HELP Garden dying plant by plant!?

Singingtwinkletoes · Yahoo User

I have Squash, Pumpkin, Beans, Peppers, Tomatoes, Cantaloupe, etc....Last week over the course of 4 to 5 days one of my really big healthy Squash plants started wilting, I thought it was thirsty so I gave it some water, but to no avail. In a few days it was dead. Then yesterday I discover the same thing is happening to my big healthy tomatoe plant. I am really sad about this as my son gave it to me as a Mother's Day gift, and it was only about 4 inches tall.....I am wondering if it would be grubs or Moles....And how can I find out?? I thought that since it is dying maybe I should carefully dig it out and see?? My kids and I worked hard on this garden and we are really hoping for pumpkins this Halloween, but we won't have anything if this continues to happen!!! Any suggestions??This is a first time garden