What Causes Holes in Cactus?

Q. My neighbor has a cactus that has these holes on one side. I am hoping you can tell us what is causing this and if this plant is doomed to die.

A. Nothing substantial came to me regarding the holes in your cactus. Generally speaking, these holes can occur from overwatering. They can also be from a disease problem if the humidity has been high or there has been rain.

My first suspicion was a bacterial disease that causes holes in some cacti but I don't think that is the case with yours. Usually this would occur during wet or humid weather. Not if the plant has been dry.

The only thing I can tell you to do is be careful how often you water. Make sure the plant has good drainage. If the hole does not have any soft tissue around it just consider it a temporary thing and not get too excited about it. If the tissue around the hole is hard and not soft then it is most likely not getting any worse.

Here is a link to a publication from the University of Arizona on diseases of cacti and succulents