Question
Hi Wayne, I am writing to you given that I have found some white stuff on all my orchids which I am not sure what it is; it looks like residue left behind from the watering, but I thought I would write to you to get your opinion.

The stuff feels like powder to me and is on all my orchids (cattleyas, phals, etc.).

To make sure it is not a fungus, I treated them with a fungicide last weekend and also cleaned up the leaves.

I have taken several pictures to give you a glimpse at it,
http://www.caripito.com/images/orchids/IMG_1422.JPG
http://www.caripito.com/images/orchids/IMG_1423.JPG
http://www.caripito.com/images/orchids/IMG_1424.JPG

Thanks!
Angelo
Orlando, Florida

Answer
Angelo, the photos are not real distinct. Now that you have cleaned the leaves, you will be able to determine how long the leaves stay clean. I cannot determine from the photos whether or not there is leakage of plant sap which would make the leaaves sticky in spots.  Sticky leaves would suggest the presence of a plant parasite such as a type of scale (there are many types).  The small white spots are not distinct enough in the photos to determine what they are.  I assume the photos were taken before you cleaned the leaves.  If so, they don't look like hard water spots.  Hard water spotting would tend to cause the leaves to look like the pot (which has hard water deposits).  Hard water would tend, over time, to form a milky film on the leaf surface and I don't see that. See if it returns , how long it takes and look for the leakage of plant sap.