I wonder how many different ways we can come up with to tell him the same thing 
You’d think mildew was some kind of great mystery that science hadn’t already studied to death a very long time ago 
2 Likes
Hey you should all listen to that podcast. Some expert knowledge will help.
The link I posted has a number and email. If you have information the plant pathologist isn’t privy to, I’m sure she’d love to hear from you. Make sure you tell her you heard it on a podcast.
You had mentioned you were an expert on the subject, so I’m sure you two have quite a lot to discuss.
3 Likes
Quite the conidi-undrum.
1 Like
I suspect the v1ru5 virus may be back 
Shaping fire: 28 seconds in
“there’s so much misinformation about powdery mildew handed down from generation to generation of cannabis growers.”
2:46 “easily the most common scourge people have to deal with is powdery mildew.”
Keep in mind this podcast has a guest from biomedical research at MIT, Kevin. It’s top notch!
3:46 “and it takes, in hops, sometimes 18 to maybe 40 days before it gets a stress event that makes it get spores.”
Love it.
Hey wait. You know something? Perhaps you are talking about Podosphaera macularis as the one growing on cannabis? It’s really interesting, but most studies are actually based on the mildew infesting hops. But instead, that organism uses both conidia and chleistothecia. Turns out, with cannabis, it’s not the same organism.
See this is the thing, I realized I was doing some cutting edge stuff when I had noticed this image:
Chasmothecia are in that cluster of mildew. I could see it. Yet
Clearly… those are different species of mildew. One with only Conidia and no Chasmothecia in the colony at all. Very much like the mildew on cannabis. The fact that isn’t pointed out in any of the mildew literature, seems… strange. So I suppose they just aren’t on it yet. But I have seen SEM images of mildew with no overwintering structures that were from cannabis. Seems like parts of the puzzle are missing, like they are not sure which species is which or which species infests which plant.
5 Likes
You know that jokers guest in that pod cast is just another failed grower. His 1st and 2nd crops succumbed to pm and then he decided to become a teacher . Just a couple more opinions
Hey everyone! Come over to my thread on powdery mildew. We can escape the abusiveness of people who fail to do their own research. I’ll answer your honest questions and tell you whatever knowledge I’ve extracted from the parasite. That way I can stay on topic like @ReikoX told me I should do, at least suggested 
thanks!
I had never seen PM before I moved to southern Colorado. I grew up in the deep South with massive humidity. Never saw it, even when growing hops.
Now, here, the humidities are frequently registering in the teens. It’s high today at 32% but was around 10-13% last week with that Arctic air and super cold temps. And, PM pops up inside the house in mid winter. I still believe the spores can lay dormant, but that’s just my brocephous science kicking in.
I need to dig around here to look for studies. With the whole state, almost, growing pot commercially, there has to be some recent info.
I used the Safer sulfur when I thought I was seeing the first signs and nothing ever bloomed. Then I discovered aphids, and after a couple weeks, I used Lost Coast Plant Therapy to get them under control. First time I’ve had them inside. I parked a few clone moms in the room and forgot to spray them.
It did a good job of defeating the aphids and no molds have materialized and look healthier now in general. PT is easy to use and has a Peppermint lingering smell. Once the plants dry, you can put them back under the lights with no burn. I normally try to do it late afternoon and leave them by the window till lights out. No burning whatsoever. PT is supposed to control PM, too.
I think I had rust fungus over the summer as well. I thought it was something else cause it slowly wiped out a lot plants. It seemed like I brought it inside as a couple of houseplants seemed to have it. I cut the leaves off that seemed to have it and then sprayed them and some clones with the PT and I think I got it. So, that’s comforting.
I was listening to Bob Hemphill on a podcast recently and he said he uses sulfur for the PM and PT for all else and says he’s keeping things in check. That’s always good to get a solid endorsement from a top breeder.
I wonder if what I see on the Bindweed in summer is Downey Mildew. It doesn’t have the powdery look at all the leaves just get covered with a white/light gray film. It doesn’t seem to spread to other plants really.
I’m just glad I’m reading and talking so much about it finally. PM really whacked my outdoor grow. I was broke when it started and was too far gone by the time I could go by more stuff. I did bud washing on them all, mostly and it was too late. The PM sucked the life out of them. There was no weight to them at all.
