What disease is this and how to treat?

[moniluhum]

Saw spots on the leaves of this plant but did not realize how serious they were until I took plant out to take a picture of it's bloom. I plan on just cutting off the leaf with the most spots. What else can i do? I have treated the plant with Physon 20 a couple of times.

[ksriramkumar]

They look like scales. Try rubbing them with a cotton/qtip dipped in isopropyl alcohol.

[Carolla]

I finally cured scale on a Phal by spraying it down with isopropyl alcohol a few times. I tried the rubbing them with the q-tip, but found I didn't get all of them that way. If its scale, you don't have to cut the leaves off, you can rub the "crud" off because they are insect type things. Good luck!

[moniluhum]

Carol. So you just used isopropyl alcohol by spraying it down. What frequency did you use? I'm on it, but too late. Cut the nasty looking leaf off. Felt it didn't have a chance.

[Carolla]

First, did you rub them to see if it is scale that would just wipe off and respond to the alcohol treatment? If so and it is, it seems to me that I remember you are to do it once a week to catch the new babies as they hatch. My Phal only had a few of them though, your plant may take more treatments. Worked on my Cymbidium with mealybug too. I couldn't get the q-tips down into the crevices, so just putting the isopropyl alcohol into a spray bottle and wetting it down worked great and is easy too. It does rather smell bad... I'd try not to breathe too much of the fumes.

[Dorsetman]

The first thing to do with any pest is remove it . Much better than trying to kill it by spraying etc ! If its not there, it can't do any damage. Wiping with cotton wool balls dipped in ( even) soapy water would be fine. If using an alcohol no problem ( probably) with phalaenopsis, but on thin leaved orchids cell damage can occur if the alcohol is used without dilution. 50:50 with water would be better. The problem with scale in particular is that they can be stuck quite firmly , so don't necessarily wipe off easily, and that is where alcohol can dissolve the waxy coating and make it easier.