Mesophyll cell collapse or fungus or what?
 

Hey! I have a question about an orchid that I got a while ago. It was like this when I got it, and the marks don't seem to have changed or grown.

I'd like to put it on the heat mat with the others, but I won't if it could be contagious.

There are two sets of marks, and the ones circled in red are the ones that have me worried. The purple ones I am pretty sure are cosmetic damage.

http://www.orchidboard.com/community...-whatsthis.jpg

The round indentations. Is that mesophyll cell collapse, possibly from cold, or fungus, or what?

Whatever it is, mechanic damage or damage from low temps and/or nutrient deficiency - it doesn't look dangerous or contagious to me. Please check the underside.

I've had similar looking areas that did not spread. Keep a close eye on it, if it spreads then remove the leaf. I'm afraid I don't know the cause.

From the photo, I can't tell if the areas are raised or sunken.

In mesophyll collapse, one can often see the intercellular "veins" forming a grid-like pattern.


Ray Barkalow
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It doesn't look like either fungus or cell collapse. When there's a mark on top of the leaf, always check the underside of the leaf. That's where critters like to hide. My guess is that it's just some kind of deformity in the cells of the leaf. I don't think it's anything to be concerned about.