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.
Decriminalization of non-medical cannabis in the United States
Ecosystem: A single mature marijuana plant can consume 23 liters of water a day, compared to 13 liters for a grape plant. Historically, many outdoor cultivators have used illegal river and lake diversions to irrigate crops. These diversions have led to dewatering of streams and rivers which is well documented in areas of Northern California. As with any other agricultural crop, increase in demand leads to increased clear cutting of forests which can increase erosion, habitat destruction, and river diversion. Legalization and subsequent regulation could mitigate such issues.