Slugs

It will probably always be there... I have had snails on my Pilosocereus for long periods of time and never noticed any scarring from them... they just use the plant to survive through the day, though, and move off it at night to go somewhere, and then back in the day. But it is some superficial scarring injury.

So ... we have slugs and snails around and I have at times seen them near some of the cacti .. so that makes sense. I just found it strange that the holes line up so well. Its not like they showed up at the base of the cactus and then it grew raising the to their current height. The slimy pests would have climbed to that same height all the way around.

How do I keep them away? Salt? I would think that would mess with the soil PH.

Thanks

A band (1/2" wide should be enough) of copper on the surface of where your pot sits, encircling the pot and they'll never crawl up it again.

CactusN00b,
I have the same condition on my blue cactus like yours. I just purchased it from Lowes on clearance due to the scaring for $2. I figured if it grows larger or send out off shouts, I can always cut, and start over. For now I will leave alone and let it grow. It may be some thing with blue cactus.
Stush

I'll give the copper a try. thanks for the tip

Stush, I think your onto something there. Its the ONLY cactus I have this problem on. Blue must taste better :)