Black substence on my cholla.

[Lactus]

Hello. So I discovered this black substance on my Opuntia fulgida v. mamillata. I think it might be a fungus. Any tips on how to get rid of it would be great.

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[Tom in Tucson]

If it's mildew you should find a new atmosphere to grow it with less humidity

[Lactus]

If it's mildew you should find a new atmosphere to grow it with less humidity

Oh yeah! It does look like mildew. Any way to clean it off or just let it dry out?

[Steve Johnson]

It does look like mildew. Any way to clean it off or just let it dry out?

Actually, that's called "sooty mold", and it's a problem when we're growing some Opuntioid species in a humid environment. Good news is that sooty mold is a bit unsightly, but by no means life-threatening. The humidity in my part of L.A. is on the high side, and whenever I see sooty mold on the extrafloral nectaries produced by my Tephrocactus inermis, I just let it dry out.

[Lactus]

It does look like mildew. Any way to clean it off or just let it dry out?

Actually, that's called "sooty mold", and it's a problem when we're growing some Opuntioid species in a humid environment. Good news is that sooty mold is a bit unsightly, but by no means life-threatening. The humidity in my part of L.A. is on the high side, and whenever I see sooty mold on the extrafloral nectaries produced by my Tephrocactus inermis, I just let it dry out.

Oh great! Thanks for the info

[tylerthecactusman]

It does look like mildew. Any way to clean it off or just let it dry out?

Actually, that's called "sooty mold", and it's a problem when we're growing some Opuntioid species in a humid environment. Good news is that sooty mold is a bit unsightly, but by no means life-threatening. The humidity in my part of L.A. is on the high side, and whenever I see sooty mold on the extrafloral nectaries produced by my Tephrocactus inermis, I just let it dry out.

I am in LA as well and close to the ocean. Reading your post I suspect this guy of mine has same issue so I am going to make sure it gets nice and dry.

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