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.
Cattle
A CAFO that discharges pollutants is required to obtain a permit, which requires a plan to manage nutrient runoff, manure, chemicals, contaminants, and other wastewater pursuant to the US Clean Water Act. The regulations involving CAFO permitting have been extensively litigated.
Commonly, CAFO wastewater and manure nutrients are applied to land at agronomic rates for use by forages or crops, and it is often assumed that various constituents of wastewater and manure, e.g. organic contaminants and pathogens, will be retained, inactivated or degraded on the land with application at such rates; however, additional evidence is needed to test reliability of such assumptions
. Concerns raised by opponents of CAFOs have included risks of contaminated water due to feedlot runoff, soil erosion, human and animal exposure to toxic chemicals, development of antibiotic resistant bacteria and an increase in "E. coli" contamination. While research suggests some of these impacts can be mitigated by developing wastewater treatment systems and planting cover crops in larger setback zones, the Union of Concerned Scientists released a report in 2008 concluding that CAFOs are generally unsustainable and externalize costs.