IAM Plant Biotech Unit
Plant Pathology Webpages
Phytoplasmoses can cause significant economic damage. They are epidemic and have a
long incubation period. Symptoms on infected trees become evident only one or two
years after contamination, when the disease has already spread to other trees or
Phytoplasmas (formerly called mycoplasma-like organisms) are considered to be
quarantaine organisms in the European Union.
These smallest known microorganisms that - on the contrary to viruses - are
able to replicate autonomously, have been termed so in 1994 to distinguish
from the animal parasites mycoplasmas. They differ from bacteria by lack of a
solid wall and have not been isolated, purified nor cultured on an axenic
medium so far. However they are pleomorphic and can strech and cross the sieve
plates to migrate towards the roots in autumn and towards the vegetation
According to EPPO certification schemes planting material of fruit trees in the
European Union must be free of phytoplasmas.
last updated October 8, 2001 by