Oh dear - looks like the squash vine borer has infested your squash plants. Start picking off the worms and destroying those egg sacks immediately. You may have some luck spraying with Bt or Bacillus thuringiensis a bacteria that kills soft bodied insects. This late in the season this insect is hard to control. To prevent the problem next year be sure you till the soil at least twice to kill any insects that overwinter. Gather and do not compost any of the vines. Look to see if the worms have infested the hallow stems of your plant. If so you can cut open the stems to cut out the worms and then try to bury the cut end of the stem in the ground. Rotate your crops next year and use row covers or Remay to cover the young plants to prevent the adult flies from landing on your cucurbit crops and laying their eggs. Keep growing, Marianne Binetti