1. Unfortunately that is not a guarantee. Big max pumpkins get very large and sometimes they grow just a little before dying. They also grow very fast, if the pumpkin isn't getting noticeably bigger it might not make it. I think softball size is a pretty good indicator of when they will make it.

2. I see no reason at all to spray pesticides if all you see are beneficial insects. I can't comment on your area but by me it is far to late to see SVB all the damage would already be done.

3. I've had pumpkins go from flower to full size, ripe fruit in as little as 30 days. You will be cutting it close but you might get some by Halloween. Assuming frost doesn't kill the plants prematurely they will definitely be ready by Thanksgiving.

I know this is a late reply and it would be interesting to hear how they are doing . Starting pumpkins late is never a good sign but there is the exception I have one pumpkin out of 4 vines and all those bees around my pumpkin patch were actually wasps stealing the pollen for the their nest and what a fine looking huge nest it was . needless to say it was a very late start for my one pumpkin (self pollenated )but only after killing all the wasps and burning the nest did things begin happening . I started roughly when you did my only pumpkin is about 21 inches around so its small and still green living on a vine that shows leaves that just don't want to die I'm not sure if the pumpkin wants to continue growing, so soon it could be time to cut and try to get its color going its very green with alot of very faint orange freckles ,and it is still hard . Goodluck I hope yours make it .

Bobboberan I have noticed in many threads that you keep referring to wasps stealing your pollen. What are you talking about? Wasps are important pollinators, and yes both bees and wasp do use some of the pollen, but that is part of the pollination process. Your success was because you hand pollinated, not because you killed the wasps.