Does this look like rust fungus?

The rains have come and the last few days have been very wet and cold. Last night it was down in the lower 50s, upper 40s with a humidity of 92+. Everybody is under shelter and out of the rain
5 of 7 are thriving… Really looking great and weathering this rain nicely. The other 2 are somewhat problematic, with 1 really giving me a run for my money. It us the bushiest, shortest girl of the bunch (5.5ft whereas the rest are ranging from 6.5-8+from) and so I have been dealing with airflow issues and, consequently, powdery mildew. I’ve been spot treating with neem before I switched over to h2o2 with good results. The WPM is still coming in spots, but I seem to have it under some control.

But this evening after work I went out for my routine inspection and I found a new issue that I believe is rust fungus. I managed to cut most, if not all the affected leaves off, but I am wondering what I can expect and how to treat it best? Or could I be seeing a deficiency making an appearance?

I’m figuring I have another 2-4 weeks look the whole crop, so I am in the home stretch. The rains have made everything much more … interesting.

Any thoughts are appreciated!

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@aaa @skydiver @mrcrabs @gremmall

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garrigan65ILGM Global Ambassador ~ BergmansLab VIP

Mar '18


First, rust is a fungi. it is opportunist. it preys on unwell plants. if something is a miss, rust is a sign. rust has been identified to have 7,000 species. it attacks crops of every description. but we’re only interested in one variety aren’t we?
if rust is present early in a grow, you have problems as it’s an indicator something in your room is a miss. usually ventilation. go through your system and double check things are in place and working properly.
rust is an air borne fungi. if given the opportunity, it WILL take hold. it usually does during flower as this is when the plants immune system is at its weakest as its energies are concentrating on re-production, not survival.
depending on what part of the grow you get it, you can cure/minimize it with either chemical or natural remedies.
it enters the leaf via the stomata and then it’s off and running.
fungacides used are generally copper based and include; thriram, manzecob, maneb or zineb at 10 day intervills.


baking soda, 1 tea spoon/ quart of water. spray on.
copper sulphate, read lables.
fungacidal soap sprays;
garlic sprays, 1/2 cup minced garlic, 1 quart of water. let sit 24hrs, strain, spray.
sulphur, one of the best natural sprays. it is low in toxicity.
micro kill, a citric based killer. i use this with great success

@growtus I went on a little hunt and found this from garrigan. I’ve not even ran across the term rust fungus so I’m interested. I’m watching here for when the gardeners wake up this morning. Other than those few spots your plants look great man


Thanks for that. I am going to see if it is spreading and try the baking soda route this weekend as it’s supposed to be effective for WPM as well.

Luckily, so far this strain appears to be pretty well suited for the climate ( it originated in BC, so it makes sense that it would do similarly well in Portland)

Anyway, thanks and I’ll update on this later!

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with the increasing weather issues…suggest you consider harvesting soon.

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Not sure but looks similar to what I had awhile back.

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It’s on my mind for sure, but looks like the weather is going to dry up a bit next week and they are under cover from the bulk of it. To add to my mental gymnastics of leaving them to bulk up, they are a Sativa dominant strain of BC origins… So I’m hoping that makes them a bit more resistant to the nasties.

The pictured plant, however, would be the first to get the axe given its foliar density and history of issues. Leads me to believe that it’s going to be the most susceptible to the mold which shall not be named.

I should add that it looks wet because I was spot treating with peroxide for WPM

Do you have documentation of this? What was the outcome?

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Links to my old journal with posts referencing my rust fungus issue.
Ended up going away after treatments if it was rust fungus.
Hope this helps.

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Thanks buddy. I’ll have a read later today!

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could also harvest biggest thickest first.