I’ve been reading up on powdery mildew because I just accepted my first cut from another grower. Here in the mid-Atlantic USA I’ve never seen PM on cannabis because (I guess) that the PM that’s floating in the air here is not the kind that attacks cannabis. Everyone I know who has seen PM first hand has accepted cuts from someone else, or lives in a very different environment like Colorado. My growing conditions have often been poor, and I’d expect to get PM after 20 years of indoor growing if it were possible.
It seems it may not be a systemic disease, but since it can fester for 3 months undetected, I wonder if that is a distinction without a difference.
All that being said, I’m treating this cut as if it had a full-blown infection for at least 3 months before flowering. Sulfur, then Nuke Em washes, then neem oil, maybe soaking the cuts in lactic acid bacteria, then into flower. From what I’ve read, it seems only oils can really ELIMINATE an infection.
I was gifted some knowledge some time ago. Hypochlorous acid. I bought a hypo generator on a black friday sale years back. Ive made hundreds of gallons with it. Does great for zucchini and squash plants that usually get infected as well. I spray even into last week of flower.
I find I have issues with powdery mildew when my room is too full and I can’t keep the humidity in check. The times I’ve had it outside was from not enough defoliation and moisture just crept up before long. I had mildew and bud rot. Now I try to keep my rooms thinner with more airflow and I try to keep a good defoliation every few weeks
I had to deal with powdery mildew when I first started growing and I didn’t know what I was doing yet and I was running a humidifier in a tent and didn’t even know what to watch for as for signs or anything because as I said I was brand new. Once I got my first case and obviously didn’t want to ruin any cannabis and I was still in the veg stage. I did a lot of research and came across Lost Coast plant therapy and had great reviews so I tried it. It you just add like 1 oz per gallon of water and a pressurized sprayer and spray away and it prevents powdery mildew, it killed 95.99% of the powdery mildew I had on those two or three plants. But rather than risk it, I just culled them and I haven’t looked back. I treat my grow every 3 weeks with lost Coast and have never seen it again and I use microscopes to inspect my stuff and veg and flower because I normally veg for months. I haven’t tried anything else.