Powder mildew is a systemic mildew that will stay in your plant nearly indefinately once you get it, the most common cause of PM infestation is an already infected clone being brought into a garden where there are plants that are un infested(mind you like i said its systemic just because its not showing up doesn't mean its gone)
The life cycle of PM begins with a spore, the spore finds its way into an enviorment that the humidity is high enough to live and a surface the live on IE: your leaf. It will then put a tap root down into your plant and suck the same nutrience that your plant feeds off of until it is full the the reproduction happens. Once full it will develoup THOUSANDS of spores and when they are ready the original spore will burst putting more young spore back into the enviornment starting the cycle over.
and remember spores breed in high humidity and spread in low humidity so treat at 2 differn't times, 1 time being if you get a hot day coming off a streak of mild days, and then the 2nd time is vise versa when the temp has been hot and it begins to dip back down, consistant temps will help greatly in the battle of PM because it will only be doing one of the the 2 things spreading or breeding not both.
Hope this helps and i made that clear enough, i wish i could Copy and paste stuff out of my brain
The life cycle of PM begins with a spore, the spore finds its way into an enviorment that the humidity is high enough to live and a surface the live on IE: your leaf. It will then put a tap root down into your plant and suck the same nutrience that your plant feeds off of until it is full the the reproduction happens. Once full it will develoup THOUSANDS of spores and when they are ready the original spore will burst putting more young spore back into the enviornment starting the cycle over.
and remember spores breed in high humidity and spread in low humidity so treat at 2 differn't times, 1 time being if you get a hot day coming off a streak of mild days, and then the 2nd time is vise versa when the temp has been hot and it begins to dip back down, consistant temps will help greatly in the battle of PM because it will only be doing one of the the 2 things spreading or breeding not both.
Hope this helps and i made that clear enough, i wish i could Copy and paste stuff out of my brain