I trimmed some of mine last year b/c I planted too close to some other veggies. It didn't seem to cause problems for me. I think others who live in rainier places or have problems with squash bugs are more hesitant to trim.

Here is a link that might be useful: Tales of a Transplanted Gardener

I don't know anything about vining squash, but bush zucchini squash has hollow stems which I wouldn't prune because it leaves the plant exposed to nasty beasties crawling down there and partying. I only trim off completely dead and whithered leaves and stems.

Mine were bush zucchini too. I cut close to the base of the plant so there wouldn't be so much open stem to capture water (and make room for a bigger party).

My plants were getting a little out of control (why they're not in the beds this year) and I couldn't take it anymore, so I hacked them back some. I'm not saying it's the greatest idea, but if you cut off some of the leaves, it's not the instant kiss of death or anything. :-)

Here is a link that might be useful: Tales of a Transplanted Gardener

I cut some leaves off of one plant last year, after it was infected with powdery mildew, and it didn't seem to hurt anything. This year my zucchini, as well as the neighbor's (all from the same pkg. of seed) are suffering from either a virus or a fungus. We've treated for fungus, but they are not improving. Yesterday I cut off all infected leaves from mine, which was most of the leaves. We'll see what happens.

Granny

Here is a link that might be useful: Annie's Kitchen Garden

I cut lvs for various reasons. Still have too many fruits and give away.

Dan