That's interesting. When researching grape phylloxera last year I kept coming across the concept of simply choosing resistant cultivars rather than fighting an uphill battle.
Yep...mildew and fungi are agriculturally speaking, huge enemies as even "treated" crops lose a % of every harvest to mildews. Natural resistance is usually the most effective way. I have personally see my wet dreams and black sour bubble x caseyband x white rhino, Dream lotus x vortex in flower 9 weeks touching leaves with plants that have active fruiting PM, and not get a single solitary spec. I've also seen strains that have little resistance be treated with every regiment you can think of...weekly sulfur burns, alternating weekly neem /
green cure, in perfectly controlled environments refruit from clean cuttings.
A lot of people don't really understand this with pm - the part you see is the equivalent of their fruits. Like their "flowers" that are active to spread spores . The real issue with pm is the parts you cant see. It lives inside the plant tissues, colonizing inside. When conditions are right it triggers a bloom of it (the white powder on leaves) Even if you keep a perfectly controlled environment, any cutting off a mother that has EVER showed pm has the virus inside of it waiting to bloom. Now, there are systemic things that kill the internal virus (theortically) ie- Copper, Phosphoric acid, and there is a bacteria - can't even begin to pretend I remember the latin name for it (dont tell my botany professor)!