Fighting PM with high ph water

I have an outdoor plant with the beginning of pm,Im in canada so theres not much choice on cemicals.Plant is in flower so Ive tried adding ph up to around 10 a drop of soap and then spraying.I dont care if it fails and have tried baking soda and oil on my lylacs and that hasnt stopped it.Do you think a high ph solution will do anything?

Lots of different information on the ratios .
But worth a try .

ya ive tried milk,even baked it in the sun for a couple hrs.the idea is that the fungus doesn't like alkalinity so since i have some ph up that just sits.thought id give it a try.how high can i go before i cause problems?

Try putting a tablespoon of vinegar in a spray bottle.