It’s part of a university study hosted here on OG in pdf form. They did a DNA analysis of powdery mildew growing on many different plants to see which one grew on which plant. The APS article @Astrodude posted just above has an excellent chart on which plant gets infested by which mildew. In my greenhouse study it was easy… at the end of the season I checked to see which plants had it, and those were the ones that had to be treated to get rid of the infestation. If you want to check, yourself, just grow a random plant without mildew on it next to one that does, and see if the infection transfers over to that plant. Then you know they are both hosts for that species of mildew.
3 Likes
I’ve had my share of mildew , with supposed clean clones over the years getting a 100 lot tray of good looking clones to have the whole works develop mildew .
Since cleaning using sulphur no more problems.
Plus I don’t accept clones any more.
3 Likes
Same here. Prefer moms from seed
1 Like
If you can make it through any talk about mildew and botrytis it should be this one:
Even though he hilariously doesn’t know how to eradicate the mildew, he’s full of incredible information.
2 Likes
So whats the official vote here then? Is it sulfur? Dr zymes? What’s the very best and least degrading to plant …flavor… health… etc? Purecrop 1 ?
My question is this: Do you know what to do when you get powdery mildew?
1 Like
My vote is be sad… lol
I like more than one option. Always a good idea to know more than one way to tie your shoe. At this point, in veg, Sulfur is easy and does no damage, so I’ll use it. I have very little plant matter to cover. Should get full coverage. But in todays world, with supply chain problems, lack of workers, just general uncertainty, I want to be as self sufficient as I can be. If i can conquer an issue like PM someday without ordering anything, or without leaving my property, well thats just priceless and I want to learn how.
Other options will allow self sufficiency
2 Likes
I haven’t had problems w shortages??
Let’s just say if sulpher was the only option I would have been pretty screwed.We all get it it works but I’m pretty sure there’s more than one way to fuck a goat and there are other options here and some of them don’t work for everyone some of them better than others.Use what works for you as long as it works.I love this place you will literally learn something everyday.I can totally relate to your urgency to conquering PM .Our weather is unforgivable in fall
I looked at the charts, and didn’t see anything about it effecting any Asteraceaes, that’s why I asked.
Does that same pm effect weed?
I only grow inside. In the gardens outside, it’s on cucurbits (all squash), and peas (legumes). Nothing on tomatoes, peppers, or potatoes (Solanaceae).
We have a lot of zinnnias because, besides being beatiful in such a variety, they are such great pollinator attractors. They haven’t gotten pm, at least that I can tell… knock on wood.
It’s usually hits later in the summer, except for the peas, they get it when they are done in June. Our extension agent said it travels up the East Coast (I’m in NC) every summer.
If I give those plants 2x sulfur treatments, would that prevent the pm?
From what I gather, the pm is family specific, but will any of these spread to cannabis?
I have pm inside, too, on the pot. I grow in a semi conditioned crawlspace. There’s junk, good stuff, tools, mechanicals, and electronics. Tents and open space. Dirt floor w/plastic on it.
I’d thought I’d gotten pm from a clone, but when I started noticing it outdoors too, I wasn’t sure.
I tried all the home remedies, plus Green Cure, and a little UV-c wand. Most things worked a little, or for a while, but I was still washing buds at every harvest.
The last straw was getting bud rot on a few ounces of, right, bud.
I hadn’t wanted to burn sulfur because of the mess it might make. I got a ClearLight Pro on ebay for $350… the price of a good zip in these parts.
36W UV-c, with a well built housing that shields me from the light. It also came with UV-c protective glasses and gloves.
Apparently UV-a&b do not kill pm. I think if it did, there wouldn’t be any outside, but IDK.
UV-c doesn’t make it through the atmosphere, but does kill pm… if it hits it directly.
Long story longer, After a couple of years of sweeping the plants almost daily, I almost don’t see any more pm, lol!
I guess my point is, I’m totally up for giving spraying sulfur a go.
It’s a perpetual, so there’s always at least one plant blooming. Don’t spray that one, right?
Twice within 2 weeks on my veggers, and pm will be gone from my life, and off of those plants til chop?
Spray all new veggers the same? Does it matter what size or age?
Man, this could give me more goofin’ off time, I like that idea!
