Hyperparasites A parasite with phytopathologic activities may be invaded on its turn, by other parasites ,like nematodes, bacteria and bacteriophages. Parasitic plants can be halfparasites having well developed leaves. Full parasites have underdeveloped or no leaves at all. They invade the xilem and the phloem of their host and get there nourishing substances . Energy system ATP does not exist.
Virus depend on ribosomes of host cells.
Energy system ATP exists and they can multiply without aid of a host cell. Purines must therefor be taken from the host. Penicillium expansum Rot of apple. Claviceps purpurea forms ascospores can infect only blossoms. Pseudopezicola tracheiphila Disease of wine.