Orange on a Cactus? Not so Good.
Hi Hap and Co.,
My beautiful barrel cactus has developed orange areas. Mostly they’re along/near the ridges, although there are some small spots further down. This side of the cactus does have some past scarring (from frost I believe). Is this orange a treatable thing? Will I lose the plant?
It looks like a form of “Rust” (a fungus). I recommend you treat with Neem Oil, a natural fungicide that works well on cacti and succulents. You can spray it on in a 1-2% solution once a week, for three treatments and it should take care of it. There may be some long term scaring where the fungus is, but usually if it is treated quickly enough it heals up and is not too disfiguring. Like all oil treatments don’t spray on a hot sunny day, only spray in evenings or on overcast days so there is no chance of the oil causing sunburn.