I had the exact same thing happen to a couple of my cukes and melons. I pulled a couple more, unnecessarily it turned out, because they were also wilty but not infested. I read a lot about SVB, but they didn't look anything like that, and according to the extension websites I visitied, we don't have them on the west coast. I have been trying to figure out what they are, but I can only look at bugs for so long before getting the heebie-jeebies. I got as far as cabbage root maggot, but they feed on roots, and nothing said they get into the stems, or also hit curcubits. I'm getting more immune to bug literature, but still had not ID'd these yet, so thank you so much for your diligence in finding the answer!
I found exactly 5 of the little maggots in each plant that had them. Here's the haul from the first day:
I planted new seeds directly in the ground to replace the ones lost. The ones that got hit were indoor-started transplants, trying to get a jump on the season, but I'm really not that far behind with the newly sprouted plants. According to this article, - https://extension.entm.purdue.edu/publications/E-30.pdf
- it's the early starts that are most vulnerable. Patience is the hardest thing for me to learn though!
Wow, I am really impressed by the way you saved your plants. I didn't know that could be done and if these nasties come again, I will definitely try it!