(Photograph = Cactobalstis cactorum egg case, John Tann)
Introduction
Most plants in Nature don’t seem to get disease, but a walk through a forest might reveal a lump on a trunk or a gooey, sticky lesion caused by a fungus. Still other plants will have brown spots on their leaves.
The Details
Cacti seem tough as nails, they have spines and withstand sun, wind, and drought. Their spines protect them from animals and their waxy skins protect them from insects and disease organisms.
However, cacti do get disease occasionally just like any other plant. Many cactus growers bring a plant home only to see it die a slow death, perhaps from overwatering. When cactus roots stay wet too long they can be infected by soil fungi. After the roots are lost the top might eventually die.
There are other problems that cacti face. Cochineal insects cause branches to become fuzzy and white. Sometimes plants are damaged by insects that pierce the skin in search of nutrients. Some fungi and bacteria invade cacti at wounds or small openings in the surface and cause black, dripping, blistering wounds. Sometimes animals damage the growing tips of cacti, and the tip becomes twisted or stunted. FIres damage some cacti. Cacti even have viral diseases.
Additional Reading: Infections of Cacti
