What is this black stuff on my phal's leaf?
 

Hi guys, I just got home from work and was making the rounds watering/spritzing everyone and I found this on my phal's leaf along with a clear, oily substance. There is also very obvious discoloration on this section of the leaf.

It was not there last night when I watered it. It is not outside and it is the only one like this. We have had the windows open for the last few nights, as it is getting into the mid-high 60s.

Any idea what this is?

maybe some kind of mite? Or white fly? I know White flies leave a sticky residue on my hibiscus this past winter

This should help, it's really informative, and something you might wanna bookmark:
http://www.houstonorchidsociety.org/...ySueBottom.pdf

Here are the charts that are listed in this PDF, that you can't really read very well.
Pesticides:
http://www.staugorchidsociety.org/PD...rchidPests.pdf

Fungicides & Bactericides:
http://www.staugorchidsociety.org/PD...idDiseases.pdf

EDIT: can u take a pic of the undersides of this leaf? (where the spots are, but other side)

Here is a pic of the back of the leaf, as requested. Still not sure what this could be :(

I'm not sure what it is either and I have never seen this on my phals, although I have seen something similar on other orchids.

I think I see tiny little dark spots that are dented in. correct?

As one member points out, this looks like either mite damage (some mites are so small you can't see them well with naked eyes, I know, sounds crazy, right?) or possible fungal attack.
The fact that this happened over night, I doubt it is mite attack though.

Whether it is mite or fungus, I would wipe out with affected area with rubbing alcohol. At least this will wipe out bugs or spores on the surface.

Then give some time to see if the condition worsens.

then, let's think of some other approach.

I can do that. :) Would fungus leave an oily residue, though? Also, I watered it right before I went to bed (had forgotten earlier in the day) and had the window open - could this be caused by evaporative cooling?

I don't know if it's evap. cooling... It could be. I don't think that fungus would leave an oily residue... Is that what you found? What color was it? A reddish-orange rust kind of color? That would signify mites for sure.

It also kinda looks like mites, except that what's on the top side of your leaf, is what the underside of a leaf infested with mites can look like.... I have had these markings on one of my orchids, a year or so ago, but it was the underside of the leaf, and turned out to be mites. But yours, I'm not really sure... Sorry. :(

I would do what NYC said, and wipe with isopropyl alcohol, on the tops and undersides of all the leaves (maybe be extra cautious, and use a new paper towel for each leaf? Just in case). And keep an eye out for any more damage. The alcohol should keep the mites under control (as long as its not a bad infestation, which I think you would notice if that was the case)

I wish I knew what it was. I have looked thru the links I posted earlier, and didn't see anything, (I had posted the links before I had any time to look).

I also looked and didn't see anything that stuck out at me. Ty though!

Well, oily residue,,,or is it clear little bead like substance that are sticky to touch?

Then, you most likely have mite damage.

Fungus do not usually leave anything oozing out, but bacteria can.

I have watered my phals and other orchids at night and never seen something like that happening overnight. so I wouldn't think that is the cause.

Water lesion shows up as a small blister like bump. Cold damage shows up as mesophyll collapse and looks very bad and easily identifiable. Also, cold damage only comes after being exposed to near freezing temperature.

Your case do not fall into neither categories.

It's definitely an oily residue...like someone rubbed that spot with olive oil. It doesn't drip or anything (that I've noticed) but has a sheen. It has not spread. I rubbed its leaves down with alcohol, so...=\