# Molybdenum deficiency



## kekon (Aug 1, 2005)

Recently i've noticed some symptoms which appear to be molibdenum deficiency. According to literature not enough molybdenum causes:

- necrosis on mid-older leaves (leaves tissue becomes transparent or there is no tissue between nerves)
- leaves edges culr upward

The process of tissue dying is fast, it tooks only a few hours ! (the literature also tells about it)

The symptoms given above appeared in my tank on Cardamine Lyrata leaves. They showed after switching from TMG fert to a different one, which consists 20 times less molybdenum. As far as i know molybdenum is required for N absorption in the form of NO3. When using NPK fert with N in urea form and micro fert with low molybdenum concentration i didn't have such issues.
At the beginning i considered it to be K deficiency but all the other plants don't show K deficiency and K level is about 10ppm (measured in a lab).


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## detlef (Dec 24, 2004)

Kekon,

do you have shrimps in your tank? The holes in the C.L. tissue look exactly as if a hungry amano shrimp was munching on it. This would also explain why you were noticing the damage within hours.

Regards,
Detlef


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## kekon (Aug 1, 2005)

I have had shrimps for a year but i'm 100% sure they don't do any damages im my plants because the symptoms appear each time i switch to fert with low Mo concentration. I don't think shrimps are able to bite plants leaves so much. Besides, the most of damaged leaves have dead, rotten and transparent tissue (glassy) without any holes. The photo i posted concerns only one leave (it's not good...) the rest ones have just rotten tissues. I added some molybdenum (0.003 ppm) and will see if it helps.


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## detlef (Dec 24, 2004)

Kekon wrote,

>I don't think shrimps are able to bite plants leaves so much. Besides, the most of damaged leaves have dead, rotten and transparent tissue (glassy) without any holes.<

I have been keeping amano shrimps for quite a long time and I know for sure how they can damage tissues. They even can bite away the red colored cells from leave surfaces (e.g. Rotala rotundifolia). After munching on the tissue the leave might look transparent/glassy or even full of holes and will eventually rot away completely afterwards.

Hungry amano shrimps can be very aggressive to leaves indeed.

Regards,
Detlef


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## kekon (Aug 1, 2005)

Well, anyway i've just cut off the damaged leaves. Cardamine Lyrata is the only affected plant. If the shrimps really do damages the new holes should appear soon if addtional Mo dose doesn't help.


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## Minsc (May 7, 2006)

What are you using to add Mo? I have very similar symptoms in my tank, which I attributed to K deficiency, but I don't understand how I could not be adding enough K...
Oh, and I don't have any shrimp.


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## kekon (Aug 1, 2005)

I used liquid water Mo solution used in agriculture. It consists 33g of Mo in 1L bottle. However, today i've notoced new "fresh" damages on most of leaves that were caused during the night ! I have a few otocinclus fish and i think they might have caused the damages. I looked closely at teh damaged leaves and it seems they are mechanical ones. I cut off affected leaves again and i will watch my tank during the night to see if any fish try do devour my cardamine lyrata  It may sound like sacrifice not to sleep at night and watching dark tank instead, but i have to figure out K or Mo deficiency... When it comes to Mo i use this product (the solution i've written about):

http://www.intermag.pl/en/produkty/nawozy_rolnicze/molibdenit.html


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## detlef (Dec 24, 2004)

Yep,

ottos can damage plant leaves as well. I'm quite sure either of them shrimps or ottos are to be blamed. Not easy to watch an otto though biting holes in complete darkness... 

Regards,
Detlef


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## kekon (Aug 1, 2005)

I replanted Cardamine Lyrata and planted it into a dofferent place in my tank and watched it at night with a help of a flashlight  Today, i've noticed no damaged leaves so it wasn't any deficiency but mechanical damages.


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## detlef (Dec 24, 2004)

So this is one of the rare situations in this hobby where a definite answer could be found. Congrats,

Detlef


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