1 Like
How much Sulfur does Epsom salt provide? Enough
Is it enough to ward off PM? Yes, structured into the plants growth.
Does it with Molasses provide a perfect balance for magnesium and Sulfur uptake? Yes it does.
How much of a percentage of sulfur to magnesium is sufficient for marijuana plants? Equal Amounts!!! 2% of plants needed nutrients are magnesium, 2% sulfur
Is Sulphur spray toxic?(Googled)
Sulfur spray is moderately toxic to humans and other mammals, so avoid direct contact and inhalation. When applying and mixing, make sure to wear long sleeves and long pants, preferably of waterproof materials. Wear waterproof gloves and cover all other areas of exposed skin
Well, here’s a gasser, (sulfur foliar spray specifically added) has been amended to the Soil Food Web Protocols, so I guess I got some learning to do, @joecrowe, feed me! Brother Feed Me!
Where’s my best reading?
2 Likes
I imagine a force field when they hit the perimeter they immediately implode. Or maybe it’s like a bug zapper situation. An invisible moat dug by god’s own hand.
One might say, “hey other fungus spores can travel thousands of miles and you can clearly get botrytis from airborne spores”. But apparently, it’s settled that the PM spore is special and IDK…really heavy…based on the “research”.
2 Likes
Cho said that we are surrounded by millions of spores and it is why we don’t need to gather them, simply prepare a place for them to grow and the will show up. Wine, Cheese & all fermented products start without there spores, they find there way.
lol! That’s quite a post. I haven’t verified the zinnia thing personally, but I’d like to try it. I know for sure the cucumber mildew will never grow on cannabis, I’ve tried that one. Same with the one on peas, it won’t infest cannabis.
Yes! Treating the vulnerable plants, like the cucumbers in the spring will eradicate the mildew. In my study, even in the same growing area, mildew was unable to spread from one plant that was placed 6 meters away to the other plant of the same species. So if you can establish a perimeter of sterilized plants, you can be mildew free. I used that knowledge to eradicate the mildew growing in the green house on various plants. You most likely got it on a clone, it’s not coming from down in the crawl space.
The reason for this is it’s an obligate biotropic ascomycete which means in order to live, it has to have the host plant. In the shaping fire podcast, they explain it’s impossible to grow the mildew in a petri dish unless you mulch up the host plant and put it in there as well.
The spraying of the sulfur is highly targeted, so that’s easy to clean up afterwards.
Yes, spray the vegetables just like the cannabis plant, it dissolves the mildew colony literally.
2 Likes
This article names the species of mildew that grows on cannabis. Interesting work with PCR testing!
3 Likes
The pathogen was identified by ITS1-ITS2 rDNA sequence comparisons available in GenBank as Golovinomyces cichoracearum. However, isolates from cannabis could not be distinguished using the ITS region from Golovinomyces ambrosiae reported to infect sunflower and giant ragweed and Golovinomyces spadiceus from dahlia (Punja, 2018). Therefore, the species of powdery mildew affecting cannabis is provisionally named G. cichoracearum sensu lato and will require additional sequence comparisons of gene regions other than the ITS to confirm the species identity.
2 Likes
I would not use that you got to be careful with the copper spray. I have no problem whatsoever with neem oil. I have research the copper spray I didn’t see anything good about it on cannabis. No good reviews at all. Neem oil with the fungus spray is what I use. This is what I use. I have no problems whatsoever. Do I see bugs yes but they aren’t eating on my plants very much.
The azamax i’ve only used a few times and it was outdoors. It doesn’t have anything for fungus. Dried molasses or molasses helps with a lot of stuff. Full of sulfur. Plus a lot of extra vitamins. Earwigs bit a few of them they didn’t like the taste of it. I don’t know of anywhere that I have read but Neem oil kills fungus. this will.
2 Likes
4 teaspoons to 2 dawn dishwashing liquid. You can go up to tablespoons. I would do it when I turn my lights off and make sure I got plenty of fans on. You will burn your leaves if you have your lights on. I use it several times. I even get the spray in the bottle and hit them when they are young. Seedlings. I don’t mess around I don’t have a problem using products to keep bugs and mold off of my plants. I can’t afford it. Rhino skin from advanced nutrients helps also in the later flower cycle. One thing that I use I don’t see anybody ever talk about it but me and a few of my friends from Maine spray starch for spider mites