I'd begin to collect Blossfeldia though...

Cereus peruvianus f. monstrosa

... Malacocarpus/Wigginsia's are close to Notocactus with similar flowers but usually have more pronounced ribs. And long soft fruits -> hence Malaco - carpus . Jorge, Parodia was named after a person called D. Parodi. ... Domingo Parodi, fue un naturalista y farmacéutico italiano, activo en Sudamé...

Thank you DaveW... First time I've heard about Malacocarpus genera :shock: I prefer notocactus, parodia means in Spanish parody, and I don't like that for naming a plant :mrgreen: Regards, Jorge Malacocarpus = Wigginsia I also prefer Notocactus, Eriocactus, Brasilicactus and Wigginsia because there...

M. bravoae?

I never spray cacti because they aren't orchids neither bromeliads, no practical use at all.
I water them when they are moved to greenhouse and temps are high enough, never give them "some drops" but good amount of water. Better later and much than earlier and little.

Nyctocereus serpentinus f. cristata??
Mammillaria haageana/elegans? geminispina? crucigera?

According to my own experience it's very effective with monocots.

Some beautiful hybrid Echinopsis eg Cabaret, Temptress, Antares, Firelight etc

I know that Roundup kills it very effectively so you only need not to spray but use small brush and put small amount of Roundup on grass stems and leaves. It will kill all rhizomes also.

Echinocereus reichenbachii subs. armatus?

Very nice positive picture, many thanks for sharing!

Hola! I never do it, because substrate always contents some amount of debris that's why no sence.
It is not aquarium.

I'd spray with some systemic insecticide x2 within 2 weeks and also give it as solution in substrate once.
E.g. Provado/Acetamiprid.

S. steinbachii? taratensis? Better to see with flowers, they flower in very early age.