Powdery Mildew on Squash
I have powdery mildew on zucchini plants. I read that a 9:1 solution of hydrogen peroxide spray will kill the mildew. I cut off some of the nastiest looking leaves but put them in my composter (a mistake I now realize). Can I spray the peroxide mix into my composter to kill the spores?
If you can retrieve any of the leaves, do so.
If you don't have a large amount of compost, you may want to discard it.
If not, I would treat the compost, I may suggest switching to Neem Oil for this.