Question
I live in Forman North Dakota and we have grown Buttercup squash for many years but the last few years the main plant starts out great also the runners but then the main plant dries up and dies then the runners  it sets on flowers and a squash then they dry up and die what could be the problem  

Answer
Shirley, based on your description, I have to believe the plants have been invaded by the squash borer.  Depending on how far it has traveled within the stem, it is not always easy to locate them.  Unfortunately, once the borer does its damage, there is little chance for the plant to survive.

There are a couple of preventive measures you can take in the future.  The first is to cover the plants with reemay while they are just seedlings. Reemay is a lightweight, spun-woven fabric that lets in air, water, and sunshine, but keeps out insects and pests.  It is commonly sold at garden centers as floating row covers.  Just be sure to remove the covering once the plant begins to flower to enable access by bees for pollination.

The second option is to wrap your stem with aluminum foil.  Many gardeners do this routinely with much success.  I would personally recommend covering the plants when young, and then wrapping the stem once the plant begins blooming.

Attached is a website that will give you additional information on the squash borer.

http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2153.html

I hope this helps.  Please write again if I can ever be of assistance.

Regards,

Mike