PM

[Oregonism]

After a shallow dive, it seems there are a few powdery mildews. 4 at least plus false powdery mildew. I just added the search term, powdery mildew AND caannabis/hemp, to google scholar.

Golovinomyces cichoracearum
Golovinomyces spadicus
Golovinomyces ambrosiae

Occurrence of Powdery Mildew Caused by Golovinomyces cichoracearum sensu lato on Cannabis sativa in Canada

First Report of Powdery Mildew Caused by Golovinomyces spadiceus on Industrial Hemp (Cannabis sativa) in Kentucky

First report of Powdery Mildew Caused by Golovinomyces ambrosiae on Cannabis sativa in Oregon

Cichoracearum was formerly identified as
Podosphaera macularis aka Spaerotheca macularis and if you wiki, PM, Podospheara xanthii aka Spaerotheca fuliginea is a common source of PM.

Also another fungus is False powdery mildew, Tricothecium roseum,
Differentiating powdery mildew from false powdery mildew


Im reading this from 2020 good overview and mention fluoropyram from a commercial use about suppresion. Other methods of brand names using h30 and baking soda and even milk is mentioned.

Evaluation of disease management approaches for powdery mildew on Cannabis sativa L. (marijuana) plants

 

[El Timbo]

The Church from Greenhouse Seed Co. was impervious to Powdery Mildew in my garden.

Just ordered 3 fem seeds of it.

 

[quiescent]

You can take the same clones and grow them different ways, and you'll find the healthiest ways grow plants which are naturally resistant to PM. An additional consideration (at least with indoor grows) is ventilation, where high filtration and flow rates will also significantly reduce the appearance of PM. So when someone says their strain is PM resistant, you'll also want to include their grow style in the equation. I have grown several strains now which people have PM issues with, and I have seen no PM issues with them.

Truly amazing to see the same clones thriving next to (and even touching) PM ridden versions of themselves, all caused solely by nutritional differences.

Hope that helps

This 100%.

You were given the answer at the start of this. It's a nutrition problem that opens the door for PM. It's poor environment/ipm/gardening practices in general that lets them kick their feet up.



^^^^^

PM when it sees your plants pumped full of nitrates, no foliar/ipm program, spots of poor airflow/low light with leaves touching leaves in your arid tent filled with medium that you let dry out too much and then over-water.

Basically, indoors, PM manifests itself in gardens that are breaking every rule. Outdoors it's still on the grower because without thin cell walls filled with nitrates there isn't a chance for PM to parasitize your plants.





The above focuses on the how and why behind a lot of other issues probably facing the cultivators of PM riddled plants.

 

[El Timbo]

You were given the answer at the start of this. It's a nutrition problem that opens the door for PM. It's poor environment/ipm/gardening practices in general that lets them kick their feet up.

So how do you explain reports of some plants being PM free in the same environment and watered/fed the same as heavily infested plants?

And are you saying that breeders that claim PM resistance for some strains are lying to us?

 

[quiescent]

So how do you explain reports of some plants being PM free in the same environment as heavily infested plants?

Read it again, slowly. Ask yourself.... Is it possible that there are differing nutritional requirements/uptake rates for different plants? Yes. Is it possible that plant has a different micro-climate than the one its right next to? Yes.

Blame the strain all you want, it's on the grower to not provide a hospitable environment for PM to take hold. I could grow OGs in a swamp surrounded by plants of many species covered in PM and not have any on the OG, soley because of proper nutrition.

You obviously haven't watched the hours of videos I posted yet. Highly suggested.

I can't tell if your previous responses in this thread are curiosity or a defense mechanism. Here's to hoping that you're humble enough to take the blame and make the necessary changes.

 

[El Timbo]

Here's to hoping that you're humble enough to take the blame and make the necessary changes.

I am making changes to how I grow (changes which are better discussed in a growing forum rather than this one) but I am also very interested in natural resistance - hence this thread.

There is PM floating about my town - I'm doing all I can to combat it but I also notice that some plants do better than others - I will continue to investigate ways to combat it but I will also look for strains that are claimed to be PM resistant.

 

[quiescent]

So how do you explain reports of some plants being PM free in the same environment and watered/fed the same as heavily infested plants?

And are you saying that breeders that claim PM resistance for some strains are lying to us?

PM resistance is real but that's more of an evolutionary thing. You don't get PM in the mountains on a dry farm for a myriad of reasons. Take that cultivar off the dry mountain; put it at sea level next to the coast and change your expectations of what you, the grower, needs to do to prevent PM from taking hold.

I'd change my gardening practices before I changed my cultivar selections knowing that the grower is steering the outcome.

 

[El Timbo]

PM resistance is real

So what's the issue in looking for PM resistant strains AND applying anti PM growing methods?

 

[El Timbo]

PM resistance is real but that's more of an evolutionary thing. You don't get PM in the mountains on a dry farm for a myriad of reasons. Take that cultivar off the dry mountain; put it at sea level next to the coast and change your expectations of what you, the grower, needs to do to prevent PM from taking hold.

So cultivars that evolved/were bred in a PM environment and are resistant would be what I'm looking for right?

 

[JockBudman]

If there's one guaranteed way tae piss me off it's the phrase "do your own research lolz" after which ah stop readin or carin about someone's opinion coz 90% of the time it's a cop out from someone who's spoutin an opinion wi fuck all tae back it up.

One of the principles of the scientific method is all claims require evidence an the one makin the claim needs tae provide it - sayin otherwise puts you on the level wi creationist godbotherers an other assorted lackwits.

Anyway, less than 5mins of google-fu and a quick skim read brought this up El Timbo - https://www.frontiersin.org/articles/10.3389/fagro.2021.720215/full

Looks like there's no evidence for general resistance but they have found a gene that can confer resistance in one particular line. Given they cannae test every plant in the world, that suggests there's likely tae be a few other genetic wonders here an there an if this research leads tae GM work down the line, there could be more in the comin decades.

Not hard tae find, even for a guy wi nae science background like me, just respect for those that do the actual research an for people askin honest an pertinent questions.

 

[El Timbo]

Does anyone have any PM related experiences with Blueberry? According to this article it is susceptible http://www.coloradogreenlab.com/blo...brid-blueberry-with-special-guest-russet-mite