Plant pathogens pose risks for agricultural, horticultural, and forest plants and may damage natural habitats of different organisms, plants as well as animals. Several plant pathogens and saprophytes may pose human health hazards, especially for immunologically compromised individuals. (See Vidaver AK, Tolin S 2000 In: Fleming DO, Hunt DL (Eds.) Biological Safety, ASM, Washington DC, pp 27–33;  host–pathogen relation; http://www.pathoplant.de.