Progressive Melting of Staurogynes repens

[WiNd08]

Hi all,

I've initially planted ~15 stems of S. repens and over the past 2 months they have created a nice carpet over the area I wanted it to grow on.

However, over the past 2weeks I have observed them melting progressively from the right-most side and eventually spreading across to the left. When the melt spread across to nearly 60% of the lawn, I decided to pull out all of the affected plants (their stems are still healthy) and placed them in a breeder box. Not surprisingly, the remaining S. repens lawn did not melt anymore, leading me to believe that it could be due to microbial infection or something alone the line.

The affected plants which are in the breeder box seems to be recovering really slowly, but I will not judge on that until I observe new stems grow out from the nodes. Currently they're pearling quite vigorously in the breeder box (primarily I think because they are nearer to the surface / light).

Another interesting point is that the Alternanthera reineckii 'mini' which are grow around the circumference of the S. repens are experience the melt as well, although they seem to be handling it pretty well, most of them have recovered after the I removed the affected S. repens.

I've read many (more than 10) threads on various forums, even on Barr's site, that hobbyist are facing the exact same problem with S. repens. Having a healthy colony which just decided to melt away one fine day.

I do not believe it has to do with nutrient deficiency as the other plants in the vicinity which are root-feeding; A. reineckii 'mini' as well as B. japonica are doing pretty well.

Summary / Symptoms:


1. Pin-holes first appearing on older leaves, subsequently melting the entire plant except most the stems.
2. Approximately 30% of the stems melt, the rest are healthy with massive root system intact.
3. Spreading from one point and spreading across the whole colony.
4. Affects A. reineckii 'mini' slightly but not severe (only 1 - 2 leaves per plant melted, but new stems are still growing normally).
5. Melting seem to stop after removal of affected plants.
6. Isolated affected plants seem to be recovering very slowly.


I have not been able to find a reason behind the melt, and reading on various other forums and sites doesn't seem to give me a proper conclusion or way to cure it.

Hopefully members of this forum would be able to solve this mystery.

Any thoughts?

Regards,
CK

[Urban Aquaria]

It could still be due to certain nutrient deficiencies... different plants require different nutrients at varying amounts (they grow and uptake nutrients at different rates too), so one type of plant may show symptoms of nutrient deficiency while others are still okay.

When you remove deteriorating plants and the remaining ones recover, it could also mean you just reduced the plant mass, so there is less competition for nutrients and more of it available to the remaining plants, hence they resume growing well.

Have you looked at gradually increasing the fertilizer dosing amounts as the plant density increase? More plant mass = more nutrient requirements, so the fertilizer dosing also has to increase to match it.

As for pin-holes on leaves in general, its usually linked to potassium deficiency, so maybe try increasing K dosing to boost up those nutrient levels, see if that helps.

[WiNd08]

Knowing that S. repens is a heavy root feeding plant, I have quite a few root tabs around the area where they are planted. CO2 levels shouldn't be a problem because even my Rotala wallichii are pearling. I maybe dosing too little Potassium as you've mentioned, been dosing 5ml/3x a week instead of the 8ml which is the recommended dose for my tank volume.

On a side note, I removed the plants but they are in the same tank in a floating breeder box so theoretically they are still the same plant mass.

I'll definitely up my K and see how it goes.

Thanks!

[fireblade]

How's your temperature like? did you use any chiller?

[WiNd08]

No chiller, but I'm living in Melbourne now. My tank temperature is at 23deg.

[AQMS]

how about your co2? is it still full?

[Gavan]

sounds like a very localized problem. shouldn't be ferts or co2 which theoretically is even throughout the tank.

have you tried planting stuff back into the dead S. repens area?


Sent from my iPhone using Tapatalk

[WiNd08]

My CO2 is still running at 2bps.

Yes it is only affected the S. repens. Now the whole patch have gotten it, again, spreading from the corner most plant. I removed them and placed all in a breeder box.
I replaced the area with some C. wendtii and they seem to be okay.

[fireblade]

Light not enough or the gravels you used is not suitable for the palnt?

My CO2 is still running at 2bps.

Yes it is only affected the S. repens. Now the whole patch have gotten it, again, spreading from the corner most plant. I removed them and placed all in a breeder box.
I replaced the area with some C. wendtii and they seem to be okay.