Powdery Mildew

Annaba said:
I think you are misinterpretin that part...it remains active to fight fungus for 2-4 weeks...it can stay in the plant for well over a year...an if you're havin your product tested for pesticide residuals, it can be found well after a year of application...fwiw.
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i appreciate that clarification, thank you.
 
Phyton35 is fairly safe to use as a copper based fungicide. I personally have not used it for pm but it works great for root disease. Systemic and safe for food crops.
 
Guymandude said:
keep in mind that PM is a systemic fungus, meaning it's throughout the entire plant. It only presents on the leaf surface. if you make the leaf surface hostile for this presentation, such as changing the ph of the surface with sulfur or baking soda, your plant will still have PM, yiu just won't be able to see it on the leaves.
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I agree, I think it’s important to use a systemic when getting clones from people. I’ve never just had pm pop up. It’s always from clones and likes to wait to show her ugly face till mid flower.
 
high temps work. 100+ for 4 hours or more.

or plant therapy or iso alcohol or peroxide or green cure sprayed every other day. but high temps kills it everywhere in the room.
 
Does anyone know what the legal cannabis industry is using to combat powdery mildew? Their product is state tested before allowed to go to market so they especially have to stay compliant.
Thanks
 
I use Serenade outdoors to try and battle mold and rot organically. We have Phlox that are susceptible to PM and right now have it. I sprayed / soaked the plants with Serenade and after a couple days in the sun... the PM is still on the leaves. When I've used Bicarb-soda w/ detergent it does clear the leaves of the PM. So fore an ornamental this is effective. I am applying Serenade to the cannabis plants regularly now and until harvest. I am experimenting now with showering the plants at harvest to remove the serenade beneficial guests.
 
I've used Serenade to get plants through the flowering period. It works only temporarily so you have to spray every 4 days.
 
Guymandude said:
keep in mind that PM is a systemic fungus, meaning it's throughout the entire plant. It only presents on the leaf surface. if you make the leaf surface hostile for this presentation, such as changing the ph of the surface with sulfur or baking soda, your plant will still have PM, yiu just won't be able to see it on the leaves.
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We don't actually know that much about the PM which infects pot except that it appears to be a novel species who's mycelium can live for up to around 45 days. Here's a link talking about the controversy of whether or not it's systemic, I can't remember off hand where I read about the study which found the mycelium can live for up to 45'ish days without expressing (it was a long time ago and my sieve like mind only retains so much).

https://www.medicinalgenomics.com/powdery-mildew-systemic/
 
ClearBarbedFunk said:
When it does appear, I just use baking soda, 1tbs per gal. From what I’ve read, your just looking to change the PH on the leaf surface.
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If you can find potassium bicarbonate instead of sodium bicarbonate it's even more effective as it destroys the mycelium as it degrades as well as changing the surface pH. It's fairly effective at suppressing PM, more so if you mix it with neem oil (and dish soap) but it won't fully stop an outbreak in my experience. There's some interesting studies coming out about using milk, they thinks it's a reaction between the proteins and UV from the sun but don't fully understand it yet. Some people swear by LAB's but I've found their of limited use, although I don't have much experience with them. Organic market gardening is a good place to learn about non-synthetic method to control PM, take it all with a grain of salt as there's a gross tendency to over exaggerate how effective they are.
 
I have used serenade, greencure, SM90, Baking Soda, ISO and milk ...and none of them worked very well for me


the only thing that worked was the Eagle 20( it was actually spectracide with Myclobutanil) and that was years n years ago, but I have never seen PM in my garden since.

Of course now that I've read a little more about it here, i'll never use it again ….and I hope I don't die from using it in the past.

geez what a damn bummer



mj
 
Somatek said:
If you can find potassium bicarbonate instead of sodium bicarbonate it's even more effective as it destroys the mycelium as it degrades as well as changing the surface pH. It's fairly effective at suppressing PM, more so if you mix it with neem oil (and dish soap) but it won't fully stop an outbreak in my experience. There's some interesting studies coming out about using milk, they thinks it's a reaction between the proteins and UV from the sun but don't fully understand it yet. Some people swear by LAB's but I've found their of limited use, although I don't have much experience with them. Organic market gardening is a good place to learn about non-synthetic method to control PM, take it all with a grain of salt as there's a gross tendency to over exaggerate how effective they are.
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Thank you for the input, much appreciated, will definitly look for the potassium vs sodium. Tried milk a few years ago in a light dep, and it got a sour aroma and was a lot of residue. Baking soda kills it to the eye, right away. Have since heard from growers here to crank up the heat, added a few fans and ran the room at 95+ for a week, lot of watering but it hasn’t come back now, and been about 3 months now.

Also seems to come around in winter, not much in summer grows. Any pm I’ve ever gotten has been from cuts acquired else where.
 
why doesn’t high temps work outdoors.....?...cause source a constant.....?...... those temps/low rh are normal here......
 
barefoot said:
why doesn’t high temps work outdoors.....?...cause source a constant.....?...... those temps/low rh are normal here......
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how high does it get and low does it get at night? i'm in the high dessert technically and during the summer i haven't seen pm on my plants but when i put the 2nd crop out in november or december, pm starts to become an issue.
 
rh is significant factor.....once optimum...light rain.warm night temps....thrives if sources available......prolly why takes till Nov/Dec where your at.....cause not much moisture till then...unless lotsa monsoon action....
 
When temps drop at night and early morning and dew points are at there highest is where your going to see PM and bud rot
 
Been alternating with big time exterminator and plant therapy consistently and love the results .
 
Thanks guys. I will try the serenade. The guy at the hydro store said Citrus acid was good for PM as well and a lot of products contain it.
 
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