Large cactus- HELP! Cosmetic damage or sick?

7 years ago

last modified: 7 years ago

My neighbor passed away and I was given some of his cacti. This one is about 4' tall. Is the damage cosmetic? Or does this cacti have a problem that needs to be fixed ASAP? I don't know how long it has looked like this. Any help is appreciated.

It does not feel mushy. I know it was in a sunny, south/west facing windowsill. I have 1 other cactus (roadkill cactus) from his apartment, so it was in similar conditions, and also has some brown spots. I've added that photo at the end. Note in the 3rd photo there's a closer look at where I assume the top got knocked off from his relatives cleaning out his apartment- but it looks healthy on the inside, no visible rot.

ID: is this a San Pedro or some kind of Trichocereus?

Featured Answer

Kara 9b SF Bay Area CA

7 years ago

last modified: 7 years ago

It’s hard to say what the specks are without seeing them. If they’re hard to scrape off and you end up taking bits of the cactus as you scrape the “eggs” off, then it’s just scarring or scabs on the cactus.

This pic is from Google.

Spider mite eggs

The reason why I suggest cutting has nothing to do with the scarring, but more because of the weak etiolated growth. That growth no matter how much sun you can give it will never go back to normal. What will happen is when you do give stronger sun the cactus’ new growth will look how it should, chubby and compact. If the etiolation was only on a small section of the cactus it wouldn’t matter much, but the weak growth is massive on the tallest one, and the cactus will become top heavy. I‘m guessing over time with strong top growth and skinny middle growth the cactus will snap or bend.

I found a pic online to show what I’m talking about.

Your cactus that’s already cut will grow off shoots like the one above, and may not need to be cut. The really tall one is the guy to watch out for. I’m just letting you know so you can weigh out your options. My persoral opinion is I think they would look better cut, but they’re yours and not mine;).

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Comments (6)

Rob Blomquist
7 years ago
That last picture makes me wonder if it's a mega-etiolated Opuntia.
Dabney S thanked Rob Blomquist
Kara 9b SF Bay Area CA
7 years ago
last modified: 7 years ago
From what I can tell the top cactus is an extremely etiolated Echinopsis pachanoi aka San Pedro. It needs to be cut and hopefully you will be able to give it stronger sun. If not the growth will be the same.

I would cut around here.

Not sure what all the damage is. Who knows tbh;). Probably wasn’t living its best life and is scarred up from something. I don’t see any visible pests, but definitely keep away from your other plants for a month or so. Keep your eye on it. I’m guessing you live on the northern hemisphere so now would be a great time to cut and repot if the soil is bad. When you do cut, do it at a slight angle so water won’t pool. Keep the fresh cut dry while it calluses. You could sprinkle a little cinnamon on the fresh cuts because it acts as a natural fungicide, but if your environment is dry don’t worry about it;).

Your Consolea rubescens/Roadkill cactus are getting nice and big. They’re beginning to get a “trunk”. What are you going to do when they turn into small trees;)?
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Kara 9b SF Bay Area CA
7 years ago
I wonder if all the scarring is from the cactus’ weak growth constantly bending. So then the cactus callused over to keep it strong. Just a thought;).
Dabney S
Original Author
7 years ago
Oh interesting thought! I just did further inspection- there were about 7 thrips at the very top of the cactus. Killed those. I used a Q-tip with a little bit of isopropyl alcohol and wiped down the cactus in those brown areas and I don't see anything other than tiny brown/red dots. Under a magnifying glass it still just looks like a tiny speck of something. Is that what a spider mite egg would look like? I used watered down neem oil and wiped off a lot of the cactus to be safe. I'm really hoping to avoid cutting the cactus where you suggested, so I'll wait to see if it gets worse over the next few weeks. If it gets worse I'll go ahead and cut as you suggested. Fingers crossed!
Dabney S
Original Author
7 years ago
Thank you so much, this is really helpful. I appreciate you taking the time to explain this and lay out options! I see what you're saying now about the etiolated growth- it's not an aesthetic issue, it's that it won't be stable if it starts to get big/normal growth again. THANK YOU again.