What could this be? Translucid patch on leaf

[rbarata]

Just like the title says...this appeared in a leaf of my phal liodoro. It's the only mark in the plant and I've noticed it today.

[jkofferdahl]

It looks to me like a spot caused by physical damage.

[rbarata]

I have the same oppinion but I'd like other oppinions.
Could this be caused by any environmental condition?
I spent the weekend out of town and forgot the A/C turned on set to 22 ºC (71 F). It has beed cold around here these days so I think these temps are not a problem but humidity falls to somewhere between 20-30%.
Usually I use the A/C at night but turn it off by bed time.

Another possibility is sunburn. With the change in sun position this phal now gets some late afternoon sun for maybe an hour or two. But I have a translucid/ almost transparent curtain in my window.
Does it look like sunburn in the early stages?

[jkofferdahl]

Originally Posted by rbarata

I have the same oppinion but I'd like other oppinions.
Could this be caused by any environmental condition?
I spent the weekend out of town and forgot the A/C turned on set to 22 ºC (71 F). It has beed cold around here these days so I think these temps are not a problem but humidity falls to somewhere between 20-30%.
Usually I use the A/C at night but turn it off by bed time.

Another possibility is sunburn. With the change in sun position this phal now gets some late afternoon sun for maybe an hour or two. But I have a translucid/ almost transparent curtain in my window.
Does it look like sunburn in the early stages?

I don't think it's sunburn. A lot of my Phals get strong afternoon light and are just fine, plus I think if it was sunburn the effected area would be larger.

[rbarata]

... if it was sunburn the effected area would be larger.

Yes, that makes sense.

[Orchid Whisperer]

Keep an eye on it. If it does not get larger, nothing to worry about.

If it gets larger, especially rapidly, it is a bacterial infection, similar to Erwinia. Treat by cutting off the rotten leaf.

[jkofferdahl]

Originally Posted by Orchid Whisperer

Keep an eye on it. If it does not get larger, nothing to worry about.

If it gets larger, especially rapidly, it is a bacterial infection, similar to Erwinia. Treat by cutting off the rotten leaf.

Hmm. Hadn't thought of that. How would it get into the leaf, though?

[estación seca]

Pathogenic bacteria are part of the environment. The Erwinia that attack Phalaenopsis are probably on almost all Phals in cultivation, but they don't attack until some factor weakens the plant.

[jkofferdahl]

Originally Posted by estación seca

Pathogenic bacteria are part of the environment. The Erwinia that attack Phalaenopsis are probably on almost all Phals in cultivation, but they don't attack until some factor weakens the plant.

That's kind of where I was going. If it's a bacterial issue - and I still am not of that mind - then either there was an injury on the site or the plant probably has more to worry about than that spot, and may need some TLC. I'm still thinking it just got bumped.

[Orchid Whisperer]

Originally Posted by jkofferdahl

That's kind of where I was going. If it's a bacterial issue - and I still am not of that mind - then either there was an injury on the site or the plant probably has more to worry about than that spot, and may need some TLC. I'm still thinking it just got bumped.

Keep in mind that (1) bacteria are incredibly tiny, an opening that you and I can't see is like an open barn door to a bacterium. (2) leaves are covered with natural openings (e.g., stomata) but also get many microscopic openings from abrasions, creases, insect bites, etc.

The times that I see bacterial infections, there is almost never a visible plant injury associated with it.