Evil Genius

Spidermites are hard to treat and you need an Acaricide to kill them for good. Make a quick Google to find a few pesticides. Personally I spray my plants with 70% alcohol and it usually reduces problems to a minimum. It doesn't kill them entirely, but it reduces their populations dramatically. Can cause burns though, so never do it in full sun.

Hard to identify. Could be something like Trichocereus pallaralensis and Chavin de Huantar. Very spiny Peruvanoids that almost look like Trichocereus bridgesii. Definitely not Trichocereus cuzcoensis because the spines are so different.

It's really borderline. Personally, I think it'll probably progress in the lowest part because you can already see various infected spots. Cutting brings other risks though because it opens wounds for the pathogens. I would probably cut, but it's a thin thin line.

Hi mate, same to you and all the rest of the SAB crew. It really was a crazy year, so let's hope it gets better. Bye Eg

Imo this is a fungal infection that has partially healed, but the problem is that you have no idea what's going on below the skin. Cutting is probably best.

Yes, merry Christmas from me too. Hope you guys have a great time with your loved ones.

I've sown this cross too. It's one of the crosses I am most thrilled about.

All three probably have a Terscheckii like Trichocereus as one parent. Can definitely see similarities to something like Trichocereus validus in 1 and 3. Number 2 could be something like Trichocereus atacamensis, Trichocereus pasacana etc. When breeders put all fruits and seeds from one plant into the same bag, this can be the outcome. Definitely interesting though.

Hi guys, here's some photos of a plant that was described as Trichocereus fabrisii. It is a slightly more columnar version of Trichocereus schickendantzii.

Hey mate, I wouldn't worry too much about mushrooms. Just remove the fruiting body aka the actual mushroom and leave it at that. Mushrooms and mycelium are everywhere in nature and they usually dont kill cacti directly unless they produce toxins. If you mean something like cobweb then the approach would be to remove the starting point and dry it out. But again, only in case of having a spiderweb like mycelium growing all over the container and the seeds.

Hi mate, yes, Trichocereus peruvianus or Trichocereus macrogonus depending on the system you use. Very nice!

Hi mate, super nice Trichocereus terscheckii. Very close to what's commonly referred to as Trichocereus validus. Totally love it.

Hey mate, it definitely happens relatively often on Trichocereus after injuries and insect attacks on the meristem. But yeah, can't really speak about hiw it is with Astrophytum. Pics?

Wish I could help, but have no idea. Could be something like Crassula.

Hey mate, these belong into the Trichocereus spachianus group. There's quite a few forms and related species that belong to it. I don't think it's the well known Trichocereus spachianus clone that's around, but it's certainly close to it. Please post flower photos when it flowers. Bye Eg