I suspect that the problem most likely has been caused by red spider mite, or a different mite. I have sprayed with a Bug Clear Ultra which advertises control of red spider, and purchased a specific miticide in preparation in case of a return of the problem. Some of the tubercles have started to pro...

Four of my Mammillarias started to grow in a spineless, like "inermis", manner, after flowering this summer. In two plants there are signs that the spine formation is returning. Does anyone know what has caused this, and the response to treat it? I have had a few other plants get red spide...

Hi.
I live in UK and NE Brazil (RN).
I have about 150 cacti in UK and about 25 in Brazil.
There are very few cacti available on sale in the small town of Areia Branca, near Mossoro, RN.
Best wishes,
David

The second looks like Echinopsis subdenudata.

From what I could see it looks like serious invisibilis. (Excuse departure for a little humor, pleae)

I have recently come across this link of a building reference to flora in Brazil including cacti, organised by region or state. I am sharing the link as some might also find it useful: http://floradobrasil.jbrj.gov.br/reflora/listaBrasil/PrincipalUC/PrincipalUC.do#CondicaoTaxonCP" onclick="...

A number of my plants growing in Brazil have recently developed a problem, producing a yellow brown discoloration from soil level rising up the base. The plants grow in the open sun for much of the day, that has not scorched them previously, but recently she has sprayed the plants with a fertiliser,...

This is the Mammillaria matudae, bought unnamed, from garden centres and coming from this route, most likely originated via Holland, and my Mammillaria tlalocii from a specialist cactus grower in UK.

Beautiful.

Thank you for sharing. Most interesting.

It will not have had cold damage in my care, (indoor windowsill with some outside daytime spring sun in the garden) and the black was not there on its purchase. Since the same thing has happened with the supplying grower, it seems to have had a common experience with its siblings. Thank you for sugg...

I thought baldianum was red flowered. Is it also white/cream flowered?

These two plants came unnamed from garden centers. The light green plant to the left has flower buds more pointed, rocket shaped tip; the dark green bodied plant has flower buds which have a spherical tip. Both produced white/ creamy colored flowers. Spines not very strong for either.

It could be polythele inermis, although it has a few spines.

I purchased an Acanthocalicium (Echinopsis) thionanthum online a few months ago. It developed a black area from the growing point, but it is not spreading, the new growth is coming from the apex and so gradually the black area is going to move down the plant. No other plants have been affected. At f...