powdery mildew

I had an issue with my dehumidifier. There are white spots on a lot of the leaves. What are my options? Any chemicals I should buy? Cut off all leaves with white spots? Or just leave it? It's a 4 weeks into flowering. the flower looks fine, it's just spots on the leaves. Humidity is completely under control now. I want to avoid having powdery mildew or toxic chemicals on the flower by the time of harvest.
Also, if necessary, what's the procedure for washing when I harvest? do you just run the flower under tap water?
Can't post pics.

hydrogen peroxide spray look it up in the search engine WPM treatment
10% milk and water solution sprayed over the leaves i would say the hydrogen peroxide spray is your best bet, ythe milk solution is best for cucumbers and melons

Spray with 3% hydrogen peroxide 2x weekly until gone

Careful not to burn your plants either.

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As go go kid suggested hydrogen peroxide foliar spray may help. People also have good luck with baking soda, you want to change the Ph of the leaf so powdery mildew can't grow there.

I use Dr Zymes Eliminator for an after harvest bath, worked better for me than hydrogen peroxide. Great foliar spray to dissolve the PM.

A good preventative is Regalia, can be used as a foliar spray or soil drench. I currently feed with 1.5 tbsp per gallon or water, 2 gallons per plant.

A few of us on this forum have invested in an AiROS hydrogen trioxide generator, keeps the air clean of spores and fights PM on the plant.

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Good luck, powdery mildew can be a heart breaker.

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Please post some pics!

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A potassium silicate spray is effective against PM. Although at 4 weeks into flower I would be careful with what you spray. Some of the products that say can be used until the day of harvest are referring to plants that have fruits or vegetables that can be washed off easily.

I've never used Regalia but from what I've read about others experiences it's an effective product. I might start experimenting with my own homemade Regalia copycat product. The active ingredient is extract from Reynoutria sachalinensis aka Giant Knotweed which happens to be an invasive species here in western Oregon and I know where large patches of it are growing.

"When sprayed on plants, extract of Reynoutria sachalinensis (giant knotweed) causes the plants to activate an internal defense system that prevents growth of certain fungi, especially powdery mildew and gray mold."