I believe what you have on your zucchini and cucumber plants is common mold/mildew,which develops at this time of the year, every year.This occurs when the nights begin to turn cool and damp.Some years this will kill your plants very quickly,other years it progresses slowly.I have tried a garden fungicide on the plants to slow it down,but I have found that it becomes a losing battle eventually.Usually by the time the plants
develop the mildew,I am usually ready to pull them anyway.When you pull them ,put the dead plants in the garbage/roadside pickup rather than in your compost bin.

mildew infection probably due to cucumber beetles. Once the damage is done nothing I am aware of can remedy the situation.

My own squash is only producing male flowers. I have four hills and have gotten three small summer squash this summer.

~Chills

chills, try frying those male blossoms.

pick the blossoms.
leave the stem on as a handle
pull out the stamen.
wash the flowers
drain
toss in seasoned flour (salt,pepper,paprika,garlic,flour)
dip in beaten egg (2 eggs+1/2 egg shell of h2o)
place in skillet of hot oil (1" deep oil)
fry on both sides until lightly browned.
Num, num tasty.
can do same for slices of zucchini.
you could stuff the flowers with a mixture of riccotta & mozzarella cheesew/herbs (about a TBSP per flower)just fold the petals over the filling. or herbed cream cheese.

my nana did this when ever zukes only produced male flowers. I think the idea was to force the plant to flower more and therefore produce more female flowers.
diggerb

Zucchini is great for frying the blossoms (in fact I said to my wife I wish I had planted Zucchini for that reason alone) but summer squash (the yellow ones) have fuzzy blooms that don't fry up as well. I learned that earlier this summer.

I'm planting Zucchini next year, and buying yellow squash at the fruit market!

Thanks..

~Chills