I don't think the color is normal (I have several of these), the lower parts of the plant look as if they have been attacked by red spider mites at least once. They usually do not make webs, the absence of webs is absolutely no proof that they have not been there.

It's difficult to say what the orange ring is. Could be another mite attack, or possibly a fungus. Look carefully for mites, to start with. Even if they are dead they should be visible with a magnifying glass.

Stuff on the bottom's just corking as far as I can tell. It was like that when I got it. I'll look at it with a magnifying glass when I get the chance, though. Just curious, what sort of things do you use to treat red spider mites on a cactus?

I have not seen that much corking on such a small plant, but I would need a better picture to make a better guess.

Some kind of miticide. I don't know what you have access to, here we only have mercaptodimetur (which is very efficient). Ordinary insecticides have little effect on them. I also discourage them using chili pepper/garlic extracts with alcohol. They even die if the alcohol level is high enough, but it is almost impossible to kill all of them with it, a systemic miticide is far better.

I found a store that carries a lot of pesticides, so I might check there. Just curious but how toxic is mercaptodimetur? Like, is it okay for indoor use?

It's from Boliva and Argentia I don't know if this will be of any help. Wide spread below the equator, no information regarding soil, or altitude. It treated as if it was an African plant as to giving water, it may not even like high humidity unless it grows in a fog belt high in the mountains. You may not be giving it enough air circulation. Most cacti are dormant this time of the year, and you may need to grow it in pure pumice and where do you live, is the plant inside our grown outside, there are far more pests then mites to worry about, thripe, mealies, fungus gmats, white flies, are not that friendly either. Norma

Rebutia and all it's clan get sunburnt very easily, and the damaged skin can become corked. That's what it looks like to me, but the photo is blurry. These plants do not tolerate heat + sun + poor air circulation very well.

Yours looks like a Rebutia pygmaea - this subsection in particular has a thick, deep taproot and needs a deep pot. A stressed plant (shallow pot, too hot, pH too far from neutral, etc.) will not look healthy.

They are native to the Andes Mountains where the sun is very strong but at high elevations in the clouds it doesn't get too hot and there is always a strong breeze. Temps regularly dip below freezing in the winter. In fact, frosts will encourage a more prolific flower display in the spring.

Re: mites, if you only have a few plants with spider mites, they can easily be treated by submerging the entire pot and plant into a bucket of lightly soapy water for a few minutes. Any pests will drown or suffocate. The plant will not be harmed at all as long as it is actively growing.

x

"Re: mites, if you only have a few plants with spider mites, they can easily be treated by submerging the entire pot and plant into a bucket of lightly soapy water for a few minutes. Any pests will drown or suffocate. The plant will not be harmed at all as long as it is actively growing. "

I usually just do this with my non-succulent plants (or just spray them off in the shower or with a hose, honestly). Problem is, I don't really want to get this thing wet right now, as far as I know.

Tap root's something I didn't know about I'll repot it this summer, although I don't think that's what's causing the rusty colored patch. Unless it would cause that.

Air circulation IS poor, which I imagine could contribute to mites, though.

Poor air circulation contributes to both sunburn and mites, yes. Is the damage located to one side, or is it more evenly distributed around the body?

Soap/horticultural oil emulsions can be sprayed on the plant too, without wetting the soil much. Mites hiding in the soil will survive, of course. Or you could remove the soil first, drench the plant and then let it dry. The pot size looks adequate.

Neem oil is another option.

Hi. Alcaline (basic) growing media can cause these symptoms with Rebutia ,Lobivia and other genera. Use acidified water (add vinegar for instance), pH 5 and add a complete fertiliser (with magnesium and trace elements) at recomended strenght. Usually plants start moving very quickly afterwards, and the results can be quite spectacular.T.

PS In the 'old days', people often used loam-based composts wich were not properly adjusted for pH, or they quickly became alcaline through the repeated use of alcaline tap-water. This often resulted in 'capping'(the appearance of a corky cap on the apex=growing tip) of plants like Rebutias and so on. It was nearly always mis-diagnosed as spider-mite damage.
Nowadays, the importance of pH and proper fertilising are better understood ; hence the tremendous progress in horticulture and the availability of thousands of species of ornamental plants wich were previously considered difficult or even impossible to grow.
Hope this helps. T.

"Is the damage located to one side, or is it more evenly distributed around the body? "

It's sort of in a ring.

"Use acidified water (add vinegar for instance)"

I can do that. Probably not right now, but this summer when I start watering it... unless I should be watering it now? As I said I read they rot easily.

Oh, for reference, I'm not entirely sure what the substrate is but I'm THINKING it's fairly inorganic, which tends to be alkaline, right?

For the time being I'll treat for mites just to be on the safe side

Less likely to be sunburn if it is ring-shaped.

Many inorganic components are alkaline, but if they make the whole substrate alkaline or not depends on the weathering rate (i.e. the mineral types) and the amounts of more acid stuff, like humus. My own cactus soils usually give a pH of around 6, despite being almost completely inorganic.

Okay, I couldn't get any miticide due to the massive snow storms that'd be going on. So, I decided to watch it and see what happened till I got back from spring break (that is, today) because I wasn't really sure if the stuff was there when I bought the plant or not.

Looks like it's getting worse, though. As I said, no miticide, so I rinsed it off in the sink, which'll hopefully help if it's mites. I DON'T think I got the soil particularly wet, judging from pot weight, and the soil's mostly inorganic and drains pretty fast anyway.

Also moved the plant away from the window in case it is sunburn.

Nothing else is showing signs of... whatever this is, at least. I had some mealy issues earlier this year but I don't think that's what's causing this. And I'm not really sure if maybe this problem was pre-existing when I got it and just never noticed it or what.

Just curious, I was under the impression these had a somewhat tuberous root system and tended to offset. If the main body gets damaged, is there any hope for it resprouting from the roots or offseting or something?

Yes, there is a good chance. Well, less so if it is a fungus.