PM

[El Timbo]

No, I have better things to do than your research.

Fair enough but don't expect people to take you seriously if you aren't prepared to back up your claims.

You asked a question, I gave you the answer and you want me to prove it. lol

My question was about PM resistant strains - I asked because I saw in a general PM thread that Sam Skunkman said that the way forward was to choose PM resistant strains.

PM can be eliminated one way for sure, Do not plant or grow any variety that gets PM, that may not be something you are willing to do but it works.
As soon as you see any PM on any variety, quit using that variety.

Different varieties have major differences in susceptibility, WLD like Afghan are the worst, hybrids with WLD in them are also bad. A few years ago I had 1000 seedlings imported from Afghanistan growing in my greenhouse, almost all got PM, while a few OHaze clones a NLD variety from near the Equator, that were also in the greenhouse and completely surrounded by the Afghans did not have or get PM, coming from a hot humid country they have a high resistance to Molds and PM unlike the Afghan WLD varieties with almost no resistance.
People that have PM problems need to only grow varieties that do not get PM, and the problem will be gone.
And not using PM prone varieties will encourage breeders to not use PM susceptible varieties in the first place to breed with.

Someone needs to start a list of PM susceptible Varieties and Landraces and Hybrids along with a list of PM resistant Varieties be they Landraces or Hybrids. There are enough growers on IC that if all their experiences were in a Cannabis PM susceptible list it would really help the newer growers without the experience to avoid WLD varieties that almost always have PM susceptibility where it is a problem. Breeders are to blame for using and making varieties that do have PM problems, I destroyed any I found, and I found a lot growing mostly imported seeds over the years looking for keepers.
-SamS

https://www.icmag.com/forum/marijua...s-of-the-great-battle-of-powdery-mildew/page6

Your initial answer was:

Bottom line, I don't think there is any such thing as a PM resistant strain

So according to you the whole premise of the thread is pointless right?

 

[Oregonism]

Peronospora farinosa is a type of downy mildew in Peronosporaceae and it effects cucumbers. However it cant exist in northern climates and might not be prevalent in its taget area, the South except in winter.

Powdery mildews are from the Erisyphales order, there isnt just one, "powdery mildew", just like there isnt one downy mildew, which seems disengenious about the cucumber to cannabis claim. I dont doubt that P. farinosa wont spread, but other Downies will.

In myy backyard practically, is a high functioning fancy viticulture industry [fancy french varieties oo lah lah] and a high functioning commercial rose industry.

Anectdotally, it is known that grapes and rose in the area will harbor mildews that can and will pass to cannabis. But realistically, specific identification of specific strains is really just getting started.....

Anything cookies north of 45 def seems to be a problem. I have withheld a bunch of cookie hybrid work from outdoors because I cant seem to hunt something not susceptible....poop.

 

[Effendi]

Fair enough but don't expect people to take you seriously if you aren't prepared to back up your claims.

Fair enough, I really don't care if you take me seriously. It's not my claim, it's science and experience. And just because you start a thread, doesn't mean that the information shared is for you. You may not be in a mindset to believe or accept it.

My response was not for you. It was for the others reading this who understand the difference between growing pot and growing something else on pot.

My question was about PM resistant strains - I asked because I saw in a general PM thread that Sam Skunkman said that the way forward was to choose PM resistant strains.

And I told you that IMHE (scientifically) no such thing exists.

BECAUSE Growing the plant and the PM that spores in the air and can grow on the surface of the leaf are two completely separate operations.

Given the right conditions and the presence of spores, PM will grow on ANY Cannabis. Again, nothing to do with Cannabis genetics. All about conditions.

But since you want to believe Sam Skunkman that there ARE these resistant strains, (he may well be correct) Why not just seek out those strains and grow them? Find out for yourself in reality rather than trying to disprove others.

So according to you the whole premise of the thread is pointless right?

Absolutely not. You have a belief that there might be cannabis genetics that might be more resistant to PM, you found one man to progress that theory and your looking for any science to back his claim. Unfortunately it's not there.

Information is always beneficial. Like I said, I probably should not have even added my .02. Your unicorn is out there.

Pics when you find it.

Happy Growing.

 

[Effendi]

In myy backyard practically, is a high functioning fancy viticulture industry [fancy french varieties oo lah lah] and a high functioning commercial rose industry.

Anectdotally, it is known that grapes and rose in the area will harbor mildews that can and will pass to cannabis.

Absolutely false my friend. I grew up in Napa and was intimately involved in both Viniculture and Poticulture through the 80's and 90's.
According to UC Davis who has spent LOTs of time and money intimately determining the detriment to Viniculture from PM.

It is absolutely a different spore FOR SURE, that effects grape verses pot. PM that effects grape does NOT pass to Pot. I'm sorry but it just doesn't.

