Weedwhacker said:I (fortunately) don't have a problem with the SVB's, but I think I've read that it helps to allow/encourage the stem to run along the ground and form roots in various places. Maybe those who have some actual experience with the borers would comment on that. 
It depends on your plant. not all squash can do that. I know I grow tatume because it can, so I do have it set up with access to the ground in some places to re-root. That said, I'm 97% certain there are no vine borers causing her this yellowing issue.
When my squash get a borer or two, the whole section up from where the borer got in is wilted and looks like it hadn't gotten water for days. you can trace the dried wilted leaves and vine down to where the borer is and just cut it out. You'll lose that section of vine, but if you have a type that can re-root and/or it isn't the entire plant, the rest of the plant will be just fine. Last year I pulled out maybe 2 or 3 of those things (and tossed them in the fire pit because EW!) but they didn't do the plant in at all.
