Cacti and Cotton Root Rot
Cotton root rot in cactus generally shows up when the soil is warm between spring and early fall. The disease tends to spread through the soil slowly, but plant death occurs quickly when temperatures are high. Sometimes, even a healthy plant can wilt and die within three days. Cactus cotton root rot symptoms include primarily severe wilt and discoloration. During the rainy season in midsummer, you may also notice a white or pale tan, pancake-like spore mat on the surface of the soil. The surest way to determine if a cactus has root rot is to pull the dead plant from the soil. The plant will come loose easily, and you’ll see strands of woolly, bronze fungus on the surface of the roots.
Cactus Root Rot Repair: What to Do About Cotton Root Rot in Cactus
Unfortunately, there are no cures if your cactus has cotton root rot. Fungicides aren’t effective because the disease is soil-borne; roots grow beyond the treated area, where they soon become infected. The best recourse is to remove dead and diseased cacti and replace them with plants that aren’t susceptible to this deadly pathogen. Plants that are generally immune to cotton root rot in cactus include:
Agave
Yucca
Aloe vera
Palm trees
Pampas grass
Mondo grass
Lilyturf
Bamboo
Iris
Calla lily
Tulips
Daffodils