Cactus
Fungi, bacteria and viruses attack cacti, the first two particularly when plants are over-watered. Fusarium rot can gain entry through a wound and cause rotting accompanied by red-violet mold. ""Helminosporium" rot" is caused by "Bipolaris cactivora" ( "Helminosporium cactivorum"); "Phytophthora" species also cause similar rotting in cacti. Fungicides may be of limited value in combating these diseases. Several viruses have been found in cacti, including cactus virus X. These appear to cause only limited visible symptoms, such as chlorotic (pale green) spots and mosaic effects (streaks and patches of paler color). However, in an "Agave" species, cactus virus X has been shown to reduce growth, particularly when the roots are dry. There are no treatments for virus diseases.
Peyote
Peyote is extremely slow growing. Cultivated specimens grow considerably faster, sometimes taking less than three years to go from seedling to mature flowering adult. More rapid growth can be achieved by grafting peyote onto mature San Pedro root stock. The top of the above-ground part of the cactus, the crown, consists of disc-shaped buttons. These are cut above the roots and sometimes dried. When done properly, the top of the root forms a callus and the root does not rot. When poor harvesting techniques are used, however, the entire plant dies. Currently in South Texas, peyote grows naturally but has been over-harvested, to the point that the state has listed it as an endangered species. The buttons are generally chewed, or boiled in water to produce a psychoactive tea. Peyote is extremely bitter and most people are nauseated before they feel the onset of the psychoactive effects.