Q.barrel cactus damage
I have had a large barrel cactus planted. It is large about 18 inches around and over a foot high. On one side about halfway down there is a yellow area about 3 inches in diameter and right next to this yellowing there is a split in one of the spines about 5 inches long. Can this plant live??
There are also a couple of dark spots close to the crown.
Seethe pictures.
Thank you.

Certified GKH Gardening Expert
This is the start of a fungal infection. This can be treated, but if the ground is compact, or stays wet for too long it will come back. Mix up a solution of a cup of water, but replace 1/4 of that with peroxide. Pour this mix over the very top of the cactus slowly, and it will do what it is designed to do. Pull water down into the crown.
This will take care of the infection, but you may have to do this every few months to combat soil conditions.