As the sun is getting lower in the sky with each fall day, our kale is
developing a milky-white mold or mildew on its leaves. Otherwise it
looks pretty healthy. Can anyone recommend a non-toxic method for
putting off the inevitable as long as possible?

Googling I found a reference to spraying with a dilute milk solution.
Didn't work for me.

TIA!

[Pacific NW garden]

You can just remove the affected leaves, Kale is a tough plant and as long as it has at least 8 or so leaves left it will be strong enough to carry on. hope this helps