Answer: Although it looks terrible, it's normal for the leaves and flowers to wilt in hot afternoon sun. The leaves usually recover overnight and look fine in the morning. Squash blossoms last only one day so they would wither and wilt within 24 hours, regardless of the heat. Small white spots could be normal, or could indicate a fungal or insect problem, but without actually knowing, I wouldn't treat it with fungicide. Inspect the undersides of the leaves for insects (whiteflies and aphids, especially). If you find them, use insecticidal soap to control them. I would simply water the plant throughly when the top of the soil is dry to the touch. Your plant should produce lots of squash as the summer progresses.
Good luck with your zucchini!
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