Daconil is useful as a preventative and as a control if you apply it before
an outbreak or before it gets beyond a few leaves. It will still slow it
down some if your investation isn't too bad, but generally speaking, when
you get it, it's only a matter of time before it is over. The plant will
continue to put out new leaves for a while and you may still get some
additional fruit, but you have to weigh those benefits against the risk of
spreading the disease to other susceptible plants, such as cukes. All
plants can get powdery mildew, but some are more susceptible than others.
I've had problems with squash and cukes, but never the nightshades
(tomatoes, peppers, eggplant, etc.)
> I noticed some circular, white, spots on the lower leaves of my yellow
> crookneck squash a few weeks ago. I didn't think much of it. Now the top
> leaves are spotted, turning yellow, and dying! Yikes! I just recently
> out the squash have powdery mildew. I have begun spraying with Daconil.
> I expect the plants to recover and produce more large leaves?
> I have tomatoes, cucumbers, and eggplants near the spotted squash. Are the
> other plants in danger of contracting the powdery mildew disease? I also
> sprayed them with daconil as a preventative measure.