black on leaves

[JoshuaR]

Hello everyone,
My cattleya has recently acquired black spots on two of the leaves. Any thoughts on what it could be, and what to do about it?

[isurus79]

Looks like sunburn to me. I think you may have given it too much light too quickly. Think of this plant as a pale skinned person that can take the light you give it, but only after it has been able to get used to the high light over time.

[JoshuaR]

Originally Posted by isurus79

Looks like sunburn to me. I think you may have given it too much light too quickly. Think of this plant as a pale skinned person that can take the light you give it, but only after it has been able to get used to the high light over time.

Interesting, I would have never thought of that, it's been in the same location for a few weeks. Thank you

[CR7cristiano]

Looks like a bit of sunburn or a bit of bacterial spotting on the leaf.....if the latter, nothing a bit of systemic fungicide wont get rid of.

[isurus79]

Originally Posted by JoshuaR

Interesting, I would have never thought of that, it's been in the same location for a few weeks. Thank you

As the sun changes its position in the sky and the temps get higher, your chances of burning go up. Its not a problem though. Your plant should be fine.

[Hawaiian Sunshine]

Originally Posted by isurus79

Looks like sunburn to me. I think you may have given it too much light too quickly. Think of this plant as a pale skinned person that can take the light you give it, but only after it has been able to get used to the high light over time.

I really hope Steve is correct that it's sunburn. In opinion though it looks like bacterial rot (black rot) where the black spots will spread down to the base of the plant. If it is black rot, my experience is that it is 90% fatal to the plant even if you were to cut the affected leaves or treat it with a bactericide. You should isolate the plant from the others in case it's bacterial so the neighboring plants do not get infected. Black rot can spread very rapidly. Please let us know how it goes.

[arijitp83]

My Cattleya has suddenly developed this black region. Due to a pre-monsoon depression it was raining for days and the plant was outside. It started as a black spot. Now I have brought the plant inside. Should I cut off that leaf? I have already applied fungicide and it is only that leaf -- its a new growth, the other leaf is still growing.

The plant was doing quite well outside in the sun and as you can see in the pictures there are many new growths. Its been only growing since I bought the plant in 2008 and did not flower yet- I do not know why!

Can anyone help me and throw some light on the above issues.

[CR7cristiano]

It probably hasn't flowered of fertilizing regimen or temperatures don't fall enough at night to initiate flowering. Given you say it has been in the sun. The other reason and could very well be the reason is because its a young plant.

[james mickelso]

Fungal black spot. It will spread very slowly but eventually kill the plant. But it is easy to stop. Take a razor blade and carefully cut off the black part into green leaf tissue. Leave none of the black on the leaf. Dab some cinnamon powder onto the cut edges. It will survive. No problem. I don't have any pics that I can find but as I do mostly rescues I get this condition all the time. It's not a concern unless you are growing a very nice collection or growing for sale.

[isurus79]

Originally Posted by arijitp83

My Cattleya has suddenly developed this black region. Due to a pre-monsoon depression it was raining for days and the plant was outside. It started as a black spot. Now I have brought the plant inside. Should I cut off that leaf? I have already applied fungicide and it is only that leaf -- its a new growth, the other leaf is still growing.

The plant was doing quite well outside in the sun and as you can see in the pictures there are many new growths. Its been only growing since I bought the plant in 2008 and did not flower yet- I do not know why!

Can anyone help me and throw some light on the above issues.

As said previously, just cut off the black part. Its a pretty small piece of the plant, so I wouldn't worry about it.

Does anyone else think this plant is a compot that never got separated when it was large enough to do so? That would explain why a plant this size hasn't bloomed even though it's large and getting plenty of sun. Its not one large mature plant, but rather lots and lots of small immature plants.