Is this a fungus on this cactus? - Ask Extension
This orange color is spreading all over my potted orchid cactus. Mostly starting from the tips and moving inward. Is it a rust? How should I treat it?
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Is this a fungus on this cactus? #743605
Asked April 10, 2021, 2:42 PM EDT
This orange color is spreading all over my potted orchid cactus. Mostly starting from the tips and moving inward. Is it a rust? How should I treat it?
Washington County Oregon
Expert Response
Thanks for your question. I'm afraid I can't diagnosis the problem just from this photo. Could you give me a little more information about your Orchid Cactus (Epiphyllum)? It looks like it is outside, have you recently moved it there? Is it getting more sun than normal or exposure to cold temperatures? What type of growing media do you have it in and what type of watering schedule do you use for this plant? Also, how quickly are the orange areas spreading and are they on all surfaces of the affected areas or only on one side? Have you had it a long time? If you could also add a photo taken from a bit farther away to show the entire plant, that could also be useful.
We put it in the garage over the winter and moved it out a few weeks ago. So I'm assuming now this is sun damage. This plant has been in my family since the 1980s. Both my grandmothers and my sister have owned and cared for it. It came to us in not great shape. We trimmed dead branches and repotted. We tried keeping it outside over the winter but it did not do well. So we put it in the garage this winter, but it obviously did not get enough sun. It's big and tough to move!
It does seem likely that your epiphyllum has a case of sunburn or frostburn, possibly both. In my yard in Washington County, we've had several days of bright sunshine interspersed with frosty nights. An orchid cactus that has spent the winter in the garage is not going to like either of those conditions. Since your plant is so large it is difficult to perform the hardening off that most plants need, but perhaps you can give it some protection where it already is. If it looks like it's going to get chilly (below 40 degrees F), try covering it with a blanket for the night. You can also shade it during mid-day and afternoon with shade cloth or even a propped-up umbrella. In the long run, it should be moved to a place where it will get a few hours of morning sun and then some shade or filtered sunlight for the rest of the day.
For the damage that has already happened, wait a few days to see if it is just cosmetic. If it starts turning black, cut those parts away with a sterile knife going back to just outside a joint.
Here's some information from OSU Extension about growing epiphyllum, including lighting and temperature needs and also how to take cuttings if you want to make some little back-up plants from undamaged new growth since you've had it in your family so long. Here's another publication from Arizona's Extension office with good pictures of different kinds of damage to cacti, though not epiphyllum specifically.
For the damage that has already happened, wait a few days to see if it is just cosmetic. If it starts turning black, cut those parts away with a sterile knife going back to just outside a joint.
Here's some information from OSU Extension about growing epiphyllum, including lighting and temperature needs and also how to take cuttings if you want to make some little back-up plants from undamaged new growth since you've had it in your family so long. Here's another publication from Arizona's Extension office with good pictures of different kinds of damage to cacti, though not epiphyllum specifically.
Good luck, I hope your plant recovers!!
