Green Dot and yellow leaves on Dendrobium

[JDawggie]

Hi All,

My Dendrobium is having an issue -- started a few weeks back, but at that time, I could not tell if the leaves were just spent as they were all on older canes.

However, it seems things are not right because newer leaves are turning yellow, after a green dot appears on the leaf (strange). The one green dot remains green while the rest of the leave turns yellow and I usually wind up removing it. I am always careful to have good ari ciculation and use sterile blades when cutting, but I am thinking this is some sort of infection or fungus...anyway have any ideas? (see picture)

[WhiteRabbit]

Can you post a pic of the plant?

[JDawggie]

Sonya...here is a picture of the full plant as well as a close-up of the underside of the leaf where the spot is. Maybe it is a material infection? I can not tell -- I have been doing some research online, but can not seem to pinpoint exactly what I am seeing. Any thoughts are greatly appreciatted.

Thanks,
Jared

[RosieC]

It could just be that an old cane is loosing it's leaves. This happens with older canes. Hopefully others more knowledgeable than me can chime in though.

[jaxorchidman]

When is the last time you repotted it? It might be that the roots are rotting on that pseudobulb and that is why it is loosing its leaves. The new growth is looking good though so I would check the roots and repot in a coarse fast draining mix. Like Rosie said also, Dens. do loose their leaves on backbulbs.

[WhiteRabbit]

Do you know how old those canes losing leaves are? You do have that newer one that looks good.
The other canes look good despite being leafless, so it's quite possible it's just shedding old foliage.

Has there been a change in environment/temps? Draft? Watering? Recent repot?

Never hurts to check the roots, repot if it hasn't been done.

[Bud]

I think the leaf had a sucking insect bite and developed a fungi colony around it. The leaf is falling off anyways so might as well cut it off.
The old long cane is shredding its old leaves...its just the plant feeling spent and want to retire...but that cane is still alive and well and might spring off a spike or keiki...
I agree with repotting it. decaying media will make the roots rot

[JDawggie]

Thanks all ...I will have a look at the roots and see what is going on -- and repot.

Jared

[WhiteRabbit]

Originally Posted by JDawggie

Thanks all ...I will have a look at the roots and see what is going on -- and repot.

Jared

Let us know how it goes, please

[calypsoB]

There have been a number of previous posts on this exact issue. The tell tale ring...
Unfortunately I don't remember what they said but I am sure if you search ring you will come up with something!
But it is something not nothing....
ETAHelp! Mysterious rings killing leaves!