If it was a natural hybrid, you would expect to find it in habitat. They've lumped Lobivia into Echinopsis anyway - whether that was a good idea, I don't know. Maybe genetic studies will result in that being changed.

They're believed to be a natural hybrid - see the first link from DaveW. I don't know if all authorities agree, but it's plausible; natural hybrids are not uncommon.

Yep, really looking good. You getting any germination from the Echinopsis ancistrophora I sent you?

Not a cactus, looks more like a Stapeliad.

Trichoderma is thought to act by weakening the hard shells of the seeds (it eats cellulose). If that theory is right, it wouldn't help with seeds that lack a hard shell.

They're too small to transplant, just mist them.

The "bloom" he means is the waxy coating on the surface that gives it a bluish appearance.

There's evidence that inoculating with Trichoderma fungus improves germination of Opuntia seeds, don't know if it helps with others. Trichoderma is produced commercially as a root rot preventer, because it attacks other fungi - but not plant roots.

It was the random curved spines that led me to speculate it might be M. ernestii.

I wouldn't swear it wasn't a Ferocactus, either. Wait and see; if it forms a cephalium, it's a Melocactus for sure.

I think it looks like a Melocactus. M. ernestii, maybe?

I never brought mine in until there was a threat of frost. Cold didn't seem to hurt, as long as they didn't get frozen.

Looks like your plant needs more light, that's why it's thin and lacks color. Stem cuttings will get you a good-sized start much faster than leaf cuttings, and this plant could use pruning anyway. Cut with a sharp knife - plants that have stems that will snap cleanly can have cuttings taken by break...

Rebutias are famous for blooming young, I've heard of seedlings blooming in their second year. This isn't strange at all.

It does seem to have spread slightly. I guess it really is black rot, but the waxy bloom on the surface made it look blue. There are types of rot that are dry, not mushy. Dry rot doesn't spread as fast as wet rot, letting the plant go dry may even stop it from spreading. I've seen plants that lived ...

Soaps don't destroy the eggs, and have no residual effect - so when you use them, you need to repeat the treatment after the eggs hatch. Imidacloprid has long term effectiveness, the main advantage to using it. I don't know about damage from Safer's, I've never used it - I use Fels Naptha laundry so...