Powdery mildew - An easily exterminated parasite

lol, I was on a mission I figured I needed adequate amounts of ammo

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When it comes to mildew, more ammo is good lol! OK! Lets retreat into some more technical aspects of investigation. This is how I examine the mildew and try to identify which colony is which, out there in the wide world.


now, everyone has seen this colony from the pumpkin, and it’s soooo much like the cannabis one. Little Conidia all over lol! So I take the image above and make this:
mildewd
That is a single reproductive chain from the mildew. Now I can see if it forms a real chain or pseudo.

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Then, I’m like… well it’s got no chasmothecia which is the asocarp where it performs sexual reproduction. Also, it’s a pseudochain, the conidia aren’t joined, just sort of balanced on top of each other. Now, I can slap the label “pumpkin mildew” on that cartoon graphic I created. Then I gather a mildew sample from the other plant and make it into a drawing as well, so I can easily compare.

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So then you’re like… ok! Cannabis mildew and pumpkin mildew look really like the same thing. At that point, how do I tell the difference? Ahhhh, you rub the colony from one plant on the other plant. If it transfers infection, then they are definitely the same kind.

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Powdery mildew resistant gene.

Plants containing this gene produce enzymes that metabolize fatty acids produced by the powdery mildew, stealing its energy before it can colonize.

Most strains contain pm resistance genes, they are simply not being activated.

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Their claim that Golovinomyces ambrosiae is growing on cannabis is right, based on their microscopic images. I would be cautiously optimistic that sunflower and ragweed mildew is the one infesting cannabis. They are studying cannabis as well, a very positive sign :wink:

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Wondering if the strepto strain in actinovate discriminates between the different species. I don’t think so… I found that treatment was superior to sulphur strictly because of residue. Although keeping the bacteria active in absence of fungus colonies seemed to allow innoculation (and hence protection) to ‘wear off’…'Cause actinovate is illegal here, and travel restrictions, I’m back to Sulphur my 2nd choice…Ever used it @JoeCrowe ?

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nope! I need something that eradicates the mildew boom like that. If I have to re-apply for an unknown time, it’s not really wiping the creature out. Sulfur is more of a sterilization routine for fungal parasites on plants. Once it hits them, they are dead. Except oomycetes, because water mold doesn’t care about sulfur.
So I have a hardcore greenhouse infestation of mildew? 15$ worth of sulfur and it’s extinct, except I actually only use 5 cents worth to wipe out the colony. Any residue isn’t a problem, because you should never spray sulfur in bloom.

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Yeah sulphur is the cheapest route. But as you point out, it is a nuclear option, after infection IMO. I prefer to use biological control as a preventative, sulphur (which I use as well) is the solution to an existing problem. I also ain’t so sure about using sulphur on a smoked product, so I seek a possibly less harmful solution. Although outdoors the Actinovate can be harmful to the soil biosphere…so thats another issue.

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I only use sulfur to eliminate a colony, I never use it to prevent anything. Remember, never spray the sulfur on a plant in bloom, that way you never smoke the sulfur. Or if you are super paranoid, you could just grow the clones of a plant that has been sterilized.
The secret people are missing is the infestation doesn’t “come out of nowhere” even though it is invisible to the human eye. I don’t use any sulfur in my cannabis grow, because there is no parasite to exterminate. You have to quarantine any new plant, and then if you microscopically inspect it, daily is best for a couple of weeks, you can wipe out the infestation on the new plant and it will never enter your grow. Once the powdery mildew is in your grow, you know you have failed to prevent infestation, by bringing it in.
If the colony is already established in your greenhouse or grow, and you are coming here now, just spray it with the sulfur and move on. The parasite will never return unless you bring in more infected plant material. Even dead plant material can harbor “things”. Multitudes of things.

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And then there’s the issue of supporting with a company with no conscience. Montsanto, “just trust us,” lol!

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Good info Joe. ahh quarantine, nice thought, but quite impossible for this hobby grower. LOL Microscopically daily for a cpl weeks…nope…meticulousness? diligence? Nope, they are all the things that take all the relaxation out of gardening, and get left behind when I leave work. Sulphur it is LOL.

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Downy mildews are Peronosporales, which are not fungi. There is a downy mildew that affects Cannabis, but is much more rare than PM. It causes necrotic leaf spots rather than powdery colonies.

The confirmed species of PM on Cannabis are Golovinomyces ambrosiae and Podospheara macularis. Leveillula taurica has been historically reported (early 20th century), but hasn’t been confirmed in modern literature to my knowledge.

