use organic material from living organisms, harming them in some way.
range of hosts: from single celled diatoms to fungi to plants to animals to humans.
Parasites cause billions of dollars in damage to crops and forests every year. For further information on the science of Plant Pathology see the home page of the American Phytopathological Society at http://www.scisoc.org/
Fungi are the major parasites of plants, causing billions of dollars in losses every year. Fungi also parasitize humans and other animals. You’ve all seen those commercials on TV for yeast infection drugs. Fungi can also parasitize other fungi, algae, and just about every organism you can think of.