Is my cactus dying? What is wrong with it?

[maisondecactus]

Hi,
My first post here
I have a 10 year old or so Mammilaria elongata which I bought it as a humble mini cactus from IKEA.

A couple of days ago I just happened to check my M. elongata and noticed the basal stems all turned red. A couple of stems fell off. I was worried about the rot and when I tried to take the cactus out of the pot, many of the finer roots just came off and the main one in the centre was intact.

Further more, I noticed there were some red spider mites (yuk!) crawling around the near by cacti. Or at least I think they are red spider mites.

I have attached several photos for your info.

Please let me know:
1) what is wrong with my M. elongata? Could it be cause by red spider mites?
2) how shall I save it? Or is it the end of the cactus?
3) is the red creature in the photo definitely red spider mites? If so what shall I do with the rest of my near by cacti regarding the red spider mites. Is there good product that I can use to protect the rest of my cacti?

Please help!I
https://cactiguide.com/forum/download/f ... w&id=51666
https://cactiguide.com/forum/download/f ... w&id=51667
https://cactiguide.com/forum/download/f ... w&id=51668
https://cactiguide.com/forum/download/f ... w&id=51669

[hegar]

Well, this is not an easy one to figure out. I have never seen that kind of discoloration on the lower part of the cactus stems. It does not look like "corking" and might indeed be caused by insects or mites. However, the image of the red mite is not focused enough and does not show the details necessary to figure out what kind of mite it is. Mites (if immature) do have six legs, while mature mites have eight legs like spiders.
In addition to having a red color, your mite pictured seems to be rather large. When you saw it move, did it move at a - for a mite or insect - brisk pace? There are large red mites around, which are predaceous and would be feeding on other mites and small pests. The red "spider mite" is not uniformly red like your specimen. Perhaps someone else on this forum has had a discoloration like this happen to her/his plant(s) and has an idea what the cause of this condition was. Overall, your plant does not look to me like it is on its way out yet. If the problem is indeed one that is caused by mites, you most likely will need to use a chemical pesticide (miticide) to combat the infestation.

Harald

[maisondecactus]

Thank you so much for your reply.
Yes the red mite moved quite quickly. And then I also saw a light beige mite as well which I thought was the same one but younger or something,
Will get miticide just in case and also repot the cactus. Currently it is bare rooted. It only has the main thick roots and lost the finer ones (just came off naturally when I took it out of the pot.

If anyone has any idea about my cactus above, please feel free to reply. I hope it won't die!

[greenknight]

I would take some cuttings from above the discolored part, just in case. I have seen cacti turn that color when they're rotting, though other kinds of stress can also cause that.

[esp_imaging]

Some plants tend to go a bit pink if stressed from lack of water.

It looks as though your compost is soaking wet. This can cause the roots to die, which then means that the shoots can't actually absorb any water and start to dry out. Stress can also cause plants to tend to shed shoots.

So, I'd repot in compost with a lot of grit, perlite etc in it to improve drainage, make sure the post has holes at the bottom to drain excess water away and only water once dry. Cuttings of M. elongata can root very easily if you give them a few weeks.

[maisondecactus]

Thank you for the replies!
The pot was very dry so I watered it quite liberally very recently. It could have turned pink due to lack of water than suddenly too much water and gone the other direction! Oh dear.
Yes I will report it with lots of grit. I will also take some cuttings just in case th large one doesn't survive.
Fingers crossed it will be ok! So glad I posted on the forum. Thank you. Will post update in future.