G. ambrosiae is probably the most common and virulent on Cannabis.

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Whoa there, yeh Monsanto is Bayer, now. Y’know to escape lawsuits because of their poisons… and I guess I should never have taken aspirin as y’know bayer was involved in gassing Jews in WW2 right??? We can’t win sometimes mate, why I’m always searching for alternatives. I’m sure everyone has used a hawthorne product at some time miracle gro ring a bell. I’ll have to see if Monsanto patented that… thanks for alerting me Fan Man…

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I know I have, but not now.

Scotts makes MG, and shilled Roundup for Monsanto. I’m not sure of the Actinovate connection, but a bag I looked at said made for monsanto. Montsanto never sold products themselves, they had others do that.

After Scotts got caught adding rat poison to their birdseed, and got slapped on the wrist with a fine that was worth the whipping to them… they didn’t look so good, and Hawthorne Gardening was born.

Scotts still shills Roundup for Bayer Crop Science/Monsanto via Hawthorne, at least to my knowledge.

Hawthorne is trying to buy any weed related business they can. Gavita, General Hydroponics, a long list. They put rat poison in birdseed, yeah I’m gonna use their plant foods!

I’m sure you know all this, but others may not.

I wouldn’t have if I knew that… there’s other options. Your choice, but you know that.

Doesn’t mean we shouldn’t try. But, you know that, too.

Good one! :slight_smile: I gotta run, we’ve got choir practice tonight, lol!

ETA: Hawthorne’s brands, so far

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@Seamonkey84 came up with a protocol that might work for you. Submerge the plant, except the roots in a bucket of sulfur water mixed with insecticidal soap. If you treat each incoming clone like that, everything should be dead. Not sure how long to soak it though. I would think 15-30min would work.

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Now there’s an idea for optimum coverage, just like I’m giving the plants a H2O2 bath tonight before I hang them. I’m upotting in a week I’ll give it a go. @Seamonkey84 did you have a thread? any more thoughts on time etc. ??

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Thanks mate, its a fine balance between long term and short term harm with a lot of products these days. Its hard to knowingly avoid products with artificial ingredients, our lifestyle demands more than finding food and water daily, and as such we are at the mercy of local affordable retail food. people in our municipality often have to drive an hour for 1 small grocery store with a poor selection, so it is hard but we try… ANYTHING we consume which didn’t exist before WW1 is basically toxic, if ya wanna split hairs. Cheers and be the change.

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There are lots of myths about powdery mildew. I don’t think I know them all, but I’ve heard quite a few, right? The number one copy and pasted mildew info that’s wrong is the humidity. They claim you would get powdery mildew at high humidity, but in my controlled environment that doesn’t climb over 45%… or what it’s set at, the mildew infested. So I read all the write ups about mildew. “the more you know” right? And at this time, I didn’t have a clue what to think. All the info was correct as far as I knew. they all agreed with the same thing. Then, if it’s really dry, the spores will fail to germinate? Good theory, it lined up with the articles about it. So I hammered the humidity. 25% max! I was amazed when it caused a big conidia bloom that made the colony explode in size. Dryness…helps it. So I turned up the humidity, and sprayed my plants with water. Barely slowed the spread.

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I mix up a gallon of garden soap solution in a pitcher, mix in 1-2 tablespoons of micronized sulfur (powder). I just give it a really good stir, then dunk the plant in and give it a swirly. I’ll leave it in for at least 30sec. The soaking was really more for any bugs I’m targeting. I’m just realizing this is a mildew thread lol. But yea, give it a good stir, dip it in, I let it settle a bit, dunk up and down or give another swirl and remove. Unless I get distracted, it’s usually a one min soak at most, I have too many plants to give baths to. The soap allows the water to stick to the surface, and the powdered sulfur is so fine that it leaves a fine coating, the undersides of the leaves are usually encrusted when it’s all dried :sweat_smile:. Only time I had issues was when I double coated. I did a dip, drip dried, then sprayed with them with more sulfur water (heavy on the sulfur) the powdered crusted the growth nodes enough to cause some damage to the new growth, but they grew out of that quickly and I didn’t see any PM after the first treatment, but did just the dip again a week or two later.

I’m also just realizing that I might have messed up the amount of sulfur I’ve been using, I though I was following @JoeCrowe mix but as a dip instead of spray, but I guess I’ve been using 25-50% as much sulfur in my treatments… should of taken notes. I think I used a 1/4c per gallon the first few times doing the treatment, as I know I would of double checked Jose’s instructions with PM in mind. But in my recent dips, hoping it’ll help with mites, I’ve only used the 1tbs in the gallon, then then they get a decent coating.

Just checked, I had used 2tbs in a qt plus soap when I first treated them as a spray, that’s what caked the nodes lol.

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