There's much controversy around the "incurable" part, I'll copy a couple of other posts of mine below to help enlighten you some more on the subject. If you take clones from infected but seemingly healthy mothers, it WILL follow the clones and be the cause of outbreaks in flower. Pay attention to what I say about the life-cycle of the disease, and the effects of plant and pathogen strains, and why all of this leads to confusion and controversy:
"Yeah, your plants has been severely overwatered, and that can cause root-rot, ie. pythium, if going on for too long.
Pythium root-rot is systemic and chronic, like plant aids, and will hurt your yields and success. It is mostly dormant in the vegetative stage and will allow for clones from the infected mother to root and grow seemingly normal, but the outbreaks starts in flower, and denies the plant the chance to reach it's full potential.
A couple of great diagnostic tools is to examine the root-tips CLOSELY. If they're well-defined and pointy in vegging plants you are ok, but if the outermost 0,5-1 mm are kinda mushy, you've got it. And in bloom you can check the run-off when watering/reservoir in hydro if you suspect an outbreak. If it's severely acidic and constantly wants to drop, it's a pretty sure sign of rot.
And again, root-rot is systemic, chronic, and follows the clones. System and pythium/plant-strain dependent, you can manage it with some success for prolonged periods, but you will not be able to rid your plants of it once you've got it, and it will to a degree hurt your yields.
Unless you do a complete kill-off and sterilization routine of your equipment of course, and start over from seeds again.
So.
AVOID overwatering at all costs - use 1/3 perlite in your mix to make sure it will not get waterlogged. The perlite will also help "supercharge" your plants, due to the excellent rate of gas exchange you achieve for the roots. Expect to water twice a day.
And if you DO get a case of overwatering, drain as best as you can ASAP, and repot into a larger pot with dry medium to help dry up the wet soil and aerate the roots again.
Pythium is almost inevitable for uninformed fresh growers to catch, and it can fuck up the whole experience for a LONG time due to it's systemic/chronic nature, and veg-dormant/bloom-triggered life-cycle.
Just a heads up, good luck with your grows man!"
"Well, for diagnosing it in veg you need to inspect the root tips CLOSELY. Sharp and well defined equals ok, mushy equals systemic rot in most cases. Tips only in veg, the rest looks just fine...
And there are a number of ways to keep it partially under control to save crops, depending on your system and available remedies, and your personal preferences. Search, here and in Google.
Remember that different strains has different tolerances to it, and it even differs between the individual plants in the same strain due to genetic diversity. There are also a multitude of pythium strains and sub-strains, with different capabilities for persistence and devastation.
And also, some claims that it is curable, and some claims that it is not...
I argue, based on mine and others experience and scientific litterature, that in the majority of cases it is NOT. But confusion in this matter easily arises from the fact that it has a veg-dormant/bloom-active life cycle, and some plants are more resistant and some pythium strains milder. And finally, the individual growers varying success in suppressing it with the applicated treatments or "cures" or implemented "preventative measures", may in some cases lead him to believe that it is cured, when infact the outbreaks are only effectively prevented .
Just make sure to keep it the fuck out of your plants in the first place, which is relatively easy with some basic knowledge, experiencence, and sound gardening practices.
And yes, pythium is everpresent in soil and water as dormant spores, and WILL activate and attack plants that are susceptible to it due to moisture stress, low O2 and/or other factors. Then, with ONE sick plant in your room, it will most likely spread to the others as aggressive, live, active pathogens with a very high disease-pressure. As opposed to the dormant, everpresent low-disease-pressure spores before given a chance to take hold...
Good luck."
https://www.rollitup.org/marijuana-plant-problems/402641-over-watering-issue-solved-5.html#post5269939
And a little more info:
Many plant-pathogens have evolved to trigger their outbreaks when the plants hormonal system changes into bloom-mode. The reason for this is that it is in the pathogens best interest to let the plants reach a large biomass to spread from once it's dead. And it's also in the pathogens interest to let the plants manage to drop some seeds, ensuring hosts for the spores to infect next season too.
If your genetics is of a high value to you Ontario, and the strains of both pythium and plants are of a nature that makes it possible to live with it for awhile, you should perhaps look into other methods than DWC, and other nutes too?
Read up on pythium and make up your own mind, there's lots of controversy around it. But I attribute that to general ignorance and confusion, and "cure"-peddling nute and pesticide companies...
Good luck.
