Weird spots on leaves

[mystcl]

These spots are appearing on 2 out of my 3 plants in the grow box. Each affected plant has about 5–7 leaves in a similar condition.

Most of the damaged leaves are on two branches of one plant, while the second plant has just one affected branch. That branch is actually touching the affected branch from the first plant.

Because of this, I’m almost convinced it might be spider mites. But the thing is, I don’t see any of those tiny black spots moving. They just look like dust. I also don’t see any webs or other typical signs of infestation.

I’m watering with 2 L every two days and adding BioBloom. The plants grew a bit tall, so the lower branches aren’t getting much light anymore. Also, I have to pull one plant out of the box every time I water, so these affected branches are rubbing against the walls or occasionally getting tangled with each other. I’m hoping this might just be mechanical damage or some kind of nutrient deficiency.

How can I be 100% sure? I first noticed these leaves about 5 days ago, and now I’m seeing 1 or 2 more each time I check.

Thanks!

 

[5 Star Trich]

View attachment 1751441
View attachment 1751442

These spots are appearing on 2 out of my 3 plants in the grow box. Each affected plant has about 5–7 leaves in a similar condition.

Most of the damaged leaves are on two branches of one plant, while the second plant has just one affected branch. That branch is actually touching the affected branch from the first plant.

Because of this, I’m almost convinced it might be spider mites. But the thing is, I don’t see any of those tiny black spots moving. They just look like dust. I also don’t see any webs or other typical signs of infestation.

I’m watering with 2 L every two days and adding BioBloom. The plants grew a bit tall, so the lower branches aren’t getting much light anymore. Also, I have to pull one plant out of the box every time I water, so these affected branches are rubbing against the walls or occasionally getting tangled with each other. I’m hoping this might just be mechanical damage or some kind of nutrient deficiency.

How can I be 100% sure? I first noticed these leaves about 5 days ago, and now I’m seeing 1 or 2 more each time I check.

Thanks!

Looks like spider mites. Look at the back of the leaves at the black spots with some magnification.

 

[BII]

Yes, almost certainly mites. Look at the black spots on bottom of leaves with whatever magnifier/microscope used to check trichomes, and you'll see the mites.

I get rid of them by 'fumigating' the tent using No-Pest Strips. Put 1 or more strips in the tent, turn off lights (tent heat source), seal up the tent while continuing running the circulation fans within the tent, come back say several hours later, turn on the lights and let the tent vent the toxic fumes to the outside as normal. Depending on your setup, it also can't hurt to have a window fan exhausting air from the room the tent's in. It would likely be best to not have any charcoal filter used be clogged up with captured pesticide, so either undo any filter or simply otherwise exhaust the tent's fumes.

The strips give off insect-killing gas (not aerosol) which the plant/plant cells do no absorb or metabolize, there are no residues (unlike using any liquid or aerosol for treatment). Any insect breathing tent air, such as mites on leaves or buds, die. Repeat this say five days later (or even several times) to make sure to kill any next generation(s) that hatch. Minimize your own exposure to strip fumes (hold your breath and run in-out of the tent room), and wash your hands or use gloves to handle. When done, reseal the strip(s) airtight so you can reuse them many times as needed. Since there is no residue or uptake of the pesticide, this can even be done in late bloom, unlike applying liquids.

 

[mystcl]

Hi guys, thanks for the replies!

I did take a look with 30x magnifier and i see no moving or legs.. that tiny black stuff looks like dust fragments.
I have also tried to shake leaves on the white paper and again, no moving or anything.

I will act as they are spidermites and do what a man has to do.

Ty again!

 

[BII]

Even if you don't see them, they can move around and be starting-up elsewhere. Spots on the underside and white spots on top from the mites sucking nutrients and chlorophyll definitely indicate mites. The bottom black "spots" could just be left behind mite waste/defecation? [When I had mites, they were white/uncolored].

 

[mystcl]

Yes, these black spots are more likely leftovers, or their poop?

One thing im certain - these black spots are dead, there is no indication of moving or anything else.
Also, i dont see any other stuff around it. I see no orange or white dots..nothing.

Facts:
1. upper side of leaves indicate spidermites problem
2. lower side of leaves indicate spidermites problem
3. spread pattern indicates spidermites problem

Here are other possible reasons, based on GPT:


Mechanical damage

• Branches rubbing against walls or other branches when you move the plant.
• Repeated contact can scrape or crush surface cells → pale speckling or scarring.
• Damage on the upper leaf side can make the lower surface sticky, trapping dust or soil particles exactly below the damaged area.

Affected branches are being rubbed against other branchess/wall when pulling plant outside the box.
Basically only affected branches are the ones from the plant being pulled outside the box and on other plant, only affected branch is the one that is being rubbed against first plant branches when pulling.

Here is picture of another leave with another damaged area. Lots of leaves have these tiny damaged spots which are not spreading. When they appear, they just stay same size.

Thrips

• Usually create silvery or pale scraping marks, often in longer streaks rather than tiny uniform dots.
• Undersides can have black fecal specks (but these are usually larger, shinier).
• You’d usually see the insects themselves (tiny, fast-moving, cigar-shaped).

Today i noticed this!
Here is the picture:

Not sure if you can see it clearly but there are silver traces, just the ones that stay behind the snail when moving. Still no signs of any animals on leaves or around.