Lets delve deep into powdery mildew for a sec

[Beng01]

Botrytis is simple to prevent because its purely environmental, so temp, humidity and airflow control are all that are needed for it to be present, but kept at bay

However white powdery mildew is my living hell because through endless research I cannot decide if it is the same

We can "prevent" it by not overcrowding, having good air circulation, not over watering, even and ample lighting, etc...

But like botrytis is PM really able to be 100% kept in check with environmental controls strictly? Spores are everywhere like mold right?

So is there any point in stressing about with proper environmental controls or is it truely alien in the sense that it affects and spreads regardless of higher or lower humidity and temps?

Lets really break this down

Personally, I have been able to keep it away even in prone areas and times of year with little fluctuations in day and night temps 78-80 day and 72 night, humidity never above 55%, lots of airflow and spacing -- so can I relax for good? Ive been stressed about something that hasnt really affected me for years and years of growing

Help

 

[CanadianJim]

Just keep something like Green Cure on hand. Or even learn the ratios for milk spray. You'll have a remedy right there. No need to stress since even if it somehow pops up. You can knock it back right away.

 

[NugHeuser]

I've got some sort of mildew popping up more and more, I've had white PM before and it would wipe off the leaves and green cure would kill it off after 1 or 2 sprays.
But the past week or two I've had this what looks like grey powder spots forming on the leaves but it would NOT wipe off and green cure isnt seeming to do anything to it, in fact just a few days ago I had to look for it to find it, now its multiplying more and more by the night.
Does this sound like normal PM or a different kind of fungus/disease?

I'm going to try nuke em tomorrow. At about day 50 of flower, up till about day 30 the humidity would get into upper 60s then I noticed some white PM popping up, put a dehu inside the tent sprayed and killed the white PM and have had temps 77-86 and rh mainly about 55%, and then this different type of what looks like fuzzy mildew spots that dont wipe off started popping up last couple weeks, just a tiny spot on a plant or two, now I'm picking leaves off daily and have been able to drop rh to ~45% past few nights but still seems to be spreading fast. Buds and plants look good though, deep green, no toxicity's, few random small yellow streaks and spots on a few leaves. Hoping maybe someone can fill me in on what that might be

 

[Dr.J20]

milk spray is a cheap and effective way to control PM. don't fret.

 

[NugHeuser]

milk spray is a cheap and effective way to control PM. don't fret.

So that still sounds like simple PM to you? I just wasnt sure since it's a little different color and doesnt wipe off the leaf and how green cure isnt doing anything to it. Was worried that it could be some type of fungal disease within the plants that cant be treated, pretty sure I've read about those somewhere.

So milk spray you say, does it matter if its 2% or what not? And do I dilute it with water?

 

[Renfro]

One thing to know about PM is that it needs times of high and low humidity. Without both it doesn't seem to happen. When I was in a humid state I never saw PM. It wasn't until moving to a dry state that I saw it for the first time. So avoid having large swings in RH%.

 

[NugHeuser]

One thing to know about PM is that it needs times of high and low humidity. Without both it doesn't seem to happen. When I was in a humid state I never saw PM. It wasn't until moving to a dry state that I saw it for the first time. So avoid having large swings in RH%.

Is all PM able to be wiped right off the leaf with your finger? I'm just trying to figure out if I have PM or something else

 

[Renfro]

Is all PM able to be wiped right off the leaf with your finger? I'm just trying to figure out if I have PM or something else

yeah sorta, the spores are a powder, it will look fuzzy under magnification

 

[NugHeuser]

yeah sorta, the spores are a powder, it will look fuzzy under magnification

Yeah whatever this is that I'm dealing with doesnt wipe off in any way, it looks like a powder but its absolutely one with the leaf. I've read about something, maybe blight? But some type of fungus out there that when your plant catches it, there is no getting rid of it, seems like I read that its systemic and will just continue to spread once you have it, that ring a bell at all?

 

[Dr.J20]

Yeah whatever this is that I'm dealing with doesnt wipe off in any way, it looks like a powder but its absolutely one with the leaf. I've read about something, maybe blight? But some type of fungus out there that when your plant catches it, there is no getting rid of it, seems like I read that its systemic and will just continue to spread once you have it, that ring a bell at all?

definitely sounds familiar and fungal. you could try neem or a copper based fungicide perhaps. best of luck!

 

[TintEastwood]

PM. Frickin nightmare. Nothing novel about it.

Interesting read.. about how the plant is infected prior to showing white fuzzy crap. So much for wiping.

Exerpt...
"spores penetrate the leaf and the cell wall with a taproot called a haustorium, which serves as its primary feeding mechanism. The pathogen then forms secondary taproots into neighboring cells, creating a mycelium network over a period of several days before producing the tell-tale white powder. "


https://www.medicinalgenomics.com/powdery-mildew-systemic/

 

[Renfro]

Yeah whatever this is that I'm dealing with doesnt wipe off in any way, it looks like a powder but its absolutely one with the leaf. I've read about something, maybe blight? But some type of fungus out there that when your plant catches it, there is no getting rid of it, seems like I read that its systemic and will just continue to spread once you have it, that ring a bell at all?

Well without pictures our hands are tied.