Blue torch black spot.

[Jtwrigh]

Noticed a couple of small black spots on this guy. Any idea what could be causing it? Thank you

[anttisepp]

These guys are very sensitive to cold air, m.b. cross-draught?

[Jtwrigh]

Interesting. Never thought of that being an issue.

[Steve Johnson]

Interesting. Never thought of that being an issue.

Please see this note to new members:

viewtopic.php?t=43819

Since it appears that you're keeping your blue torch in the house, I don't think you'd have the problem anttisepp just described. IMO the black spot would be more consistent with the beginning of a fungal infection -- lack of free air flow in the house may be causing it. Unfortunately I can't give you any recommendations on what to do about it. If we know your geographical location, other members may be able to give you some advice you can use.

[Jtwrigh]

I’m in Breckenridge,CO. I’m in zone 5a. So cacti are grown indoor.

[anttisepp]

Pilosocereus is a great indoor plant because as a brasilian it doesn't need cool overwintering. Keeping dry on a sunny place is only what it needs. Other cacti usually try to grow when you cannot provide really cool place. But mixing brasilians with others often brings sad losts - tropical plants can't bear prolonged cold temps, even repeated cold cross-draught can be fatal.

[ohugal]

I have had a Pilocereus in the past with very similar symptoms. It was grown indoors, so cold air or low temperatures weren't the cause. Lack of fresh air and good air circulation could be the cause. A friend of mine gave me a few Pilocerei before leaving abroad. They hibernated at temperatures of 5°. Sometimes even 2°C. They were kept dry, but one developed black spots similar to yours. The others seem to be fine. Perhaps next winter I will place them with my succulents in a slightly warmer room.