Have you checked for svb?

Here is a link that might be useful: squash vine borer

They're covered in tulle, and as I said, the leaves recover quickly in the late afternoon. So no, it's not SVBs. I'm taking great pains to avoid SVBs.

How large are your vines? And have you had as many cool evenings this Spring as many parts of Texas have had (haven't kept up with weather in your neck of the woods)? My initial thought is that young vines may not have yet developed a deep enough root structure with all these cool evenings this Spring to overcome late afternoon heat. If they come back after the heat subsides, I think they're probably fine, just still trying to grow into the afternoon warmth. It's been a bit of a weird Spring for us here. Hope they do ok - butternut squash is da bomb! Mine are still pretty small, unfortunately.

That's what I'm thinking. The vines are only about four feet long. So perhaps the roots just aren't deep enough yet. They were watered deeply yesterday, but today, in full sun at 85F they were just starting to droop at 3pm. I was getting worried, but they perked back up completely by 5pm, when the temp was pretty much the same, but the sun was lower.

Yes, up until today, we've had evening temps in the high 50s, if not lower, for weeks at a time. Now, I don't want to overwater, at least because by doing so, I'm discouraging the roots from going deep, where they really belong. The soil is excellent, and loamy down to at least a spade depth, so they ought to get there.

I understand that leave wilting is very common squash response to heat, but I'd like to believe that if they're going to survive the temperatures that are coming, they'd be stronger now. The plants are beautiful. No other signs of stress. The fruit are all about three inches long.

With 4' vines and 3" fruit, I think you're just fine. Squash (all the cubits) likes warm soil, you know? It's so weird to have 50F evenings in mid-May ... and I bet if you dig down 6" you'll find that your soil is still a bit coolish. At least it is here. Be on the defensive for SVB and, if you're successful against that nasty critter, I bet you have a nice harvest this year. Good luck!

PS - my vines here in North Texas are only 1' long. Slowest start I can recall in many years ... :) A friend of mine from Philly sent pics of her squash vines and they are 8' already there. Rashem' frashem'

Thanks, Robyn. When I grew butternut last year, I lost a few stems to SVBs, and I hadn't really taken any protection at all. Everyone thinks that butternuts are immune to SVBs, but that's not true. They are "resistant", which means that the SVBs have to work harder to bore into them than, say, zukes. My SVBs work hard!

So I did some strategizing, and finally decided that tulle, which is pretty cheap, and manual fertilization, which is pretty easy, was the way to go. That compared with close daily inspection for eggs, painting stems with BT, slipping hose or aluminum foil over them, or doing surgery to extract SVBs from them.

If it works, I'll get more ambitious and try some less resistant varieties.

But you're right. Warm soil helps, and we haven't had a lot of that.