looks like SVB

You should try to slice open further up to see if you can remove the grub before he does more damage. Then you can try to bury the remaining stalk so it can keep growing.

Also, check your other zukes for frass, that orange sawdust looking stuff. That means the grubs are eating your zukes and that will destroy them. You can also spray into the crevice that the bugs make to kill them if you don't want to slice open the plant. Or inject liquid BT into the stalks.

Yes, it is Squash Vine Borers (the tell-tale sign is the "frass" or saw-dust looking material). If you can remove the larvae (white worm type thing) by gently slicing the stem and pulling it out then, I have read, you can bury the affected area and it will root and hopefully give you fruit.

If the plant is severely wilted and the stem is rotted (like several of mine were) you should pull the plant making sure to drown (kill) the larvae in the stem. You can also inject the stem with either BT or Spinosad. See the link below.

I have planted a second go around...never done a second round so I am curious to see what comes of a late June planting of summer squash in Upstate South Carolina. I am checking for eggs on the stalk daily and have a needle and BT ready to inject if the larva get into the stem.

They have sprouted...yeah! But the rain...ugh, the rain...

Here is a link that might be useful: Spinosad Injection in Squash

yup. sure enough. I performed emergency surgery and took out a lot of the little buggers.I sprayed inside the stems and covered them over with good soil.
We will see... some of them had already rerooted themselves. None of them had become wilted as of yet, maybe because of all the rain.
No squash yet either- just blossoms.
I never even saw the moths, maybe because of the rain. I hadn't planted a garden for over 20 years so they weren't in my soil to begin with. Could the pupaes come in bagged leaves we gathered from the neighborhood?
Thanks for your help!

Keep watching your plants and prepare to do some more emergency surgery. The only way I've ever been to control squash vine borers is solid monitoring and surgery.

The amount of rain is not relevant if a SVB has destroyed the plant's ability to move water through the stem. If they're not wilted and sad, the plant has a chance.

A Follow up:
All the patients survived the emergency surgery. After I stomped on the worms, I covered the stems with leaf gro- a local awesome compost- as that is all I had on hand, and figured what the heck.
All of the plants are thriving and growing huge- and blooming- no squashes at all yet, however. I would have thought I would see some by now.
Thanks for the help.

Thanks for the update :). I learn so much when I see what works and doesn't work for others.