Hello! I've been inspecting my 8 years old cactus and noticed some brown spots (which I assume are spider mites?) and I thought it was corking at the base, but the base seems soft (softer than the green part).
I got it a year ago and repotted it in a well draining soil, I also water it very seldom..
What do you think it is and what should I do?
Thank you so much in advance!

In your first picture can check what the 3 joined spots are in between the ribs - right in the center. It almost looks like they are some scale insects, but the picture is not of high quality enough.

As to the brown area of the plant near the roots: soft or squishy? And when did you water last, and where do you keep the plant light/temperature wise?
Soft does not have to be bad, squishy is almost always bad. Outwardly what you have photographed does not look too alarming. There could definitely be something going on with the plant health wise, but what you can see in the picture does not immediately scream rot, however there are plenty of bugs that may not make the plant rot, but still be affecting its healthy negatively.

mcvansoest said:In your first picture can check what the 3 joined spots are in between the ribs - right in the center. It almost looks like they are some scale insects, but the picture is not of high quality enough.

As to the brown area of the plant near the roots: soft or squishy? And when did you water last, and where do you keep the plant light/temperature wise?
Soft does not have to be bad, squishy is almost always bad. Outwardly what you have photographed does not look too alarming. There could definitely be something going on with the plant health wise, but what you can see in the picture does not immediately scream rot, however there are plenty of bugs that may not make the plant rot, but still be affecting its healthy negatively.

Thank you so much for your reply!

I don't think it's scales, because I've inspected the plant with a magnifying glass and there's nothing moving or showing, besides very tiny red dots.. However I have a couple of other succulent infested with mealybugs (ugh!), that I'm treating with rubbing alcohol - but they've never been close to each other and I haven't seen any mealybugs on this one.

I pinched the cactus and it would definitely take a lot more than just pinching to squish it, but it feels softer in the brown area.

I don't even remember the last time I watered - it must've been at least 3 weeks ago. For now I keep it indoors and it gets light, but it's not next to the window.

I'll attach a picture of the roots, maybe it can reveal something.

Thank you again for replying!

Hi Please my Christmas tree cactus is white something like white powder I think is probably dead soon or later if someone have idea what the problem is thank you

To @goldenhourpictures...

What roots? There's your problem - for some reason, your cactus has no roots, either because of too much or too little water. A plant with no roots can't absorb moisture.

Yeah Daisy is right, not enough roots for the size of the cactus. How does the root mass compare to what it looked like when you repotted it? These kind of cacti normally make quite a large mass of roots. What is there looks relatively good, so it should be able to recover. You said you watered it last 3 weeks ago how was the soil when you took the plant out of it. Completely dry or still moist?

The green part of the cactus looks surprisingly good for a plant with so little roots. If the soil was quite dry after 3 weeks I think you might be able to water it somewhat more frequently as long as the cactus is fairly warm and you provide it plenty of sun light.

@Vlasta for this kind of thing it is probably better to start a new thread. I think it is likely some kind of fungus due to the plant being wet and relatively cold with very little to no airflow. You might be able to save the unaffected plants - unpot it all remove the affected plants and clean the remaining stems with soapy water try to get as much of the soil off and then repot in fast draining soil then provide as much light as possible and do not water the plant unless the soil is completely dry, if at all possible try to provide some air circulation around the plant.

I also thought that was weird when I got it and repotted it - very small roots compared to my other cacti and ever since I repotted it last spring it looks like they shrunk even more.

When I took it out they were completely dry.

Hi Please my opuntia cactus have something on the bottom I don't know 🤔 what is it. I hope 🤞 is not bugs 🐛 like the Christmas tree cactus 🌵 the cactus is dead thank you for the help

Hi! My 4 year old cactus has shrunk and is turning brown at the bottom. I left it outdoors since summer (I live in Northern California, it gets down to 45-50 at night and we also had a rainy week 2 weeks ago), it also became soft to touch. Can this be due to cold or underwatering? I checked for bugs, but didn't find any. Is there any way I can help it? Please help us!

goldenhourpictures said:I also thought that was weird when I got it and repotted it - very small roots compared to my other cacti and ever since I repotted it last spring it looks like they shrunk even more.

When I took it out they were completely dry.

I have a feeling that your cactus ever had root rot, but it somehow healed and currently growing new roots

Your cactus is Mammillaria spinosissima 'Un Pico'. It may have gotten too cold and too wet but hopefully once inside for the winter it will survive. Keep it warm and go easy on the water. Where ever you had it outside, it wasn't getting enough sun.