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CHARACTERISTICS OF PHYTOPLASMAS

At one time, phytoplasmas were called mycoplasma-like organisms (MLOs) because they resembled organisms (mycoplasmas) that cause diseases in animals. Recently the name phytoplasma was coined to describe mycoplasmas that specifically cause plant diseases.

Phytoplasmas are rather odd bacteria-like organisms. They differ from true bacteria in that they are much smaller, and in that they lack a cell wall. Because of their small size, diseases caused by phytoplasmas (often called "yellows") were, for a long time, considered to be viral diseases.

Phytoplasmas live and reproduce in the plant's food-conducting tissue (called the PHLOEM). As is the case with bacteria, phytoplasmas reproduce by binary fission. Phytoplasmas are transmitted by insects, in particular, leafhoppers. These insects are phloem-feeders.