Hi, all you gardeners!

My cactus has developed a hole. I don't think anything is attacking
it. It lives in a lab at a university. It is the only plant. There
aren't many (any?) insects around.

I don't know whether I am underwatering the plant, and that has caused
the hole? Overwatering? Perhaps the cactus is being attacked by a
fungus (although I don't see any signs of a fungus)? Maybe it's just
normal for cacti to develop a hole occasionally, and it will close up
after a while.

You will ask what kind of cactus it is. My answer will tell you how
much I know about plants: It is the cactus I bought my son for
Christmas, and he rejected. It is kind of barrel-shaped. It has long
ridges that run from its base to its crown. There are thorns (light,
wispy) emanating from the top of the ridges. There are also valleys
(of course) between the ridges, and it is in one of these that the
cactus has become "unzipped."

On some days, the cactus is the only bright spot in the day. We got a
cactus so it wouldn't die, and depress us, but . . .

Is there a cactus expert out there?

Regards,

Rick