Squash Problems

Having problems with my Spaghetti squash. I have 4 plants here, and one of them took a bad turn a couple of days ago. I took this picture this morning showing all 4 squash plants. The other three looked healthy this morning. (Click for larger pictures).

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This evening another squash plant (the furthest one away in the above picture) looked all wilted, but most leaves still look good. I have examined both plants for Squash Borer Worms but found no evidence. I gave the garden a drink of water because the dirt was dry, but the rest of the garden including 2 other Spaghetti Squash and other yellow squash plants all look good.

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