Q. Over the years I planted perhaps 10 different golden barrel cacti. Nearly all died the same way. I first notice a hole in the main body of the plant. It looks like a rodent gnawed the hole. I have never found anything inside the plant. The plant retains its color and appears healthy. After about a year the root system is gone and I remove the plant. Can you explain? Golden barrel cactus with pups A. When I lose a barrel cactus that way and the hole is at the bottom of the plant it is usually from poor soil drainage and watering too often. The roots rot as well as the interior. Reduce the frequency of your watering and make sure the soil drains extremely well.             If you catch the problem early enough you can arrest the damage by shutting off the water until the plant recovers. After that, water less often. If they are watered more than once every two weeks this might be the problem. They rely on storage water during times of water shortages. The size of the plant increases after a heavy rain and decreases when water is scarce because of the stored water. The only creature that I would think might be interested in barrel cactus and might be able to damage them are ground squirrels. But they usually harvest fruits from them, not the fleshy interior.