But realistically, specific identification of specific strains is really just getting started.....

Truth, there really are 100's of different variants of Mycelium's and other bio-growths that effect wide swaths of all kinds of horticulture. Pot is not like all the others. I swear.

Anything cookies north of 45 def seems to be a problem. I have withheld a bunch of cookie hybrid work from outdoors because I cant seem to hunt something not susceptible....poop.

Nice growers experience report. In my experience, cookies hybrids are much more susceptible to all kinds of problems, the most of which is Herms.
That's why every other cross out there is a cookies cross. All happy accidents. Or not so happy.

Carry on

Demosthenes

 

[El Timbo]

But since you want to believe Sam Skunkman that there ARE these resistant strains, (he may well be correct) Why not just seek out those strains and grow them? Find out for yourself in reality rather than trying to disprove others.

That is the point of this thread....

 

[Oregonism]

Effendi I remain skeptical, but I dont discount anyones opinion, or try not to, fellow, poticulturist, more reading to follow on my part.

I am working with some unkown older haze hybrids, also C99 and Jack along with all being oucroseed to an old cat piss skunk. These do well outdoors, even as I have been selecting for shorter finish times. Kinda tried and true.....but selecting is the biggest pain the ass of course.

45N and 40 inches of rain a year, I have gotten a little Pm in my journey, to say the least.



ps. These haze hybrids throughout the years look like a really good source to search thru, but this confuses me about cookies, it just seems like a skunk/ haze or haze hybrid with some Afghani that doesnt like the PM. I dont care what they say about the lineage, its dominance shows in eveything from Forum cut outcrosses to ogkb, strawpicanna types, og cookies hybrids, chem cookie hybrids. Even things like Duct tape type crosses with GG4 as dad.

 

[f-e]

Might of been useful, all them roses. I like to treat the area around my outdoor grows with fungicides too nasty to put on my plants. Eagle 20 and the like. Or with anything left after spraying mine. This lowers the chance of a large accumulation of spores near my plants.

I would be surprised to see all forms of PM catalogued along with testing on cannabis. Offering proof to some of the arguments here. If we see something we don't like the look of nearby, it's better to eradicate it than start looking up what it might be and if you will be susceptible to it.

A few years back it got to almost everybody I know. It was well documented on all gardening and agricultural sites. Some individual or set had found favourable conditions, and didn't look interested what they grew upon. People passed it around indoors for a year or so afterwards. The bit to take from this is that is wasn't the plants that were susceptible, it was a persistent and difficult type of PM. Only isolated patches seemed to get through the winter though, and just one winter. If I was looking at the same stuff on my walks.. I don't swab and culture the stuff?

 

[BadRabbit]

Are Sativa landrace more resistant since they come from tropical climates and less dense flowers

Hi Alpo: The other grower who pointed out that sat buds tend to be less dense makes a good point that I'm sure is true. However, I just ran a room of all sativa landrace plants and had PM all over the place. I was surprised by this too ... but it is what it is.

 

[El Timbo]

I don't think it's as simple as sativa verus indica... if a landrace population has never been exposed to PM in its history then it probably won't have evolved resistance or had it bred into it.

 

[El Timbo]

It's not really mould as we view it. Mould is a cotton like growth. PM is a fungus. It's everywhere, you can't escape it. You just need to use enough preventative measures to stop it ever getting a real hold.

I agree - but in any given environment (especially outdoors) some plants will be more or less resistant and I think it would be useful to hear some experiences of plants that weren't affected when others nearby were.

 

[El Timbo]

Anectdotally, it is known that grapes and rose in the area will harbor mildews that can and will pass to cannabis. But realistically, specific identification of specific strains is really just getting started.....

I've had a long break from growing cannabis - I'm growing in the same place as before though. At that time I never had PM - I didn't even know what it was. A couple of years ago all the wild prickly pear cactus on the hill beside my house were affected and basically killed by it and it affected a lot of the ficus plants grown by my neighbours and the ivy on my terrace. The prickly pears seem to be growing back now but the PM is still around.

 

[djonkoman]

I do have one experience of a plant that stayed free from PM while plants from other strains right next to it did have it.
unfortunatly I can't give you much usefull input where to look for resistance though, since this was one of my own crosses, and I never ever experienced PM on cannabis myself, so I have no idea which of the ancestors of the cross the resistance may have come from (maybe all of them).

