Is this a quick moving fungus?

This condition appeared only on one of four plants in just a day. Assuming it’s a form of fungus. While have great control of grow room environment. This plant is in the furthest corner of the grow tent. Microscopic examination of the top and bottom of an infected leaf shows no parasite. Have sprayed with a copper solution. Anyone else seen this condition ? Thanks… SonOfHeisenberg.

Copper is toxic and I wouldn’t spray it on a flowering plant. Hydrogen peroxide is effective and very safe.

What is your humidity? Fungus usually appears in humid environments with little airflow.


Did you spray anything on the plant before this appeared?

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I ask because the only thing I can find is called phytotoxicity which occurs when a chemical is applied to the leaves and the plant reacts to it. Fungus would be more random than that and usually is in round spots not stripes. The pic below is an example of phytotoxicity in a different plant. It was sprayed with a pesticide.



Everyone. Thanks for the quick response. As background, this is my fourth grow and the first issue I have encountered. What’s interesting is that the “Health Issue Presentation”. Looking at other general problems encountered with grows, there is no photos of the issue shown the “affected areas between the veins”. The issue is so very distinct and should be able to easily be identified.

So, Grow Conditions: Well, have a well-controlled grow room. Great air circulation with numerous fans. However, the problem plant is tucked in the corner. The expected air exchange could/may could have been less than optimal. (?). It’s been correct with circulation fan adjustment.

Watering rings are used, under the white planter covering. Plants have not had water splash or been sprayed with anything to date.

Conditions: 1.5mS/cm. Ph 5.5, CO2 = 1000ppm, Light 12/12 @ 1000 - 1100 PPFD, Day 80F. Night 70F (min.) RH Day 40% Night 40% Running dehumidifier to keep RH to the required level and not loses CO2 up the exhaust vent.

99.9% sure it’s a fungus. Not a mold because of the well-defined infected areas.

Per a responder’s concern about the toxicity of the fungicide used for the first time on the corner infected plant. Total on board with that point.

Clarification: I misspoke (As a retired engineer with a strong chemical background in plating and copper solutions, and always using the term copper sulfate. That is incorrect…

The fungicide used is not the more potent “Copper Sulfate”. But a very weak .08% “Copper Octanoate” Proven safe for years, for early application to plants and vegs. I would not want to use it in the final stages of flowering, say, just before harvest but we are in early stages of flowering. Risk/reward seems reasonable.

So have sprayed the affected plant. Again only one of the 4 plants in the grow tent show the “infection”. Experience with the fungicide in the past with tomato’s /pumpkins, as shown it to clear up this kind of problem(s) very fast, a few days.

If there is no additional spreading of the condition after the next 3-4 days. I should be able to conclude the problem has been properly identified and addressed successfully….

But if anyone has seen this issue before. please respond. Thanks again. SonOfHeisenberg.

Will update status in a few days

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A PM revelation? The dehumidifier and the air conditioner were turned on for the first time since last summer, just a few days ago…. I bet there were fungus/mold spores in one or both equipment that just started to infect the plants. What you all think? Always look for the simplest answer, because it usually ends up being that!

If you are growing in soil your ph is low. should be between 6.4 to 6.8.

YES!!! YES!!! Even though only having issue with one out of 4 plants and think it could be a fungus. Not ruling out a potential “Magnesium Deficiency” caused by slowly creeping lower irrigation water Ph. The water reservoir does have a continuous air bubbling (using outside grow tent air) that tends too slowly lower the Ph. The PH of the present irritation water in 5.5-6.0

This is a hydro grow. It did take a reasonable amount of Ph “UP” to get the Ph to test at 6.0-6.5 range. Closely watching other 3 healthy plants.

FYI. When using the air in the grow tent (@1000PPM CO2) for the reservoir bubbler. The Ph of the irrigation does a nosedive lower. Been there. Done that…

Air/Fan blowing damage to leaf from friction…I just plucked it after thinking it looked familiar.

Just a possibility…


Dang, nice setup @SonofHeisenberg! So that’s a closed loop and everything?

I’ve never seen anything like that. The setup or your issue. It’s really strange how it so regular like that, it must be the plant itself doing it, anything foreign should be more random I would think.


Could it have been from that metal ring there?

Thanks for the constructive feedback. As. Background. This a Hydro grow using Hydrotron clay as growth media. Don’t think it’s wind damage. Girls close to fan show no wind damage issue. Again, only one plant out of 4 shows this condition. Don’t think it’s the metal ring. Have done 4 grows with the support/training rings with no issues. (See pic).

Don’t see any additional “Spreading” of the “striping” on the infected plant or the other three girls. So, the 4 girls have had a light spray of veg/fruit safe fungicide and the Ph of the irritation water has been raised to 6.3 from 5.0-5.5. Will give it a few days and report again. Thanks again. SonOfHeisenberg

Uploading: Grow3A.jpg…



Dude, that’s one hell of a mega tent set up! Major engineering work well done! The recessed flush mounted air conditioner wins the prize. :heart::heart::heart:

By the way, that’s the strangest thing I’ve ever seen on a plant. So totally regular yet random. I’m speechless!

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If those center sections of the leaf are high or raised points, then I’d guess it is a rub mark from something. :thinking::thinking:

On second thought, it’s not a rub due to the various locations on the plant.

Could it be a variegated-like susceptibility issue to a deficiency? :thinking:

That’s the best I can come up with.

Well… After 7 days … The “Striped Mottling”. never progressed further (?) And it was only on. two cola’s on one of 4 plants The affected area was sprayed with a fruit/flower safe fungicide. Maybe it was a fungus… maybe it was just plant genetics… or maybe just a reaction to plant stress…

Affected 1 plant in rear right corner

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I’ve seen similar markings on leaves and have thought there might be a muncher feasting on my girls but all I’ve seen lately is a few gnats.
I’ve had fungus issues in the past and with my current grow I tried a sulfur compound that I found on Amazon. I had concerns about copper so I went with Sulfur. Never had any good results with Neem’s. I mixed the fine powder with water in a sprayer and showered the girls down every few weeks. This was the first grow (up until now) where I got ahead of the fungus.
Now @ 14 weeks, 5 weeks into flowering I find this, any ideas . .

I’m thinking calcium deficiency, probably caused by the nute strength, assuming you’re using those.

If it’s a fungus you could sort of smear it. Check for bugs to be careful too.

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A 4 Week Update. So, this condition continues to develop. Condition really centered on only the TOP of plant. But only one of three girls (?) Condition does not respond to a general fungicide spray. This is a hydro grow with will maintained water reservoir. Other two plant thriving with same irrigation water. Did a 3ml/ gallon hydrogen peroxide addition to the water 3 weeks ago just in case there was some root rot developing on the one plant… No. visible response. No negative response from the other three from the HP treatment.

Other two gals had lack of fragrance and lack of stickiness on the very top buds, contributed to excessive light PPFD @ 1000-1100. When dropped back to 800PPFD the girl’s showed appreciation with fragrance and stickiness starting to return.

Other than the modeling on the one girl… the bud development is progressing nicely… Going to attribute the modeling to. “Unknown Factors” and move on. @omeyer @CurrDogg420

Things in general going well