In barrel cactus, it occurs when conditions are moist, when the plant is too deep in soil, and when the cactus sustains injury. For this reason, clean, sterile soil and proper planting methods must be observed to prevent the pathogen from invading your cactus. Once the plant has the disease, there is no effective pythium root rot treatment.Can you plant barrel cactus too deep in soil?
Do not plant barrel cactus too deep in soil. Only cover the roots with soil. The fleshy part of the barrel should not be above the ground. I have noticed that many of the big box stores that cater to us do-it-yourselfers sell barrel cacti that is planted too deep.