Just thought I'd share my experience with this evil fungus
IMO it's difficult to find good information out there, because every time you start a post like this, every Tom, Dick and Harry is going to chime in with (uniformed) OP's trying to tell you it's nute burn, nutrient dificiency, heat stress, blah blah blah, ad nauseaum.
So I'll just add that I went through a battle with this shite recently, it started attacking my seedling within their 2nd week and within about 8-9 days I had to pull em ALL, 30 high-grade beans down the shitter.
Btw, I tried anti-fungal copper and it actually seemed to INCREASE the growth, didn't work at all, but then the bottles been in my arsenal for over 2 years so it's possible that had something to do with it.
Anyway, did a shit load of research, what I could find, and I decided to pick up a product called
Aqua Quest Seranade RTU which is an organic anti-fungal product whose main ingredient is Bacillus Subtilis before starting my next grow. I sterilized my grow room to the best of my abilities but knowing the resilience of the fungal spores I decided to start the seedlings in my bedroom closet upstairs, as far away from the disease vector as possible.
Things went without a hitch up until about the 3rd week after germination. I had just transplanted them into their 2nd stage containers (6" pots) which also increased the amount of water/feed dramatically. Up until then the humidity in the closet had been fairly low (due to the start of winter things were pretty dry), around 35%. But now it went up to the 50% range, and after a heavy feeding the next evening, it shot up to 60% (btw I'm using hempy mix 40% perlite/60% coir).
The next day they showed the familiar signs of the fungal infection, with all but 5 or 6 out of 24 plants showing some spots and brownish crispy tips and edges. It was that sudden change in humidity that triggered it I'm certain. So I meticulously bathed EVERY leaf with the Seranade, (btw this stuff STINKS, lol) and I also tripled the normal dose of HG Subculture-B and Subculture-M (which are innoculants containing beneficial bacteria and mycorrhizal fungi) in the next feeding - my research showed that soil innoculation can help plants develope resistence via several methods, but basicatlly a healthier plant is able to fight off infections and you really can't OD the plants with these additives. I also trimmed away, and have continued to trim away, any of the understory necessary to allow good air circulation and keep a fan blowing down there to avoid any pockets of high humidity.
I also immediately purchased a good dehumidifer with a digital humidity controll and set it at 35%, and I also cut off as much of the infected leaves as possible. Some of these plants were quite small and had only a few leaves, so in some cases I just cut off the infected part so they'd have SOME means of photosynthesis. Two didn't make it past the initial infection, they looked so weak with all the leaves badly damaged that I just yanked them to avoid wasting space.
The results? WORKED LIKE A CHARM!!! Now not to say that they didnt' suffer, which they did, and I had to do another thorough application with Serenade 3 days later and a general spray 5 days later just to be safe, but over those next 10 days they all recovered .
It's been 5 weeks since the infection, about 3 weeks into flower now, and they are in amazing shape, I can honestly say I've not see my plants look this healthy before. A couple of times the humidity has accidentally crept above 50% due to the 2 gal bucket filling up and shutting of the humidifier while I was away, and each time I almost immediately saw the beginning signs of the fungus returning, almost always starting with leaves near the bottom, closest to the medium and so humidity - now I make SURE that the humidifier's reservoir is emptied before I leave the house.
BOTTOM LINE: IMO KEEP YOUR HUMIDITY LOW TO AVOID PROBLEMS IN THE FIRST PLACE, AND SECOND DEFINITELY ADD SERENADE TO YOUR ARSENAL IF YOU HAVE ANY SUCH LEAF SPOT OR RUST FUNGUS PROBLEMS, AND ALSO BE SURE TO ADD GH SUB-B AND SUB-M OR SIMILAR PRODUCTS TO KEEP YOUR BABIES HEALTHY!
P.S. Make sure you feed your bennies with plenty of carbs, I use backstrap molassas with every feeding so that they thrive
and keep fighting for you and your girls ;?D
Especially with healthy plants right nearby
