Spots on Stems - Spreading

I have an outdoor grow with multiple strains: GG#4, Forbidden Fruit, and Strawberry Banana.
Happy Frog Soil
Botanicare: Pure Blend Pro, Cal-Mag, Silica Blast
Microbe Life: Photosynthesis Plus
pH: 6.2 (I use a Bluelab Pen for accuracy)

Two weeks ago, I saw some yellowing leaves at the base of two of my plants.
The leaves seem to yellow from the base and then outwards.
The main veins in the leaves seem to blacken as well.
Eventually they die and fall off.

It also seems to be spreading to another plant close to them.
Since then I have stripped off all of the infected leaves and quarantined the plants.

I regularly spray Spinosad and Neem for pests and I also check the plants under a microscope for signs of small pests.
All seems clear. I even sprayed some SNS 244C Fungicide to see if that would clear it up.

The only identifying factor I can see are these brown/red spots that seem to appear on the stems of the leaves that will eventually die. It also seems to be spreading throughout the plants. (See pictures).
Has anyone seen anything like this?

It doesn’t seem to be pests.
It doesn;t seem to be a deficiency. (Flushed twice with perfect pH and feed them mildly).
The only thing I can think of is some disease I’ve never seen.

Any ideas would be much appreciated!!

@garrigan62 @dbrn32 @Donaldj @Countryboyjvd1971 @Hogmaster @Willd @WillyJ

You might want to complete this too so they info when they pop over:

Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA

Strain; Type, Bag seed, ILGM… name of strain:

How many plants:

Age from Sprout and Flower:

Soil in pots, Hydroponic, or Coco / Brand and type of Soil & Size of Pots:

How often do you water and how do you determine when to do so?

PH of water and runoff or solution in reservoir:

What is strength of nutrient mix? EC, or TDS:

Indoor or Outdoor:

Light system, size and height from plants:

Temps; Day, Night:

Humidity; Day, Night:

Ventilation system; Yes, No, Size:

AC, Humidifier, De-humidifier:

Co2; Yes, No:

Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you.

1 Like

Both a Magnesium and/or Phosphorus deficiency are highly unlikely, but I had performed remedying measures just in case. I flushed with clean water with pH of 6.2 for a week and then added in Cal-Mag. The plants are extremely healthy besides the few infected leaves. 95% of the plant is healthy green and growing quickly.

Additional info per request:

Soil in 15 gallon pots.
I water with 5ml per gallon of each solution listed, which is a conservative feeding regimen.
I water 1.5 gallons per plant every other day or when the top 2 inches of soil is dry.

All other info is in original post.

Manganese is not magnesium :wink: and is very rare flushing will only further deplete if you are dealing with a hungry plant a conservative feeding routine on a hungry strain during stages of it’s cycle will not be enough which is why many nutrient lines increase dosing through plants life. How often do you calibrate your ph meter? you don’t need to be defensive I am just another set of eyes which may be able to draw your attention to something that could be simple or a real issue it is in the end you who finds the answer all I do is help present more possible options as to what it could be :slight_smile: I can’t run tests look feel smell your plants so I hope only to help you answer your own question

1 Like

I apologize. I thought you were talking about Magnesium. I have never even heard of Manganese. I will look into it further to see if increasing the nutrients will help.

I have been growing for quite some time and truly don’t think the plants have a nutrient defficiency though. I really believe this is some sort of disease by the way it is moving through the plant. I just can’t put my finger on what it could be and what the proper management steps I should take.

The closest thing I could find is possibly a rust fungus or some sort of cross disease from my garden or grape vines, which are mostly healthy.

I truly appreciate all the help and all the eyes I can get. I have battled many things in my garden, but haven’t seen anything like this. It seems so identifiable with those spots that are identical on 3 plants now, but I just can’t seem to find a reference.

1 Like

You are already using a fuguscide

just an option

1 Like

I haven’t up-rooted a plant this season, but I have run into Root-Knot before.

About a month ago, I did add beneficial nematodes to the entire garden as a preventative measure. I did this mainly for grub prevention, but I hear it is supposed to work for things like this as well.

I might try to pluck one up tonight and check it out.
At this point, I just want to know whats going on.

The SNS 244C Fungicide I sprayed once was a shot in the dark I felt like.
It really only has certain oils in it, and to be honest, I didn’t have much hope for it.

I scoured many forums last night and found a few others with the same “Black Spots on Stems”. Most of the posts ended with no true identification, but one post that went pretty deep, landed on Leaf Spot Fungus (aka Rust Spot). Looks like this is a tough one to get rid of as well, as it seems to be systemic.

I think the best I can do is purchase a better fungicide, but more importantly, spray on a consistent schedule to hold it at bay.

My plan is to purchase some Serenade and spray on a 7 day interval for 3 weeks.
Hopefully I will see some results. Does anyone have experience with Serenade?
I was thinking about GreenCure, but I think Serenade will do a better job and is listed as Organic. Adding another round of beneficial nematodes probably couldn’t hurt either.

What do you think?

Just me but sound as if you are over watering.

Most people who have rust fungus, or think they do. Dont. I’ve read all about it thinking I had something similar. Turns out it was a deficiency, never really figured out which one, I just kept it at bay by feeding every other watering with 3/4 strength nutes. Not to say that’s your problem. Just sayin.

Here are some microscope pictures of the spots: