Euphorbia mammillaris 'Variegata'

@sherrisgarden I finally remembered to clean this guy up a bit and snap a pic. 😅 No pink blush to speak of this winter, but there's that orange crap, creeping higher and higher up the stalks! 🤷🏻‍♀️

Your plant is much larger than mine. Jealous. Is there a drastic change from day time vs night time temperatures ?

#euphorbscanlooklikeanything

@sherrisgarden it started as 3 stems each about 3" tall when I got it in 2017, so I've had it for a minute. 😆 If you separate the arms off yours and root them next to the parent plant then you'll get a way bigger bunch much faster. Temperatures have been 50ish at night and 70ish during the day, but the orange stays no matter the temps, so it doesn't seem to be stress. It seems excessive to be corking, so I've been worried that it's fungal rust.

@sunlovin I was thinking rust, too! Do you have any experience with it? It hasn't seemed to spread to any of the plants immediately near it. The only course of action I've seen for such an extensive case is to toss the plant, which I'm totally NOT doing! 🤣

@sunlovin actually nevermind, maybe. After looking it up again rust seems to be more spotty and random than this..? 🤔 Idk! 🤷🏻‍♀️

@sunlovin aw, sad! What kind of Opuntia is/was it? If it's perceptibly spreading then it's probably better safe than sorry. I closely inspect all the surrounding plants regularly and haven't seen this spread to anything else. I've read that even if you start a clean cutting the fungus is already in the plant's system, like you said, and it'll become problematic again.

It’s in a Joseph Coat. I’ve read it will affect new leaves more and it was right. It’s more prevalent in spring.

Impressive. An oldie for sure 😉

@sunlovin aw! I guess at least it isn't a rare cactus..? ☹️😬

So what's the answer @beatnikcrab ? Neem oil or cinnamon or copper dust or what?

@emch all of the above are noted as treatments for it. Daconil fungicide also seems to get high marks as a treatment option, and it's probably the one I'd use, since this is neither an edible plant nor a popular one with pollinators (not sure if they'd be affected by it anyways). No treatment option would reverse the damage, though, and it seems like everything would just control the spread rather than actually eliminate the fungus. I'm not even sure if this actually IS rust to begin with, as ⬇️