Paleo, I have seen that before, caused by high temps and moisture. I would just remove the damaged leaves. Can you give us a link to the Face Book page?

The page on facebook as far as I know deals mostly with another type of fungus, the one that attacks in blisters, Endophyllum sempervivi.
That photo is straight from their website like I mentioned in my post.

I am not sure what to say about high temps and moisture, other leaves just dry out nicely and do not turn to mush like a rotten apple.
Maybe this discrepancy is not random but pathogen influenced.

Necroing this old thread with bad news:

I have a very mature colony of what I believe are sempervivum on my west-facing stone wall in Portland, OR, USA. The wall/colony is probably 3ft tall and 8 feet long. It is completely infested with endophyllum sempervivi this spring. Do I need to remove all of it? I seriously wonder if the stone wall would survive this, as the colony is at least 15 years old. It is also on plants elsewhere in my yard. Should I attempt a fungicide treatment?

Any help is appreciated, thanks.

Hi Pdxthings, and welcome to NGA.
I am really sorry to hear about your wall of S. tectorum being infected with endophyllum sempervivi. I am afraid the only solution is to remove everything. Do not add it to a compost pile, put it in bags and add to your trash can, not the yard debri bin.
You can harvest any rosettes that look healthy, pot them up in new soil, and keep them isolated. I think I would first harvest any that look perfectly healthy. Then go about removing and disguarding the rest. Clean all debri, you can even remove a couple of inches of soil. Let the area sit for about a month. Ad new compost and replant the area. I found a wonderful source for the most amazing compost, Premium Mix, at a local landscape supply here in Oregon City. Not sure where you live?

When you are ready to plant please send me a treemail. I have several hundred rosettes you can have to get the area planted again. They are a mix of sizes, shapes, textures and colors.

I'm more curious than anything. Has endophyllum sempervivi been seen in the US before? I haven't seen anything about it here in the states before Pdxthing's post.

Nathaniel, apparently this has been in the US for some time. This article was published in 1917. The origins of the infected plants were traced back to Holland. Scroll to page 85.

2021 article. https://www.agaveville.org/vie...

It looks like it does have a know presence in the US. We all need to be aware, and watchful. Isolate all incoming plants until you know they are healthy.

Thank you for your question Nathaniel.

Very scary.

I am interested in plant pathogens, although I don't think I want to mess with this

@Pdxthings How is the wall of sempervivum doing? Have you decided what you are going to do?