Round Rings of Fungus?

[orchidkaye]

These rings have been showing up on multiple orchids in my collection. Can anyone help with this?

[Bud]

Its fungus alright....notice the yellow rings around the dark spots.
Sterilize your scissors and cut the affected part, and dab the wound with cinnamon paste (water and cinnamon powder)
Due to moist and warm weather ....or droplets of cold water reacting to the sun makes dark spots that fungi likes to infest....sometimes sucking insects bore holes that fungi can get into....
makes sure not to wet leaves or dry them with paper towels....
spray healthy leaves if you have physan20 as a sterilizer and preventive measure

[orchidkaye]

Thank you, good grief, between the fungus and the grasshoppers I might not have a collection after the summer.

[HighSeas]

Ooooh I SO hate grasshoppers! KILL THEM! KILL THEM! KILL THEM!

[tucker85]

I certainly could be wrong, but it looks more like sunburn to me. Are these orchids getting stronger light than they're accustomed to?

[Ray]

Tucker, wouldn't burning be more uniform?

To me, the concentric circles suggest a wound, begun by a sucking insect, that got a subsequent infection.

[gnathaniel]

I agree this is probably sunburn followed by localized tissue death, I've induced enough in my collection to be pretty familiar with it. Sunburn can vary dramatically among adjacent growths, probably due to environmental variables like angle to the sun, minute variations in air movement, age and nutrient load of the particular growth, etc. There's a threshold beyond which plant tissues are unable to cope with environmental stress, so anytime conditions are in the marginal zone you're likely to see idiosyncratic results like this-- again speaking from personal experience, minor frost damage can manifest in similar ways.

[james mickelso]

Anthracnose would be my guess. Staugorchidsociety.org. Look it up.

[tucker85]

Here are some pictures of sunburn.

Images of Sunburn on Orchids

[Vanda lover]

My first though was sunburn as well. I have an onc that has a patch on it's leaf which appeared at the same time that the sunlight intensified. It isn't spreading.