I got a new bottle of PT. A little pricey at $30 (with local discount) a 12 ounce bottle that makes 12 gallons. I’ll be doing preventative on everything this summer. It rained an unusually large amount last year and that seemed to be why that rust fungus was so bad. It was killing weeds too. Knock on wood, but I’m gonna stick with sulfur and Plant Therapy this year and prove it as my go to answer. I hope I’m right and can keep it to just those two products.
I have really strong natural insect predators in summer that always seem to keep the bugs away. Only in late fall when those predators leave for the season will the aphids proliferate. By then most have infested the natural weeds and are locked onto a couple of their favorite weeds and don’t seem to jump to my cannabis. PM now…. Not so lucky.
4 Likes
Ooops, wake and baked and created a book, sorry. Maybe I can get it published.
3 Likes
I had it 3 growsin a row. Was Gifted clones each time.
3rd time seeds and one clone . Still got it.
Went from basement to garage . Followed out there
I shut down growing in that basement furnace room for month and half. Mopped the floors and walls with bleach an water .(of the basement furnace room. And tent with peroxide many times lol)
Germed all from seed. grew in another room for 45 days and back in furnace room a month and half . Tent blocked solid with plants - not a sign . Knock on wood.
I’m guessing it came from friends clone . My plants were pretty unhealthy anyway the strong ones were pretty resistant.
I tried sulfur spray through Veg and all flower (woops) Also peroxide 1/10 spray thorough every 3-4 days …and a copper powder you mix and spray. Leaves residue stain on leafs. Not pretty but Works for short term.
Havent changed any RH in basement room so must of been brought in.
5 Likes
I hesitate to mention this, because I can’t personally vouch for it…but it was told to me by a good friend in Mass who grows during the winter. He had a bottle of pure peppermint oil, and said don’t even bother with all of the other “crap, like peroxide, Safer…just go straight to this.”
I’d bet Amazon has it.
Might be worth a try if your at the end of your rope…
Lob
3 Likes
There is no such thing as once and for all for PM or mites. The PM spores are always out there, as are other plant hosts for mites. At least here in the PNW. For PM it depends on the strain. GDP for example is hugely susceptible to PM, so I had to keep spraying neem every 3 weeks. For White Widow, I only had to spray the 2x dose of neem and that was it. No more PM. For Mexican landraces, I never had any PM on them at all. But PM is a new world disease, and so being a new world landrace, they are PM resistant.
In my 40+ years of growing experience, 2 doses of neem will effectively eliminate a PM infection, when applied at the correct strength. That being 100:1 water to refined neem oil. Most pre-diluted neem sprays are not strong enough for PM. GDP is ~the~ most PM susceptible strain I have ever grown out of HUNDREDS of strains. The GDP clones were completely covered with PM. 2 sprays with neem and it was gone 2 weeks later. Yes, all gone. But it may come back, depending. Neem at this strength is also effective against broad mites and their eggs. But while neem is a contact spray for all stages of mites and mite eggs, broad mites are extremely difficult to eradicate completely with anything but Avid (abamectin) in my experience. And mites will likely return after they are eradicated. They dine on blackberries and cane berries now from coast to coast, as well as hemp and other plant species, and hence they are everywhere like PM now.
2 Likes
What you said is easy to disprove. Get a pet urine flashlight and you can literally see where the mildew is. Check around with the light and see. As for the neem oil, I’ll be dosing the mildew under the microscope to see what effect it actually has. I’ll use your mixing ratio to dose it.
2 Likes
So after 2 plus weeks of spraying sulfer on flowering plants making seeds, im happy to say i am getting mature seeds from said plants and will be chopping soon. Its been over a month since i sprayed my veg room and i see absolutely zero signs of pm. Dreamcatcher, that i used as a test plant, is absolutely thriving. Thanks Joe.
6 Likes
More proof sulphur works!
4 Likes
lol, every time sulfur eradicates mildew, god kills a dow chemist. Just kidding! Thanks for the report!
3 Likes
Wow, it’s been 2 years! I wonder how many people have read this thread and exterminated the powdery mildew. Probably a boatload! Ugh, and before it was just a stream of garbage suggestions, each more useless than the last. Kung pow! Take that, powdery mildew. I’ll be kicking back and enjoying the taste of victory over a pathetic parasite.
4 Likes