Hello JoAnne,

Thank you for your question.

When you see a drastic difference between two, like plants in a garden bed, it gives you a much better idea as to what is going on. You can discount nutrition, soil, fungus and most likely viral infections. The photo you sent is consistent with Squash Vine Borer: https://extension.umn.edu/yard-and-garden-insects/squash-vine-borers#cultural-controls-3112161

Look for borer holes in the vine close to the root. Inside you should find a yellow to orange-ish mush and possibly the white borer larvae. The damage to the plant in the photo is terminal. Now what do you do for the other plant? You may want to treat the other plant for the remainder of July with pesticides to keep eggs from being laid on the other plant. Please see the website given above for pesticides that are effective against The Squash Vine Borer. The following article also has a non-chemical method to prevent the borers from entering the vine – wrapping the stem with aluminum foil. There is also a suggestion for “layering” the stem to promote root growth if the borer is discovered before the entire vine dies. https://extension.umd.edu/resource/squash-vine-borer-vegetables/

Hope this helps.

Hello JoAnne,

I was talking to a colleague yesterday, and if you did not find evidence of a vine borer, bacterial wilt will cause wilting of the entire plant like you have experienced.  To verify a bacterial infection, break the "stem" part of a leaf and when it pulls apart, if there is a stringy substance, the infection is bacterial in nature.  The bacterial wilt will generally manifest just before bloom, so in your region, this may be too early to be bacterial wilt.