vine borer revenge!
This year I've had some issues with my squash, I thought it was a disease rotting my vines when infact it was bugs! these squash vine borers attacked my zucchini, butternut, and decimated my pumpkins! I've gotten revenge by digging about 3-4 inches around where my pumpkins and squash were and sifted the soil by hand - do this until you find the pupae of these damn grubs. Take a knife and cut them up or drop them in a nice hot bucket of water, they just squeak and bounce back if you try to smash them.
You know you have a pupae when you grab on to something that feels like a really nice soft piece of wood, sometimes if you put pressure on them they do a squishy sounding squeak/hiss (like water/air escaping from a bag)
You can also burn the vines of decimated plants killing the remaining grubs in them. To save vines, either make a cut in the vine near the noticeable damage, you can work the grub out and destroy it in a way of your choosing, they also like the leaf stems so keep an eye on those.