Mammillaria sickness

[Cidermanrolls]

Does anyone know of a sickness that is infectious within a Mammillaria collection?
The collection photo shows my Mammillaria bench and the gaps show quite how many plants I’ve lost this summer. Losses are focusssed on this bench. There have been many fewer elsewhere in my three greenhouses.
Losses affect repotted plants and ones that have not been reported for ages.
The roots of dead plants are not affected by root mealy.
Feeding is light.
Other pictures show two typical dying plants.
Any thoughts?

[Cidermanrolls]

Two of the plants

[Cidermanrolls]

Sick and healthy, side by side

[habanerocat]

I lost four plants this summer and can't remember ever loosing a plant during the summer before. The symptoms were similar and I just put it down to over watering. The ones lost had been potted on recently, so I was guessing I got the mix wrong or something like that. Most of my collection have been potted on recently so it's a bit of a mystery really.

The only other thing I can think of is that I had Red Spider Mite last summer and used a lot of SB Plant Invigilator. I'm not saying it's that either, just throwing it out there as a comparison.

[Phil_SK]

I find that when I get plants ailing a bit like this that it's just some indeterminable cultivation glitch. I'm a bit clearer on how to resolve it, though. Any plant that's struggling gets depotted and the old soil and any fragile roots breaking away. I usually find there's hardly any root (maybe a few woody main roots but no fine/feeder roots) and occasionally I end up gouging the bottom of the stem to get some rot out, but lets hope that isn't necessary! The last of the soil gets brushed off with a toothbrush and the plant left to recover as you might a cutting then potted up into as small a pot as possible in your favourite rooting medium (eg cat litter successor).
Here's a Matucana in a 2" pot and a Gymnocalycium in a 4" pot that had this treatment last year.

mat1.JPG (30.49 KiB) Viewed 1854 times

gym1.JPG (119.01 KiB) Viewed 1854 times

[Ali Baba]

Have you considered a nutrient deficiency?

[Tony R]

Overall, I think the collection is looking rather tired, just like the older parts of my mammillaria collection. Rejuvenation in fresh soil will work wonders, based on the other half of my collection which got dealt with last year.

[el48tel]

Overall, I think the collection is looking rather tired, just like the older parts of my mammillaria collection. Rejuvenation in fresh soil will work wonders, based on the other half of my collection which got dealt with last year.

Think there's much truth in that. I "inherited" a few plants a couple of months ago which looked equally poorly. Fresh compost and a nitrogen fertiliser feed seems to be revitalising them. And before the purists shoot me down, subsequent feeds have been more potassium based.

[Eric Williams]

Hi, the browning could be caused by physiological problems and nor by pests etc. The plants you inheritated may have been stressed previously. Re potting into your particular compost and adhering to your normal cultivation methods will probably sort it out. As Tony said repotting does wonderful things to a neglected ot tired plant. Cheers