What is this??? Phalaenopsis leaf damage - Orchid Board

rachel.gazelles · #1 02-01-2012, 07:20 PM

When watering one of my phals this morning, I noticed some strange spots on the underside of one of the leaves, then when I lifted up the leaf under it, it was just COVERED in it. I don't know how I haven't noticed this before, but it was on the end of my shelf and the only plant next to it is an oncidium that isn't showing any sign of trouble. Those two leaves are the only ones affected. I have isolated the plant, but it's really freaking me out. What could this be? And should I be worried about all my orchids??

Leafmite · #2 02-02-2012, 12:25 AM

I can't really see it very well but is it spider mites or scale that you have found? Hopefully, someone else can see the pictures better and let you know what it is.
Leafmite

---------- Post added at 12:25 AM ---------- Previous post was at 12:20 AM ----------

Okay, it doesn't look like scale. Does it rub off with cotton dipped in alcohol?

silken · #3 02-02-2012, 12:27 AM

Is it raised or sunken?

rachel.gazelles · #4 02-02-2012, 01:12 AM

Hi Leafmite and Silken, thank you for the replies. I took closer pictures, with both the flash on and off to try to show the detail. I also noticed it is on a third leaf, all on the same side of the phal. The other side of the phal seems fine though.
It is sunken in, to the point that when held up to the light, I can see the little veins in the leaf. Also, it does not rub off with anything.. And the top side of the leaf is unaffected, only the under side has this problem.

silken · #5 02-02-2012, 01:23 AM

It could be cell collapse which is often caused from the plant being badly chilled or watered with cold water. But I would think it would be on the top of the leaf also. Never really seen anything like it. I would be very careful not to touch your other plants after handling that one.

The other thing, but again it looks a bit different, is a virus or bacteria, not sure what that causes a cell collapse in Phals and spreads very quickly to others. I and several others I know have had this problem. But again, ours shows on the top of the leaf.

Maybe someone else can comment. If the plant is healthy otherwise and has other clear leaves, I might be tempted to get rid of those leaves. If you do, cut with a sterilized blade and remove all of the marked parts. Then seal the cut ends with a bit of cinnamon or sulfur powder. Make sure the blade you used is not used on anything else unless sterilized.

Gage · #6 02-02-2012, 01:35 AM

When I have seen this type of sunken patches on the underside of a Phal it has been mites.

camille1585 · #7 02-02-2012, 05:12 AM

Looks like it may be an extreme reaction to mites rather than cell collapse, which it doesn't look like at all if the top of the leaves are fine.

rachel.gazelles · #8 02-02-2012, 10:17 AM

Looking at pictures, yes it does look like mite damage. I dont see any mite or webbing on the actual plant, but sometimes could they be too small to see? Do I need to throw away the plant? How can I check to make sure my other orchids don't have it

camille1585 · #9 02-02-2012, 10:23 AM

Take something white (papertowel, tissue...) and wipe the underside of the leaves with it. If you seen any reddish spots on the paper, then you've got mites. That's the easiest way to check.

rachel.gazelles · #10 02-02-2012, 10:50 AM

Aww, when rubbing a paper towel on the Phal, it is covered in red spots. I think I'm just going to have to throw the plant away rather than risk passing them around. I'm glad this isn't one I'm terribly attached to. I suppose I will have to go through my whole collection with a paper towel to make sure I don't have any more.
Thank you all so much for your help. Its nice to get individual special help from experts!