I would treat them for powdery mildew(I've been spraying w/diluted milk)after removing the affected leaves, and give the plant a bit of fertilizer. I did this to my plant a couple weeks ago and it's putting out more blossoms(male and female).

but answer me this..... do zucchinis typically stop producing so early, or do they continue until frost ?

Under perfect conditions, you may be able to keep them going, I get about6-8 weeks of production and plow them down when they get straggly. If I want more, I will do a fall planting. 50 zukes per plant is an exceptional yield. Only the fall planting goes til frost here.

Here in CA they seem to produce forever, but when I was in TX and they caught powdery mildew that would stop production until I got the disease under control and then would pick up again. I used baking soda in water to treat if I remember right.

If you can get the powdery mildew under control, then the plants may put out some more. But it will likely be a losing battle that the PM will eventually win. So you decide how your garden space is best used. If a few more squash are most important, battle the PM. Or you could cut your losses there and clear the space for some fall plantings. Root veggies, spinach, lettuce, peas, etc.

I agree with Susancol that the PM will eventually win. But, if you treat, you can extend your harvest until frost. I usually plant only one or two plants, so every zuke counts. I start looking for PM signs mid-summer and treat for the rest of the season. This year I have only one plant, but have three cucumber(bush-type)in a box that developed PM before the zuke did. This is my first time using diluted milk and it seems to be working at keeping PM at bay, although I repeat spraying after a heavy rain. Both the zuke and cukes are putting out new clear growth.