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Black substence on my cholla.

Posted: Sun Jul 10, 2022 4:42 pm
by 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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Re: Black substence on my cholla.

Posted: Sun Jul 10, 2022 7:56 pm
by Tom in Tucson
If it's mildew you should find a new atmosphere to grow it with less humidity

Re: Black substence on my cholla.

Posted: Sun Jul 10, 2022 8:19 pm
by Lactus
Tom in Tucson wrote: Sun Jul 10, 2022 7:56 pm 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?

Re: Black substence on my cholla.

Posted: Sun Jul 10, 2022 9:49 pm
by Steve Johnson
Lactus wrote: Sun Jul 10, 2022 8:19 pmIt 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.

Re: Black substence on my cholla.

Posted: Sun Jul 10, 2022 10:21 pm
by Lactus
Steve Johnson wrote: Sun Jul 10, 2022 9:49 pm
Lactus wrote: Sun Jul 10, 2022 8:19 pmIt 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

Re: Black substence on my cholla.

Posted: Wed Aug 31, 2022 4:49 pm
by tylerthecactusman
Steve Johnson wrote: Sun Jul 10, 2022 9:49 pm
Lactus wrote: Sun Jul 10, 2022 8:19 pmIt 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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