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I'm having some luck with Dr Zymes Eliminator in my veg tent, just as the PM spores are incubating - they form a dried water drop look.
It took a couple of applications but is finally beating back the PM. It's quite strong at recommended strengths and burned the leaf that I treated too frequently. I backed off the spray application and use a dropper to target each outbreak individually.
After 3 days I'm finally noticing progress.
Good to apply up until harvest, made from food safe ingredients.
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As Renfro said, the AirROS is the cat's meow for treating PM. I bought one about 10 days ago and the PM in my flower tent has stopped progressing and looks like it's going to retreat.
The most expensive piece of gardening equipment I've bought and is promising to be worth the money.
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Powdery Mildew stops growing at 90 F and dies at 100 F. If you heat your tent to +100 F for an hour you may kill the mildew but not the spores, which can survive 500 F.
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