Rusty leaves

[T120]

Hi,
some of my plants have what looks like a rust on the leaves,can anybody tell me what it is and how to cure it!!Thanks

 

[Justin]

That looks like some severe fungal infection. You should cut the infected parts out using a sterilized tool, and dust with cinnamon. Increase air circulation in your growing area. Also check for spider mites.

 

[SlipperFan]

What Justin said, and:
http://homeguides.sfgate.com/causes-leaf-spot-fungus-orchids-32582.html
http://cloudsorchids.com/doctor/dfungal.htm

 

[Eric Muehlbauer]

I'm not sure what causes this disease, fungal or bacterial, but it is something that is more common in the summer. It is disfiguring, but not usually fatal, and the damage usually does not expand to the entire plant.

 

[abax]

You might give Cleary's 3336 a try. It won't save the infected leaves, but new leaves should come out clean.
Cleary's is a systemic fungicide that is used as a drench.

 

[Ozpaph]

looks like leaf damage with secondary infection.
Cinnamon + the above suggestions.

 

[SlipperKing]

Too dry and too warm(too much light) No disease involved. Give the plants what they need water and shadier conditions.

 

[naoki]

I'm not sure about the first photo, but I did get something similar to the second photo on my P. malipoense and P. hirsutissimum when they were too close to T5HO and leaf temp was high. I moved to a cooler location, and it was ok. So what Rick H said makes sense. It is interesting that the area close to the crown (but with a small distance from it) of relatively new leaves seems to show this symptom most even though the tip of the leaves could be closer to the heat source. Also, I stupidly exposed my plants to cold temp (40F) briefly last week, and similar things happened....