Is this fertiliser burn?

[OrchidLoverSA]

Hello all, this started out as a couple of small white spots on the new growth. At first I thought it was scale, but on closer inspection I couldn't find any critters. Still, I wiped the whole thing down with surgical spirits. Now the white spots have turned into a white blotch (see pictures). The only change in culture has been weekly fertiliser instead of every second week. Could that be it? Some of my other orchids also have small white spots on the new growths.

http://www.orchidboard.com/community...py-phrag-2.jpg

Oh, and it's culture is as follows: Hot, humid, bright light, standing in a tray of tap water (tap water is very orchid friendly in these parts).

[euplusia]

Orchids deposit a fertilizer overdose in the leaf tips, so this is very unlikely. Can't tell you the reason of the original discoloration, however alcohol used for medical desinfection may have caused plant cell demolition. It is designed to kill virus capsids and cell walls of bacteria and fungi.

[tucker85]

Do you have very hard water in your area? The first pictures look a little like hard water mineral deposits. I'm not sure what kind of orchid that is but if it's a phrag, some of them are sensitive to water quality. Some phrags need high quality water, like rainwater. With most other orchids it's not as important.

[NYCorchidman]

As mentioned, fertilizer burn is very easy to identify as it will show up as leaf tip burn in nearly black tips.

One of my paphiopedilums ( white complex) also shows some small white patches on the underside of some leaves. I have no clue what it is though.

[OrchidLoverSA]

Thanks all, I don't think it was due to the surgical spirits, I use it on all my plants and this is the first time it's happened, but I'll stop using it on this specific plant until I'm sure. And yes, I forgot to mention that it's a phrag. I've had it for three years now and it's never complained about the water before... The other phrags. I have all look perfectly normal. It's strange though, apart from the funny colour, the new growth seems perfectly healthy. And I'm sure it's not sun damage, what do you guys think?

[Optimist]

Look up images for orchid leaf viruses. This light coloration looks like a virus. Is it possible you bought a new plant with a virus?

[OCRC_Dir_China]

A good magnifying glass helps allot, when inspecting orchid plants for problems.

[theroc1217]

The brown definitely looks like mineral build up. The white spotting may be a response to that.

[OrchidLoverSA]

Not a month goes by that I do not buy a new plant, but this oldie is the only blotchy one though. I'll look up viruses though, thanks for the suggestion!

[Orchid Whisperer]

You can't really diagnose viruses by appearance alone. If this blooms and the flowers have some malformation or color break, then I would be more suspicious of virus, but the only way to know is through virus testing.

OrchidLoverSA:
The white line on the leaf does look like hard water deposits. The white splotches - not sure. Has there been any light change/ gotten any brighter than usual? I always think sunburn when I see white blotches.