I believe powdery mildew is not systemic although it does seem like it sometimes lol, and i agree, better off just trashing the strains that have it seems damn near impossible to kill off.
i think the most important part regarding pm is to find the source, not only kill the pm. otherwise it'll always come back.
for instance: i quite often saw ventilation systems running in circulating mode in small setups (< 10m²), meaning the exhaust air flows back into the room.
in this case the exhaust air is filled with spores and the active carbon filter being close to the lamp is a perfect incubator for the spores due the heat.
a friend of mine had exactly this situation. the pm always came back couple months after using a systemic fungicide like eagle20. i realized what was going on, told him.
he got a new filter and changed the setup so the exhaust air was going out of the room. after that no more pm.
so always try to find out where the pm is coming, take action and then treat the plant with a fungicide.
Just got finished reading every single post in this thread. All I can say is that I am quite enlightened in many subjects and astonished at the results of others. Thank you very much DJM, for all of the helpful information and having the personality you do.
On a side note, I can say that personally studying leaf and stem infected with PM, I uncovered zero evidence of the fungi actually entering the body of plants. It seemed to create larger colonies around the outer edge of stoma, but I could never find evidence of the actual mycelium growing inside the plants. This is just my personal experience and observations under 400-2000X magnification. Some PM mycelium and spore bodies on a leaf surface at 800X View Image
I sprinkle DE on the surface of my coco water it in. Then I sprinkle some on top again. Every transplant. I have no bugs. I haven't had anything other then knats sense forever but this has wiped them out and it is easy and cheap to do. DE will eliminate any soft bodied insect so can you say preventative?
[URL=https://www.icmag.com/ic/picture.php?albumid=59947&pictureid=1408128&thumb=1]View Image[/url]
Hope you dont mind us shooting the shit in your thread Dj...
Is that a 5 gallon air pot?
Hows that Flexi tank holding up?
I've got 3 of the GH Covert Tank 66 Gal.. I set 3 of them up only to return to find water trapped under them and around them. Not sure which of the 3 were leaking, so I just took them all back down and switched to Brutes.
I love the idea of collapsible reservoirs, but wary of them now.
You're right on this on.
PM is not systemic as it does not enter the plant and circulate within the plant and re-surface as an infection elsewhere.
Spores are air borne and easily cause infections where ever it finds a hospitable host.
It can get its organs "into" a plant but it does not spread that way. It can only spread on the surface.
Source: Robert C. Clarks - "Hemp pests and diseases"
I never had a PM issue in my life till about a year ago. Taking in cuts I suppose. And so I started spraying all the normal organic stuff. Tea, Green Cure, Baking soda. Im perpetual so I could not get crazy. And so I would only spray Eagle 20 in veg. I never had it show in Veg not once not even in the dome's on the babys. But every time a few weeks into flower they would start every time.
I had a friend suggest a sulfur burner it doesn't hurt the flowers and what not but I could not bring myself to do it. Thinking the PM was systemic I dint see the point.
And so one day my AC froze up and I wasn't there to catch it. (won't happen again BTW) By the time I did my rooms had gotten hot bad. It was like 100 and the RH was like 100. I lost some crops to say the least. But it ended my PM issue. Same plants same environment I even have a higher humidity now with following DJ suggestions and nothing not a drop. Im so thankful and I know now what to do. Its spores flying around from cracks and crevices. And I will attack it there if I end up with again some how.
Didn't notice the pm discussion until now, but had something to throw in. I have battled pm off and on throughout the years, was never fun, but was never really that bad. Then like 16 months ago I brought some cuts in and bam there was pm. This time it was different though, my bubba would just fucking cover itself in it. I tried EVERYTHING, and that shit would not stay gone. Finally after 1 year of every horrible thing in history, I finally ditched the bubba in frustration. Didn't even bother to e20 the cuts, burned sulfur a couple times and flipped them. Expected the stuff to come back, figured I was done, but it was gone.i think the most important part regarding pm is to find the source, not only kill the pm. otherwise it'll always come back.
for instance: i quite often saw ventilation systems running in circulating mode in small setups (< 10m²), meaning the exhaust air flows back into the room.
in this case the exhaust air is filled with spores and the active carbon filter being close to the lamp is a perfect incubator for the spores due the heat.
a friend of mine had exactly this situation. the pm always came back couple months after using a systemic fungicide like eagle20. i realized what was going on, told him.
he got a new filter and changed the setup so the exhaust air was going out of the room. after that no more pm.
so always try to find out where the pm is coming, take action and then treat the plant with a fungicide.