Those flowers a dying and falling off because of lack of pollination. What has been the bee activity around you?

I have the same problem. The flowers are not opening to get pollinated. Today I pried an almost open flower the rest of the way open and pollinated it myself. I'll see how that works out.

Let me know how that goes for you. Mine are dropping off before they are even an inch long. :-(

There isn't enough there to pry open!

The other odd thing is that the male flowers are unaffected - they are opening just fine and are easily 4-6 inches across.

Having this same problem a month later in central Ohio. I just did a search hoping to find an answer here in GW and found your post. I agree, it cannot be lack of pollination because the flower buds do not een open before the tiny fruit (sometimes less than an inch) yellows & drops when touched. I, too, have 4-5 nice fruits getting big, 5" to 10" long, but it is really getting late for more to set on and hope to ripen. Since the vines are trellised, I have supported the squash with slings they are so heavy! And, yes, no problem with the male flowers... Grrr...

As an update, I've determined that it's probably due to one of two causes. The least likely of the two is simply watering. If the plant is not getting enough water, it may be conserving it's resources for the existing fruit and not starting any new ones.

Like I said, I think this is the lesser option.

The more likely option, is just that the plant doesn't want too many fruit at any given time, period. More of that resource conservation issue. I still have the original four squashes on my vine (and man are they big!), but now that they are almost mature, my vine has started putting out new female fruit!

I have three new squashes starting to develop now, so I think that I just needed to wait for the first few fruit to mature and then the vine started picking up again.

Good luck with yours!

I read of another possibility a couple of days ago and tried to add a post but was having some kind of computer problem and could not--and now I cannot remember where I found the info! But it suggested that the plant may exhibit the symptoms we are seeing when there are temperature extremes, and here in central OH we have been experiencing hot days (mid 80s or more) followed by unseasonably cool nighttime temps (drops of 25-30 degrees)--wonderful for sleeping but horribly conducive to powdery mildew and perhaps also the squash plant's inability to set fruit.
And then we had a terrific wind/rain storm (not enough rain, sadly) Tuesday and one of my nice, full-size-but-still-immature butternuts broke off the vine and fell to the ground even though I had had it supported in a sling because of its size/weight. I need to add a separate post in the forums or someplace to see if there is a way to prepare "green" squash to make it edible. I just hate to see it go into the compost bin!