I used to think maybe the species of PM affecting cannabis did not occur here, or maybe the climate is too cold, since I never ever experienced it while seeing plenty of pics online. botrytis on the other hand is my main enemy here. mildews on other plants are also rare in my garden, sometimes with a longer period of warm dry weather in summer I get mildew on brassica's (like kale), and I think I once saw a small spot on a strawberry plant, and I think I once had some on a tomato plant as well. but mainly it's just on the brassica's, and that one I haven't seen spread to any other plant species around it even if all brassica-plants are heavily infested. so, probably a brassica-specific species of mildew.

however, last year someone I know came to me asking advice about some plant issues, at first I was told these plants were suffering from botrytis, which caused me to ask a bit further since it was in the middle of summer and these plants(autoflowers) had only just started to flower. so if they got botrytis under those circumstances they would have been really, really sensitive. personally I mostly see botrytis in september, usually only in plants at least midway into flower, and never with just 1 day of rain, it needs to be raining regularly for botrytis to occur (unless you grow crappy genetics without a shred of resistance, but botrytis resistance is more complex than mildew, absolute resistance against botrytis is pretty much impossible, but there can be a very big difference in how fast they get it, and how fast it spreads once it appears).

with those further questions it became clear this person got some bad info from someone else who called it botrytis while it actually was PM.
which made me even more surprised since I never ever saw it on cannabis in real life, only online pics.
I still had some late-sown plants leftover that I still needed to plant out at guerilla, so I offered this person one of these plants to see if it would hold up better then those commercial seedbank autoflowers.

my plant was planted right next to the mildew infested plants, and never got PM.

so I know now that at least 1 of my lines is resistant to at least 1 strain of PM.

but since I never had any experience with PM myself, I have no idea if I was just somehow lucky all those years, or if PM resistance is just a really common trait and the susceptible plants are the outliers. or if it just happens to be that everything I grew was resistant (I never grew the typical commercial indoor strains since those would probably not survive well outdoors here, especially during the botrytis season in autumn, and many would probably finish too late).
my suspicion is that a lot of cannabis is resistant to PM and actually the susceptible ones are the weird, rare ones.

 

[Douglas.Curtis]

How do you determine if it is resistant or not? you grow a strain in a 70% humidity basement and it doesn't get moldy?

Since resistance is directly tied to absorption of the necessary nutrients, yes this is indeed a great way to find plants which can find what they need. I have sprouted many herb plants in fungi polluted environments, specifically to find the more resistant plants to clone. Basil and aloe do not like spore rich environments much, but you can find keepers of them and the same is true of cannabis.

 

[El Timbo]

Of potential interest... https://www.nrgene.com/blog/powdery-mildew-resistance/

https://www.marijuanaventure.com/genetic-breakthrough-ending-powdery-mildew/

 

[FletchF.Fletch]

Hola El Timbo, very useful and interesting thread.

The Church from Greenhouse Seed Co. was impervious to Powdery Mildew in my garden. Before gaining control with a product called Mildew Cure from SaferGro. The Church had zero PM with infected plants growing right next to, on top of, and intertwined between. The absolute most Resistant strain.

Mildew Cure lists these ingredients:

Cottonseed Oil 30%
Corn Oil 30%
Garlic Oil 23%

Inert Ingredients: 17%

Citric Acid, Lauric Acid, Sodium Bicarbonate, Water

Could probably source ingredients and make your own spray. It kills Mildew.

 

[El Timbo]

The Church from Greenhouse Seed Co. was impervious to Powdery Mildew in my garden. Before gaining control with a product called Mildew Cure from SaferGro. The Church had zero PM with infected plants growing right next to, on top of, and intertwined between. The absolute most Resistant strain.

Good to hear Fletch... Did you grow several of them with the same results or just one? I think we have to be careful about declaring a strain to be resistant based on one plant...

 

[FletchF.Fletch]

Sorry, 5 out of 5 female seeds had No problems with a persistent/out of control PM issue. 4 of the 5 were allowed 1 time through., the Biggest yielder was kept for many clone crops afterwards.

Eventually got complete control over the Powdery Mildew. Armor Si helps as a preventative, and to bolster plants fighting it. Total amazement when that Mildew Cure came into play. Funny thing is it smells like food when you spray it, thanks to the Garlic Oil no doubt.

Neville's Haze was also very, very PM resistant for me at that time, as were Barney's Bluberry OG, and Dairy Queen from Subcool.

 

[oceangrownkush]

Get some physan 20 for pm. Very effective. I've read that leb27 is very mold resistant

 

[El Timbo]

When you grow different plants side by side and some are affected and others aren't you can assume that those that aren't are resistant.

I think this should be qualified - resistant in that certain environment.

 

[El Timbo]

Are Sativa landrace more resistant since they come from tropical climates and less dense flowers

According to Dubi from ACE, tropical sativas tend to be resistant to botrytis (grey mould) but not so much to PM. He says that their most PM resistant strain (at the population level) is Pakistani Citral Kush.