yellow spots on kovachii

[Bjorn]

This one Puzzles me;Its something we have discussed in another thread but now its there again; earlier this year I had these yellow discolorations on one of my kovachii seedlings. Picture from March


Now it looks like this (June) and it seems to "heal"


However, I found this other shoot that seems to have started growing rapidly and that looks like this:

Not the best of photos, but you see what I mean. What is going on? Is it too rapid growth or?

 

[Justin]

can u test for virus?

 

[Bjorn]

No, but would virus heal? More likely to be some nutrient imbalance I'd guess.

 

[Justin]

good point. we had a plant at our society you would swear had virus marks.but tested negative so it was nutritional.

i often get those yellow bands on some paphs like sanderianum. either not enough water or nutrients at a specific moment of leaf growth.

 

[orcoholic]

Had same thing happen. Never found out why, but it doesn't seem to be a problem. I thought is was due to some kind of nutrient deficiency when that part of the leaf grew. It happened in a couple Phals too.

 

[naoki]

There might be a several reasons to see the similar pattern. As others suggested, this seems to show up more frequently when the plants are growing rapidly (or under a load). My recent one is with P. lindleyanum kaieteurum. It started to shoot the inflorescence, and I observed the band. But this was slightly different from the previous one (P. "wallisii"). This time the older leaves slightly became yellow in addition to the band (in the previous time, the older leaves didn't change color). I'm not sure the white balance is correct or not, but Pk looks tiny bit yellowish?? In my new case, I had a couple weeks where I was keeping it a bit too dry (I'm not growing this one with tray of water, and I was a bit busy).

Did you check the pH of pour-through by any chance?

Was it around March, you went to your formulation of fertilizer?

 

[Stone]

The first pic clearly show symmetrical markings formed when the leaf was still folded and young so this can only be some kind of mechanical damage.

 

[Bjorn]

Naoki, the pH is around 7 on the low side difficult to measure due to lack of buffering. It may look a bit yellowish, but mostly that seems to be due to camera or lighting, I have checked in daylight and it is grassgreen, not dark green but like grass. But then, its on a low nutrients diet without urea soooooo.......
I started my own fertiliser around march first, but the yellow leaves might have been there at that time. The shoot just recently started expanding and the inner leaves are normal green. Might have to do with root activity, the roots started growing approx two months ago, now they are rapidly growing, previously they were not.

 

[Bjorn]

The first pic clearly show symmetrical markings formed when the leaf was still folded and young so this can only be some kind of mechanical damage.

I did initially consider some pest, but the marking was also present at the opposite leaf, that is not in the picture. Mechanical damage sounds strange, but never say never.....could be. But would it green up?

 

[Secundino]

I have seen those markings too, but have no pic. It must be nutritional; some movable element; it always appears not with the youngest, but with the second or third leaf, half grown or nearly full grown, and fades - heals - within a few months. Last noticed it with my roth, which is fairly strong growing. It is like a short-term imbalance the plant does relocate quickly and then needs time to 'repair'.

 

[NYEric]

Idk. They are bigger than any Pk I ever grew. Good luck.

 

[Ozpaph]

fertilizer/chemical 'burn'???

 

[Bjorn]

fertilizer/chemical 'burn'???

Would not think so, <100ppm TDS. Seems to occur and then further growth is normal. With time the yellow disappears as well.

 

[cnycharles]

I think in cases where you have very rapidly growing plants/orchids you can starve them at points with a 'normal' feeding. If you weren't keeping plants sitting in water that normally you would, and the roots may have been a little inactive then the constant easy supply of nutrients might not have been available.
Pattern on a leaf always makes me nervous but if tests say nothing then maybe clean.
Another point in 'why would it heal if virus' could be that normally they done show or are covered but stress may allow us to see physical symptoms. It's been said I think here that some genera don't usually show reactions to having virus... And if a test doesn't check for a 'different' virus then it would show negative results (like drug test for nicotine in body but person using cocaine; negative test result but drug in system)
I had a phal species red leaves white pink flowers (sanderiana) that the spike would grow so fast that the tip would just crash. I historically severely under fertilized and some fast moving things like that would suffer


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[Stone]

I have seen those markings too, but have no pic. It must be nutritional; some movable element

The first pic problem absolutely cannot be nutritional. Have another look. The pattern of damage on each side of the leaf is a mirror image of the other side. A nutritional problem cannot translocate from one side of the leaf to the other and make exactly the same marking while leaving the tissue in between green.
Further up the leaf you can see a brown spot on one side and a corresopnding discolouration on the other.
This definitly happend while the leaf was small and still folded and my guess would be mealy bug, mite and/or fungal damage which has now gone. But it could also be from a concentration of some chemical too.
The other plant could well have (have had) a nutritional issue for whatever reason.

 

[Happypaphy7]

You can look at it and think all day, but for virus, you have to test to know for sure, and there are many viruses that affect orchids.
Certain lab here will test for a few, not just two most common types, if you paid more money for the service.

Plus, virused plants will not heal. It's something you are stuck with unless a miracle takes place!

I'm not saying it is because you just can't do that, but likelihood might be there.
I also do not believe it is nutritional as Mike says.

 

[ehanes7612]

I get those every now and then (especially caudatum types)_ , and usually coincides with a rapid growth ( and probably the need for me to step up the watering)..for example during a heat wave..doesn't seem to affect the plant in any way..things still bloom on schedule and grow like 'weeds'

 

[Bjorn]

I am pretty convinced that it has to do with nutrients and root activity. Root activity was low when these spots formed, then rapid growth commenced with the roots lagging behind. After a while roots are up to speed but the tissue has got the spots - at least for a while.