Virus, Fungus, Bacteria, Insect OR ?

[Bikerdoc5968]

I want some help with four of my Phal's that seem to have gotten some kind of illness from ????? I don't know what it is. It seems to cause the affected leaves to become deformed as you can see from Pic 1. It starts out as a lime-green "watery looking" circular lesion, then yellows with a dark center and extends as you can see in the remaining pics. So what is it?????!!!!!!! If anyone knows....thanks. I have placed the affected plants off to the side away from the others in the GH.

[Gin]

I found this on the Mo. Bot. site . the problem may be the first ailment listed .

Leaf Spots
Several fungal leaf spot diseases attack orchids. They usually begin as yellow areas on the leaf undersides, but as they darken the spots are visible on both sides.

Anthracnose <-------
This starts as a sunken, brown, sharply-defined discoloration. Fruiting bodies develop in large numbers on the dead tissue. The causative fungus is Colletotrichum.

Cercospora
This leaf spot disease is caused by numerous Cercospora spp. and starts as yellow spots on the undersides of leaves that enlarge and eventually engulf the whole leaf. Old spots are purplish-black. Leaves fall from the plant prematurely. Once a leaf is infected the condition cannot be reversed.

Septoria
The spots start as small, sunken, yellow lesions on either leaf surface that enlarge into circular or irregular patches. Leaves fall off prematurely.

Rust
Rust is caused by several fungi genera. Orange, yellow or rust brown spore-bearing pustules develop on the leaves. Rust fungi have high reproductive rates, so plants should be isolated.

Other leaf spot fungi include Diplodia, Guignardia, Phyllosticta, Sooty Blotch (Gloeodes), Fusarium, Flyspeck (Schizothyrium)

Here is a link to the whole page .. Kemper Center Factsheet
A picture .. Plant Disease Diagnostics, University of MN

If it progresses and cannot be stopped removing the leaf is an option . First I would try a fungicide , Captan , or even powdered sulfur might work . Maybe someone else can come up with a better one . ... Gin

[Bikerdoc5968]

Thanks, Gin. I have already removed the nasties after taking the pics and have been applying fungicide since I felt it might be same and is about the easiest ailment to start with.

[sunset]

If spots look wet at the border, quickly progress with a bad fragrant, it is sure a bacterial attack.

In the photo, you can suppose the bacterial progression seeing the dark wet area in the border of the spot of the leaf. If it is that, it is extremely contagious. If a drop touches the spot, it can contaminate other part of the leaves creating others spots.

You can save the orchids by several ways. I will not explain how here because, in function of the low of each country, some drugs are legal or not.

[MeOrchids]

When dealing with infections it is often important to not only address the infection, but also the initial cause. This can be due to introduction of a new (diseased plant), improper culture (e.g. too much water/wet leaves, lack of airflow, not enough light/sunburn, poor nutrition, etc.), lack of a reasonably sanitary environment (dead flowers/leaves not disposed of, growing in area which fungi/bacteria can find places to hide or are not cleaned) or a general weakening of plants due to viral infection.

If the cause is not addressed it may be a never ending battle