A comparative scanning and transmission electron microscope study for the detection of mycoplasma-like organisms.

Transmission electron microscopy (TEM) is the only method by which the characteristic ultrastructure of mycoplasma-like organisms (MLOs) can be observed. However TEM is a cumbersome technique that permits only the investigation of a restricted area of the plant. This fact, in addition to the low concentration of MLOs in the infected tissues, makes their localization often very difficult, particularly in woody plants. Other techniques involving fluorescence microscopy (see DALE, 1988 for a review) have been used for the same purpose, although these methods cannot result in definitive identification of the MLOs and are in some instances quite laborious and time-consuming as well.