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leaf deformation, crystalline layer on bottom of leaves

S

SeedySimon

Member
Hi,


Maybe some of you guys know more about this...

One out of many seedlings started showing strange symptoms, the leaves are starting to deform a little and there is some crystalline layer mainly on the bottom side of the leaves which can be rubbed off but won't come off when sprayed with plenty of water.



For better image quality I uploaded some pictures externally:
https://imgur.com/a/UZpMUMu



While it is probably some fungus disease, I have never seen anything like this, so I am curious if anybody can tell me more?
 
T

TanzanianMagic

Well-known member
Veteran
SeedySimon said:
Hi,


Maybe some of you guys know more about this...

One out of many seedlings started showing strange symptoms, the leaves are starting to deform a little and there is some crystalline layer mainly on the bottom side of the leaves which can be rubbed off but won't come off when sprayed with plenty of water.

For better image quality I uploaded some pictures externally:
https://imgur.com/a/UZpMUMu

While it is probably some fungus disease, I have never seen anything like this, so I am curious if anybody can tell me more?
Click to expand...
Some kind of small insect has been munching on the side of the leaf (red circle).

On top of that, the yellow and yellow and brown blotch at the lower leaf (yellow circle) looks like mildew.

Other than that, the seedling looks great. Nice growth at the tip, no purpling of the stem (enough K).

Just some insect investation and mildew - better airflow. I like to use a combination of neem oil, dish soap and pyrethrum (organically approved) if I really want to knock back any insects.
 

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S

SeedySimon

Member
Thanks for your opinion, TanzanianMagic. However, it is not mildew, it is not this powdery white but rather a layer of crystalline appearance. At least is not the mildew I know... and to be honest I have not seen a lot of mildew in my growers life as I always keep my grow environment well ventilated ;)



While mainly the big leaves are affected, this stuff is all over the plant, also in the upper part, mainly on the bottom of the leaves.



Well, I will keep the plant around a little longer to see how it develops... for the sake of curiosity.
 
f-e

f-e

Well-known member
Mentor
Veteran
You might be seconds away from an epic infestation. I only have your description to go on though.
 
T

TanzanianMagic

Well-known member
Veteran
SeedySimon said:
Thanks for your opinion, TanzanianMagic. However, it is not mildew, it is not this powdery white but rather a layer of crystalline appearance. At least is not the mildew I know... and to be honest I have not seen a lot of mildew in my growers life as I always keep my grow environment well ventilated ;)
Click to expand...
What does it look like under a magnifying glass or microscope?

Also, there are many kinds of mildew.

The reason it looks like mildew, is the necrotic patch surrounded by yellowing leaf. That's the fungus expanding.

Then, there is a crystalline layer everywhere? That's mildew starting to block the light.

Then, the small insects are likely also tracking mildew spores around.
 
S

SeedySimon

Member
Epic infestation? Nah. But then I keep the affected two plants separately, of course.


Thanks for your opinion, TanzanianMagic.


The yellowing of the leaf is very local and has not expanded.

The crystalline layer is more or less on all leaves, the more heavily affected ones also show some deformation. It is mostly found on the bottom of the leaves.


Here are some more pictures. The ones shot with the microscope are not of a very high resolution unluckily. Well, Aliexpress ;)


https://imgur.com/a/SmMnrN6
 
MJPassion

MJPassion

Observer
ICMag Donor
Veteran
The crystaline layer on the bottom of the leaf appears to be cystolithic hairs, a type of non-glandular trichome produced by thousands of different kinds of plants.


They're purpose is to maintain a layer of air around the plant to help regulate plant surface temps as well as a water repellant.
 
G

GatorGumbo

MJPassion said:
The crystaline layer on the bottom of the leaf appears to be cystolithic hairs, a type of non-glandular trichome produced by thousands of different kinds of plants.


They're purpose is to maintain a layer of air around the plant to help regulate plant surface temps as well as a water repellant.
Click to expand...

That's my first thought also, but I've never seen a cannabis plant where it's that distinct. Maybe I just haven't been around the block enough times yet.

OP, are you using distilled water on the leaves or tap water at all? Water that is too heavy can leave deposits on them which causes problems.
 
S

SeedySimon

Member
MJPassion said:
The crystaline layer on the bottom of the leaf appears to be cystolithic hairs, a type of non-glandular trichome produced by thousands of different kinds of plants.
/quote]


Sorry that I cannot provide any better quality of microscopic images, but this is definitely some kind of disease and not just cystolithic hairs.



GatorGumbo said:
OP, are you using distilled water on the leaves or tap water at all?
Click to expand...



The affected plants were not sprayed at all. Normally I use osmosis filtered water, but to be honest even in the past when I was spraying tap water with quite a high EC I didn't notice any problems.
Click to expand...
 
G

GatorGumbo

Once in a while is fine just don't do it a lot, that's from my own experiences though.

Would be a good idea to isolate that plant until you sort it out.

Wish I could be of more help.
 
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