Phytoplasmas are specialised bacteria that are obligate parasites of plant phloem tissue and transmitting insects (vectors). They were discovered by scientists in 1967 and were named mycoplasma-like organisms or MLOs. Since their discovery, phytoplasmas have resisted all attempts to becultured in vitro in any cell free media, hence routine cultivation in artificial media is still to be established. Nevertheless, still under trial stage, phytoplasma growth in specific artificial media has recently been shown. They are characterised by their lack of a cell wall, a pleiomorphic or filamentous shape, normally with a diameter less than 1 μm, and their very small genomes.