Black substence on my cholla.

Trouble shoot problems you are having with your cactus.
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Lactus
Posts: 92
Joined: Wed Feb 02, 2022 4:58 am
Location: Humboldt CA Zone 9

Black substence on my cholla.

Post 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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Tom in Tucson
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Joined: Sun Jan 02, 2022 4:12 pm
Location: NW Tucson AZ area

Re: Black substence on my cholla.

Post by Tom in Tucson »

If it's mildew you should find a new atmosphere to grow it with less humidity
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Lactus
Posts: 92
Joined: Wed Feb 02, 2022 4:58 am
Location: Humboldt CA Zone 9

Re: Black substence on my cholla.

Post 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?
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Steve Johnson
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Joined: Thu Nov 03, 2011 4:44 am
Location: Los Angeles, CA (Zone 10b)

Re: Black substence on my cholla.

Post 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.
If you just want photos without all the blather, please visit my Flickr gallery.
My location: Los Angeles, CA (Zone 10b)
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Lactus
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Joined: Wed Feb 02, 2022 4:58 am
Location: Humboldt CA Zone 9

Re: Black substence on my cholla.

Post 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
tylerthecactusman
Posts: 2
Joined: Mon Aug 29, 2022 11:20 pm
Location: Los Angeles, CA (Zone 10b)

Re: Black substence on my cholla.

Post 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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