end of the season and minimize overwintering.